std: Deprecate std::old_io::fs

This commit deprecates the majority of std::old_io::fs in favor of std::fs and
its new functionality. Some functions remain non-deprecated but are now behind a
feature gate called `old_fs`. These functions will be deprecated once
suitable replacements have been implemented.

The compiler has been migrated to new `std::fs` and `std::path` APIs where
appropriate as part of this change.

80 files changed, 1430 insertions, 1209 deletions

diff --git a/mk/docs.mk b/mk/docs.mk
index 743032f676d..f7ab86d3a29 100644
--- a/mk/docs.mk
+++ b/mk/docs.mk
@@ -273,11 +273,13 @@ compiler-docs: $(COMPILER_DOC_TARGETS)
 trpl: doc/book/index.html
 
 doc/book/index.html: $(RUSTBOOK_EXE) $(wildcard $(S)/src/doc/trpl/*.md) | doc/
+	@$(call E, rustbook: $@)
 	$(Q)rm -rf doc/book
 	$(Q)$(RUSTBOOK) build $(S)src/doc/trpl doc/book
 
 style: doc/style/index.html
 
 doc/style/index.html: $(RUSTBOOK_EXE) $(wildcard $(S)/src/doc/style/*.md) | doc/
+	@$(call E, rustbook: $@)
 	$(Q)rm -rf doc/style
 	$(Q)$(RUSTBOOK) build $(S)src/doc/style doc/style
diff --git a/src/compiletest/common.rs b/src/compiletest/common.rs
index 2c046d25279..fe556cecef6 100644
--- a/src/compiletest/common.rs
+++ b/src/compiletest/common.rs
@@ -11,6 +11,7 @@ pub use self::Mode::*;
 
 use std::fmt;
 use std::str::FromStr;
+use std::path::PathBuf;
 
 #[derive(Clone, Copy, PartialEq, Debug)]
 pub enum Mode {
@@ -68,13 +69,13 @@ pub struct Config {
     pub run_lib_path: String,
 
     // The rustc executable
-    pub rustc_path: Path,
+    pub rustc_path: PathBuf,
 
     // The clang executable
-    pub clang_path: Option<Path>,
+    pub clang_path: Option<PathBuf>,
 
     // The llvm binaries path
-    pub llvm_bin_path: Option<Path>,
+    pub llvm_bin_path: Option<PathBuf>,
 
     // The valgrind path
     pub valgrind_path: Option<String>,
@@ -84,13 +85,13 @@ pub struct Config {
     pub force_valgrind: bool,
 
     // The directory containing the tests to run
-    pub src_base: Path,
+    pub src_base: PathBuf,
 
     // The directory where programs should be built
-    pub build_base: Path,
+    pub build_base: PathBuf,
 
     // Directory for auxiliary libraries
-    pub aux_base: Path,
+    pub aux_base: PathBuf,
 
     // The name of the stage being built (stage1, etc)
     pub stage_id: String,
@@ -105,7 +106,7 @@ pub struct Config {
     pub filter: Option<String>,
 
     // Write out a parseable log of tests that were run
-    pub logfile: Option<Path>,
+    pub logfile: Option<PathBuf>,
 
     // A command line to prefix program execution with,
     // for running under valgrind
@@ -133,7 +134,7 @@ pub struct Config {
     pub lldb_version: Option<String>,
 
     // Path to the android tools
-    pub android_cross_path: Path,
+    pub android_cross_path: PathBuf,
 
     // Extra parameter to run adb on arm-linux-androideabi
     pub adb_path: String,
diff --git a/src/compiletest/compiletest.rs b/src/compiletest/compiletest.rs
index 4993dd140d3..b9e6f1842ee 100644
--- a/src/compiletest/compiletest.rs
+++ b/src/compiletest/compiletest.rs
@@ -21,6 +21,11 @@
 #![feature(test)]
 #![feature(unicode)]
 #![feature(core)]
+#![feature(path)]
+#![feature(os)]
+#![feature(io)]
+#![feature(fs)]
+#![feature(net)]
 
 #![deny(warnings)]
 
@@ -31,8 +36,9 @@ extern crate getopts;
 extern crate log;
 
 use std::env;
+use std::fs;
 use std::old_io;
-use std::old_io::fs;
+use std::path::{Path, PathBuf};
 use std::thunk::Thunk;
 use getopts::{optopt, optflag, reqopt};
 use common::Config;
@@ -114,9 +120,9 @@ pub fn parse_config(args: Vec<String> ) -> Config {
         panic!()
     }
 
-    fn opt_path(m: &getopts::Matches, nm: &str) -> Path {
+    fn opt_path(m: &getopts::Matches, nm: &str) -> PathBuf {
         match m.opt_str(nm) {
-            Some(s) => Path::new(s),
+            Some(s) => PathBuf::new(&s),
             None => panic!("no option (=path) found for {}", nm),
         }
     }
@@ -131,10 +137,10 @@ pub fn parse_config(args: Vec<String> ) -> Config {
         compile_lib_path: matches.opt_str("compile-lib-path").unwrap(),
         run_lib_path: matches.opt_str("run-lib-path").unwrap(),
         rustc_path: opt_path(matches, "rustc-path"),
-        clang_path: matches.opt_str("clang-path").map(|s| Path::new(s)),
+        clang_path: matches.opt_str("clang-path").map(|s| PathBuf::new(&s)),
         valgrind_path: matches.opt_str("valgrind-path"),
         force_valgrind: matches.opt_present("force-valgrind"),
-        llvm_bin_path: matches.opt_str("llvm-bin-path").map(|s| Path::new(s)),
+        llvm_bin_path: matches.opt_str("llvm-bin-path").map(|s| PathBuf::new(&s)),
         src_base: opt_path(matches, "src-base"),
         build_base: opt_path(matches, "build-base"),
         aux_base: opt_path(matches, "aux-base"),
@@ -142,7 +148,7 @@ pub fn parse_config(args: Vec<String> ) -> Config {
         mode: matches.opt_str("mode").unwrap().parse().ok().expect("invalid mode"),
         run_ignored: matches.opt_present("ignored"),
         filter: filter,
-        logfile: matches.opt_str("logfile").map(|s| Path::new(s)),
+        logfile: matches.opt_str("logfile").map(|s| PathBuf::new(&s)),
         runtool: matches.opt_str("runtool"),
         host_rustcflags: matches.opt_str("host-rustcflags"),
         target_rustcflags: matches.opt_str("target-rustcflags"),
@@ -276,9 +282,9 @@ pub fn make_tests(config: &Config) -> Vec<test::TestDescAndFn> {
     debug!("making tests from {:?}",
            config.src_base.display());
     let mut tests = Vec::new();
-    let dirs = fs::readdir(&config.src_base).unwrap();
-    for file in &dirs {
-        let file = file.clone();
+    let dirs = fs::read_dir(&config.src_base).unwrap();
+    for file in dirs {
+        let file = file.unwrap().path();
         debug!("inspecting file {:?}", file.display());
         if is_test(config, &file) {
             let t = make_test(config, &file, || {
@@ -301,7 +307,7 @@ pub fn is_test(config: &Config, testfile: &Path) -> bool {
           _ => vec!(".rc".to_string(), ".rs".to_string())
         };
     let invalid_prefixes = vec!(".".to_string(), "#".to_string(), "~".to_string());
-    let name = testfile.filename_str().unwrap();
+    let name = testfile.file_name().unwrap().to_str().unwrap();
 
     let mut valid = false;
 
@@ -337,9 +343,9 @@ pub fn make_test_name(config: &Config, testfile: &Path) -> test::TestName {
 
     // Try to elide redundant long paths
     fn shorten(path: &Path) -> String {
-        let filename = path.filename_str();
-        let p = path.dir_path();
-        let dir = p.filename_str();
+        let filename = path.file_name().unwrap().to_str();
+        let p = path.parent().unwrap();
+        let dir = p.file_name().unwrap().to_str();
         format!("{}/{}", dir.unwrap_or(""), filename.unwrap_or(""))
     }
 
@@ -348,19 +354,17 @@ pub fn make_test_name(config: &Config, testfile: &Path) -> test::TestName {
 
 pub fn make_test_closure(config: &Config, testfile: &Path) -> test::TestFn {
     let config = (*config).clone();
-    // FIXME (#9639): This needs to handle non-utf8 paths
-    let testfile = testfile.as_str().unwrap().to_string();
+    let testfile = testfile.to_path_buf();
     test::DynTestFn(Thunk::new(move || {
-        runtest::run(config, testfile)
+        runtest::run(config, &testfile)
     }))
 }
 
 pub fn make_metrics_test_closure(config: &Config, testfile: &Path) -> test::TestFn {
     let config = (*config).clone();
-    // FIXME (#9639): This needs to handle non-utf8 paths
-    let testfile = testfile.as_str().unwrap().to_string();
+    let testfile = testfile.to_path_buf();
     test::DynMetricFn(box move |mm: &mut test::MetricMap| {
-        runtest::run_metrics(config, testfile, mm)
+        runtest::run_metrics(config, &testfile, mm)
     })
 }
 
diff --git a/src/compiletest/errors.rs b/src/compiletest/errors.rs
index 7411a9b48d4..25f962c5785 100644
--- a/src/compiletest/errors.rs
+++ b/src/compiletest/errors.rs
@@ -9,7 +9,10 @@
 // except according to those terms.
 use self::WhichLine::*;
 
-use std::old_io::{BufferedReader, File};
+use std::fs::File;
+use std::io::BufReader;
+use std::io::prelude::*;
+use std::path::Path;
 
 pub struct ExpectedError {
     pub line: uint,
@@ -29,7 +32,7 @@ enum WhichLine { ThisLine, FollowPrevious(uint), AdjustBackward(uint) }
 ///          //~| ERROR message two for that same line.
 // Load any test directives embedded in the file
 pub fn load_errors(testfile: &Path) -> Vec<ExpectedError> {
-    let mut rdr = BufferedReader::new(File::open(testfile).unwrap());
+    let rdr = BufReader::new(File::open(testfile).unwrap());
 
     // `last_nonfollow_error` tracks the most recently seen
     // line with an error template that did not use the
diff --git a/src/compiletest/header.rs b/src/compiletest/header.rs
index e5570fe0b8f..21cebc61b3a 100644
--- a/src/compiletest/header.rs
+++ b/src/compiletest/header.rs
@@ -9,6 +9,10 @@
 // except according to those terms.
 
 use std::env;
+use std::fs::File;
+use std::io::BufReader;
+use std::io::prelude::*;
+use std::path::{Path, PathBuf};
 
 use common::Config;
 use common;
@@ -23,7 +27,7 @@ pub struct TestProps {
     pub run_flags: Option<String>,
     // If present, the name of a file that this test should match when
     // pretty-printed
-    pub pp_exact: Option<Path>,
+    pub pp_exact: Option<PathBuf>,
     // Modules from aux directory that should be compiled
     pub aux_builds: Vec<String> ,
     // Environment settings to use during execution
@@ -62,7 +66,7 @@ pub fn load_props(testfile: &Path) -> TestProps {
     let mut pretty_mode = None;
     let mut pretty_compare_only = false;
     let mut forbid_output = Vec::new();
-    iter_header(testfile, |ln| {
+    iter_header(testfile, &mut |ln| {
         match parse_error_pattern(ln) {
           Some(ep) => error_patterns.push(ep),
           None => ()
@@ -219,7 +223,7 @@ pub fn is_test_ignored(config: &Config, testfile: &Path) -> bool {
         }
     }
 
-    let val = iter_header(testfile, |ln| {
+    let val = iter_header(testfile, &mut |ln| {
         !parse_name_directive(ln, "ignore-test") &&
         !parse_name_directive(ln, &ignore_target(config)) &&
         !parse_name_directive(ln, &ignore_stage(config)) &&
@@ -232,12 +236,8 @@ pub fn is_test_ignored(config: &Config, testfile: &Path) -> bool {
     !val
 }
 
-fn iter_header<F>(testfile: &Path, mut it: F) -> bool where
-    F: FnMut(&str) -> bool,
-{
-    use std::old_io::{BufferedReader, File};
-
-    let mut rdr = BufferedReader::new(File::open(testfile).unwrap());
+fn iter_header(testfile: &Path, it: &mut FnMut(&str) -> bool) -> bool {
+    let rdr = BufReader::new(File::open(testfile).unwrap());
     for ln in rdr.lines() {
         // Assume that any directives will be found before the first
         // module or function. This doesn't seem to be an optimization
@@ -322,12 +322,12 @@ fn parse_exec_env(line: &str) -> Option<(String, String)> {
     })
 }
 
-fn parse_pp_exact(line: &str, testfile: &Path) -> Option<Path> {
+fn parse_pp_exact(line: &str, testfile: &Path) -> Option<PathBuf> {
     match parse_name_value_directive(line, "pp-exact") {
-      Some(s) => Some(Path::new(s)),
+      Some(s) => Some(PathBuf::new(&s)),
       None => {
         if parse_name_directive(line, "pp-exact") {
-            testfile.filename().map(|s| Path::new(s))
+            testfile.file_name().map(|s| PathBuf::new(s))
         } else {
             None
         }
diff --git a/src/compiletest/procsrv.rs b/src/compiletest/procsrv.rs
index 148a43e6c78..b684dbcface 100644
--- a/src/compiletest/procsrv.rs
+++ b/src/compiletest/procsrv.rs
@@ -8,7 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::old_io::process::{ProcessExit, Command, Process, ProcessOutput};
+use std::process::{ExitStatus, Command, Child, Output, Stdio};
+use std::io::prelude::*;
 use std::dynamic_lib::DynamicLibrary;
 
 fn add_target_env(cmd: &mut Command, lib_path: &str, aux_path: Option<&str>) {
@@ -25,10 +26,10 @@ fn add_target_env(cmd: &mut Command, lib_path: &str, aux_path: Option<&str>) {
     let var = DynamicLibrary::envvar();
     let newpath = DynamicLibrary::create_path(&path);
     let newpath = String::from_utf8(newpath).unwrap();
-    cmd.env(var.to_string(), newpath);
+    cmd.env(var, &newpath);
 }
 
-pub struct Result {pub status: ProcessExit, pub out: String, pub err: String}
+pub struct Result {pub status: ExitStatus, pub out: String, pub err: String}
 
 pub fn run(lib_path: &str,
            prog: &str,
@@ -38,10 +39,13 @@ pub fn run(lib_path: &str,
            input: Option<String>) -> Option<Result> {
 
     let mut cmd = Command::new(prog);
-    cmd.args(args);
+    cmd.args(args)
+       .stdin(Stdio::piped())
+       .stdout(Stdio::piped())
+       .stderr(Stdio::piped());
     add_target_env(&mut cmd, lib_path, aux_path);
     for (key, val) in env {
-        cmd.env(key, val);
+        cmd.env(&key, &val);
     }
 
     match cmd.spawn() {
@@ -49,13 +53,13 @@ pub fn run(lib_path: &str,
             if let Some(input) = input {
                 process.stdin.as_mut().unwrap().write_all(input.as_bytes()).unwrap();
             }
-            let ProcessOutput { status, output, error } =
+            let Output { status, stdout, stderr } =
                 process.wait_with_output().unwrap();
 
             Some(Result {
                 status: status,
-                out: String::from_utf8(output).unwrap(),
-                err: String::from_utf8(error).unwrap()
+                out: String::from_utf8(stdout).unwrap(),
+                err: String::from_utf8(stderr).unwrap()
             })
         },
         Err(..) => None
@@ -67,13 +71,16 @@ pub fn run_background(lib_path: &str,
            aux_path: Option<&str>,
            args: &[String],
            env: Vec<(String, String)> ,
-           input: Option<String>) -> Option<Process> {
+           input: Option<String>) -> Option<Child> {
 
     let mut cmd = Command::new(prog);
-    cmd.args(args);
+    cmd.args(args)
+       .stdin(Stdio::piped())
+       .stdout(Stdio::piped())
+       .stderr(Stdio::piped());
     add_target_env(&mut cmd, lib_path, aux_path);
     for (key, val) in env {
-        cmd.env(key, val);
+        cmd.env(&key, &val);
     }
 
     match cmd.spawn() {
diff --git a/src/compiletest/runtest.rs b/src/compiletest/runtest.rs
index 7ac8a9b041c..7fb1a436ba3 100644
--- a/src/compiletest/runtest.rs
+++ b/src/compiletest/runtest.rs
@@ -11,35 +11,30 @@
 use self::TargetLocation::*;
 
 use common::Config;
-use common::{CompileFail, ParseFail, Pretty, RunFail, RunPass, RunPassValgrind, DebugInfoGdb};
-use common::{Codegen, DebugInfoLldb};
+use common::{CompileFail, ParseFail, Pretty, RunFail, RunPass, RunPassValgrind};
+use common::{Codegen, DebugInfoLldb, DebugInfoGdb};
 use errors;
 use header::TestProps;
 use header;
 use procsrv;
 use util::logv;
-#[cfg(target_os = "windows")]
-use util;
-
-#[cfg(target_os = "windows")]
-use std::ascii::AsciiExt;
-use std::old_io::File;
-use std::old_io::fs::PathExtensions;
-use std::old_io::fs;
-use std::old_io::net::tcp;
-use std::old_io::process::ProcessExit;
-use std::old_io::process;
-use std::old_io::timer;
-use std::old_io;
+
 use std::env;
+use std::ffi::OsStr;
+use std::fmt;
+use std::fs::{self, File};
+use std::io::BufReader;
+use std::io::prelude::*;
 use std::iter::repeat;
+use std::net::TcpStream;
+use std::old_io::timer;
+use std::path::{Path, PathBuf};
+use std::process::{Command, Output, ExitStatus};
 use std::str;
-use std::string::String;
-use std::thread;
 use std::time::Duration;
 use test::MetricMap;
 
-pub fn run(config: Config, testfile: String) {
+pub fn run(config: Config, testfile: &Path) {
     match &*config.target {
 
         "arm-linux-androideabi" | "aarch64-linux-android" => {
@@ -55,12 +50,11 @@ pub fn run(config: Config, testfile: String) {
     run_metrics(config, testfile, &mut _mm);
 }
 
-pub fn run_metrics(config: Config, testfile: String, mm: &mut MetricMap) {
+pub fn run_metrics(config: Config, testfile: &Path, mm: &mut MetricMap) {
     if config.verbose {
         // We're going to be dumping a lot of info. Start on a new line.
         print!("\n\n");
     }
-    let testfile = Path::new(testfile);
     debug!("running {:?}", testfile.display());
     let props = header::load_props(&testfile);
     debug!("loaded props");
@@ -127,8 +121,8 @@ fn run_rfail_test(config: &Config, props: &TestProps, testfile: &Path) {
     };
 
     // The value our Makefile configures valgrind to return on failure
-    const VALGRIND_ERR: int = 100;
-    if proc_res.status.matches_exit_status(VALGRIND_ERR) {
+    const VALGRIND_ERR: i32 = 100;
+    if proc_res.status.code() == Some(VALGRIND_ERR) {
         fatal_proc_rec("run-fail test isn't valgrind-clean!", &proc_res);
     }
 
@@ -139,10 +133,10 @@ fn run_rfail_test(config: &Config, props: &TestProps, testfile: &Path) {
 
 fn check_correct_failure_status(proc_res: &ProcRes) {
     // The value the rust runtime returns on failure
-    const RUST_ERR: int = 101;
-    if !proc_res.status.matches_exit_status(RUST_ERR) {
+    const RUST_ERR: i32 = 101;
+    if proc_res.status.code() != Some(RUST_ERR) {
         fatal_proc_rec(
-            &format!("failure produced the wrong error: {:?}",
+            &format!("failure produced the wrong error: {}",
                      proc_res.status),
             proc_res);
     }
@@ -201,8 +195,8 @@ fn run_pretty_test(config: &Config, props: &TestProps, testfile: &Path) {
     let rounds =
         match props.pp_exact { Some(_) => 1, None => 2 };
 
-    let src = File::open(testfile).read_to_end().unwrap();
-    let src = String::from_utf8(src.clone()).unwrap();
+    let mut src = String::new();
+    File::open(testfile).unwrap().read_to_string(&mut src).unwrap();
     let mut srcs = vec!(src);
 
     let mut round = 0;
@@ -226,9 +220,10 @@ fn run_pretty_test(config: &Config, props: &TestProps, testfile: &Path) {
 
     let mut expected = match props.pp_exact {
         Some(ref file) => {
-            let filepath = testfile.dir_path().join(file);
-            let s = File::open(&filepath).read_to_end().unwrap();
-            String::from_utf8(s).unwrap()
+            let filepath = testfile.parent().unwrap().join(file);
+            let mut s = String::new();
+            File::open(&filepath).unwrap().read_to_string(&mut s).unwrap();
+            s
         }
         None => { srcs[srcs.len() - 2].clone() }
     };
@@ -283,7 +278,7 @@ fn run_pretty_test(config: &Config, props: &TestProps, testfile: &Path) {
                                      pretty_type.to_string()),
                         props.exec_env.clone(),
                         &config.compile_lib_path,
-                        Some(aux_dir.as_str().unwrap()),
+                        Some(aux_dir.to_str().unwrap()),
                         Some(src))
     }
 
@@ -299,11 +294,11 @@ fn run_pretty_test(config: &Config, props: &TestProps, testfile: &Path) {
                             pretty_type,
                             format!("--target={}", config.target),
                             "-L".to_string(),
-                            aux_dir.as_str().unwrap().to_string());
+                            aux_dir.to_str().unwrap().to_string());
         args.extend(split_maybe_args(&config.target_rustcflags).into_iter());
         args.extend(split_maybe_args(&props.compile_flags).into_iter());
         return ProcArgs {
-            prog: config.rustc_path.as_str().unwrap().to_string(),
+            prog: config.rustc_path.to_str().unwrap().to_string(),
             args: args,
         };
     }
@@ -345,14 +340,14 @@ actual:\n\
                             "--crate-type=lib".to_string(),
                             format!("--target={}", target),
                             "-L".to_string(),
-                            config.build_base.as_str().unwrap().to_string(),
+                            config.build_base.to_str().unwrap().to_string(),
                             "-L".to_string(),
-                            aux_dir.as_str().unwrap().to_string());
+                            aux_dir.to_str().unwrap().to_string());
         args.extend(split_maybe_args(&config.target_rustcflags).into_iter());
         args.extend(split_maybe_args(&props.compile_flags).into_iter());
         // FIXME (#9639): This needs to handle non-utf8 paths
         return ProcArgs {
-            prog: config.rustc_path.as_str().unwrap().to_string(),
+            prog: config.rustc_path.to_str().unwrap().to_string(),
             args: args,
         };
     }
@@ -390,18 +385,19 @@ fn run_debuginfo_gdb_test(config: &Config, props: &TestProps, testfile: &Path) {
             // write debugger script
             let mut script_str = String::with_capacity(2048);
             script_str.push_str("set charset UTF-8\n");
-            script_str.push_str(&format!("file {}\n", exe_file.as_str().unwrap()));
+            script_str.push_str(&format!("file {}\n", exe_file.to_str().unwrap()));
             script_str.push_str("target remote :5039\n");
             script_str.push_str(&format!("set solib-search-path \
                                          ./{}/stage2/lib/rustlib/{}/lib/\n",
                                          config.host, config.target));
             for line in breakpoint_lines.iter() {
                 script_str.push_str(&format!("break {:?}:{}\n",
-                                             testfile.filename_display(),
+                                             testfile.file_name().unwrap()
+                                                     .to_string_lossy(),
                                              *line)[..]);
             }
             script_str.push_str(&cmds);
-            script_str.push_str("quit\n");
+            script_str.push_str("\nquit\n");
 
             debug!("script_str = {}", script_str);
             dump_output_file(config,
@@ -415,7 +411,7 @@ fn run_debuginfo_gdb_test(config: &Config, props: &TestProps, testfile: &Path) {
                          None,
                          &[
                             "push".to_string(),
-                            exe_file.as_str().unwrap().to_string(),
+                            exe_file.to_str().unwrap().to_string(),
                             config.adb_test_dir.clone()
                          ],
                          vec!(("".to_string(), "".to_string())),
@@ -440,9 +436,8 @@ fn run_debuginfo_gdb_test(config: &Config, props: &TestProps, testfile: &Path) {
                                   if config.target.contains("aarch64")
                                   {"64"} else {""},
                                   config.adb_test_dir.clone(),
-                                  str::from_utf8(
-                                      exe_file.filename()
-                                      .unwrap()).unwrap());
+                                  exe_file.file_name().unwrap().to_str()
+                                          .unwrap());
 
             let mut process = procsrv::run_background("",
                                                       &config.adb_path
@@ -459,16 +454,12 @@ fn run_debuginfo_gdb_test(config: &Config, props: &TestProps, testfile: &Path) {
             loop {
                 //waiting 1 second for gdbserver start
                 timer::sleep(Duration::milliseconds(1000));
-                let result = thread::spawn(move || {
-                    tcp::TcpStream::connect("127.0.0.1:5039").unwrap();
-                }).join();
-                if result.is_err() {
-                    continue;
+                if TcpStream::connect("127.0.0.1:5039").is_ok() {
+                    break
                 }
-                break;
             }
 
-            let tool_path = match config.android_cross_path.as_str() {
+            let tool_path = match config.android_cross_path.to_str() {
                 Some(x) => x.to_string(),
                 None => fatal("cannot find android cross path")
             };
@@ -479,7 +470,7 @@ fn run_debuginfo_gdb_test(config: &Config, props: &TestProps, testfile: &Path) {
                 vec!("-quiet".to_string(),
                      "-batch".to_string(),
                      "-nx".to_string(),
-                     format!("-command={}", debugger_script.as_str().unwrap()));
+                     format!("-command={}", debugger_script.to_str().unwrap()));
 
             let mut gdb_path = tool_path;
             gdb_path.push_str(&format!("/bin/{}-gdb", config.target));
@@ -503,12 +494,12 @@ fn run_debuginfo_gdb_test(config: &Config, props: &TestProps, testfile: &Path) {
             };
 
             debugger_run_result = ProcRes {
-                status: status,
+                status: Status::Normal(status),
                 stdout: out,
                 stderr: err,
                 cmdline: cmdline
             };
-            if process.signal_kill().is_err() {
+            if process.kill().is_err() {
                 println!("Adb process is already finished.");
             }
         }
@@ -518,7 +509,7 @@ fn run_debuginfo_gdb_test(config: &Config, props: &TestProps, testfile: &Path) {
                 .expect("Could not find Rust source root");
             let rust_pp_module_rel_path = Path::new("./src/etc");
             let rust_pp_module_abs_path = rust_src_root.join(rust_pp_module_rel_path)
-                                                       .as_str()
+                                                       .to_str()
                                                        .unwrap()
                                                        .to_string();
             // write debugger script
@@ -538,7 +529,7 @@ fn run_debuginfo_gdb_test(config: &Config, props: &TestProps, testfile: &Path) {
                         // GDB's script auto loading safe path
                         script_str.push_str(
                             &format!("add-auto-load-safe-path {}\n",
-                                     rust_pp_module_abs_path.replace("\\", "\\\\"))
+                                     rust_pp_module_abs_path.replace(r"\", r"\\"))
                                 );
                     }
                 }
@@ -553,21 +544,24 @@ fn run_debuginfo_gdb_test(config: &Config, props: &TestProps, testfile: &Path) {
             script_str.push_str("set print pretty off\n");
 
             // Add the pretty printer directory to GDB's source-file search path
-            script_str.push_str(&format!("directory {}\n", rust_pp_module_abs_path)[..]);
+            script_str.push_str(&format!("directory {}\n",
+                                         rust_pp_module_abs_path));
 
             // Load the target executable
             script_str.push_str(&format!("file {}\n",
-                                         exe_file.as_str().unwrap().replace("\\", "\\\\"))[..]);
+                                         exe_file.to_str().unwrap()
+                                                 .replace(r"\", r"\\")));
 
             // Add line breakpoints
             for line in &breakpoint_lines {
                 script_str.push_str(&format!("break '{}':{}\n",
-                                             testfile.filename_display(),
-                                             *line)[..]);
+                                             testfile.file_name().unwrap()
+                                                     .to_string_lossy(),
+                                             *line));
             }
 
             script_str.push_str(&cmds);
-            script_str.push_str("quit\n");
+            script_str.push_str("\nquit\n");
 
             debug!("script_str = {}", script_str);
             dump_output_file(config,
@@ -576,13 +570,8 @@ fn run_debuginfo_gdb_test(config: &Config, props: &TestProps, testfile: &Path) {
                              "debugger.script");
 
             // run debugger script with gdb
-            #[cfg(windows)]
-            fn debugger() -> String {
-                "gdb.exe".to_string()
-            }
-            #[cfg(unix)]
-            fn debugger() -> String {
-                "gdb".to_string()
+            fn debugger() -> &'static str {
+                if cfg!(windows) {"gdb.exe"} else {"gdb"}
             }
 
             let debugger_script = make_out_name(config, testfile, "debugger.script");
@@ -592,10 +581,10 @@ fn run_debuginfo_gdb_test(config: &Config, props: &TestProps, testfile: &Path) {
                 vec!("-quiet".to_string(),
                      "-batch".to_string(),
                      "-nx".to_string(),
-                     format!("-command={}", debugger_script.as_str().unwrap()));
+                     format!("-command={}", debugger_script.to_str().unwrap()));
 
             let proc_args = ProcArgs {
-                prog: debugger(),
+                prog: debugger().to_string(),
                 args: debugger_opts,
             };
 
@@ -618,7 +607,7 @@ fn run_debuginfo_gdb_test(config: &Config, props: &TestProps, testfile: &Path) {
     check_debugger_output(&debugger_run_result, &check_lines);
 }
 
-fn find_rust_src_root(config: &Config) -> Option<Path> {
+fn find_rust_src_root(config: &Config) -> Option<PathBuf> {
     let mut path = config.src_base.clone();
     let path_postfix = Path::new("src/etc/lldb_batchmode.py");
 
@@ -632,8 +621,6 @@ fn find_rust_src_root(config: &Config) -> Option<Path> {
 }
 
 fn run_debuginfo_lldb_test(config: &Config, props: &TestProps, testfile: &Path) {
-    use std::old_io::process::{Command, ProcessOutput};
-
     if config.lldb_python_dir.is_none() {
         fatal("Can't run LLDB test because LLDB's python path is not set.");
     }
@@ -685,11 +672,12 @@ fn run_debuginfo_lldb_test(config: &Config, props: &TestProps, testfile: &Path)
         .expect("Could not find Rust source root");
     let rust_pp_module_rel_path = Path::new("./src/etc/lldb_rust_formatters.py");
     let rust_pp_module_abs_path = rust_src_root.join(rust_pp_module_rel_path)
-                                               .as_str()
+                                               .to_str()
                                                .unwrap()
                                                .to_string();
 
-    script_str.push_str(&format!("command script import {}\n", &rust_pp_module_abs_path[..])[..]);
+    script_str.push_str(&format!("command script import {}\n",
+                                 &rust_pp_module_abs_path[..])[..]);
     script_str.push_str("type summary add --no-value ");
     script_str.push_str("--python-function lldb_rust_formatters.print_val ");
     script_str.push_str("-x \".*\" --category Rust\n");
@@ -707,7 +695,7 @@ fn run_debuginfo_lldb_test(config: &Config, props: &TestProps, testfile: &Path)
     }
 
     // Finally, quit the debugger
-    script_str.push_str("quit\n");
+    script_str.push_str("\nquit\n");
 
     // Write the script into a file
     debug!("script_str = {}", script_str);
@@ -735,22 +723,19 @@ fn run_debuginfo_lldb_test(config: &Config, props: &TestProps, testfile: &Path)
                 rust_src_root: &Path)
                 -> ProcRes {
         // Prepare the lldb_batchmode which executes the debugger script
-        let lldb_script_path = rust_src_root.join(Path::new("./src/etc/lldb_batchmode.py"));
+        let lldb_script_path = rust_src_root.join("src/etc/lldb_batchmode.py");
 
         let mut cmd = Command::new("python");
-        cmd.arg(lldb_script_path)
+        cmd.arg(&lldb_script_path)
            .arg(test_executable)
            .arg(debugger_script)
-           .env_set_all(&[("PYTHONPATH", config.lldb_python_dir.clone().unwrap())]);
-
-        let (status, out, err) = match cmd.spawn() {
-            Ok(process) => {
-                let ProcessOutput { status, output, error } =
-                    process.wait_with_output().unwrap();
+           .env("PYTHONPATH", config.lldb_python_dir.as_ref().unwrap());
 
+        let (status, out, err) = match cmd.output() {
+            Ok(Output { status, stdout, stderr }) => {
                 (status,
-                 String::from_utf8(output).unwrap(),
-                 String::from_utf8(error).unwrap())
+                 String::from_utf8(stdout).unwrap(),
+                 String::from_utf8(stderr).unwrap())
             },
             Err(e) => {
                 fatal(&format!("Failed to setup Python process for \
@@ -760,7 +745,7 @@ fn run_debuginfo_lldb_test(config: &Config, props: &TestProps, testfile: &Path)
 
         dump_output(config, test_executable, &out, &err);
         return ProcRes {
-            status: status,
+            status: Status::Normal(status),
             stdout: out,
             stderr: err,
             cmdline: format!("{:?}", cmd)
@@ -776,8 +761,6 @@ struct DebuggerCommands {
 
 fn parse_debugger_commands(file_path: &Path, debugger_prefix: &str)
                            -> DebuggerCommands {
-    use std::old_io::{BufferedReader, File};
-
     let command_directive = format!("{}-command", debugger_prefix);
     let check_directive = format!("{}-check", debugger_prefix);
 
@@ -785,7 +768,7 @@ fn parse_debugger_commands(file_path: &Path, debugger_prefix: &str)
     let mut commands = vec!();
     let mut check_lines = vec!();
     let mut counter = 1;
-    let mut reader = BufferedReader::new(File::open(file_path).unwrap());
+    let reader = BufReader::new(File::open(file_path).unwrap());
     for line in reader.lines() {
         match line {
             Ok(line) => {
@@ -963,16 +946,17 @@ fn check_expected_errors(expected_errors: Vec<errors::ExpectedError> ,
 
     let prefixes = expected_errors.iter().map(|ee| {
         format!("{}:{}:", testfile.display(), ee.line)
-    }).collect::<Vec<String> >();
-
-    #[cfg(windows)]
-    fn prefix_matches( line : &str, prefix : &str ) -> bool {
-        line.to_ascii_lowercase().starts_with(&prefix.to_ascii_lowercase())
-    }
-
-    #[cfg(unix)]
-    fn prefix_matches( line : &str, prefix : &str ) -> bool {
-        line.starts_with( prefix )
+    }).collect::<Vec<String>>();
+
+    fn prefix_matches(line: &str, prefix: &str) -> bool {
+        use std::ascii::AsciiExt;
+        // On windows just translate all '\' path separators to '/'
+        let line = line.replace(r"\", "/");
+        if cfg!(windows) {
+            line.to_ascii_lowercase().starts_with(&prefix.to_ascii_lowercase())
+        } else {
+            line.starts_with(prefix)
+        }
     }
 
     // A multi-line error will have followup lines which will always
@@ -1113,12 +1097,42 @@ struct ProcArgs {
 }
 
 struct ProcRes {
-    status: ProcessExit,
+    status: Status,
     stdout: String,
     stderr: String,
     cmdline: String,
 }
 
+enum Status {
+    Parsed(i32),
+    Normal(ExitStatus),
+}
+
+impl Status {
+    fn code(&self) -> Option<i32> {
+        match *self {
+            Status::Parsed(i) => Some(i),
+            Status::Normal(ref e) => e.code(),
+        }
+    }
+
+    fn success(&self) -> bool {
+        match *self {
+            Status::Parsed(i) => i == 0,
+            Status::Normal(ref e) => e.success(),
+        }
+    }
+}
+
+impl fmt::Display for Status {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Status::Parsed(i) => write!(f, "exit code: {}", i),
+            Status::Normal(ref e) => e.fmt(f),
+        }
+    }
+}
+
 fn compile_test(config: &Config, props: &TestProps,
                 testfile: &Path) -> ProcRes {
     compile_test_(config, props, testfile, &[])
@@ -1133,7 +1147,7 @@ fn compile_test_(config: &Config, props: &TestProps,
     let aux_dir = aux_output_dir_name(config, testfile);
     // FIXME (#9639): This needs to handle non-utf8 paths
     let mut link_args = vec!("-L".to_string(),
-                             aux_dir.as_str().unwrap().to_string());
+                             aux_dir.to_str().unwrap().to_string());
     link_args.extend(extra_args.iter().cloned());
     let args = make_compile_args(config,
                                  props,
@@ -1160,7 +1174,7 @@ fn exec_compiled_test(config: &Config, props: &TestProps,
                             make_run_args(config, props, testfile),
                             env,
                             &config.run_lib_path,
-                            Some(aux_dir.as_str().unwrap()),
+                            Some(aux_dir.to_str().unwrap()),
                             None)
         }
     }
@@ -1179,7 +1193,7 @@ fn compose_and_run_compiler(
 
     let aux_dir = aux_output_dir_name(config, testfile);
     // FIXME (#9639): This needs to handle non-utf8 paths
-    let extra_link_args = vec!("-L".to_string(), aux_dir.as_str().unwrap().to_string());
+    let extra_link_args = vec!("-L".to_string(), aux_dir.to_str().unwrap().to_string());
 
     for rel_ab in &props.aux_builds {
         let abs_ab = config.aux_base.join(rel_ab);
@@ -1196,7 +1210,8 @@ fn compose_and_run_compiler(
                               crate_type,
                               |a,b| {
                                   let f = make_lib_name(a, b, testfile);
-                                  TargetLocation::ThisDirectory(f.dir_path())
+                                  let parent = f.parent().unwrap();
+                                  TargetLocation::ThisDirectory(parent.to_path_buf())
                               },
                               &abs_ab);
         let auxres = compose_and_run(config,
@@ -1204,7 +1219,7 @@ fn compose_and_run_compiler(
                                      aux_args,
                                      Vec::new(),
                                      &config.compile_lib_path,
-                                     Some(aux_dir.as_str().unwrap()),
+                                     Some(aux_dir.to_str().unwrap()),
                                      None);
         if !auxres.status.success() {
             fatal_proc_rec(
@@ -1226,13 +1241,13 @@ fn compose_and_run_compiler(
                     args,
                     Vec::new(),
                     &config.compile_lib_path,
-                    Some(aux_dir.as_str().unwrap()),
+                    Some(aux_dir.to_str().unwrap()),
                     input)
 }
 
 fn ensure_dir(path: &Path) {
     if path.is_dir() { return; }
-    fs::mkdir(path, old_io::USER_RWX).unwrap();
+    fs::create_dir(path).unwrap();
 }
 
 fn compose_and_run(config: &Config, testfile: &Path,
@@ -1246,8 +1261,8 @@ fn compose_and_run(config: &Config, testfile: &Path,
 }
 
 enum TargetLocation {
-    ThisFile(Path),
-    ThisDirectory(Path),
+    ThisFile(PathBuf),
+    ThisDirectory(PathBuf),
 }
 
 fn make_compile_args<F>(config: &Config,
@@ -1265,9 +1280,9 @@ fn make_compile_args<F>(config: &Config,
         &*config.target
     };
     // FIXME (#9639): This needs to handle non-utf8 paths
-    let mut args = vec!(testfile.as_str().unwrap().to_string(),
+    let mut args = vec!(testfile.to_str().unwrap().to_string(),
                         "-L".to_string(),
-                        config.build_base.as_str().unwrap().to_string(),
+                        config.build_base.to_str().unwrap().to_string(),
                         format!("--target={}", target));
     args.push_all(&extras);
     if !props.no_prefer_dynamic {
@@ -1284,7 +1299,7 @@ fn make_compile_args<F>(config: &Config,
             path
         }
     };
-    args.push(path.as_str().unwrap().to_string());
+    args.push(path.to_str().unwrap().to_string());
     if props.force_host {
         args.extend(split_maybe_args(&config.host_rustcflags).into_iter());
     } else {
@@ -1292,24 +1307,24 @@ fn make_compile_args<F>(config: &Config,
     }
     args.extend(split_maybe_args(&props.compile_flags).into_iter());
     return ProcArgs {
-        prog: config.rustc_path.as_str().unwrap().to_string(),
+        prog: config.rustc_path.to_str().unwrap().to_string(),
         args: args,
     };
 }
 
-fn make_lib_name(config: &Config, auxfile: &Path, testfile: &Path) -> Path {
+fn make_lib_name(config: &Config, auxfile: &Path, testfile: &Path) -> PathBuf {
     // what we return here is not particularly important, as it
     // happens; rustc ignores everything except for the directory.
     let auxname = output_testname(auxfile);
     aux_output_dir_name(config, testfile).join(&auxname)
 }
 
-fn make_exe_name(config: &Config, testfile: &Path) -> Path {
+fn make_exe_name(config: &Config, testfile: &Path) -> PathBuf {
     let mut f = output_base_name(config, testfile);
     if !env::consts::EXE_SUFFIX.is_empty() {
-        let mut fname = f.filename().unwrap().to_vec();
-        fname.extend(env::consts::EXE_SUFFIX.bytes());
-        f.set_filename(fname);
+        let mut fname = f.file_name().unwrap().to_os_string();
+        fname.push_os_str(OsStr::from_str(env::consts::EXE_SUFFIX));
+        f.set_file_name(&fname);
     }
     f
 }
@@ -1322,7 +1337,7 @@ fn make_run_args(config: &Config, props: &TestProps, testfile: &Path) ->
     let exe_file = make_exe_name(config, testfile);
 
     // FIXME (#9639): This needs to handle non-utf8 paths
-    args.push(exe_file.as_str().unwrap().to_string());
+    args.push(exe_file.to_str().unwrap().to_string());
 
     // Add the arguments in the run_flags directive
     args.extend(split_maybe_args(&props.run_flags).into_iter());
@@ -1375,29 +1390,28 @@ fn program_output(config: &Config, testfile: &Path, lib_path: &str, prog: String
                      input).expect(&format!("failed to exec `{}`", prog));
     dump_output(config, testfile, &out, &err);
     return ProcRes {
-        status: status,
+        status: Status::Normal(status),
         stdout: out,
         stderr: err,
         cmdline: cmdline,
     };
 }
 
-// Linux and mac don't require adjusting the library search path
-#[cfg(unix)]
-fn make_cmdline(_libpath: &str, prog: &str, args: &[String]) -> String {
-    format!("{} {}", prog, args.connect(" "))
-}
-
-#[cfg(windows)]
 fn make_cmdline(libpath: &str, prog: &str, args: &[String]) -> String {
+    use util;
 
-    // Build the LD_LIBRARY_PATH variable as it would be seen on the command line
-    // for diagnostic purposes
-    fn lib_path_cmd_prefix(path: &str) -> String {
-        format!("{}=\"{}\"", util::lib_path_env_var(), util::make_new_path(path))
-    }
+    // Linux and mac don't require adjusting the library search path
+    if cfg!(unix) {
+        format!("{} {}", prog, args.connect(" "))
+    } else {
+        // Build the LD_LIBRARY_PATH variable as it would be seen on the command line
+        // for diagnostic purposes
+        fn lib_path_cmd_prefix(path: &str) -> String {
+            format!("{}=\"{}\"", util::lib_path_env_var(), util::make_new_path(path))
+        }
 
-    format!("{} {} {}", lib_path_cmd_prefix(libpath), prog, args.connect(" "))
+        format!("{} {} {}", lib_path_cmd_prefix(libpath), prog, args.connect(" "))
+    }
 }
 
 fn dump_output(config: &Config, testfile: &Path, out: &str, err: &str) {
@@ -1409,25 +1423,25 @@ fn dump_output(config: &Config, testfile: &Path, out: &str, err: &str) {
 fn dump_output_file(config: &Config, testfile: &Path,
                     out: &str, extension: &str) {
     let outfile = make_out_name(config, testfile, extension);
-    File::create(&outfile).write_all(out.as_bytes()).unwrap();
+    File::create(&outfile).unwrap().write_all(out.as_bytes()).unwrap();
 }
 
-fn make_out_name(config: &Config, testfile: &Path, extension: &str) -> Path {
+fn make_out_name(config: &Config, testfile: &Path, extension: &str) -> PathBuf {
     output_base_name(config, testfile).with_extension(extension)
 }
 
-fn aux_output_dir_name(config: &Config, testfile: &Path) -> Path {
+fn aux_output_dir_name(config: &Config, testfile: &Path) -> PathBuf {
     let f = output_base_name(config, testfile);
-    let mut fname = f.filename().unwrap().to_vec();
-    fname.extend("libaux".bytes());
-    f.with_filename(fname)
+    let mut fname = f.file_name().unwrap().to_os_string();
+    fname.push_os_str(OsStr::from_str("libaux"));
+    f.with_file_name(&fname)
 }
 
-fn output_testname(testfile: &Path) -> Path {
-    Path::new(testfile.filestem().unwrap())
+fn output_testname(testfile: &Path) -> PathBuf {
+    PathBuf::new(testfile.file_stem().unwrap())
 }
 
-fn output_base_name(config: &Config, testfile: &Path) -> Path {
+fn output_base_name(config: &Config, testfile: &Path) -> PathBuf {
     config.build_base
         .join(&output_testname(testfile))
         .with_extension(&config.stage_id)
@@ -1542,11 +1556,11 @@ fn _arm_exec_compiled_test(config: &Config,
                      Some("".to_string()))
         .expect(&format!("failed to exec `{}`", config.adb_path));
 
-    let mut exitcode: int = 0;
+    let mut exitcode: i32 = 0;
     for c in exitcode_out.chars() {
         if !c.is_numeric() { break; }
         exitcode = exitcode * 10 + match c {
-            '0' ... '9' => c as int - ('0' as int),
+            '0' ... '9' => c as i32 - ('0' as i32),
             _ => 101,
         }
     }
@@ -1587,7 +1601,7 @@ fn _arm_exec_compiled_test(config: &Config,
                 &stderr_out);
 
     ProcRes {
-        status: process::ProcessExit::ExitStatus(exitcode),
+        status: Status::Parsed(exitcode),
         stdout: stdout_out,
         stderr: stderr_out,
         cmdline: cmdline
@@ -1597,16 +1611,17 @@ fn _arm_exec_compiled_test(config: &Config,
 fn _arm_push_aux_shared_library(config: &Config, testfile: &Path) {
     let tdir = aux_output_dir_name(config, testfile);
 
-    let dirs = fs::readdir(&tdir).unwrap();
-    for file in &dirs {
-        if file.extension_str() == Some("so") {
+    let dirs = fs::read_dir(&tdir).unwrap();
+    for file in dirs {
+        let file = file.unwrap().path();
+        if file.extension().and_then(|s| s.to_str()) == Some("so") {
             // FIXME (#9639): This needs to handle non-utf8 paths
             let copy_result = procsrv::run("",
                                            &config.adb_path,
                                            None,
                                            &[
                                             "push".to_string(),
-                                            file.as_str()
+                                            file.to_str()
                                                 .unwrap()
                                                 .to_string(),
                                             config.adb_test_dir.to_string(),
@@ -1627,14 +1642,14 @@ fn _arm_push_aux_shared_library(config: &Config, testfile: &Path) {
 
 // codegen tests (vs. clang)
 
-fn append_suffix_to_stem(p: &Path, suffix: &str) -> Path {
+fn append_suffix_to_stem(p: &Path, suffix: &str) -> PathBuf {
     if suffix.len() == 0 {
-        (*p).clone()
+        p.to_path_buf()
     } else {
-        let mut stem = p.filestem().unwrap().to_vec();
-        stem.extend("-".bytes());
-        stem.extend(suffix.bytes());
-        p.with_filename(stem)
+        let mut stem = p.file_stem().unwrap().to_os_string();
+        stem.push_os_str(OsStr::from_str("-"));
+        stem.push_os_str(OsStr::from_str(suffix));
+        p.with_file_name(&stem)
     }
 }
 
@@ -1643,7 +1658,7 @@ fn compile_test_and_save_bitcode(config: &Config, props: &TestProps,
     let aux_dir = aux_output_dir_name(config, testfile);
     // FIXME (#9639): This needs to handle non-utf8 paths
     let mut link_args = vec!("-L".to_string(),
-                             aux_dir.as_str().unwrap().to_string());
+                             aux_dir.to_str().unwrap().to_string());
     let llvm_args = vec!("--emit=llvm-bc,obj".to_string(),
                          "--crate-type=lib".to_string());
     link_args.extend(llvm_args.into_iter());
@@ -1651,7 +1666,8 @@ fn compile_test_and_save_bitcode(config: &Config, props: &TestProps,
                                  props,
                                  link_args,
                                  |a, b| TargetLocation::ThisDirectory(
-                                     output_base_name(a, b).dir_path()),
+                                     output_base_name(a, b).parent()
+                                        .unwrap().to_path_buf()),
                                  testfile);
     compose_and_run_compiler(config, props, testfile, args, None)
 }
@@ -1663,12 +1679,12 @@ fn compile_cc_with_clang_and_save_bitcode(config: &Config, _props: &TestProps,
     let testcc = testfile.with_extension("cc");
     let proc_args = ProcArgs {
         // FIXME (#9639): This needs to handle non-utf8 paths
-        prog: config.clang_path.as_ref().unwrap().as_str().unwrap().to_string(),
+        prog: config.clang_path.as_ref().unwrap().to_str().unwrap().to_string(),
         args: vec!("-c".to_string(),
                    "-emit-llvm".to_string(),
                    "-o".to_string(),
-                   bitcodefile.as_str().unwrap().to_string(),
-                   testcc.as_str().unwrap().to_string())
+                   bitcodefile.to_str().unwrap().to_string(),
+                   testcc.to_str().unwrap().to_string())
     };
     compose_and_run(config, testfile, proc_args, Vec::new(), "", None, None)
 }
@@ -1682,10 +1698,10 @@ fn extract_function_from_bitcode(config: &Config, _props: &TestProps,
     let prog = config.llvm_bin_path.as_ref().unwrap().join("llvm-extract");
     let proc_args = ProcArgs {
         // FIXME (#9639): This needs to handle non-utf8 paths
-        prog: prog.as_str().unwrap().to_string(),
+        prog: prog.to_str().unwrap().to_string(),
         args: vec!(format!("-func={}", fname),
-                   format!("-o={}", extracted_bc.as_str().unwrap()),
-                   bitcodefile.as_str().unwrap().to_string())
+                   format!("-o={}", extracted_bc.to_str().unwrap()),
+                   bitcodefile.to_str().unwrap().to_string())
     };
     compose_and_run(config, testfile, proc_args, Vec::new(), "", None, None)
 }
@@ -1699,16 +1715,17 @@ fn disassemble_extract(config: &Config, _props: &TestProps,
     let prog = config.llvm_bin_path.as_ref().unwrap().join("llvm-dis");
     let proc_args = ProcArgs {
         // FIXME (#9639): This needs to handle non-utf8 paths
-        prog: prog.as_str().unwrap().to_string(),
-        args: vec!(format!("-o={}", extracted_ll.as_str().unwrap()),
-                   extracted_bc.as_str().unwrap().to_string())
+        prog: prog.to_str().unwrap().to_string(),
+        args: vec!(format!("-o={}", extracted_ll.to_str().unwrap()),
+                   extracted_bc.to_str().unwrap().to_string())
     };
     compose_and_run(config, testfile, proc_args, Vec::new(), "", None, None)
 }
 
 
 fn count_extracted_lines(p: &Path) -> uint {
-    let x = File::open(&p.with_extension("ll")).read_to_end().unwrap();
+    let mut x = Vec::new();
+    File::open(&p.with_extension("ll")).unwrap().read_to_end(&mut x).unwrap();
     let x = str::from_utf8(&x).unwrap();
     x.lines().count()
 }
diff --git a/src/compiletest/util.rs b/src/compiletest/util.rs
index c0d7c59ef6a..16e2806f72c 100644
--- a/src/compiletest/util.rs
+++ b/src/compiletest/util.rs
@@ -8,10 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use common::Config;
-
-#[cfg(target_os = "windows")]
 use std::env;
+use common::Config;
 
 /// Conversion table from triple OS name to Rust SYSNAME
 const OS_TABLE: &'static [(&'static str, &'static str)] = &[
@@ -36,24 +34,20 @@ pub fn get_os(triple: &str) -> &'static str {
     panic!("Cannot determine OS from triple");
 }
 
-#[cfg(target_os = "windows")]
 pub fn make_new_path(path: &str) -> String {
-
+    assert!(cfg!(windows));
     // Windows just uses PATH as the library search path, so we have to
     // maintain the current value while adding our own
     match env::var(lib_path_env_var()) {
-      Ok(curr) => {
-        format!("{}{}{}", path, path_div(), curr)
-      }
-      Err(..) => path.to_string()
+        Ok(curr) => {
+            format!("{}{}{}", path, path_div(), curr)
+        }
+        Err(..) => path.to_string()
     }
 }
 
-#[cfg(target_os = "windows")]
 pub fn lib_path_env_var() -> &'static str { "PATH" }
-
-#[cfg(target_os = "windows")]
-pub fn path_div() -> &'static str { ";" }
+fn path_div() -> &'static str { ";" }
 
 pub fn logv(config: &Config, s: String) {
     debug!("{}", s);
diff --git a/src/liballoc/lib.rs b/src/liballoc/lib.rs
index 7c65a99d4b0..b1fdf139b0c 100644
--- a/src/liballoc/lib.rs
+++ b/src/liballoc/lib.rs
@@ -73,6 +73,7 @@
 #![feature(unboxed_closures)]
 #![feature(unsafe_no_drop_flag)]
 #![feature(core)]
+#![feature(unique)]
 #![cfg_attr(test, feature(test, alloc, rustc_private))]
 #![cfg_attr(all(not(feature = "external_funcs"), not(feature = "external_crate")),
             feature(libc))]
diff --git a/src/libgetopts/lib.rs b/src/libgetopts/lib.rs
index 6240b0e6afd..6b9d6cb0000 100644
--- a/src/libgetopts/lib.rs
+++ b/src/libgetopts/lib.rs
@@ -93,6 +93,7 @@
 #![feature(int_uint)]
 #![feature(staged_api)]
 #![feature(str_words)]
+#![feature(core)]
 #![cfg_attr(test, feature(rustc_private))]
 
 #[cfg(test)] #[macro_use] extern crate log;
diff --git a/src/librustc/lib.rs b/src/librustc/lib.rs
index aa51320ee7f..2d542eafbe1 100644
--- a/src/librustc/lib.rs
+++ b/src/librustc/lib.rs
@@ -39,6 +39,9 @@
 #![feature(staged_api)]
 #![feature(std_misc)]
 #![feature(os)]
+#![feature(path)]
+#![feature(fs)]
+#![feature(io)]
 #![cfg_attr(test, feature(test))]
 
 extern crate arena;
diff --git a/src/librustc/metadata/creader.rs b/src/librustc/metadata/creader.rs
index bc3071d8db2..a19ccceb057 100644
--- a/src/librustc/metadata/creader.rs
+++ b/src/librustc/metadata/creader.rs
@@ -21,6 +21,7 @@ use metadata::decoder;
 use metadata::loader;
 use metadata::loader::CratePaths;
 
+use std::path::{Path, PathBuf};
 use std::rc::Rc;
 use syntax::ast;
 use syntax::abi;
@@ -126,7 +127,7 @@ fn register_native_lib(sess: &Session,
 // Extra info about a crate loaded for plugins or exported macros.
 struct ExtensionCrate {
     metadata: PMDSource,
-    dylib: Option<Path>,
+    dylib: Option<PathBuf>,
     target_only: bool,
 }
 
@@ -551,7 +552,8 @@ impl<'a> CrateReader<'a> {
     }
 
     /// Look for a plugin registrar. Returns library path and symbol name.
-    pub fn find_plugin_registrar(&mut self, span: Span, name: &str) -> Option<(Path, String)> {
+    pub fn find_plugin_registrar(&mut self, span: Span, name: &str)
+                                 -> Option<(PathBuf, String)> {
         let ekrate = self.read_extension_crate(span, &CrateInfo {
              name: name.to_string(),
              ident: name.to_string(),
@@ -574,7 +576,7 @@ impl<'a> CrateReader<'a> {
             .map(|id| decoder::get_symbol(ekrate.metadata.as_slice(), id));
 
         match (ekrate.dylib.as_ref(), registrar) {
-            (Some(dylib), Some(reg)) => Some((dylib.clone(), reg)),
+            (Some(dylib), Some(reg)) => Some((dylib.to_path_buf(), reg)),
             (None, Some(_)) => {
                 let message = format!("plugin `{}` only found in rlib format, \
                                        but must be available in dylib format",
diff --git a/src/librustc/metadata/cstore.rs b/src/librustc/metadata/cstore.rs
index 62098733023..47ec31c0f1a 100644
--- a/src/librustc/metadata/cstore.rs
+++ b/src/librustc/metadata/cstore.rs
@@ -25,6 +25,7 @@ use util::nodemap::{FnvHashMap, NodeMap};
 
 use std::cell::RefCell;
 use std::rc::Rc;
+use std::path::PathBuf;
 use flate::Bytes;
 use syntax::ast;
 use syntax::codemap;
@@ -78,8 +79,8 @@ pub enum NativeLibraryKind {
 // must be non-None.
 #[derive(PartialEq, Clone)]
 pub struct CrateSource {
-    pub dylib: Option<(Path, PathKind)>,
-    pub rlib: Option<(Path, PathKind)>,
+    pub dylib: Option<(PathBuf, PathKind)>,
+    pub rlib: Option<(PathBuf, PathKind)>,
     pub cnum: ast::CrateNum,
 }
 
@@ -172,7 +173,7 @@ impl CStore {
     // topological sort of all crates putting the leaves at the right-most
     // positions.
     pub fn get_used_crates(&self, prefer: LinkagePreference)
-                           -> Vec<(ast::CrateNum, Option<Path>)> {
+                           -> Vec<(ast::CrateNum, Option<PathBuf>)> {
         let mut ordering = Vec::new();
         fn visit(cstore: &CStore, cnum: ast::CrateNum,
                  ordering: &mut Vec<ast::CrateNum>) {
diff --git a/src/librustc/metadata/decoder.rs b/src/librustc/metadata/decoder.rs
index 994cb3f0f25..90046398c59 100644
--- a/src/librustc/metadata/decoder.rs
+++ b/src/librustc/metadata/decoder.rs
@@ -34,9 +34,9 @@ use middle::astencode::vtable_decoder_helpers;
 
 use std::collections::HashMap;
 use std::hash::{self, Hash, SipHasher};
-use std::num::FromPrimitive;
-use std::num::Int;
-use std::old_io;
+use std::io::prelude::*;
+use std::io;
+use std::num::{FromPrimitive, Int};
 use std::rc::Rc;
 use std::slice::bytes;
 use std::str;
@@ -1191,7 +1191,7 @@ fn get_attributes(md: rbml::Doc) -> Vec<ast::Attribute> {
 }
 
 fn list_crate_attributes(md: rbml::Doc, hash: &Svh,
-                         out: &mut old_io::Writer) -> old_io::IoResult<()> {
+                         out: &mut io::Write) -> io::Result<()> {
     try!(write!(out, "=Crate Attributes ({})=\n", *hash));
 
     let r = get_attributes(md);
@@ -1236,7 +1236,7 @@ pub fn get_crate_deps(data: &[u8]) -> Vec<CrateDep> {
     return deps;
 }
 
-fn list_crate_deps(data: &[u8], out: &mut old_io::Writer) -> old_io::IoResult<()> {
+fn list_crate_deps(data: &[u8], out: &mut io::Write) -> io::Result<()> {
     try!(write!(out, "=External Dependencies=\n"));
     for dep in &get_crate_deps(data) {
         try!(write!(out, "{} {}-{}\n", dep.cnum, dep.name, dep.hash));
@@ -1275,7 +1275,7 @@ pub fn get_crate_name(data: &[u8]) -> String {
     maybe_get_crate_name(data).expect("no crate name in crate")
 }
 
-pub fn list_crate_metadata(bytes: &[u8], out: &mut old_io::Writer) -> old_io::IoResult<()> {
+pub fn list_crate_metadata(bytes: &[u8], out: &mut io::Write) -> io::Result<()> {
     let hash = get_crate_hash(bytes);
     let md = rbml::Doc::new(bytes);
     try!(list_crate_attributes(md, &hash, out));
diff --git a/src/librustc/metadata/filesearch.rs b/src/librustc/metadata/filesearch.rs
index d1091b1d3f7..22a4a6fc978 100644
--- a/src/librustc/metadata/filesearch.rs
+++ b/src/librustc/metadata/filesearch.rs
@@ -14,9 +14,9 @@ pub use self::FileMatch::*;
 
 use std::collections::HashSet;
 use std::env;
-use std::os;
-use std::old_io::fs::PathExtensions;
-use std::old_io::fs;
+use std::fs;
+use std::io::prelude::*;
+use std::path::{Path, PathBuf};
 
 use util::fs as myfs;
 use session::search_paths::{SearchPaths, PathKind};
@@ -50,20 +50,20 @@ impl<'a> FileSearch<'a> {
                 FileMatches => found = true,
                 FileDoesntMatch => ()
             }
-            visited_dirs.insert(path.as_vec().to_vec());
+            visited_dirs.insert(path.to_path_buf());
         }
 
         debug!("filesearch: searching lib path");
         let tlib_path = make_target_lib_path(self.sysroot,
                                              self.triple);
-        if !visited_dirs.contains(tlib_path.as_vec()) {
+        if !visited_dirs.contains(&tlib_path) {
             match f(&tlib_path, PathKind::All) {
                 FileMatches => found = true,
                 FileDoesntMatch => ()
             }
         }
 
-        visited_dirs.insert(tlib_path.as_vec().to_vec());
+        visited_dirs.insert(tlib_path);
         // Try RUST_PATH
         if !found {
             let rustpath = rust_path();
@@ -71,10 +71,10 @@ impl<'a> FileSearch<'a> {
                 let tlib_path = make_rustpkg_lib_path(
                     self.sysroot, path, self.triple);
                 debug!("is {} in visited_dirs? {}", tlib_path.display(),
-                        visited_dirs.contains(&tlib_path.as_vec().to_vec()));
+                        visited_dirs.contains(&tlib_path));
 
-                if !visited_dirs.contains(tlib_path.as_vec()) {
-                    visited_dirs.insert(tlib_path.as_vec().to_vec());
+                if !visited_dirs.contains(&tlib_path) {
+                    visited_dirs.insert(tlib_path.clone());
                     // Don't keep searching the RUST_PATH if one match turns up --
                     // if we did, we'd get a "multiple matching crates" error
                     match f(&tlib_path, PathKind::All) {
@@ -88,7 +88,7 @@ impl<'a> FileSearch<'a> {
         }
     }
 
-    pub fn get_lib_path(&self) -> Path {
+    pub fn get_lib_path(&self) -> PathBuf {
         make_target_lib_path(self.sysroot, self.triple)
     }
 
@@ -97,11 +97,13 @@ impl<'a> FileSearch<'a> {
     {
         self.for_each_lib_search_path(|lib_search_path, kind| {
             debug!("searching {}", lib_search_path.display());
-            match fs::readdir(lib_search_path) {
+            match fs::read_dir(lib_search_path) {
                 Ok(files) => {
+                    let files = files.filter_map(|p| p.ok().map(|s| s.path()))
+                                     .collect::<Vec<_>>();
                     let mut rslt = FileDoesntMatch;
-                    fn is_rlib(p: & &Path) -> bool {
-                        p.extension_str() == Some("rlib")
+                    fn is_rlib(p: &Path) -> bool {
+                        p.extension().and_then(|s| s.to_str()) == Some("rlib")
                     }
                     // Reading metadata out of rlibs is faster, and if we find both
                     // an rlib and a dylib we only read one of the files of
@@ -143,59 +145,60 @@ impl<'a> FileSearch<'a> {
     }
 
     // Returns a list of directories where target-specific dylibs might be located.
-    pub fn get_dylib_search_paths(&self) -> Vec<Path> {
+    pub fn get_dylib_search_paths(&self) -> Vec<PathBuf> {
         let mut paths = Vec::new();
         self.for_each_lib_search_path(|lib_search_path, _| {
-            paths.push(lib_search_path.clone());
+            paths.push(lib_search_path.to_path_buf());
             FileDoesntMatch
         });
         paths
     }
 
     // Returns a list of directories where target-specific tool binaries are located.
-    pub fn get_tools_search_paths(&self) -> Vec<Path> {
-        let mut p = Path::new(self.sysroot);
-        p.push(find_libdir(self.sysroot));
-        p.push(rustlibdir());
-        p.push(self.triple);
+    pub fn get_tools_search_paths(&self) -> Vec<PathBuf> {
+        let mut p = PathBuf::new(self.sysroot);
+        p.push(&find_libdir(self.sysroot));
+        p.push(&rustlibdir());
+        p.push(&self.triple);
         p.push("bin");
         vec![p]
     }
 }
 
-pub fn relative_target_lib_path(sysroot: &Path, target_triple: &str) -> Path {
-    let mut p = Path::new(find_libdir(sysroot));
+pub fn relative_target_lib_path(sysroot: &Path, target_triple: &str) -> PathBuf {
+    let mut p = PathBuf::new(&find_libdir(sysroot));
     assert!(p.is_relative());
-    p.push(rustlibdir());
+    p.push(&rustlibdir());
     p.push(target_triple);
     p.push("lib");
     p
 }
 
 fn make_target_lib_path(sysroot: &Path,
-                        target_triple: &str) -> Path {
+                        target_triple: &str) -> PathBuf {
     sysroot.join(&relative_target_lib_path(sysroot, target_triple))
 }
 
 fn make_rustpkg_lib_path(sysroot: &Path,
                          dir: &Path,
-                         triple: &str) -> Path {
-    let mut p = dir.join(find_libdir(sysroot));
+                         triple: &str) -> PathBuf {
+    let mut p = dir.join(&find_libdir(sysroot));
     p.push(triple);
     p
 }
 
-pub fn get_or_default_sysroot() -> Path {
+pub fn get_or_default_sysroot() -> PathBuf {
     // Follow symlinks.  If the resolved path is relative, make it absolute.
-    fn canonicalize(path: Option<Path>) -> Option<Path> {
-        path.and_then(|path|
+    fn canonicalize(path: Option<PathBuf>) -> Option<PathBuf> {
+        path.and_then(|path| {
             match myfs::realpath(&path) {
                 Ok(canon) => Some(canon),
                 Err(e) => panic!("failed to get realpath: {}", e),
-            })
+            }
+        })
     }
 
-    match canonicalize(os::self_exe_name()) {
+    match canonicalize(env::current_exe().ok()) {
         Some(mut p) => { p.pop(); p.pop(); p }
         None => panic!("can't determine value for sysroot")
     }
@@ -216,16 +219,16 @@ pub fn get_rust_path() -> Option<String> {
 /// $HOME/.rust
 /// DIR/.rust for any DIR that's the current working directory
 /// or an ancestor of it
-pub fn rust_path() -> Vec<Path> {
-    let mut env_rust_path: Vec<Path> = match get_rust_path() {
+pub fn rust_path() -> Vec<PathBuf> {
+    let mut env_rust_path: Vec<PathBuf> = match get_rust_path() {
         Some(env_path) => {
             let env_path_components =
                 env_path.split(PATH_ENTRY_SEPARATOR);
-            env_path_components.map(|s| Path::new(s)).collect()
+            env_path_components.map(|s| PathBuf::new(s)).collect()
         }
         None => Vec::new()
     };
-    let mut cwd = os::getcwd().unwrap();
+    let cwd = env::current_dir().unwrap();
     // now add in default entries
     let cwd_dot_rust = cwd.join(".rust");
     if !env_rust_path.contains(&cwd_dot_rust) {
@@ -234,17 +237,15 @@ pub fn rust_path() -> Vec<Path> {
     if !env_rust_path.contains(&cwd) {
         env_rust_path.push(cwd.clone());
     }
-    loop {
-        if { let f = cwd.filename(); f.is_none() || f.unwrap() == b".." } {
-            break
-        }
-        cwd.set_filename(".rust");
-        if !env_rust_path.contains(&cwd) && cwd.exists() {
-            env_rust_path.push(cwd.clone());
+    let mut cur = &*cwd;
+    while let Some(parent) = cur.parent() {
+        let candidate = parent.join(".rust");
+        if !env_rust_path.contains(&candidate) && candidate.exists() {
+            env_rust_path.push(candidate.clone());
         }
-        cwd.pop();
+        cur = parent;
     }
-    if let Some(h) = os::homedir() {
+    if let Some(h) = env::home_dir() {
         let p = h.join(".rust");
         if !env_rust_path.contains(&p) && p.exists() {
             env_rust_path.push(p);
@@ -267,7 +268,7 @@ fn find_libdir(sysroot: &Path) -> String {
 
     match option_env!("CFG_LIBDIR_RELATIVE") {
         Some(libdir) if libdir != "lib" => return libdir.to_string(),
-        _ => if sysroot.join(primary_libdir_name()).join(rustlibdir()).exists() {
+        _ => if sysroot.join(&primary_libdir_name()).join(&rustlibdir()).exists() {
             return primary_libdir_name();
         } else {
             return secondary_libdir_name();
diff --git a/src/librustc/metadata/loader.rs b/src/librustc/metadata/loader.rs
index 07082d81876..d83470354ac 100644
--- a/src/librustc/metadata/loader.rs
+++ b/src/librustc/metadata/loader.rs
@@ -226,13 +226,14 @@ use metadata::filesearch::{FileSearch, FileMatches, FileDoesntMatch};
 use syntax::codemap::Span;
 use syntax::diagnostic::SpanHandler;
 use util::fs;
+use util::common;
 use rustc_back::target::Target;
 
-use std::ffi::CString;
 use std::cmp;
 use std::collections::HashMap;
-use std::old_io::fs::PathExtensions;
-use std::old_io;
+use std::io::prelude::*;
+use std::io;
+use std::path::{Path, PathBuf};
 use std::ptr;
 use std::slice;
 use std::time::Duration;
@@ -240,7 +241,7 @@ use std::time::Duration;
 use flate;
 
 pub struct CrateMismatch {
-    path: Path,
+    path: PathBuf,
     got: String,
 }
 
@@ -262,8 +263,8 @@ pub struct Context<'a> {
 }
 
 pub struct Library {
-    pub dylib: Option<(Path, PathKind)>,
-    pub rlib: Option<(Path, PathKind)>,
+    pub dylib: Option<(PathBuf, PathKind)>,
+    pub rlib: Option<(PathBuf, PathKind)>,
     pub metadata: MetadataBlob,
 }
 
@@ -275,12 +276,12 @@ pub struct ArchiveMetadata {
 
 pub struct CratePaths {
     pub ident: String,
-    pub dylib: Option<Path>,
-    pub rlib: Option<Path>
+    pub dylib: Option<PathBuf>,
+    pub rlib: Option<PathBuf>
 }
 
 impl CratePaths {
-    fn paths(&self) -> Vec<Path> {
+    fn paths(&self) -> Vec<PathBuf> {
         match (&self.dylib, &self.rlib) {
             (&None,    &None)              => vec!(),
             (&Some(ref p), &None) |
@@ -400,7 +401,7 @@ impl<'a> Context<'a> {
         //
         // The goal of this step is to look at as little metadata as possible.
         self.filesearch.search(|path, kind| {
-            let file = match path.filename_str() {
+            let file = match path.file_name().and_then(|s| s.to_str()) {
                 None => return FileDoesntMatch,
                 Some(file) => file,
             };
@@ -416,7 +417,7 @@ impl<'a> Context<'a> {
                 if file.starts_with(&staticlib_prefix[..]) &&
                    file.ends_with(".a") {
                     staticlibs.push(CrateMismatch {
-                        path: path.clone(),
+                        path: path.to_path_buf(),
                         got: "static".to_string()
                     });
                 }
@@ -506,9 +507,9 @@ impl<'a> Context<'a> {
     // read the metadata from it if `*slot` is `None`. If the metadata couldn't
     // be read, it is assumed that the file isn't a valid rust library (no
     // errors are emitted).
-    fn extract_one(&mut self, m: HashMap<Path, PathKind>, flavor: &str,
-                   slot: &mut Option<MetadataBlob>) -> Option<(Path, PathKind)> {
-        let mut ret = None::<(Path, PathKind)>;
+    fn extract_one(&mut self, m: HashMap<PathBuf, PathKind>, flavor: &str,
+                   slot: &mut Option<MetadataBlob>) -> Option<(PathBuf, PathKind)> {
+        let mut ret = None::<(PathBuf, PathKind)>;
         let mut error = 0;
 
         if slot.is_some() {
@@ -587,7 +588,7 @@ impl<'a> Context<'a> {
         if triple != self.triple {
             info!("Rejecting via crate triple: expected {} got {}", self.triple, triple);
             self.rejected_via_triple.push(CrateMismatch {
-                path: libpath.clone(),
+                path: libpath.to_path_buf(),
                 got: triple.to_string()
             });
             return false;
@@ -599,7 +600,7 @@ impl<'a> Context<'a> {
                 if *myhash != hash {
                     info!("Rejecting via hash: expected {} got {}", *myhash, hash);
                     self.rejected_via_hash.push(CrateMismatch {
-                        path: libpath.clone(),
+                        path: libpath.to_path_buf(),
                         got: myhash.as_str().to_string()
                     });
                     false
@@ -627,13 +628,13 @@ impl<'a> Context<'a> {
         let mut rlibs = HashMap::new();
         let mut dylibs = HashMap::new();
         {
-            let locs = locs.iter().map(|l| Path::new(&l[..])).filter(|loc| {
+            let locs = locs.iter().map(|l| PathBuf::new(&l[..])).filter(|loc| {
                 if !loc.exists() {
                     sess.err(&format!("extern location for {} does not exist: {}",
                                      self.crate_name, loc.display()));
                     return false;
                 }
-                let file = match loc.filename_str() {
+                let file = match loc.file_name().and_then(|s| s.to_str()) {
                     Some(file) => file,
                     None => {
                         sess.err(&format!("extern location for {} is not a file: {}",
@@ -658,7 +659,7 @@ impl<'a> Context<'a> {
             // Now that we have an iterator of good candidates, make sure
             // there's at most one rlib and at most one dylib.
             for loc in locs {
-                if loc.filename_str().unwrap().ends_with(".rlib") {
+                if loc.file_name().unwrap().to_str().unwrap().ends_with(".rlib") {
                     rlibs.insert(fs::realpath(&loc).unwrap(),
                                  PathKind::ExternFlag);
                 } else {
@@ -714,7 +715,7 @@ fn get_metadata_section(is_osx: bool, filename: &Path) -> Result<MetadataBlob, S
     let dur = Duration::span(|| {
         ret = Some(get_metadata_section_imp(is_osx, filename));
     });
-    info!("reading {} => {}ms", filename.filename_display(),
+    info!("reading {:?} => {}ms", filename.file_name().unwrap(),
           dur.num_milliseconds());
     return ret.unwrap();;
 }
@@ -723,7 +724,7 @@ fn get_metadata_section_imp(is_osx: bool, filename: &Path) -> Result<MetadataBlo
     if !filename.exists() {
         return Err(format!("no such file: '{}'", filename.display()));
     }
-    if filename.filename_str().unwrap().ends_with(".rlib") {
+    if filename.file_name().unwrap().to_str().unwrap().ends_with(".rlib") {
         // Use ArchiveRO for speed here, it's backed by LLVM and uses mmap
         // internally to read the file. We also avoid even using a memcpy by
         // just keeping the archive along while the metadata is in use.
@@ -742,7 +743,7 @@ fn get_metadata_section_imp(is_osx: bool, filename: &Path) -> Result<MetadataBlo
         };
     }
     unsafe {
-        let buf = CString::new(filename.as_vec()).unwrap();
+        let buf = common::path2cstr(filename);
         let mb = llvm::LLVMRustCreateMemoryBufferWithContentsOfFile(buf.as_ptr());
         if mb as int == 0 {
             return Err(format!("error reading library: '{}'",
@@ -811,7 +812,7 @@ pub fn read_meta_section_name(is_osx: bool) -> &'static str {
 
 // A diagnostic function for dumping crate metadata to an output stream
 pub fn list_file_metadata(is_osx: bool, path: &Path,
-                          out: &mut old_io::Writer) -> old_io::IoResult<()> {
+                          out: &mut io::Write) -> io::Result<()> {
     match get_metadata_section(is_osx, path) {
         Ok(bytes) => decoder::list_crate_metadata(bytes.as_slice(), out),
         Err(msg) => {
diff --git a/src/librustc/middle/dataflow.rs b/src/librustc/middle/dataflow.rs
index faed3f5977f..a1ce8d18184 100644
--- a/src/librustc/middle/dataflow.rs
+++ b/src/librustc/middle/dataflow.rs
@@ -19,7 +19,7 @@ pub use self::EntryOrExit::*;
 use middle::cfg;
 use middle::cfg::CFGIndex;
 use middle::ty;
-use std::old_io;
+use std::io;
 use std::usize;
 use std::iter::repeat;
 use syntax::ast;
@@ -103,7 +103,7 @@ impl<'a, 'tcx, O:DataFlowOperator> DataFlowContext<'a, 'tcx, O> {
 impl<'a, 'tcx, O:DataFlowOperator> pprust::PpAnn for DataFlowContext<'a, 'tcx, O> {
     fn pre(&self,
            ps: &mut pprust::State,
-           node: pprust::AnnNode) -> old_io::IoResult<()> {
+           node: pprust::AnnNode) -> io::Result<()> {
         let id = match node {
             pprust::NodeIdent(_) | pprust::NodeName(_) => 0,
             pprust::NodeExpr(expr) => expr.id,
@@ -485,13 +485,15 @@ impl<'a, 'tcx, O:DataFlowOperator+Clone+'static> DataFlowContext<'a, 'tcx, O> {
 
         debug!("Dataflow result for {}:", self.analysis_name);
         debug!("{}", {
-            self.pretty_print_to(box old_io::stderr(), blk).unwrap();
+            let mut v = Vec::new();
+            self.pretty_print_to(box &mut v, blk).unwrap();
+            println!("{}", String::from_utf8(v).unwrap());
             ""
         });
     }
 
-    fn pretty_print_to(&self, wr: Box<old_io::Writer+'static>,
-                       blk: &ast::Block) -> old_io::IoResult<()> {
+    fn pretty_print_to<'b>(&self, wr: Box<io::Write + 'b>,
+                           blk: &ast::Block) -> io::Result<()> {
         let mut ps = pprust::rust_printer_annotated(wr, self);
         try!(ps.cbox(pprust::indent_unit));
         try!(ps.ibox(0));
diff --git a/src/librustc/middle/infer/region_inference/graphviz.rs b/src/librustc/middle/infer/region_inference/graphviz.rs
index 43cd1fc8edb..6211fde7919 100644
--- a/src/librustc/middle/infer/region_inference/graphviz.rs
+++ b/src/librustc/middle/infer/region_inference/graphviz.rs
@@ -28,8 +28,10 @@ use util::ppaux::Repr;
 
 use std::borrow::Cow;
 use std::collections::hash_map::Entry::Vacant;
-use std::old_io::{self, File};
 use std::env;
+use std::fs::File;
+use std::io;
+use std::io::prelude::*;
 use std::sync::atomic::{AtomicBool, Ordering, ATOMIC_BOOL_INIT};
 use syntax::ast;
 
@@ -256,10 +258,11 @@ pub type ConstraintMap<'tcx> = FnvHashMap<Constraint, SubregionOrigin<'tcx>>;
 
 fn dump_region_constraints_to<'a, 'tcx:'a >(tcx: &'a ty::ctxt<'tcx>,
                                             map: &ConstraintMap<'tcx>,
-                                            path: &str) -> old_io::IoResult<()> {
+                                            path: &str) -> io::Result<()> {
     debug!("dump_region_constraints map (len: {}) path: {}", map.len(), path);
     let g = ConstraintGraph::new(tcx, format!("region_constraints"), map);
-    let mut f = File::create(&Path::new(path));
     debug!("dump_region_constraints calling render");
-    dot::render(&g, &mut f)
+    let mut v = Vec::new();
+    dot::render(&g, &mut v).unwrap();
+    File::create(path).and_then(|mut f| f.write_all(&v))
 }
diff --git a/src/librustc/plugin/load.rs b/src/librustc/plugin/load.rs
index a419d4134b4..8267b79ff9e 100644
--- a/src/librustc/plugin/load.rs
+++ b/src/librustc/plugin/load.rs
@@ -14,10 +14,12 @@ use session::Session;
 use metadata::creader::CrateReader;
 use plugin::registry::Registry;
 
-use std::mem;
-use std::os;
-use std::dynamic_lib::DynamicLibrary;
 use std::borrow::ToOwned;
+use std::dynamic_lib::DynamicLibrary;
+use std::env;
+use std::mem;
+use std::old_path;
+use std::path::PathBuf;
 use syntax::ast;
 use syntax::codemap::{Span, COMMAND_LINE_SP};
 use syntax::ptr::P;
@@ -100,10 +102,11 @@ impl<'a> PluginLoader<'a> {
     // Dynamically link a registrar function into the compiler process.
     fn dylink_registrar(&mut self,
                         span: Span,
-                        path: Path,
+                        path: PathBuf,
                         symbol: String) -> PluginRegistrarFun {
         // Make sure the path contains a / or the linker will search for it.
-        let path = os::getcwd().unwrap().join(&path);
+        let path = env::current_dir().unwrap().join(&path);
+        let path = old_path::Path::new(path.to_str().unwrap());
 
         let lib = match DynamicLibrary::open(Some(&path)) {
             Ok(lib) => lib,
diff --git a/src/librustc/session/config.rs b/src/librustc/session/config.rs
index 536caece21f..a4355803f4a 100644
--- a/src/librustc/session/config.rs
+++ b/src/librustc/session/config.rs
@@ -38,6 +38,7 @@ use std::collections::HashMap;
 use std::collections::hash_map::Entry::{Occupied, Vacant};
 use std::env;
 use std::fmt;
+use std::path::PathBuf;
 
 use llvm;
 
@@ -89,7 +90,7 @@ pub struct Options {
     // this.
     pub search_paths: SearchPaths,
     pub libs: Vec<(String, cstore::NativeLibraryKind)>,
-    pub maybe_sysroot: Option<Path>,
+    pub maybe_sysroot: Option<PathBuf>,
     pub target_triple: String,
     // User-specified cfg meta items. The compiler itself will add additional
     // items to the crate config, and during parsing the entire crate config
@@ -103,7 +104,7 @@ pub struct Options {
     pub no_analysis: bool,
     pub debugging_opts: DebuggingOptions,
     /// Whether to write dependency files. It's (enabled, optional filename).
-    pub write_dependency_info: (bool, Option<Path>),
+    pub write_dependency_info: (bool, Option<PathBuf>),
     pub prints: Vec<PrintRequest>,
     pub cg: CodegenOptions,
     pub color: ColorConfig,
@@ -142,7 +143,7 @@ pub enum PrintRequest {
 
 pub enum Input {
     /// Load source from file
-    File(Path),
+    File(PathBuf),
     /// The string is the source
     Str(String)
 }
@@ -150,7 +151,8 @@ pub enum Input {
 impl Input {
     pub fn filestem(&self) -> String {
         match *self {
-            Input::File(ref ifile) => ifile.filestem_str().unwrap().to_string(),
+            Input::File(ref ifile) => ifile.file_stem().unwrap()
+                                           .to_str().unwrap().to_string(),
             Input::Str(_) => "rust_out".to_string(),
         }
     }
@@ -158,14 +160,14 @@ impl Input {
 
 #[derive(Clone)]
 pub struct OutputFilenames {
-    pub out_directory: Path,
+    pub out_directory: PathBuf,
     pub out_filestem: String,
-    pub single_output_file: Option<Path>,
+    pub single_output_file: Option<PathBuf>,
     pub extra: String,
 }
 
 impl OutputFilenames {
-    pub fn path(&self, flavor: OutputType) -> Path {
+    pub fn path(&self, flavor: OutputType) -> PathBuf {
         match self.single_output_file {
             Some(ref path) => return path.clone(),
             None => {}
@@ -173,8 +175,8 @@ impl OutputFilenames {
         self.temp_path(flavor)
     }
 
-    pub fn temp_path(&self, flavor: OutputType) -> Path {
-        let base = self.out_directory.join(self.filestem());
+    pub fn temp_path(&self, flavor: OutputType) -> PathBuf {
+        let base = self.out_directory.join(&self.filestem());
         match flavor {
             OutputTypeBitcode => base.with_extension("bc"),
             OutputTypeAssembly => base.with_extension("s"),
@@ -185,8 +187,8 @@ impl OutputFilenames {
         }
     }
 
-    pub fn with_extension(&self, extension: &str) -> Path {
-        self.out_directory.join(self.filestem()).with_extension(extension)
+    pub fn with_extension(&self, extension: &str) -> PathBuf {
+        self.out_directory.join(&self.filestem()).with_extension(extension)
     }
 
     pub fn filestem(&self) -> String {
@@ -897,7 +899,7 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
 
     let cg = build_codegen_options(matches);
 
-    let sysroot_opt = matches.opt_str("sysroot").map(|m| Path::new(m));
+    let sysroot_opt = matches.opt_str("sysroot").map(|m| PathBuf::new(&m));
     let target = matches.opt_str("target").unwrap_or(
         host_triple().to_string());
     let opt_level = {
diff --git a/src/librustc/session/mod.rs b/src/librustc/session/mod.rs
index 67c39bcca81..a478cb79796 100644
--- a/src/librustc/session/mod.rs
+++ b/src/librustc/session/mod.rs
@@ -26,8 +26,9 @@ use syntax::{ast, codemap};
 
 use rustc_back::target::Target;
 
+use std::path::{Path, PathBuf};
 use std::cell::{Cell, RefCell};
-use std::os;
+use std::env;
 
 pub mod config;
 pub mod search_paths;
@@ -44,11 +45,11 @@ pub struct Session {
     pub entry_fn: RefCell<Option<(NodeId, codemap::Span)>>,
     pub entry_type: Cell<Option<config::EntryFnType>>,
     pub plugin_registrar_fn: Cell<Option<ast::NodeId>>,
-    pub default_sysroot: Option<Path>,
+    pub default_sysroot: Option<PathBuf>,
     // The name of the root source file of the crate, in the local file system. The path is always
     // expected to be absolute. `None` means that there is no source file.
-    pub local_crate_source_file: Option<Path>,
-    pub working_dir: Path,
+    pub local_crate_source_file: Option<PathBuf>,
+    pub working_dir: PathBuf,
     pub lint_store: RefCell<lint::LintStore>,
     pub lints: RefCell<NodeMap<Vec<(lint::LintId, codemap::Span, String)>>>,
     pub crate_types: RefCell<Vec<config::CrateType>>,
@@ -310,7 +311,7 @@ fn split_msg_into_multilines(msg: &str) -> Option<String> {
 }
 
 pub fn build_session(sopts: config::Options,
-                     local_crate_source_file: Option<Path>,
+                     local_crate_source_file: Option<PathBuf>,
                      registry: diagnostics::registry::Registry)
                      -> Session {
     // FIXME: This is not general enough to make the warning lint completely override
@@ -333,7 +334,7 @@ pub fn build_session(sopts: config::Options,
 }
 
 pub fn build_session_(sopts: config::Options,
-                      local_crate_source_file: Option<Path>,
+                      local_crate_source_file: Option<PathBuf>,
                       span_diagnostic: diagnostic::SpanHandler)
                       -> Session {
     let host = match Target::search(config::host_triple()) {
@@ -355,7 +356,7 @@ pub fn build_session_(sopts: config::Options,
         if path.is_absolute() {
             path.clone()
         } else {
-            os::getcwd().unwrap().join(&path)
+            env::current_dir().unwrap().join(&path)
         }
     );
 
@@ -378,7 +379,7 @@ pub fn build_session_(sopts: config::Options,
         plugin_registrar_fn: Cell::new(None),
         default_sysroot: default_sysroot,
         local_crate_source_file: local_crate_source_file,
-        working_dir: os::getcwd().unwrap(),
+        working_dir: env::current_dir().unwrap(),
         lint_store: RefCell::new(lint::LintStore::new()),
         lints: RefCell::new(NodeMap()),
         crate_types: RefCell::new(Vec::new()),
diff --git a/src/librustc/session/search_paths.rs b/src/librustc/session/search_paths.rs
index c314a999f24..f85fb303910 100644
--- a/src/librustc/session/search_paths.rs
+++ b/src/librustc/session/search_paths.rs
@@ -9,15 +9,16 @@
 // except according to those terms.
 
 use std::slice;
+use std::path::{Path, PathBuf};
 
 #[derive(Clone, Debug)]
 pub struct SearchPaths {
-    paths: Vec<(PathKind, Path)>,
+    paths: Vec<(PathKind, PathBuf)>,
 }
 
 pub struct Iter<'a> {
     kind: PathKind,
-    iter: slice::Iter<'a, (PathKind, Path)>,
+    iter: slice::Iter<'a, (PathKind, PathBuf)>,
 }
 
 #[derive(Eq, PartialEq, Clone, Copy, Debug)]
@@ -49,7 +50,7 @@ impl SearchPaths {
         } else {
             (PathKind::All, path)
         };
-        self.paths.push((kind, Path::new(path)));
+        self.paths.push((kind, PathBuf::new(path)));
     }
 
     pub fn iter(&self, kind: PathKind) -> Iter {
diff --git a/src/librustc/util/common.rs b/src/librustc/util/common.rs
index ca740f53782..0b32f7f69eb 100644
--- a/src/librustc/util/common.rs
+++ b/src/librustc/util/common.rs
@@ -12,11 +12,13 @@
 
 use std::cell::{RefCell, Cell};
 use std::collections::HashMap;
+use std::collections::hash_state::HashState;
+use std::ffi::CString;
 use std::fmt::Debug;
 use std::hash::Hash;
 use std::iter::repeat;
+use std::path::Path;
 use std::time::Duration;
-use std::collections::hash_state::HashState;
 
 use syntax::ast;
 use syntax::visit;
@@ -222,3 +224,14 @@ pub fn memoized<T, U, S, F>(cache: &RefCell<HashMap<T, U, S>>, arg: T, f: F) ->
         }
     }
 }
+
+#[cfg(unix)]
+pub fn path2cstr(p: &Path) -> CString {
+    use std::os::unix::prelude::*;
+    use std::ffi::AsOsStr;
+    CString::new(p.as_os_str().as_bytes()).unwrap()
+}
+#[cfg(windows)]
+pub fn path2cstr(p: &Path) -> CString {
+    CString::new(p.to_str().unwrap()).unwrap()
+}
diff --git a/src/librustc_back/archive.rs b/src/librustc_back/archive.rs
index 97b1a8aaaba..a6994387f8d 100644
--- a/src/librustc_back/archive.rs
+++ b/src/librustc_back/archive.rs
@@ -10,11 +10,12 @@
 
 //! A helper class for dealing with static archives
 
-use std::old_io::fs::PathExtensions;
-use std::old_io::process::{Command, ProcessOutput};
-use std::old_io::{fs, TempDir};
-use std::old_io;
-use std::os;
+use std::env;
+use std::fs::{self, TempDir};
+use std::io::prelude::*;
+use std::io;
+use std::path::{Path, PathBuf};
+use std::process::{Command, Output, Stdio};
 use std::str;
 use syntax::diagnostic::Handler as ErrorHandler;
 
@@ -22,8 +23,8 @@ pub const METADATA_FILENAME: &'static str = "rust.metadata.bin";
 
 pub struct ArchiveConfig<'a> {
     pub handler: &'a ErrorHandler,
-    pub dst: Path,
-    pub lib_search_paths: Vec<Path>,
+    pub dst: PathBuf,
+    pub lib_search_paths: Vec<PathBuf>,
     pub slib_prefix: String,
     pub slib_suffix: String,
     pub maybe_ar_prog: Option<String>
@@ -31,8 +32,8 @@ pub struct ArchiveConfig<'a> {
 
 pub struct Archive<'a> {
     handler: &'a ErrorHandler,
-    dst: Path,
-    lib_search_paths: Vec<Path>,
+    dst: PathBuf,
+    lib_search_paths: Vec<PathBuf>,
     slib_prefix: String,
     slib_suffix: String,
     maybe_ar_prog: Option<String>
@@ -45,25 +46,25 @@ pub struct ArchiveBuilder<'a> {
     archive: Archive<'a>,
     work_dir: TempDir,
     /// Filename of each member that should be added to the archive.
-    members: Vec<Path>,
+    members: Vec<PathBuf>,
     should_update_symbols: bool,
 }
 
 fn run_ar(handler: &ErrorHandler, maybe_ar_prog: &Option<String>,
           args: &str, cwd: Option<&Path>,
-          paths: &[&Path]) -> ProcessOutput {
+          paths: &[&Path]) -> Output {
     let ar = match *maybe_ar_prog {
         Some(ref ar) => &ar[..],
         None => "ar"
     };
     let mut cmd = Command::new(ar);
 
-    cmd.arg(args).args(paths);
+    cmd.arg(args).args(paths).stdout(Stdio::piped()).stderr(Stdio::piped());
     debug!("{:?}", cmd);
 
     match cwd {
         Some(p) => {
-            cmd.cwd(p);
+            cmd.current_dir(p);
             debug!("inside {:?}", p.display());
         }
         None => {}
@@ -75,9 +76,9 @@ fn run_ar(handler: &ErrorHandler, maybe_ar_prog: &Option<String>,
             if !o.status.success() {
                 handler.err(&format!("{:?} failed with: {}", cmd, o.status));
                 handler.note(&format!("stdout ---\n{}",
-                                  str::from_utf8(&o.output).unwrap()));
+                                  str::from_utf8(&o.stdout).unwrap()));
                 handler.note(&format!("stderr ---\n{}",
-                                  str::from_utf8(&o.error).unwrap())
+                                  str::from_utf8(&o.stderr).unwrap())
                              );
                 handler.abort_if_errors();
             }
@@ -93,14 +94,15 @@ fn run_ar(handler: &ErrorHandler, maybe_ar_prog: &Option<String>,
 }
 
 pub fn find_library(name: &str, osprefix: &str, ossuffix: &str,
-                    search_paths: &[Path], handler: &ErrorHandler) -> Path {
+                    search_paths: &[PathBuf],
+                    handler: &ErrorHandler) -> PathBuf {
     // On Windows, static libraries sometimes show up as libfoo.a and other
     // times show up as foo.lib
     let oslibname = format!("{}{}{}", osprefix, name, ossuffix);
     let unixlibname = format!("lib{}.a", name);
 
     for path in search_paths {
-        debug!("looking for {} inside {:?}", name, path.display());
+        debug!("looking for {} inside {:?}", name, path);
         let test = path.join(&oslibname[..]);
         if test.exists() { return test }
         if oslibname != unixlibname {
@@ -142,7 +144,7 @@ impl<'a> Archive<'a> {
     /// Lists all files in an archive
     pub fn files(&self) -> Vec<String> {
         let output = run_ar(self.handler, &self.maybe_ar_prog, "t", None, &[&self.dst]);
-        let output = str::from_utf8(&output.output).unwrap();
+        let output = str::from_utf8(&output.stdout).unwrap();
         // use lines_any because windows delimits output with `\r\n` instead of
         // just `\n`
         output.lines_any().map(|s| s.to_string()).collect()
@@ -172,7 +174,7 @@ impl<'a> ArchiveBuilder<'a> {
 
     /// Adds all of the contents of a native library to this archive. This will
     /// search in the relevant locations for a library named `name`.
-    pub fn add_native_library(&mut self, name: &str) -> old_io::IoResult<()> {
+    pub fn add_native_library(&mut self, name: &str) -> io::Result<()> {
         let location = find_library(name,
                                     &self.archive.slib_prefix,
                                     &self.archive.slib_suffix,
@@ -187,7 +189,7 @@ impl<'a> ArchiveBuilder<'a> {
     /// This ignores adding the bytecode from the rlib, and if LTO is enabled
     /// then the object file also isn't added.
     pub fn add_rlib(&mut self, rlib: &Path, name: &str,
-                    lto: bool) -> old_io::IoResult<()> {
+                    lto: bool) -> io::Result<()> {
         // Ignoring obj file starting with the crate name
         // as simple comparison is not enough - there
         // might be also an extra name suffix
@@ -205,11 +207,11 @@ impl<'a> ArchiveBuilder<'a> {
     }
 
     /// Adds an arbitrary file to this archive
-    pub fn add_file(&mut self, file: &Path) -> old_io::IoResult<()> {
-        let filename = Path::new(file.filename().unwrap());
+    pub fn add_file(&mut self, file: &Path) -> io::Result<()> {
+        let filename = Path::new(file.file_name().unwrap());
         let new_file = self.work_dir.path().join(&filename);
         try!(fs::copy(file, &new_file));
-        self.members.push(filename);
+        self.members.push(filename.to_path_buf());
         Ok(())
     }
 
@@ -224,10 +226,10 @@ impl<'a> ArchiveBuilder<'a> {
     pub fn build(self) -> Archive<'a> {
         // Get an absolute path to the destination, so `ar` will work even
         // though we run it from `self.work_dir`.
-        let abs_dst = os::getcwd().unwrap().join(&self.archive.dst);
+        let abs_dst = env::current_dir().unwrap().join(&self.archive.dst);
         assert!(!abs_dst.is_relative());
-        let mut args = vec![&abs_dst];
-        let mut total_len = abs_dst.as_vec().len();
+        let mut args = vec![&*abs_dst];
+        let mut total_len = abs_dst.to_string_lossy().len();
 
         if self.members.is_empty() {
             // OSX `ar` does not allow using `r` with no members, but it does
@@ -245,7 +247,7 @@ impl<'a> ArchiveBuilder<'a> {
         const ARG_LENGTH_LIMIT: uint = 32_000;
 
         for member_name in &self.members {
-            let len = member_name.as_vec().len();
+            let len = member_name.to_string_lossy().len();
 
             // `len + 1` to account for the space that's inserted before each
             // argument.  (Windows passes command-line arguments as a single
@@ -258,7 +260,7 @@ impl<'a> ArchiveBuilder<'a> {
 
                 args.clear();
                 args.push(&abs_dst);
-                total_len = abs_dst.as_vec().len();
+                total_len = abs_dst.to_string_lossy().len();
             }
 
             args.push(member_name);
@@ -275,7 +277,7 @@ impl<'a> ArchiveBuilder<'a> {
     }
 
     fn add_archive<F>(&mut self, archive: &Path, name: &str,
-                      mut skip: F) -> old_io::IoResult<()>
+                      mut skip: F) -> io::Result<()>
         where F: FnMut(&str) -> bool,
     {
         let loc = TempDir::new("rsar").unwrap();
@@ -283,7 +285,7 @@ impl<'a> ArchiveBuilder<'a> {
         // First, extract the contents of the archive to a temporary directory.
         // We don't unpack directly into `self.work_dir` due to the possibility
         // of filename collisions.
-        let archive = os::getcwd().unwrap().join(archive);
+        let archive = env::current_dir().unwrap().join(archive);
         run_ar(self.archive.handler, &self.archive.maybe_ar_prog,
                "x", Some(loc.path()), &[&archive]);
 
@@ -296,9 +298,10 @@ impl<'a> ArchiveBuilder<'a> {
         // We skip any files explicitly desired for skipping, and we also skip
         // all SYMDEF files as these are just magical placeholders which get
         // re-created when we make a new archive anyway.
-        let files = try!(fs::readdir(loc.path()));
-        for file in &files {
-            let filename = file.filename_str().unwrap();
+        let files = try!(fs::read_dir(loc.path()));
+        for file in files {
+            let file = try!(file).path();
+            let filename = file.file_name().unwrap().to_str().unwrap();
             if skip(filename) { continue }
             if filename.contains(".SYMDEF") { continue }
 
@@ -313,8 +316,8 @@ impl<'a> ArchiveBuilder<'a> {
                 filename
             };
             let new_filename = self.work_dir.path().join(&filename[..]);
-            try!(fs::rename(file, &new_filename));
-            self.members.push(Path::new(filename));
+            try!(fs::rename(&file, &new_filename));
+            self.members.push(PathBuf::new(&filename));
         }
         Ok(())
     }
diff --git a/src/librustc_back/fs.rs b/src/librustc_back/fs.rs
index 56d71820176..c00c33d4c2f 100644
--- a/src/librustc_back/fs.rs
+++ b/src/librustc_back/fs.rs
@@ -8,14 +8,29 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::old_io;
+use std::io;
 use std::old_io::fs;
+use std::old_io;
+use std::old_path;
 use std::os;
+use std::path::{Path, PathBuf};
 
 /// Returns an absolute path in the filesystem that `path` points to. The
 /// returned path does not contain any symlinks in its hierarchy.
-pub fn realpath(original: &Path) -> old_io::IoResult<Path> {
-    const MAX_LINKS_FOLLOWED: uint = 256;
+#[allow(deprecated)] // readlink is deprecated
+pub fn realpath(original: &Path) -> io::Result<PathBuf> {
+    let old = old_path::Path::new(original.to_str().unwrap());
+    match old_realpath(&old) {
+        Ok(p) => Ok(PathBuf::new(p.as_str().unwrap())),
+        Err(e) => Err(io::Error::new(io::ErrorKind::Other,
+                                     "realpath error",
+                                     Some(e.to_string())))
+    }
+}
+
+#[allow(deprecated)]
+fn old_realpath(original: &old_path::Path) -> old_io::IoResult<old_path::Path> {
+    const MAX_LINKS_FOLLOWED: usize = 256;
     let original = try!(os::getcwd()).join(original);
 
     // Right now lstat on windows doesn't work quite well
@@ -55,7 +70,7 @@ pub fn realpath(original: &Path) -> old_io::IoResult<Path> {
 mod test {
     use std::old_io;
     use std::old_io::fs::{File, symlink, mkdir, mkdir_recursive};
-    use super::realpath;
+    use super::old_realpath as realpath;
     use std::old_io::TempDir;
 
     #[test]
diff --git a/src/librustc_back/lib.rs b/src/librustc_back/lib.rs
index 9005c666afb..2b028a5c626 100644
--- a/src/librustc_back/lib.rs
+++ b/src/librustc_back/lib.rs
@@ -33,14 +33,18 @@
 #![feature(box_syntax)]
 #![feature(collections)]
 #![feature(core)]
+#![feature(old_fs)]
+#![feature(fs)]
 #![feature(hash)]
 #![feature(int_uint)]
+#![feature(io)]
 #![feature(old_io)]
-#![feature(os)]
 #![feature(old_path)]
+#![feature(os)]
+#![feature(path)]
 #![feature(rustc_private)]
 #![feature(staged_api)]
-#![feature(path)]
+#![feature(tempdir)]
 
 extern crate syntax;
 extern crate serialize;
diff --git a/src/librustc_back/rpath.rs b/src/librustc_back/rpath.rs
index 943ff52925a..4f9f1447d8a 100644
--- a/src/librustc_back/rpath.rs
+++ b/src/librustc_back/rpath.rs
@@ -10,26 +10,20 @@
 
 use std::collections::HashSet;
 use std::env;
-use std::old_io::IoError;
-use std::os;
+use std::io;
+use std::path::{Path, PathBuf};
 use syntax::ast;
 
-pub struct RPathConfig<F, G> where
-    F: FnOnce() -> Path,
-    G: FnMut(&Path) -> Result<Path, IoError>,
-{
-    pub used_crates: Vec<(ast::CrateNum, Option<Path>)>,
-    pub out_filename: Path,
+pub struct RPathConfig<'a> {
+    pub used_crates: Vec<(ast::CrateNum, Option<PathBuf>)>,
+    pub out_filename: PathBuf,
     pub is_like_osx: bool,
     pub has_rpath: bool,
-    pub get_install_prefix_lib_path: F,
-    pub realpath: G,
+    pub get_install_prefix_lib_path: &'a mut FnMut() -> PathBuf,
+    pub realpath: &'a mut FnMut(&Path) -> io::Result<PathBuf>,
 }
 
-pub fn get_rpath_flags<F, G>(config: RPathConfig<F, G>) -> Vec<String> where
-    F: FnOnce() -> Path,
-    G: FnMut(&Path) -> Result<Path, IoError>,
-{
+pub fn get_rpath_flags(config: &mut RPathConfig) -> Vec<String> {
     // No rpath on windows
     if !config.has_rpath {
         return Vec::new();
@@ -54,10 +48,7 @@ fn rpaths_to_flags(rpaths: &[String]) -> Vec<String> {
     return ret;
 }
 
-fn get_rpaths<F, G>(mut config: RPathConfig<F, G>, libs: &[Path]) -> Vec<String> where
-    F: FnOnce() -> Path,
-    G: FnMut(&Path) -> Result<Path, IoError>,
-{
+fn get_rpaths(config: &mut RPathConfig, libs: &[PathBuf]) -> Vec<String> {
     debug!("output: {:?}", config.out_filename.display());
     debug!("libs:");
     for libpath in libs {
@@ -67,7 +58,7 @@ fn get_rpaths<F, G>(mut config: RPathConfig<F, G>, libs: &[Path]) -> Vec<String>
     // Use relative paths to the libraries. Binaries can be moved
     // as long as they maintain the relative relationship to the
     // crates they depend on.
-    let rel_rpaths = get_rpaths_relative_to_output(&mut config, libs);
+    let rel_rpaths = get_rpaths_relative_to_output(config, libs);
 
     // And a final backup rpath to the global library location.
     let fallback_rpaths = vec!(get_install_prefix_rpath(config));
@@ -90,18 +81,12 @@ fn get_rpaths<F, G>(mut config: RPathConfig<F, G>, libs: &[Path]) -> Vec<String>
     return rpaths;
 }
 
-fn get_rpaths_relative_to_output<F, G>(config: &mut RPathConfig<F, G>,
-                                       libs: &[Path]) -> Vec<String> where
-    F: FnOnce() -> Path,
-    G: FnMut(&Path) -> Result<Path, IoError>,
-{
+fn get_rpaths_relative_to_output(config: &mut RPathConfig,
+                                 libs: &[PathBuf]) -> Vec<String> {
     libs.iter().map(|a| get_rpath_relative_to_output(config, a)).collect()
 }
 
-fn get_rpath_relative_to_output<F, G>(config: &mut RPathConfig<F, G>, lib: &Path) -> String where
-    F: FnOnce() -> Path,
-    G: FnMut(&Path) -> Result<Path, IoError>,
-{
+fn get_rpath_relative_to_output(config: &mut RPathConfig, lib: &Path) -> String {
     // Mac doesn't appear to support $ORIGIN
     let prefix = if config.is_like_osx {
         "@loader_path"
@@ -109,23 +94,36 @@ fn get_rpath_relative_to_output<F, G>(config: &mut RPathConfig<F, G>, lib: &Path
         "$ORIGIN"
     };
 
-    let cwd = os::getcwd().unwrap();
+    let cwd = env::current_dir().unwrap();
     let mut lib = (config.realpath)(&cwd.join(lib)).unwrap();
     lib.pop();
     let mut output = (config.realpath)(&cwd.join(&config.out_filename)).unwrap();
     output.pop();
-    let relative = lib.path_relative_from(&output);
-    let relative = relative.expect("could not create rpath relative to output");
+    let relative = relativize(&lib, &output);
     // FIXME (#9639): This needs to handle non-utf8 paths
-    format!("{}/{}",
-            prefix,
-            relative.as_str().expect("non-utf8 component in path"))
+    format!("{}/{}", prefix,
+            relative.to_str().expect("non-utf8 component in path"))
 }
 
-fn get_install_prefix_rpath<F, G>(config: RPathConfig<F, G>) -> String where
-    F: FnOnce() -> Path,
-    G: FnMut(&Path) -> Result<Path, IoError>,
-{
+fn relativize(path: &Path, rel: &Path) -> PathBuf {
+    let mut res = PathBuf::new("");
+    let mut cur = rel;
+    while !path.starts_with(cur) {
+        res.push("..");
+        match cur.parent() {
+            Some(p) => cur = p,
+            None => panic!("can't create relative paths across filesystems"),
+        }
+    }
+    match path.relative_from(cur) {
+        Some(s) => { res.push(s); res }
+        None => panic!("couldn't create relative path from {:?} to {:?}",
+                       rel, path),
+    }
+
+}
+
+fn get_install_prefix_rpath(config: &mut RPathConfig) -> String {
     let path = (config.get_install_prefix_lib_path)();
     let path = env::current_dir().unwrap().join(&path);
     // FIXME (#9639): This needs to handle non-utf8 paths
@@ -147,6 +145,7 @@ fn minimize_rpaths(rpaths: &[String]) -> Vec<String> {
 mod test {
     use super::{RPathConfig};
     use super::{minimize_rpaths, rpaths_to_flags, get_rpath_relative_to_output};
+    use std::path::{Path, PathBuf};
 
     #[test]
     fn test_rpaths_to_flags() {
@@ -195,50 +194,31 @@ mod test {
     }
 
     #[test]
-    #[cfg(any(target_os = "linux", target_os = "android"))]
     fn test_rpath_relative() {
-        let config = &mut RPathConfig {
-            used_crates: Vec::new(),
-            out_filename: Path::new("bin/rustc"),
-            get_install_prefix_lib_path: || panic!(),
-            has_rpath: true,
-            is_like_osx: false,
-            realpath: |p| Ok(p.clone())
-        };
-        let res = get_rpath_relative_to_output(config, &Path::new("lib/libstd.so"));
-        assert_eq!(res, "$ORIGIN/../lib");
-    }
-
-    #[test]
-    #[cfg(any(target_os = "freebsd",
-              target_os = "dragonfly",
-              target_os = "bitrig",
-              target_os = "openbsd"))]
-    fn test_rpath_relative() {
-        let config = &mut RPathConfig {
-            used_crates: Vec::new(),
-            has_rpath: true,
-            is_like_osx: false,
-            out_filename: Path::new("bin/rustc"),
-            get_install_prefix_lib_path: || panic!(),
-            realpath: |p| Ok(p.clone())
-        };
-        let res = get_rpath_relative_to_output(config, &Path::new("lib/libstd.so"));
-        assert_eq!(res, "$ORIGIN/../lib");
-    }
-
-    #[test]
-    #[cfg(target_os = "macos")]
-    fn test_rpath_relative() {
-        let config = &mut RPathConfig {
-            used_crates: Vec::new(),
-            has_rpath: true,
-            is_like_osx: true,
-            out_filename: Path::new("bin/rustc"),
-            get_install_prefix_lib_path: || panic!(),
-            realpath: |p| Ok(p.clone())
-        };
-        let res = get_rpath_relative_to_output(config, &Path::new("lib/libstd.so"));
-        assert_eq!(res, "@loader_path/../lib");
+        if cfg!(target_os = "macos") {
+            let config = &mut RPathConfig {
+                used_crates: Vec::new(),
+                has_rpath: true,
+                is_like_osx: true,
+                out_filename: PathBuf::new("bin/rustc"),
+                get_install_prefix_lib_path: &mut || panic!(),
+                realpath: &mut |p| Ok(p.to_path_buf()),
+            };
+            let res = get_rpath_relative_to_output(config,
+                                                   Path::new("lib/libstd.so"));
+            assert_eq!(res, "@loader_path/../lib");
+        } else {
+            let config = &mut RPathConfig {
+                used_crates: Vec::new(),
+                out_filename: PathBuf::new("bin/rustc"),
+                get_install_prefix_lib_path: &mut || panic!(),
+                has_rpath: true,
+                is_like_osx: false,
+                realpath: &mut |p| Ok(p.to_path_buf()),
+            };
+            let res = get_rpath_relative_to_output(config,
+                                                   Path::new("lib/libstd.so"));
+            assert_eq!(res, "$ORIGIN/../lib");
+        }
     }
 }
diff --git a/src/librustc_back/target/mod.rs b/src/librustc_back/target/mod.rs
index d09a7c355d3..4663901a7b4 100644
--- a/src/librustc_back/target/mod.rs
+++ b/src/librustc_back/target/mod.rs
@@ -48,7 +48,7 @@
 use serialize::json::Json;
 use syntax::{diagnostic, abi};
 use std::default::Default;
-use std::old_io::fs::PathExtensions;
+use std::io::prelude::*;
 
 mod windows_base;
 mod linux_base;
@@ -302,23 +302,26 @@ impl Target {
         base
     }
 
-    /// Search RUST_TARGET_PATH for a JSON file specifying the given target triple. Note that it
-    /// could also just be a bare filename already, so also check for that. If one of the hardcoded
-    /// targets we know about, just return it directly.
+    /// Search RUST_TARGET_PATH for a JSON file specifying the given target
+    /// triple. Note that it could also just be a bare filename already, so also
+    /// check for that. If one of the hardcoded targets we know about, just
+    /// return it directly.
     ///
-    /// The error string could come from any of the APIs called, including filesystem access and
-    /// JSON decoding.
+    /// The error string could come from any of the APIs called, including
+    /// filesystem access and JSON decoding.
     pub fn search(target: &str) -> Result<Target, String> {
         use std::env;
-        use std::os;
         use std::ffi::OsString;
-        use std::old_io::File;
-        use std::old_path::Path;
+        use std::fs::File;
+        use std::path::{Path, PathBuf};
         use serialize::json;
 
         fn load_file(path: &Path) -> Result<Target, String> {
-            let mut f = try!(File::open(path).map_err(|e| format!("{:?}", e)));
-            let obj = try!(json::from_reader(&mut f).map_err(|e| format!("{:?}", e)));
+            let mut f = try!(File::open(path).map_err(|e| e.to_string()));
+            let mut contents = Vec::new();
+            try!(f.read_to_end(&mut contents).map_err(|e| e.to_string()));
+            let obj = try!(json::from_reader(&mut &contents[..])
+                                .map_err(|e| e.to_string()));
             Ok(Target::from_json(obj))
         }
 
@@ -390,15 +393,16 @@ impl Target {
         let path = {
             let mut target = target.to_string();
             target.push_str(".json");
-            Path::new(target)
+            PathBuf::new(&target)
         };
 
-        let target_path = env::var_os("RUST_TARGET_PATH").unwrap_or(OsString::from_str(""));
+        let target_path = env::var_os("RUST_TARGET_PATH")
+                              .unwrap_or(OsString::from_str(""));
 
         // FIXME 16351: add a sane default search path?
 
-        for dir in os::split_paths(target_path.to_str().unwrap()).iter() {
-            let p =  dir.join(path.clone());
+        for dir in env::split_paths(&target_path) {
+            let p =  dir.join(&path);
             if p.is_file() {
                 return load_file(&p);
             }
diff --git a/src/librustc_driver/driver.rs b/src/librustc_driver/driver.rs
index 425ec7ec452..73682faf1a7 100644
--- a/src/librustc_driver/driver.rs
+++ b/src/librustc_driver/driver.rs
@@ -32,10 +32,10 @@ use super::Compilation;
 use serialize::json;
 
 use std::env;
-use std::os;
 use std::ffi::OsString;
-use std::old_io::fs;
-use std::old_io;
+use std::fs;
+use std::io::{self, Write};
+use std::path::{Path, PathBuf};
 use syntax::ast;
 use syntax::ast_map;
 use syntax::attr;
@@ -48,8 +48,8 @@ use syntax;
 pub fn compile_input(sess: Session,
                      cfg: ast::CrateConfig,
                      input: &Input,
-                     outdir: &Option<Path>,
-                     output: &Option<Path>,
+                     outdir: &Option<PathBuf>,
+                     output: &Option<PathBuf>,
                      addl_plugins: Option<Vec<String>>,
                      control: CompileController) {
     macro_rules! controller_entry_point{($point: ident, $make_state: expr) => ({
@@ -166,7 +166,7 @@ pub fn anon_src() -> String {
 pub fn source_name(input: &Input) -> String {
     match *input {
         // FIXME (#9639): This needs to handle non-utf8 paths
-        Input::File(ref ifile) => ifile.as_str().unwrap().to_string(),
+        Input::File(ref ifile) => ifile.to_str().unwrap().to_string(),
         Input::Str(_) => anon_src()
     }
 }
@@ -243,12 +243,12 @@ pub struct CompileState<'a, 'ast: 'a, 'tcx: 'a> {
 impl<'a, 'ast, 'tcx> CompileState<'a, 'ast, 'tcx> {
     fn empty(input: &'a Input,
              session: &'a Session,
-             out_dir: &'a Option<Path>)
+             out_dir: &'a Option<PathBuf>)
              -> CompileState<'a, 'ast, 'tcx> {
         CompileState {
             input: input,
             session: session,
-            out_dir: out_dir.as_ref(),
+            out_dir: out_dir.as_ref().map(|s| &**s),
             cfg: None,
             krate: None,
             crate_name: None,
@@ -263,7 +263,7 @@ impl<'a, 'ast, 'tcx> CompileState<'a, 'ast, 'tcx> {
 
     fn state_after_parse(input: &'a Input,
                          session: &'a Session,
-                         out_dir: &'a Option<Path>,
+                         out_dir: &'a Option<PathBuf>,
                          krate: &'a ast::Crate)
                          -> CompileState<'a, 'ast, 'tcx> {
         CompileState {
@@ -274,7 +274,7 @@ impl<'a, 'ast, 'tcx> CompileState<'a, 'ast, 'tcx> {
 
     fn state_after_expand(input: &'a Input,
                           session: &'a Session,
-                          out_dir: &'a Option<Path>,
+                          out_dir: &'a Option<PathBuf>,
                           expanded_crate: &'a ast::Crate,
                           crate_name: &'a str)
                           -> CompileState<'a, 'ast, 'tcx> {
@@ -287,7 +287,7 @@ impl<'a, 'ast, 'tcx> CompileState<'a, 'ast, 'tcx> {
 
     fn state_after_write_deps(input: &'a Input,
                               session: &'a Session,
-                              out_dir: &'a Option<Path>,
+                              out_dir: &'a Option<PathBuf>,
                               ast_map: &'a ast_map::Map<'ast>,
                               expanded_crate: &'a ast::Crate,
                               crate_name: &'a str)
@@ -302,7 +302,7 @@ impl<'a, 'ast, 'tcx> CompileState<'a, 'ast, 'tcx> {
 
     fn state_after_analysis(input: &'a Input,
                             session: &'a Session,
-                            out_dir: &'a Option<Path>,
+                            out_dir: &'a Option<PathBuf>,
                             expanded_crate: &'a ast::Crate,
                             analysis: &'a ty::CrateAnalysis<'tcx>,
                             tcx: &'a ty::ctxt<'tcx>)
@@ -318,7 +318,7 @@ impl<'a, 'ast, 'tcx> CompileState<'a, 'ast, 'tcx> {
 
     fn state_after_llvm(input: &'a Input,
                         session: &'a Session,
-                        out_dir: &'a Option<Path>,
+                        out_dir: &'a Option<PathBuf>,
                         trans: &'a trans::CrateTranslation)
                         -> CompileState<'a, 'ast, 'tcx> {
         CompileState {
@@ -472,7 +472,7 @@ pub fn phase_2_configure_and_expand(sess: &Session,
             if cfg!(windows) {
                 _old_path = env::var_os("PATH").unwrap_or(_old_path);
                 let mut new_path = sess.host_filesearch(PathKind::All).get_dylib_search_paths();
-                new_path.extend(os::split_paths(_old_path.to_str().unwrap()).into_iter());
+                new_path.extend(env::split_paths(&_old_path));
                 env::set_var("PATH", &env::join_paths(new_path.iter()).unwrap());
             }
             let features = sess.features.borrow();
@@ -717,7 +717,7 @@ pub fn phase_5_run_llvm_passes(sess: &Session,
 
         // Remove assembly source, unless --save-temps was specified
         if !sess.opts.cg.save_temps {
-            fs::unlink(&outputs.temp_path(config::OutputTypeAssembly)).unwrap();
+            fs::remove_file(&outputs.temp_path(config::OutputTypeAssembly)).unwrap();
         }
     } else {
         time(sess.time_passes(), "LLVM passes", (), |_|
@@ -737,7 +737,7 @@ pub fn phase_6_link_output(sess: &Session,
                            outputs: &OutputFilenames) {
     let old_path = env::var_os("PATH").unwrap_or(OsString::from_str(""));
     let mut new_path = sess.host_filesearch(PathKind::All).get_tools_search_paths();
-    new_path.extend(os::split_paths(old_path.to_str().unwrap()).into_iter());
+    new_path.extend(env::split_paths(&old_path));
     env::set_var("PATH", &env::join_paths(new_path.iter()).unwrap());
 
     time(sess.time_passes(), "linking", (), |_|
@@ -793,17 +793,17 @@ fn write_out_deps(sess: &Session,
         _ => return,
     };
 
-    let result = (|| -> old_io::IoResult<()> {
+    let result = (|| -> io::Result<()> {
         // Build a list of files used to compile the output and
         // write Makefile-compatible dependency rules
         let files: Vec<String> = sess.codemap().files.borrow()
                                    .iter().filter(|fmap| fmap.is_real_file())
                                    .map(|fmap| escape_dep_filename(&fmap.name))
                                    .collect();
-        let mut file = try!(old_io::File::create(&deps_filename));
+        let mut file = try!(fs::File::create(&deps_filename));
         for path in &out_filenames {
-            try!(write!(&mut file as &mut Writer,
-                          "{}: {}\n\n", path.display(), files.connect(" ")));
+            try!(write!(&mut file,
+                        "{}: {}\n\n", path.display(), files.connect(" ")));
         }
         Ok(())
     })();
@@ -896,8 +896,8 @@ pub fn collect_crate_metadata(session: &Session,
 }
 
 pub fn build_output_filenames(input: &Input,
-                              odir: &Option<Path>,
-                              ofile: &Option<Path>,
+                              odir: &Option<PathBuf>,
+                              ofile: &Option<PathBuf>,
                               attrs: &[ast::Attribute],
                               sess: &Session)
                            -> OutputFilenames {
@@ -908,7 +908,7 @@ pub fn build_output_filenames(input: &Input,
             // We want to toss everything after the final '.'
             let dirpath = match *odir {
                 Some(ref d) => d.clone(),
-                None => Path::new(".")
+                None => PathBuf::new(".")
             };
 
             // If a crate name is present, we use it as the link name
@@ -936,8 +936,9 @@ pub fn build_output_filenames(input: &Input,
                 sess.warn("ignoring --out-dir flag due to -o flag.");
             }
             OutputFilenames {
-                out_directory: out_file.dir_path(),
-                out_filestem: out_file.filestem_str().unwrap().to_string(),
+                out_directory: out_file.parent().unwrap().to_path_buf(),
+                out_filestem: out_file.file_stem().unwrap()
+                                      .to_str().unwrap().to_string(),
                 single_output_file: ofile,
                 extra: sess.opts.cg.extra_filename.clone(),
             }
diff --git a/src/librustc_driver/lib.rs b/src/librustc_driver/lib.rs
index 15fae351ddb..aa8b7c7785d 100644
--- a/src/librustc_driver/lib.rs
+++ b/src/librustc_driver/lib.rs
@@ -30,7 +30,6 @@
 #![feature(old_io)]
 #![feature(libc)]
 #![feature(os)]
-#![feature(old_path)]
 #![feature(quote)]
 #![feature(rustc_diagnostic_macros)]
 #![feature(rustc_private)]
@@ -38,6 +37,9 @@
 #![feature(staged_api)]
 #![feature(unicode)]
 #![feature(exit_status)]
+#![feature(path)]
+#![feature(io)]
+#![feature(fs)]
 
 extern crate arena;
 extern crate flate;
@@ -73,9 +75,10 @@ use rustc::metadata;
 use rustc::util::common::time;
 
 use std::cmp::Ordering::Equal;
-use std::old_io::{self, stdio};
-use std::iter::repeat;
 use std::env;
+use std::iter::repeat;
+use std::old_io::{self, stdio};
+use std::path::PathBuf;
 use std::sync::mpsc::channel;
 use std::thread;
 
@@ -159,14 +162,14 @@ pub fn run_compiler<'a>(args: &[String],
 }
 
 // Extract output directory and file from matches.
-fn make_output(matches: &getopts::Matches) -> (Option<Path>, Option<Path>) {
-    let odir = matches.opt_str("out-dir").map(|o| Path::new(o));
-    let ofile = matches.opt_str("o").map(|o| Path::new(o));
+fn make_output(matches: &getopts::Matches) -> (Option<PathBuf>, Option<PathBuf>) {
+    let odir = matches.opt_str("out-dir").map(|o| PathBuf::new(&o));
+    let ofile = matches.opt_str("o").map(|o| PathBuf::new(&o));
     (odir, ofile)
 }
 
 // Extract input (string or file and optional path) from matches.
-fn make_input(free_matches: &[String]) -> Option<(Input, Option<Path>)> {
+fn make_input(free_matches: &[String]) -> Option<(Input, Option<PathBuf>)> {
     if free_matches.len() == 1 {
         let ifile = &free_matches[0][..];
         if ifile == "-" {
@@ -174,7 +177,7 @@ fn make_input(free_matches: &[String]) -> Option<(Input, Option<Path>)> {
             let src = String::from_utf8(contents).unwrap();
             Some((Input::Str(src), None))
         } else {
-            Some((Input::File(Path::new(ifile)), Some(Path::new(ifile))))
+            Some((Input::File(PathBuf::new(ifile)), Some(PathBuf::new(ifile))))
         }
     } else {
         None
@@ -215,14 +218,15 @@ pub trait CompilerCalls<'a> {
                      &getopts::Matches,
                      &Session,
                      &Input,
-                     &Option<Path>,
-                     &Option<Path>)
+                     &Option<PathBuf>,
+                     &Option<PathBuf>)
                      -> Compilation;
 
     // Called after we extract the input from the arguments. Gives the implementer
     // an opportunity to change the inputs or to add some custom input handling.
     // The default behaviour is to simply pass through the inputs.
-    fn some_input(&mut self, input: Input, input_path: Option<Path>) -> (Input, Option<Path>) {
+    fn some_input(&mut self, input: Input, input_path: Option<PathBuf>)
+                  -> (Input, Option<PathBuf>) {
         (input, input_path)
     }
 
@@ -234,10 +238,10 @@ pub trait CompilerCalls<'a> {
     fn no_input(&mut self,
                 &getopts::Matches,
                 &config::Options,
-                &Option<Path>,
-                &Option<Path>,
+                &Option<PathBuf>,
+                &Option<PathBuf>,
                 &diagnostics::registry::Registry)
-                -> Option<(Input, Option<Path>)>;
+                -> Option<(Input, Option<PathBuf>)>;
 
     // Parse pretty printing information from the arguments. The implementer can
     // choose to ignore this (the default will return None) which will skip pretty
@@ -293,10 +297,10 @@ impl<'a> CompilerCalls<'a> for RustcDefaultCalls {
     fn no_input(&mut self,
                 matches: &getopts::Matches,
                 sopts: &config::Options,
-                odir: &Option<Path>,
-                ofile: &Option<Path>,
+                odir: &Option<PathBuf>,
+                ofile: &Option<PathBuf>,
                 descriptions: &diagnostics::registry::Registry)
-                -> Option<(Input, Option<Path>)> {
+                -> Option<(Input, Option<PathBuf>)> {
         match matches.free.len() {
             0 => {
                 if sopts.describe_lints {
@@ -346,8 +350,8 @@ impl<'a> CompilerCalls<'a> for RustcDefaultCalls {
                      matches: &getopts::Matches,
                      sess: &Session,
                      input: &Input,
-                     odir: &Option<Path>,
-                     ofile: &Option<Path>)
+                     odir: &Option<PathBuf>,
+                     ofile: &Option<PathBuf>)
                      -> Compilation {
         RustcDefaultCalls::print_crate_info(sess, Some(input), odir, ofile).and_then(
             || RustcDefaultCalls::list_metadata(sess, matches, input))
@@ -400,11 +404,12 @@ impl RustcDefaultCalls {
         if r.contains(&("ls".to_string())) {
             match input {
                 &Input::File(ref ifile) => {
-                    let mut stdout = old_io::stdout();
                     let path = &(*ifile);
+                    let mut v = Vec::new();
                     metadata::loader::list_file_metadata(sess.target.target.options.is_like_osx,
                                                          path,
-                                                         &mut stdout).unwrap();
+                                                         &mut v).unwrap();
+                    println!("{}", String::from_utf8(v).unwrap());
                 }
                 &Input::Str(_) => {
                     early_error("cannot list metadata for stdin");
@@ -419,8 +424,8 @@ impl RustcDefaultCalls {
 
     fn print_crate_info(sess: &Session,
                         input: Option<&Input>,
-                        odir: &Option<Path>,
-                        ofile: &Option<Path>)
+                        odir: &Option<PathBuf>,
+                        ofile: &Option<PathBuf>)
                         -> Compilation {
         if sess.opts.prints.len() == 0 {
             return Compilation::Continue;
@@ -457,7 +462,8 @@ impl RustcDefaultCalls {
                                                              style,
                                                              &id,
                                                              &t_outputs.with_extension(""));
-                        println!("{}", fname.filename_display());
+                        println!("{}", fname.file_name().unwrap()
+                                            .to_string_lossy());
                     }
                 }
             }
diff --git a/src/librustc_driver/pretty.rs b/src/librustc_driver/pretty.rs
index f433e67d878..ffb2a05e437 100644
--- a/src/librustc_driver/pretty.rs
+++ b/src/librustc_driver/pretty.rs
@@ -38,8 +38,11 @@ use syntax::ptr::P;
 
 use graphviz as dot;
 
-use std::old_io::{self, MemReader};
+use std::fs::File;
+use std::io::{self, Write};
+use std::old_io;
 use std::option;
+use std::path::PathBuf;
 use std::str::FromStr;
 
 #[derive(Copy, PartialEq, Debug)]
@@ -208,7 +211,7 @@ impl<'ast> PrinterSupport<'ast> for IdentifiedAnnotation<'ast> {
 impl<'ast> pprust::PpAnn for IdentifiedAnnotation<'ast> {
     fn pre(&self,
            s: &mut pprust::State,
-           node: pprust::AnnNode) -> old_io::IoResult<()> {
+           node: pprust::AnnNode) -> io::Result<()> {
         match node {
             pprust::NodeExpr(_) => s.popen(),
             _ => Ok(())
@@ -216,7 +219,7 @@ impl<'ast> pprust::PpAnn for IdentifiedAnnotation<'ast> {
     }
     fn post(&self,
             s: &mut pprust::State,
-            node: pprust::AnnNode) -> old_io::IoResult<()> {
+            node: pprust::AnnNode) -> io::Result<()> {
         match node {
             pprust::NodeIdent(_) | pprust::NodeName(_) => Ok(()),
 
@@ -259,7 +262,7 @@ impl<'ast> PrinterSupport<'ast> for HygieneAnnotation<'ast> {
 impl<'ast> pprust::PpAnn for HygieneAnnotation<'ast> {
     fn post(&self,
             s: &mut pprust::State,
-            node: pprust::AnnNode) -> old_io::IoResult<()> {
+            node: pprust::AnnNode) -> io::Result<()> {
         match node {
             pprust::NodeIdent(&ast::Ident { name: ast::Name(nm), ctxt }) => {
                 try!(pp::space(&mut s.s));
@@ -294,7 +297,7 @@ impl<'tcx> PrinterSupport<'tcx> for TypedAnnotation<'tcx> {
 impl<'tcx> pprust::PpAnn for TypedAnnotation<'tcx> {
     fn pre(&self,
            s: &mut pprust::State,
-           node: pprust::AnnNode) -> old_io::IoResult<()> {
+           node: pprust::AnnNode) -> io::Result<()> {
         match node {
             pprust::NodeExpr(_) => s.popen(),
             _ => Ok(())
@@ -302,7 +305,7 @@ impl<'tcx> pprust::PpAnn for TypedAnnotation<'tcx> {
     }
     fn post(&self,
             s: &mut pprust::State,
-            node: pprust::AnnNode) -> old_io::IoResult<()> {
+            node: pprust::AnnNode) -> io::Result<()> {
         let tcx = &self.analysis.ty_cx;
         match node {
             pprust::NodeExpr(expr) => {
@@ -507,7 +510,7 @@ pub fn pretty_print_input(sess: Session,
                           input: &Input,
                           ppm: PpMode,
                           opt_uii: Option<UserIdentifiedItem>,
-                          ofile: Option<Path>) {
+                          ofile: Option<PathBuf>) {
     let krate = driver::phase_1_parse_input(&sess, cfg, input);
 
     let krate = if let PpmSource(PpmEveryBodyLoops) = ppm {
@@ -547,24 +550,15 @@ pub fn pretty_print_input(sess: Session,
                             .unwrap()
                             .as_bytes()
                             .to_vec();
-    let mut rdr = MemReader::new(src);
+    let mut rdr = &src[..];
 
-    let out = match ofile {
-        None => box old_io::stdout() as Box<Writer+'static>,
-        Some(p) => {
-            let r = old_io::File::create(&p);
-            match r {
-                Ok(w) => box w as Box<Writer+'static>,
-                Err(e) => panic!("print-print failed to open {} due to {}",
-                                p.display(), e),
-            }
-        }
-    };
+    let mut out = Vec::new();
 
     match (ppm, opt_uii) {
-        (PpmSource(s), None) =>
+        (PpmSource(s), None) => {
+            let out: &mut Write = &mut out;
             s.call_with_pp_support(
-                sess, ast_map, &arenas, id, out, |annotation, out| {
+                sess, ast_map, &arenas, id, box out, |annotation, out| {
                     debug!("pretty printing source code {:?}", s);
                     let sess = annotation.sess();
                     pprust::print_crate(sess.codemap(),
@@ -575,9 +569,11 @@ pub fn pretty_print_input(sess: Session,
                                         out,
                                         annotation.pp_ann(),
                                         is_expanded)
-                }),
+            })
+        }
 
-        (PpmSource(s), Some(uii)) =>
+        (PpmSource(s), Some(uii)) => {
+            let out: &mut Write = &mut out;
             s.call_with_pp_support(
                 sess, ast_map, &arenas, id, (out,uii), |annotation, (out,uii)| {
                     debug!("pretty printing source code {:?}", s);
@@ -589,7 +585,7 @@ pub fn pretty_print_input(sess: Session,
                                                       sess.diagnostic(),
                                                       src_name.to_string(),
                                                       &mut rdr,
-                                                      out,
+                                                      box out,
                                                       annotation.pp_ann(),
                                                       is_expanded);
                     for node_id in uii.all_matching_node_ids(ast_map) {
@@ -600,7 +596,8 @@ pub fn pretty_print_input(sess: Session,
                         try!(pp::hardbreak(&mut pp_state.s));
                     }
                     pp::eof(&mut pp_state.s)
-                }),
+                })
+        }
 
         (PpmFlowGraph(mode), opt_uii) => {
             debug!("pretty printing flow graph for {:?}", opt_uii);
@@ -618,6 +615,7 @@ pub fn pretty_print_input(sess: Session,
             });
 
             let code = blocks::Code::from_node(node);
+            let out: &mut Writer = &mut out;
             match code {
                 Some(code) => {
                     let variants = gather_flowgraph_variants(&sess);
@@ -642,14 +640,25 @@ pub fn pretty_print_input(sess: Session,
                 }
             }
         }
-    }.unwrap()
+    }.unwrap();
+
+    match ofile {
+        None => print!("{}", String::from_utf8(out).unwrap()),
+        Some(p) => {
+            match File::create(&p) {
+                Ok(mut w) => w.write_all(&out).unwrap(),
+                Err(e) => panic!("print-print failed to open {} due to {}",
+                                p.display(), e),
+            }
+        }
+    }
 }
 
 fn print_flowgraph<W:old_io::Writer>(variants: Vec<borrowck_dot::Variant>,
                                  analysis: ty::CrateAnalysis,
                                  code: blocks::Code,
                                  mode: PpFlowGraphMode,
-                                 mut out: W) -> old_io::IoResult<()> {
+                                 mut out: W) -> io::Result<()> {
     let ty_cx = &analysis.ty_cx;
     let cfg = match code {
         blocks::BlockCode(block) => cfg::CFG::new(ty_cx, &*block),
@@ -689,17 +698,10 @@ fn print_flowgraph<W:old_io::Writer>(variants: Vec<borrowck_dot::Variant>,
         }
     }
 
-    fn expand_err_details(r: old_io::IoResult<()>) -> old_io::IoResult<()> {
+    fn expand_err_details(r: old_io::IoResult<()>) -> io::Result<()> {
         r.map_err(|ioerr| {
-            let orig_detail = ioerr.detail.clone();
-            let m = "graphviz::render failed";
-            old_io::IoError {
-                detail: Some(match orig_detail {
-                    None => m.to_string(),
-                    Some(d) => format!("{}: {}", m, d)
-                }),
-                ..ioerr
-            }
+            io::Error::new(io::ErrorKind::Other, "graphviz::render failed",
+                           Some(ioerr.to_string()))
         })
     }
 }
diff --git a/src/librustc_llvm/archive_ro.rs b/src/librustc_llvm/archive_ro.rs
index 14a99026aac..f54480e3e52 100644
--- a/src/librustc_llvm/archive_ro.rs
+++ b/src/librustc_llvm/archive_ro.rs
@@ -16,6 +16,7 @@ use ArchiveRef;
 use std::ffi::CString;
 use std::mem;
 use std::raw;
+use std::path::Path;
 
 pub struct ArchiveRO {
     ptr: ArchiveRef,
@@ -29,14 +30,25 @@ impl ArchiveRO {
     /// If this archive is used with a mutable method, then an error will be
     /// raised.
     pub fn open(dst: &Path) -> Option<ArchiveRO> {
-        unsafe {
-            let s = CString::new(dst.as_vec()).unwrap();
+        return unsafe {
+            let s = path2cstr(dst);
             let ar = ::LLVMRustOpenArchive(s.as_ptr());
             if ar.is_null() {
                 None
             } else {
                 Some(ArchiveRO { ptr: ar })
             }
+        };
+
+        #[cfg(unix)]
+        fn path2cstr(p: &Path) -> CString {
+            use std::os::unix::prelude::*;
+            use std::ffi::AsOsStr;
+            CString::new(p.as_os_str().as_bytes()).unwrap()
+        }
+        #[cfg(windows)]
+        fn path2cstr(p: &Path) -> CString {
+            CString::new(p.to_str().unwrap()).unwrap()
         }
     }
 
diff --git a/src/librustc_llvm/lib.rs b/src/librustc_llvm/lib.rs
index 09a187befb2..0a1416ff566 100644
--- a/src/librustc_llvm/lib.rs
+++ b/src/librustc_llvm/lib.rs
@@ -28,9 +28,9 @@
 #![feature(int_uint)]
 #![feature(libc)]
 #![feature(link_args)]
-#![feature(old_path)]
 #![feature(staged_api)]
 #![feature(std_misc)]
+#![feature(path)]
 
 extern crate libc;
 #[macro_use] #[no_link] extern crate rustc_bitflags;
diff --git a/src/librustc_trans/back/link.rs b/src/librustc_trans/back/link.rs
index 7b377ac3611..1e84bc4b8e0 100644
--- a/src/librustc_trans/back/link.rs
+++ b/src/librustc_trans/back/link.rs
@@ -27,12 +27,13 @@ use util::common::time;
 use util::ppaux;
 use util::sha2::{Digest, Sha256};
 
-use std::old_io::fs::PathExtensions;
-use std::old_io::{fs, TempDir, Command};
-use std::old_io;
+use std::ffi::{AsOsStr, OsString};
+use std::fs::{self, TempDir, PathExt};
+use std::io::{self, Read, Write};
 use std::mem;
+use std::path::{Path, PathBuf};
+use std::process::Command;
 use std::str;
-use std::string::String;
 use flate;
 use serialize::hex::ToHex;
 use syntax::ast;
@@ -156,7 +157,7 @@ pub fn find_crate_name(sess: Option<&Session>,
         return validate(s.to_string(), Some(attr.span));
     }
     if let Input::File(ref path) = *input {
-        if let Some(s) = path.filestem_str() {
+        if let Some(s) = path.file_stem().and_then(|s| s.to_str()) {
             return validate(s.to_string(), None);
         }
     }
@@ -356,7 +357,7 @@ pub fn get_cc_prog(sess: &Session) -> String {
 }
 
 pub fn remove(sess: &Session, path: &Path) {
-    match fs::unlink(path) {
+    match fs::remove_file(path) {
         Ok(..) => {}
         Err(e) => {
             sess.err(&format!("failed to remove {}: {}",
@@ -371,7 +372,7 @@ pub fn remove(sess: &Session, path: &Path) {
 pub fn link_binary(sess: &Session,
                    trans: &CrateTranslation,
                    outputs: &OutputFilenames,
-                   crate_name: &str) -> Vec<Path> {
+                   crate_name: &str) -> Vec<PathBuf> {
     let mut out_filenames = Vec::new();
     for &crate_type in &*sess.crate_types.borrow() {
         if invalid_output_for_target(sess, crate_type) {
@@ -425,35 +426,35 @@ pub fn invalid_output_for_target(sess: &Session,
 }
 
 fn is_writeable(p: &Path) -> bool {
-    match p.stat() {
+    match p.metadata() {
         Err(..) => true,
-        Ok(m) => m.perm & old_io::USER_WRITE == old_io::USER_WRITE
+        Ok(m) => !m.permissions().readonly()
     }
 }
 
 pub fn filename_for_input(sess: &Session,
                           crate_type: config::CrateType,
                           name: &str,
-                          out_filename: &Path) -> Path {
+                          out_filename: &Path) -> PathBuf {
     let libname = format!("{}{}", name, sess.opts.cg.extra_filename);
     match crate_type {
         config::CrateTypeRlib => {
-            out_filename.with_filename(format!("lib{}.rlib", libname))
+            out_filename.with_file_name(&format!("lib{}.rlib", libname))
         }
         config::CrateTypeDylib => {
             let (prefix, suffix) = (&sess.target.target.options.dll_prefix,
                                     &sess.target.target.options.dll_suffix);
-            out_filename.with_filename(format!("{}{}{}",
-                                               prefix,
-                                               libname,
-                                               suffix))
+            out_filename.with_file_name(&format!("{}{}{}",
+                                                  prefix,
+                                                 libname,
+                                                 suffix))
         }
         config::CrateTypeStaticlib => {
-            out_filename.with_filename(format!("lib{}.a", libname))
+            out_filename.with_file_name(&format!("lib{}.a", libname))
         }
         config::CrateTypeExecutable => {
             let suffix = &sess.target.target.options.exe_suffix;
-            out_filename.with_filename(format!("{}{}", libname, suffix))
+            out_filename.with_file_name(&format!("{}{}", libname, suffix))
         }
     }
 }
@@ -462,7 +463,7 @@ fn link_binary_output(sess: &Session,
                       trans: &CrateTranslation,
                       crate_type: config::CrateType,
                       outputs: &OutputFilenames,
-                      crate_name: &str) -> Path {
+                      crate_name: &str) -> PathBuf {
     let obj_filename = outputs.temp_path(OutputTypeObject);
     let out_filename = match outputs.single_output_file {
         Some(ref file) => file.clone(),
@@ -507,10 +508,10 @@ fn link_binary_output(sess: &Session,
     out_filename
 }
 
-fn archive_search_paths(sess: &Session) -> Vec<Path> {
+fn archive_search_paths(sess: &Session) -> Vec<PathBuf> {
     let mut search = Vec::new();
     sess.target_filesearch(PathKind::Native).for_each_lib_search_path(|path, _| {
-        search.push(path.clone());
+        search.push(path.to_path_buf());
         FileDoesntMatch
     });
     return search;
@@ -529,7 +530,7 @@ fn link_rlib<'a>(sess: &'a Session,
     let handler = &sess.diagnostic().handler;
     let config = ArchiveConfig {
         handler: handler,
-        dst: out_filename.clone(),
+        dst: out_filename.to_path_buf(),
         lib_search_paths: archive_search_paths(sess),
         slib_prefix: sess.target.target.options.staticlib_prefix.clone(),
         slib_suffix: sess.target.target.options.staticlib_suffix.clone(),
@@ -588,7 +589,9 @@ fn link_rlib<'a>(sess: &'a Session,
             // the same filename for metadata (stomping over one another)
             let tmpdir = TempDir::new("rustc").ok().expect("needs a temp dir");
             let metadata = tmpdir.path().join(METADATA_FILENAME);
-            match fs::File::create(&metadata).write_all(&trans.metadata) {
+            match fs::File::create(&metadata).and_then(|mut f| {
+                f.write_all(&trans.metadata)
+            }) {
                 Ok(..) => {}
                 Err(e) => {
                     sess.err(&format!("failed to write {}: {}",
@@ -613,28 +616,32 @@ fn link_rlib<'a>(sess: &'a Session,
                 let bc_deflated_filename = obj_filename.with_extension(
                     &format!("{}.bytecode.deflate", i));
 
-                let bc_data = match fs::File::open(&bc_filename).read_to_end() {
-                    Ok(buffer) => buffer,
+                let mut bc_data = Vec::new();
+                match fs::File::open(&bc_filename).and_then(|mut f| {
+                    f.read_to_end(&mut bc_data)
+                }) {
+                    Ok(..) => {}
                     Err(e) => sess.fatal(&format!("failed to read bytecode: {}",
                                                  e))
-                };
+                }
 
                 let bc_data_deflated = match flate::deflate_bytes(&bc_data[..]) {
                     Some(compressed) => compressed,
-                    None => sess.fatal(&format!("failed to compress bytecode from {}",
-                                               bc_filename.display()))
+                    None => sess.fatal(&format!("failed to compress bytecode \
+                                                 from {}",
+                                                 bc_filename.display()))
                 };
 
                 let mut bc_file_deflated = match fs::File::create(&bc_deflated_filename) {
                     Ok(file) => file,
                     Err(e) => {
-                        sess.fatal(&format!("failed to create compressed bytecode \
-                                            file: {}", e))
+                        sess.fatal(&format!("failed to create compressed \
+                                             bytecode file: {}", e))
                     }
                 };
 
                 match write_rlib_bytecode_object_v1(&mut bc_file_deflated,
-                                                    bc_data_deflated.as_slice()) {
+                                                    &bc_data_deflated) {
                     Ok(()) => {}
                     Err(e) => {
                         sess.err(&format!("failed to write compressed bytecode: \
@@ -670,15 +677,23 @@ fn link_rlib<'a>(sess: &'a Session,
     ab
 }
 
-fn write_rlib_bytecode_object_v1<T: Writer>(writer: &mut T,
-                                            bc_data_deflated: &[u8])
-                                         -> ::std::old_io::IoResult<()> {
+fn write_rlib_bytecode_object_v1(writer: &mut Write,
+                                 bc_data_deflated: &[u8]) -> io::Result<()> {
     let bc_data_deflated_size: u64 = bc_data_deflated.len() as u64;
 
-    try! { writer.write_all(RLIB_BYTECODE_OBJECT_MAGIC) };
-    try! { writer.write_le_u32(1) };
-    try! { writer.write_le_u64(bc_data_deflated_size) };
-    try! { writer.write_all(&bc_data_deflated[..]) };
+    try!(writer.write_all(RLIB_BYTECODE_OBJECT_MAGIC));
+    try!(writer.write_all(&[1, 0, 0, 0]));
+    try!(writer.write_all(&[
+        (bc_data_deflated_size >>  0) as u8,
+        (bc_data_deflated_size >>  8) as u8,
+        (bc_data_deflated_size >> 16) as u8,
+        (bc_data_deflated_size >> 24) as u8,
+        (bc_data_deflated_size >> 32) as u8,
+        (bc_data_deflated_size >> 40) as u8,
+        (bc_data_deflated_size >> 48) as u8,
+        (bc_data_deflated_size >> 56) as u8,
+    ]));
+    try!(writer.write_all(&bc_data_deflated));
 
     let number_of_bytes_written_so_far =
         RLIB_BYTECODE_OBJECT_MAGIC.len() +                // magic id
@@ -690,7 +705,7 @@ fn write_rlib_bytecode_object_v1<T: Writer>(writer: &mut T,
     // padding byte to make it even. This works around a crash bug in LLDB
     // (see issue #15950)
     if number_of_bytes_written_so_far % 2 == 1 {
-        try! { writer.write_u8(0) };
+        try!(writer.write_all(&[0]));
     }
 
     return Ok(());
@@ -796,13 +811,13 @@ fn link_natively(sess: &Session, trans: &CrateTranslation, dylib: bool,
                                  pname,
                                  prog.status));
                 sess.note(&format!("{:?}", &cmd));
-                let mut output = prog.error.clone();
-                output.push_all(&prog.output);
+                let mut output = prog.stderr.clone();
+                output.push_all(&prog.stdout);
                 sess.note(str::from_utf8(&output[..]).unwrap());
                 sess.abort_if_errors();
             }
-            debug!("linker stderr:\n{}", String::from_utf8(prog.error).unwrap());
-            debug!("linker stdout:\n{}", String::from_utf8(prog.output).unwrap());
+            debug!("linker stderr:\n{}", String::from_utf8(prog.stderr).unwrap());
+            debug!("linker stdout:\n{}", String::from_utf8(prog.stdout).unwrap());
         },
         Err(e) => {
             sess.err(&format!("could not exec the linker `{}`: {}",
@@ -866,9 +881,9 @@ fn link_args(cmd: &mut Command,
         if t.options.is_like_osx {
             let morestack = lib_path.join("libmorestack.a");
 
-            let mut v = b"-Wl,-force_load,".to_vec();
-            v.push_all(morestack.as_vec());
-            cmd.arg(&v[..]);
+            let mut v = OsString::from_str("-Wl,-force_load,");
+            v.push_os_str(morestack.as_os_str());
+            cmd.arg(&v);
         } else {
             cmd.args(&["-Wl,--whole-archive", "-lmorestack", "-Wl,--no-whole-archive"]);
         }
@@ -878,7 +893,7 @@ fn link_args(cmd: &mut Command,
     // executable. This metadata is in a separate object file from the main
     // object file, so we link that in here.
     if dylib {
-        cmd.arg(obj_filename.with_extension("metadata.o"));
+        cmd.arg(&obj_filename.with_extension("metadata.o"));
     }
 
     if t.options.is_like_osx {
@@ -991,9 +1006,9 @@ fn link_args(cmd: &mut Command,
             cmd.args(&["-dynamiclib", "-Wl,-dylib"]);
 
             if sess.opts.cg.rpath {
-                let mut v = "-Wl,-install_name,@rpath/".as_bytes().to_vec();
-                v.push_all(out_filename.filename().unwrap());
-                cmd.arg(&v[..]);
+                let mut v = OsString::from_str("-Wl,-install_name,@rpath/");
+                v.push_os_str(out_filename.file_name().unwrap());
+                cmd.arg(&v);
             }
         } else {
             cmd.arg("-shared");
@@ -1006,23 +1021,23 @@ fn link_args(cmd: &mut Command,
     if sess.opts.cg.rpath {
         let sysroot = sess.sysroot();
         let target_triple = &sess.opts.target_triple;
-        let get_install_prefix_lib_path = || {
+        let mut get_install_prefix_lib_path = || {
             let install_prefix = option_env!("CFG_PREFIX").expect("CFG_PREFIX");
             let tlib = filesearch::relative_target_lib_path(sysroot, target_triple);
-            let mut path = Path::new(install_prefix);
+            let mut path = PathBuf::new(install_prefix);
             path.push(&tlib);
 
             path
         };
-        let rpath_config = RPathConfig {
+        let mut rpath_config = RPathConfig {
             used_crates: sess.cstore.get_used_crates(cstore::RequireDynamic),
-            out_filename: out_filename.clone(),
+            out_filename: out_filename.to_path_buf(),
             has_rpath: sess.target.target.options.has_rpath,
             is_like_osx: sess.target.target.options.is_like_osx,
-            get_install_prefix_lib_path: get_install_prefix_lib_path,
-            realpath: ::util::fs::realpath
+            get_install_prefix_lib_path: &mut get_install_prefix_lib_path,
+            realpath: &mut ::util::fs::realpath
         };
-        cmd.args(&rpath::get_rpath_flags(rpath_config));
+        cmd.args(&rpath::get_rpath_flags(&mut rpath_config));
     }
 
     // Finally add all the linker arguments provided on the command line along
@@ -1082,7 +1097,7 @@ fn add_local_native_libraries(cmd: &mut Command, sess: &Session) {
     let search_path = archive_search_paths(sess);
     for l in staticlibs {
         if takes_hints {
-            cmd.arg(format!("-l{}", l));
+            cmd.arg(&format!("-l{}", l));
         } else {
             // -force_load is the OSX equivalent of --whole-archive, but it
             // involves passing the full path to the library to link.
@@ -1091,9 +1106,9 @@ fn add_local_native_libraries(cmd: &mut Command, sess: &Session) {
                                             &sess.target.target.options.staticlib_suffix,
                                             &search_path[..],
                                             &sess.diagnostic().handler);
-            let mut v = b"-Wl,-force_load,".to_vec();
-            v.push_all(lib.as_vec());
-            cmd.arg(&v[..]);
+            let mut v = OsString::from_str("-Wl,-force_load,");
+            v.push_os_str(lib.as_os_str());
+            cmd.arg(&v);
         }
     }
     if takes_hints {
@@ -1103,7 +1118,7 @@ fn add_local_native_libraries(cmd: &mut Command, sess: &Session) {
     for &(ref l, kind) in others {
         match kind {
             cstore::NativeUnknown => {
-                cmd.arg(format!("-l{}", l));
+                cmd.arg(&format!("-l{}", l));
             }
             cstore::NativeFramework => {
                 cmd.arg("-framework").arg(&l[..]);
@@ -1150,18 +1165,18 @@ fn add_upstream_rust_crates(cmd: &mut Command, sess: &Session,
         let src = sess.cstore.get_used_crate_source(cnum).unwrap();
         match kind {
             cstore::RequireDynamic => {
-                add_dynamic_crate(cmd, sess, src.dylib.unwrap().0)
+                add_dynamic_crate(cmd, sess, &src.dylib.unwrap().0)
             }
             cstore::RequireStatic => {
-                add_static_crate(cmd, sess, tmpdir, src.rlib.unwrap().0)
+                add_static_crate(cmd, sess, tmpdir, &src.rlib.unwrap().0)
             }
         }
 
     }
 
     // Converts a library file-stem into a cc -l argument
-    fn unlib<'a>(config: &config::Config, stem: &'a [u8]) -> &'a [u8] {
-        if stem.starts_with("lib".as_bytes()) && !config.target.options.is_like_windows {
+    fn unlib<'a>(config: &config::Config, stem: &'a str) -> &'a str {
+        if stem.starts_with("lib") && !config.target.options.is_like_windows {
             &stem[3..]
         } else {
             stem
@@ -1170,7 +1185,7 @@ fn add_upstream_rust_crates(cmd: &mut Command, sess: &Session,
 
     // Adds the static "rlib" versions of all crates to the command line.
     fn add_static_crate(cmd: &mut Command, sess: &Session, tmpdir: &Path,
-                        cratepath: Path) {
+                        cratepath: &Path) {
         // When performing LTO on an executable output, all of the
         // bytecode from the upstream libraries has already been
         // included in our object file output. We need to modify all of
@@ -1186,12 +1201,12 @@ fn add_upstream_rust_crates(cmd: &mut Command, sess: &Session,
         // If we're not doing LTO, then our job is simply to just link
         // against the archive.
         if sess.lto() {
-            let name = cratepath.filename_str().unwrap();
+            let name = cratepath.file_name().unwrap().to_str().unwrap();
             let name = &name[3..name.len() - 5]; // chop off lib/.rlib
             time(sess.time_passes(),
                  &format!("altering {}.rlib", name),
                  (), |()| {
-                let dst = tmpdir.join(cratepath.filename().unwrap());
+                let dst = tmpdir.join(cratepath.file_name().unwrap());
                 match fs::copy(&cratepath, &dst) {
                     Ok(..) => {}
                     Err(e) => {
@@ -1205,7 +1220,11 @@ fn add_upstream_rust_crates(cmd: &mut Command, sess: &Session,
                 // Fix up permissions of the copy, as fs::copy() preserves
                 // permissions, but the original file may have been installed
                 // by a package manager and may be read-only.
-                match fs::chmod(&dst, old_io::USER_READ | old_io::USER_WRITE) {
+                match fs::metadata(&dst).and_then(|m| {
+                    let mut perms = m.permissions();
+                    perms.set_readonly(false);
+                    fs::set_permissions(&dst, perms)
+                }) {
                     Ok(..) => {}
                     Err(e) => {
                         sess.err(&format!("failed to chmod {} when preparing \
@@ -1227,7 +1246,7 @@ fn add_upstream_rust_crates(cmd: &mut Command, sess: &Session,
                 archive.remove_file(&format!("{}.o", name));
                 let files = archive.files();
                 if files.iter().any(|s| s.ends_with(".o")) {
-                    cmd.arg(dst);
+                    cmd.arg(&dst);
                 }
             });
         } else {
@@ -1236,19 +1255,18 @@ fn add_upstream_rust_crates(cmd: &mut Command, sess: &Session,
     }
 
     // Same thing as above, but for dynamic crates instead of static crates.
-    fn add_dynamic_crate(cmd: &mut Command, sess: &Session, cratepath: Path) {
+    fn add_dynamic_crate(cmd: &mut Command, sess: &Session, cratepath: &Path) {
         // If we're performing LTO, then it should have been previously required
         // that all upstream rust dependencies were available in an rlib format.
         assert!(!sess.lto());
 
         // Just need to tell the linker about where the library lives and
         // what its name is
-        let dir = cratepath.dirname();
-        if !dir.is_empty() { cmd.arg("-L").arg(dir); }
-
-        let mut v = "-l".as_bytes().to_vec();
-        v.push_all(unlib(&sess.target, cratepath.filestem().unwrap()));
-        cmd.arg(&v[..]);
+        if let Some(dir) = cratepath.parent() {
+            cmd.arg("-L").arg(dir);
+        }
+        let filestem = cratepath.file_stem().unwrap().to_str().unwrap();
+        cmd.arg(&format!("-l{}", unlib(&sess.target, filestem)));
     }
 }
 
@@ -1286,7 +1304,7 @@ fn add_upstream_native_libraries(cmd: &mut Command, sess: &Session) {
         for &(kind, ref lib) in &libs {
             match kind {
                 cstore::NativeUnknown => {
-                    cmd.arg(format!("-l{}", *lib));
+                    cmd.arg(&format!("-l{}", *lib));
                 }
                 cstore::NativeFramework => {
                     cmd.arg("-framework");
diff --git a/src/librustc_trans/back/lto.rs b/src/librustc_trans/back/lto.rs
index d8a296bf041..db9966e0548 100644
--- a/src/librustc_trans/back/lto.rs
+++ b/src/librustc_trans/back/lto.rs
@@ -59,7 +59,7 @@ pub fn run(sess: &session::Session, llmod: ModuleRef,
         };
 
         let archive = ArchiveRO::open(&path).expect("wanted an rlib");
-        let file = path.filename_str().unwrap();
+        let file = path.file_name().unwrap().to_str().unwrap();
         let file = &file[3..file.len() - 5]; // chop off lib/.rlib
         debug!("reading {}", file);
         for i in iter::count(0, 1) {
diff --git a/src/librustc_trans/back/write.rs b/src/librustc_trans/back/write.rs
index cd14fe529b1..156cfa6c4b2 100644
--- a/src/librustc_trans/back/write.rs
+++ b/src/librustc_trans/back/write.rs
@@ -18,17 +18,19 @@ use llvm::{ModuleRef, TargetMachineRef, PassManagerRef, DiagnosticInfoRef, Conte
 use llvm::SMDiagnosticRef;
 use trans::{CrateTranslation, ModuleTranslation};
 use util::common::time;
+use util::common::path2cstr;
 use syntax::codemap;
 use syntax::diagnostic;
 use syntax::diagnostic::{Emitter, Handler, Level, mk_handler};
 
 use std::ffi::{CStr, CString};
-use std::old_io::Command;
-use std::old_io::fs;
+use std::fs;
 use std::iter::Unfold;
+use std::mem;
+use std::path::Path;
+use std::process::{Command, Stdio};
 use std::ptr;
 use std::str;
-use std::mem;
 use std::sync::{Arc, Mutex};
 use std::sync::mpsc::channel;
 use std::thread;
@@ -67,7 +69,7 @@ pub fn write_output_file(
         output: &Path,
         file_type: llvm::FileType) {
     unsafe {
-        let output_c = CString::new(output.as_vec()).unwrap();
+        let output_c = path2cstr(output);
         let result = llvm::LLVMRustWriteOutputFile(
                 target, pm, m, output_c.as_ptr(), file_type);
         if !result {
@@ -424,7 +426,7 @@ unsafe fn optimize_and_codegen(cgcx: &CodegenContext,
     if config.emit_no_opt_bc {
         let ext = format!("{}.no-opt.bc", name_extra);
         let out = output_names.with_extension(&ext);
-        let out = CString::new(out.as_vec()).unwrap();
+        let out = path2cstr(&out);
         llvm::LLVMWriteBitcodeToFile(llmod, out.as_ptr());
     }
 
@@ -477,7 +479,7 @@ unsafe fn optimize_and_codegen(cgcx: &CodegenContext,
                     if config.emit_lto_bc {
                         let name = format!("{}.lto.bc", name_extra);
                         let out = output_names.with_extension(&name);
-                        let out = CString::new(out.as_vec()).unwrap();
+                        let out = path2cstr(&out);
                         llvm::LLVMWriteBitcodeToFile(llmod, out.as_ptr());
                     }
                 },
@@ -511,7 +513,7 @@ unsafe fn optimize_and_codegen(cgcx: &CodegenContext,
     if config.emit_bc {
         let ext = format!("{}.bc", name_extra);
         let out = output_names.with_extension(&ext);
-        let out = CString::new(out.as_vec()).unwrap();
+        let out = path2cstr(&out);
         llvm::LLVMWriteBitcodeToFile(llmod, out.as_ptr());
     }
 
@@ -519,7 +521,7 @@ unsafe fn optimize_and_codegen(cgcx: &CodegenContext,
         if config.emit_ir {
             let ext = format!("{}.ll", name_extra);
             let out = output_names.with_extension(&ext);
-            let out = CString::new(out.as_vec()).unwrap();
+            let out = path2cstr(&out);
             with_codegen(tm, llmod, config.no_builtins, |cpm| {
                 llvm::LLVMRustPrintModule(cpm, llmod, out.as_ptr());
             })
@@ -717,12 +719,11 @@ pub fn run_passes(sess: &Session,
         cmd.arg("-nostdlib");
 
         for index in 0..trans.modules.len() {
-            cmd.arg(crate_output.with_extension(&format!("{}.o", index)));
+            cmd.arg(&crate_output.with_extension(&format!("{}.o", index)));
         }
 
-        cmd.arg("-r")
-           .arg("-o")
-           .arg(windows_output_path.as_ref().unwrap_or(output_path));
+        cmd.arg("-r").arg("-o")
+           .arg(windows_output_path.as_ref().map(|s| &**s).unwrap_or(output_path));
 
         cmd.args(&sess.target.target.options.post_link_args);
 
@@ -730,9 +731,7 @@ pub fn run_passes(sess: &Session,
             println!("{:?}", &cmd);
         }
 
-        cmd.stdin(::std::old_io::process::Ignored)
-           .stdout(::std::old_io::process::InheritFd(1))
-           .stderr(::std::old_io::process::InheritFd(2));
+        cmd.stdin(Stdio::null());
         match cmd.status() {
             Ok(status) => {
                 if !status.success() {
@@ -964,9 +963,9 @@ pub fn run_assembler(sess: &Session, outputs: &OutputFilenames) {
     let pname = get_cc_prog(sess);
     let mut cmd = Command::new(&pname[..]);
 
-    cmd.arg("-c").arg("-o").arg(outputs.path(config::OutputTypeObject))
-                           .arg(outputs.temp_path(config::OutputTypeAssembly));
-    debug!("{:?}", &cmd);
+    cmd.arg("-c").arg("-o").arg(&outputs.path(config::OutputTypeObject))
+                           .arg(&outputs.temp_path(config::OutputTypeAssembly));
+    debug!("{:?}", cmd);
 
     match cmd.output() {
         Ok(prog) => {
@@ -975,8 +974,8 @@ pub fn run_assembler(sess: &Session, outputs: &OutputFilenames) {
                                  pname,
                                  prog.status));
                 sess.note(&format!("{:?}", &cmd));
-                let mut note = prog.error.clone();
-                note.push_all(&prog.output);
+                let mut note = prog.stderr.clone();
+                note.push_all(&prog.stdout);
                 sess.note(str::from_utf8(&note[..]).unwrap());
                 sess.abort_if_errors();
             }
diff --git a/src/librustc_trans/lib.rs b/src/librustc_trans/lib.rs
index 71317d5875b..dcc79e90cc5 100644
--- a/src/librustc_trans/lib.rs
+++ b/src/librustc_trans/lib.rs
@@ -29,9 +29,7 @@
 #![feature(collections)]
 #![feature(core)]
 #![feature(int_uint)]
-#![feature(old_io)]
 #![feature(libc)]
-#![feature(old_path)]
 #![feature(quote)]
 #![feature(rustc_diagnostic_macros)]
 #![feature(rustc_private)]
@@ -39,6 +37,11 @@
 #![feature(staged_api)]
 #![feature(std_misc)]
 #![feature(unicode)]
+#![feature(io)]
+#![feature(fs)]
+#![feature(path)]
+#![feature(os)]
+#![feature(tempdir)]
 
 extern crate arena;
 extern crate flate;
diff --git a/src/librustc_trans/save/mod.rs b/src/librustc_trans/save/mod.rs
index 371b9268fba..3c6cb5f9de9 100644
--- a/src/librustc_trans/save/mod.rs
+++ b/src/librustc_trans/save/mod.rs
@@ -33,8 +33,9 @@ use middle::def;
 use middle::ty::{self, Ty};
 
 use std::cell::Cell;
-use std::old_io::{self, File, fs};
 use std::env;
+use std::fs::{self, File};
+use std::path::{Path, PathBuf};
 
 use syntax::ast_util::{self, PostExpansionMethod};
 use syntax::ast::{self, NodeId, DefId};
@@ -1537,6 +1538,7 @@ impl<'l, 'tcx, 'v> Visitor<'v> for DxrVisitor<'l, 'tcx> {
     }
 }
 
+#[allow(deprecated)]
 pub fn process_crate(sess: &Session,
                      krate: &ast::Crate,
                      analysis: &ty::CrateAnalysis,
@@ -1557,15 +1559,15 @@ pub fn process_crate(sess: &Session,
     info!("Dumping crate {}", cratename);
 
     // find a path to dump our data to
-    let mut root_path = match env::var("DXR_RUST_TEMP_FOLDER") {
-        Ok(val) => Path::new(val),
-        Err(..) => match odir {
+    let mut root_path = match env::var_os("DXR_RUST_TEMP_FOLDER") {
+        Some(val) => PathBuf::new(&val),
+        None => match odir {
             Some(val) => val.join("dxr"),
-            None => Path::new("dxr-temp"),
+            None => PathBuf::new("dxr-temp"),
         },
     };
 
-    match fs::mkdir_recursive(&root_path, old_io::USER_RWX) {
+    match fs::create_dir_all(&root_path) {
         Err(e) => sess.err(&format!("Could not create directory {}: {}",
                            root_path.display(), e)),
         _ => (),
@@ -1579,7 +1581,7 @@ pub fn process_crate(sess: &Session,
     // Create output file.
     let mut out_name = cratename.clone();
     out_name.push_str(".csv");
-    root_path.push(out_name);
+    root_path.push(&out_name);
     let output_file = match File::create(&root_path) {
         Ok(f) => box f,
         Err(e) => {
@@ -1595,7 +1597,7 @@ pub fn process_crate(sess: &Session,
         collected_paths: vec!(),
         collecting: false,
         fmt: FmtStrs::new(box Recorder {
-                            out: output_file as Box<Writer+'static>,
+                            out: output_file,
                             dump_spans: false,
                         },
                         SpanUtils {
diff --git a/src/librustc_trans/save/recorder.rs b/src/librustc_trans/save/recorder.rs
index 937f2d07677..f7c0d6a983f 100644
--- a/src/librustc_trans/save/recorder.rs
+++ b/src/librustc_trans/save/recorder.rs
@@ -13,7 +13,7 @@ pub use self::Row::*;
 use super::escape;
 use super::span_utils::SpanUtils;
 
-use std::vec::Vec;
+use std::io::Write;
 
 use syntax::ast;
 use syntax::ast::{NodeId,DefId};
@@ -23,7 +23,7 @@ const ZERO_DEF_ID: DefId = DefId { node: 0, krate: 0 };
 
 pub struct Recorder {
     // output file
-    pub out: Box<Writer+'static>,
+    pub out: Box<Write+'static>,
     pub dump_spans: bool,
 }
 
diff --git a/src/librustc_trans/trans/debuginfo.rs b/src/librustc_trans/trans/debuginfo.rs
index f3b7058336b..142262a25bd 100644
--- a/src/librustc_trans/trans/debuginfo.rs
+++ b/src/librustc_trans/trans/debuginfo.rs
@@ -206,10 +206,12 @@ use middle::pat_util;
 use session::config::{self, FullDebugInfo, LimitedDebugInfo, NoDebugInfo};
 use util::nodemap::{DefIdMap, NodeMap, FnvHashMap, FnvHashSet};
 use util::ppaux;
+use util::common::path2cstr;
 
 use libc::{c_uint, c_longlong};
-use std::ffi::CString;
 use std::cell::{Cell, RefCell};
+use std::ffi::CString;
+use std::path::Path;
 use std::ptr;
 use std::rc::{Rc, Weak};
 use syntax::util::interner::Interner;
@@ -1588,20 +1590,13 @@ fn compile_unit_metadata(cx: &CrateContext) -> DIDescriptor {
                 cx.sess().warn("debuginfo: Invalid path to crate's local root source file!");
                 fallback_path(cx)
             } else {
-                match abs_path.path_relative_from(work_dir) {
+                match abs_path.relative_from(work_dir) {
                     Some(ref p) if p.is_relative() => {
-                        // prepend "./" if necessary
-                        let dotdot = b"..";
-                        let prefix: &[u8] = &[dotdot[0], ::std::old_path::SEP_BYTE];
-                        let mut path_bytes = p.as_vec().to_vec();
-
-                        if &path_bytes[..2] != prefix &&
-                           &path_bytes[..2] != dotdot {
-                            path_bytes.insert(0, prefix[0]);
-                            path_bytes.insert(1, prefix[1]);
+                        if p.starts_with(Path::new("./")) {
+                            path2cstr(p)
+                        } else {
+                            path2cstr(&Path::new(".").join(p))
                         }
-
-                        CString::new(path_bytes).unwrap()
                     }
                     _ => fallback_path(cx)
                 }
@@ -1614,7 +1609,7 @@ fn compile_unit_metadata(cx: &CrateContext) -> DIDescriptor {
                            (option_env!("CFG_VERSION")).expect("CFG_VERSION"));
 
     let compile_unit_name = compile_unit_name.as_ptr();
-    let work_dir = CString::new(work_dir.as_vec()).unwrap();
+    let work_dir = path2cstr(&work_dir);
     let producer = CString::new(producer).unwrap();
     let flags = "\0";
     let split_name = "\0";
@@ -1716,7 +1711,7 @@ fn file_metadata(cx: &CrateContext, full_path: &str) -> DIFile {
     debug!("file_metadata: {}", full_path);
 
     // FIXME (#9639): This needs to handle non-utf8 paths
-    let work_dir = cx.sess().working_dir.as_str().unwrap();
+    let work_dir = cx.sess().working_dir.to_str().unwrap();
     let file_name =
         if full_path.starts_with(work_dir) {
             &full_path[work_dir.len() + 1..full_path.len()]
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 36d39fa58ba..c39451b15ad 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -49,7 +49,7 @@ use rustc::middle::stability;
 
 use std::rc::Rc;
 use std::u32;
-use std::old_path::Path as FsPath; // Conflicts with Path struct
+use std::path::PathBuf;
 
 use core::DocContext;
 use doctree;
@@ -118,7 +118,7 @@ impl<T: Clean<U>, U> Clean<Vec<U>> for syntax::owned_slice::OwnedSlice<T> {
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Crate {
     pub name: String,
-    pub src: FsPath,
+    pub src: PathBuf,
     pub module: Option<Item>,
     pub externs: Vec<(ast::CrateNum, ExternalCrate)>,
     pub primitives: Vec<PrimitiveType>,
@@ -191,7 +191,7 @@ impl<'a, 'tcx> Clean<Crate> for visit_ast::RustdocVisitor<'a, 'tcx> {
 
         let src = match cx.input {
             Input::File(ref path) => path.clone(),
-            Input::Str(_) => FsPath::new("") // FIXME: this is wrong
+            Input::Str(_) => PathBuf::new("") // FIXME: this is wrong
         };
 
         Crate {
diff --git a/src/librustdoc/externalfiles.rs b/src/librustdoc/externalfiles.rs
index 942aec7d22f..6cfe7a33dd4 100644
--- a/src/librustdoc/externalfiles.rs
+++ b/src/librustdoc/externalfiles.rs
@@ -8,7 +8,12 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::{old_io, str};
+use std::fs::File;
+use std::io::prelude::*;
+use std::io;
+use std::old_io;
+use std::path::{PathBuf, Path};
+use std::str;
 
 #[derive(Clone)]
 pub struct ExternalHtml{
@@ -33,16 +38,17 @@ impl ExternalHtml {
     }
 }
 
-pub fn load_string(input: &Path) -> old_io::IoResult<Option<String>> {
-    let mut f = try!(old_io::File::open(input));
-    let d = try!(f.read_to_end());
+pub fn load_string(input: &Path) -> io::Result<Option<String>> {
+    let mut f = try!(File::open(input));
+    let mut d = Vec::new();
+    try!(f.read_to_end(&mut d));
     Ok(str::from_utf8(&d).map(|s| s.to_string()).ok())
 }
 
 macro_rules! load_or_return {
     ($input: expr, $cant_read: expr, $not_utf8: expr) => {
         {
-            let input = Path::new($input);
+            let input = PathBuf::new($input);
             match ::externalfiles::load_string(&input) {
                 Err(e) => {
                     let _ = writeln!(&mut old_io::stderr(),
diff --git a/src/librustdoc/flock.rs b/src/librustdoc/flock.rs
index 79e348cb03e..51c58861b4b 100644
--- a/src/librustdoc/flock.rs
+++ b/src/librustdoc/flock.rs
@@ -20,7 +20,9 @@ pub use self::imp::Lock;
 
 #[cfg(unix)]
 mod imp {
-    use std::ffi::CString;
+    use std::ffi::{AsOsStr, CString};
+    use std::os::unix::prelude::*;
+    use std::path::Path;
     use libc;
     use std::os as stdos;
 
@@ -114,7 +116,7 @@ mod imp {
 
     impl Lock {
         pub fn new(p: &Path) -> Lock {
-            let buf = CString::new(p.as_vec()).unwrap();
+            let buf = CString::new(p.as_os_str().as_bytes()).unwrap();
             let fd = unsafe {
                 libc::open(buf.as_ptr(), libc::O_RDWR | libc::O_CREAT,
                            libc::S_IRWXU)
@@ -163,8 +165,11 @@ mod imp {
 #[cfg(windows)]
 mod imp {
     use libc;
+    use std::ffi::AsOsStr;
     use std::mem;
+    use std::os::windows::prelude::*;
     use std::os;
+    use std::path::Path;
     use std::ptr;
 
     const LOCKFILE_EXCLUSIVE_LOCK: libc::DWORD = 0x00000002;
@@ -190,7 +195,7 @@ mod imp {
 
     impl Lock {
         pub fn new(p: &Path) -> Lock {
-            let mut p_16: Vec<u16> = p.as_str().unwrap().utf16_units().collect();
+            let mut p_16: Vec<_> = p.as_os_str().encode_wide().collect();
             p_16.push(0);
             let handle = unsafe {
                 libc::CreateFileW(p_16.as_ptr(),
diff --git a/src/librustdoc/html/layout.rs b/src/librustdoc/html/layout.rs
index c537e370723..3acd17dedd5 100644
--- a/src/librustdoc/html/layout.rs
+++ b/src/librustdoc/html/layout.rs
@@ -9,7 +9,8 @@
 // except according to those terms.
 
 use std::fmt;
-use std::old_io;
+use std::io::prelude::*;
+use std::io;
 
 use externalfiles::ExternalHtml;
 
@@ -31,8 +32,8 @@ pub struct Page<'a> {
 }
 
 pub fn render<T: fmt::Display, S: fmt::Display>(
-    dst: &mut old_io::Writer, layout: &Layout, page: &Page, sidebar: &S, t: &T)
-    -> old_io::IoResult<()>
+    dst: &mut io::Write, layout: &Layout, page: &Page, sidebar: &S, t: &T)
+    -> io::Result<()>
 {
     write!(dst,
 r##"<!DOCTYPE html>
@@ -159,7 +160,7 @@ r##"<!DOCTYPE html>
     )
 }
 
-pub fn redirect(dst: &mut old_io::Writer, url: &str) -> old_io::IoResult<()> {
+pub fn redirect(dst: &mut io::Write, url: &str) -> io::Result<()> {
     // <script> triggers a redirect before refresh, so this is fine.
     write!(dst,
 r##"<!DOCTYPE html>
diff --git a/src/librustdoc/html/render.rs b/src/librustdoc/html/render.rs
index 735487611dc..add44769bab 100644
--- a/src/librustdoc/html/render.rs
+++ b/src/librustdoc/html/render.rs
@@ -38,11 +38,13 @@ use std::cell::RefCell;
 use std::cmp::Ordering;
 use std::collections::{HashMap, HashSet};
 use std::default::Default;
+use std::ffi::OsStr;
 use std::fmt;
-use std::old_io::fs::PathExtensions;
-use std::old_io::{fs, File, BufferedWriter, BufferedReader};
-use std::old_io;
+use std::fs::{self, File};
+use std::io::prelude::*;
+use std::io::{self, BufWriter, BufReader};
 use std::iter::repeat;
+use std::path::{PathBuf, Path};
 use std::str;
 use std::sync::Arc;
 
@@ -89,10 +91,10 @@ pub struct Context {
     pub root_path: String,
     /// The path to the crate root source minus the file name.
     /// Used for simplifying paths to the highlighted source code files.
-    pub src_root: Path,
+    pub src_root: PathBuf,
     /// The current destination folder of where HTML artifacts should be placed.
     /// This changes as the context descends into the module hierarchy.
-    pub dst: Path,
+    pub dst: PathBuf,
     /// This describes the layout of each page, and is not modified after
     /// creation of the context (contains info like the favicon and added html).
     pub layout: layout::Layout,
@@ -220,7 +222,7 @@ struct SourceCollector<'a> {
     /// Processed source-file paths
     seen: HashSet<String>,
     /// Root destination to place all HTML output into
-    dst: Path,
+    dst: PathBuf,
 }
 
 /// Wrapper struct to render the source code of a file. This will do things like
@@ -257,11 +259,15 @@ thread_local!(pub static CURRENT_LOCATION_KEY: RefCell<Vec<String>> =
 /// Generates the documentation for `crate` into the directory `dst`
 pub fn run(mut krate: clean::Crate,
            external_html: &ExternalHtml,
-           dst: Path,
-           passes: HashSet<String>) -> old_io::IoResult<()> {
+           dst: PathBuf,
+           passes: HashSet<String>) -> io::Result<()> {
+    let src_root = match krate.src.parent() {
+        Some(p) => p.to_path_buf(),
+        None => PathBuf::new(""),
+    };
     let mut cx = Context {
         dst: dst,
-        src_root: krate.src.dir_path(),
+        src_root: src_root,
         passes: passes,
         current: Vec::new(),
         root_path: String::new(),
@@ -392,7 +398,7 @@ pub fn run(mut krate: clean::Crate,
     cx.krate(krate, summary)
 }
 
-fn build_index(krate: &clean::Crate, cache: &mut Cache) -> old_io::IoResult<String> {
+fn build_index(krate: &clean::Crate, cache: &mut Cache) -> io::Result<String> {
     // Build the search index from the collected metadata
     let mut nodeid_to_pathid = HashMap::new();
     let mut pathid_to_nodeid = Vec::new();
@@ -437,7 +443,7 @@ fn build_index(krate: &clean::Crate, cache: &mut Cache) -> old_io::IoResult<Stri
     }
 
     // Collect the index into a string
-    let mut w = Vec::new();
+    let mut w = io::Cursor::new(Vec::new());
     try!(write!(&mut w, r#"searchIndex['{}'] = {{"items":["#, krate.name));
 
     let mut lastpath = "".to_string();
@@ -480,13 +486,13 @@ fn build_index(krate: &clean::Crate, cache: &mut Cache) -> old_io::IoResult<Stri
 
     try!(write!(&mut w, "]}};"));
 
-    Ok(String::from_utf8(w).unwrap())
+    Ok(String::from_utf8(w.into_inner()).unwrap())
 }
 
 fn write_shared(cx: &Context,
                 krate: &clean::Crate,
                 cache: &Cache,
-                search_index: String) -> old_io::IoResult<()> {
+                search_index: String) -> io::Result<()> {
     // Write out the shared files. Note that these are shared among all rustdoc
     // docs placed in the output directory, so this needs to be a synchronized
     // operation with respect to all other rustdocs running around.
@@ -518,10 +524,10 @@ fn write_shared(cx: &Context,
                include_bytes!("static/SourceCodePro-Semibold.woff")));
 
     fn collect(path: &Path, krate: &str,
-               key: &str) -> old_io::IoResult<Vec<String>> {
+               key: &str) -> io::Result<Vec<String>> {
         let mut ret = Vec::new();
         if path.exists() {
-            for line in BufferedReader::new(File::open(path)).lines() {
+            for line in BufReader::new(try!(File::open(path))).lines() {
                 let line = try!(line);
                 if !line.starts_with(key) {
                     continue
@@ -567,14 +573,14 @@ fn write_shared(cx: &Context,
             mydst.push(part);
             try!(mkdir(&mydst));
         }
-        mydst.push(format!("{}.{}.js",
-                           remote_item_type.to_static_str(),
-                           remote_path[remote_path.len() - 1]));
+        mydst.push(&format!("{}.{}.js",
+                            remote_item_type.to_static_str(),
+                            remote_path[remote_path.len() - 1]));
         let all_implementors = try!(collect(&mydst, &krate.name,
                                             "implementors"));
 
-        try!(mkdir(&mydst.dir_path()));
-        let mut f = BufferedWriter::new(try!(File::create(&mydst)));
+        try!(mkdir(mydst.parent().unwrap()));
+        let mut f = BufWriter::new(try!(File::create(&mydst)));
         try!(writeln!(&mut f, "(function() {{var implementors = {{}};"));
 
         for implementor in &all_implementors {
@@ -606,7 +612,7 @@ fn write_shared(cx: &Context,
 }
 
 fn render_sources(cx: &mut Context,
-                  krate: clean::Crate) -> old_io::IoResult<clean::Crate> {
+                  krate: clean::Crate) -> io::Result<clean::Crate> {
     info!("emitting source files");
     let dst = cx.dst.join("src");
     try!(mkdir(&dst));
@@ -624,15 +630,15 @@ fn render_sources(cx: &mut Context,
 
 /// Writes the entire contents of a string to a destination, not attempting to
 /// catch any errors.
-fn write(dst: Path, contents: &[u8]) -> old_io::IoResult<()> {
-    File::create(&dst).write_all(contents)
+fn write(dst: PathBuf, contents: &[u8]) -> io::Result<()> {
+    try!(File::create(&dst)).write_all(contents)
 }
 
 /// Makes a directory on the filesystem, failing the task if an error occurs and
 /// skipping if the directory already exists.
-fn mkdir(path: &Path) -> old_io::IoResult<()> {
+fn mkdir(path: &Path) -> io::Result<()> {
     if !path.exists() {
-        fs::mkdir(path, old_io::USER_RWX)
+        fs::create_dir(path)
     } else {
         Ok(())
     }
@@ -648,21 +654,17 @@ fn shortty(item: &clean::Item) -> ItemType {
 /// static HTML tree.
 // FIXME (#9639): The closure should deal with &[u8] instead of &str
 // FIXME (#9639): This is too conservative, rejecting non-UTF-8 paths
-fn clean_srcpath<F>(src_root: &Path, src: &[u8], mut f: F) where
+fn clean_srcpath<F>(src_root: &Path, p: &Path, mut f: F) where
     F: FnMut(&str),
 {
-    let p = Path::new(src);
-
     // make it relative, if possible
-    let p = p.path_relative_from(src_root).unwrap_or(p);
+    let p = p.relative_from(src_root).unwrap_or(p);
 
-    if p.as_vec() != b"." {
-        for c in p.str_components().map(|x|x.unwrap()) {
-            if ".." == c {
-                f("up");
-            } else {
-                f(c)
-            }
+    for c in p.iter().map(|x| x.to_str().unwrap()) {
+        if ".." == c {
+            f("up");
+        } else {
+            f(c)
         }
     }
 }
@@ -733,13 +735,14 @@ impl<'a> DocFolder for SourceCollector<'a> {
 
 impl<'a> SourceCollector<'a> {
     /// Renders the given filename into its corresponding HTML source file.
-    fn emit_source(&mut self, filename: &str) -> old_io::IoResult<()> {
-        let p = Path::new(filename);
+    fn emit_source(&mut self, filename: &str) -> io::Result<()> {
+        let p = PathBuf::new(filename);
 
         // If we couldn't open this file, then just returns because it
         // probably means that it's some standard library macro thing and we
         // can't have the source to it anyway.
-        let contents = match File::open(&p).read_to_end() {
+        let mut contents = Vec::new();
+        match File::open(&p).and_then(|mut f| f.read_to_end(&mut contents)) {
             Ok(r) => r,
             // macros from other libraries get special filenames which we can
             // safely ignore
@@ -759,18 +762,20 @@ impl<'a> SourceCollector<'a> {
         // Create the intermediate directories
         let mut cur = self.dst.clone();
         let mut root_path = String::from_str("../../");
-        clean_srcpath(&self.cx.src_root, p.dirname(), |component| {
+        clean_srcpath(&self.cx.src_root, &p, |component| {
             cur.push(component);
             mkdir(&cur).unwrap();
             root_path.push_str("../");
         });
 
-        let mut fname = p.filename().expect("source has no filename").to_vec();
-        fname.extend(".html".bytes());
-        cur.push(fname);
-        let mut w = BufferedWriter::new(try!(File::create(&cur)));
+        let mut fname = p.file_name().expect("source has no filename")
+                         .to_os_string();
+        fname.push_os_str(OsStr::from_str(".html"));
+        cur.push(&fname);
+        let mut w = BufWriter::new(try!(File::create(&cur)));
 
-        let title = format!("{} -- source", cur.filename_display());
+        let title = format!("{} -- source", cur.file_name().unwrap()
+                                               .to_string_lossy());
         let desc = format!("Source to the Rust file `{}`.", filename);
         let page = layout::Page {
             title: &title,
@@ -779,7 +784,7 @@ impl<'a> SourceCollector<'a> {
             description: &desc,
             keywords: get_basic_keywords(),
         };
-        try!(layout::render(&mut w as &mut Writer, &self.cx.layout,
+        try!(layout::render(&mut w, &self.cx.layout,
                             &page, &(""), &Source(contents)));
         try!(w.flush());
         return Ok(());
@@ -1081,7 +1086,7 @@ impl Context {
     /// This currently isn't parallelized, but it'd be pretty easy to add
     /// parallelization to this function.
     fn krate(mut self, mut krate: clean::Crate,
-             stability: stability_summary::ModuleSummary) -> old_io::IoResult<()> {
+             stability: stability_summary::ModuleSummary) -> io::Result<()> {
         let mut item = match krate.module.take() {
             Some(i) => i,
             None => return Ok(())
@@ -1091,7 +1096,7 @@ impl Context {
         // render stability dashboard
         try!(self.recurse(stability.name.clone(), |this| {
             let json_dst = &this.dst.join("stability.json");
-            let mut json_out = BufferedWriter::new(try!(File::create(json_dst)));
+            let mut json_out = BufWriter::new(try!(File::create(json_dst)));
             try!(write!(&mut json_out, "{}", json::as_json(&stability)));
 
             let mut title = stability.name.clone();
@@ -1106,7 +1111,7 @@ impl Context {
                 keywords: get_basic_keywords(),
             };
             let html_dst = &this.dst.join("stability.html");
-            let mut html_out = BufferedWriter::new(try!(File::create(html_dst)));
+            let mut html_out = BufWriter::new(try!(File::create(html_dst)));
             layout::render(&mut html_out, &this.layout, &page,
                            &Sidebar{ cx: this, item: &item },
                            &stability)
@@ -1131,12 +1136,12 @@ impl Context {
     /// all sub-items which need to be rendered.
     ///
     /// The rendering driver uses this closure to queue up more work.
-    fn item<F>(&mut self, item: clean::Item, mut f: F) -> old_io::IoResult<()> where
+    fn item<F>(&mut self, item: clean::Item, mut f: F) -> io::Result<()> where
         F: FnMut(&mut Context, clean::Item),
     {
-        fn render(w: old_io::File, cx: &Context, it: &clean::Item,
-                  pushname: bool) -> old_io::IoResult<()> {
-            info!("Rendering an item to {}", w.path().display());
+        fn render(w: File, cx: &Context, it: &clean::Item,
+                  pushname: bool) -> io::Result<()> {
+            info!("Rendering an item to {}", w.path().unwrap().display());
             // A little unfortunate that this is done like this, but it sure
             // does make formatting *a lot* nicer.
             CURRENT_LOCATION_KEY.with(|slot| {
@@ -1177,7 +1182,7 @@ impl Context {
             // We have a huge number of calls to write, so try to alleviate some
             // of the pain by using a buffered writer instead of invoking the
             // write syscall all the time.
-            let mut writer = BufferedWriter::new(w);
+            let mut writer = BufWriter::new(w);
             if !cx.render_redirect_pages {
                 try!(layout::render(&mut writer, &cx.layout, &page,
                                     &Sidebar{ cx: cx, item: it },
@@ -1238,7 +1243,7 @@ impl Context {
             // Things which don't have names (like impls) don't get special
             // pages dedicated to them.
             _ if item.name.is_some() => {
-                let dst = self.dst.join(item_path(&item));
+                let dst = self.dst.join(&item_path(&item));
                 let dst = try!(File::create(&dst));
                 render(dst, self, &item, true)
             }
@@ -1307,7 +1312,7 @@ impl<'a> Item<'a> {
         // has anchors for the line numbers that we're linking to.
         if ast_util::is_local(self.item.def_id) {
             let mut path = Vec::new();
-            clean_srcpath(&cx.src_root, self.item.source.filename.as_bytes(),
+            clean_srcpath(&cx.src_root, Path::new(&self.item.source.filename),
                           |component| {
                 path.push(component.to_string());
             });
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index fc304884ec9..b4522ad680b 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -34,6 +34,10 @@
 #![feature(test)]
 #![feature(unicode)]
 #![feature(str_words)]
+#![feature(io)]
+#![feature(fs)]
+#![feature(path)]
+#![feature(tempdir)]
 
 extern crate arena;
 extern crate getopts;
@@ -53,10 +57,12 @@ extern crate "serialize" as rustc_serialize; // used by deriving
 use std::cell::RefCell;
 use std::collections::HashMap;
 use std::env;
-use std::old_io::File;
-use std::old_io;
+use std::fs::File;
+use std::io::{self, Read, Write};
+use std::path::PathBuf;
 use std::rc::Rc;
 use std::sync::mpsc::channel;
+
 use externalfiles::ExternalHtml;
 use serialize::Decodable;
 use serialize::json::{self, Json};
@@ -242,7 +248,7 @@ pub fn main_args(args: &[String]) -> int {
     let should_test = matches.opt_present("test");
     let markdown_input = input.ends_with(".md") || input.ends_with(".markdown");
 
-    let output = matches.opt_str("o").map(|s| Path::new(s));
+    let output = matches.opt_str("o").map(|s| PathBuf::new(&s));
     let cfgs = matches.opt_strs("cfg");
 
     let external_html = match ExternalHtml::load(
@@ -261,7 +267,8 @@ pub fn main_args(args: &[String]) -> int {
         (true, false) => {
             return test::run(input, cfgs, libs, externs, test_args, crate_name)
         }
-        (false, true) => return markdown::render(input, output.unwrap_or(Path::new("doc")),
+        (false, true) => return markdown::render(input,
+                                                 output.unwrap_or(PathBuf::new("doc")),
                                                  &matches, &external_html,
                                                  !matches.opt_present("markdown-no-toc")),
         (false, false) => {}
@@ -278,7 +285,8 @@ pub fn main_args(args: &[String]) -> int {
     info!("going to format");
     match matches.opt_str("w").as_ref().map(|s| &**s) {
         Some("html") | None => {
-            match html::render::run(krate, &external_html, output.unwrap_or(Path::new("doc")),
+            match html::render::run(krate, &external_html,
+                                    output.unwrap_or(PathBuf::new("doc")),
                                     passes.into_iter().collect()) {
                 Ok(()) => {}
                 Err(e) => panic!("failed to generate documentation: {}", e),
@@ -286,7 +294,7 @@ pub fn main_args(args: &[String]) -> int {
         }
         Some("json") => {
             match json_output(krate, json_plugins,
-                              output.unwrap_or(Path::new("doc.json"))) {
+                              output.unwrap_or(PathBuf::new("doc.json"))) {
                 Ok(()) => {}
                 Err(e) => panic!("failed to write json: {}", e),
             }
@@ -364,15 +372,15 @@ fn rust_input(cratefile: &str, externs: core::Externs, matches: &getopts::Matche
     let cfgs = matches.opt_strs("cfg");
     let triple = matches.opt_str("target");
 
-    let cr = Path::new(cratefile);
+    let cr = PathBuf::new(cratefile);
     info!("starting to run rustc");
 
     let (tx, rx) = channel();
     std::thread::spawn(move || {
         use rustc::session::config::Input;
 
-        let cr = cr;
-        tx.send(core::run_core(paths, cfgs, externs, Input::File(cr), triple)).unwrap();
+        tx.send(core::run_core(paths, cfgs, externs, Input::File(cr),
+                               triple)).unwrap();
     }).join().map_err(|_| "rustc failed").unwrap();
     let (mut krate, analysis) = rx.recv().unwrap();
     info!("finished with rustc");
@@ -451,13 +459,12 @@ fn rust_input(cratefile: &str, externs: core::Externs, matches: &getopts::Matche
 /// This input format purely deserializes the json output file. No passes are
 /// run over the deserialized output.
 fn json_input(input: &str) -> Result<Output, String> {
-    let mut input = match File::open(&Path::new(input)) {
-        Ok(f) => f,
-        Err(e) => {
-            return Err(format!("couldn't open {}: {}", input, e))
-        }
+    let mut bytes = Vec::new();
+    match File::open(input).and_then(|mut f| f.read_to_end(&mut bytes)) {
+        Ok(()) => {}
+        Err(e) => return Err(format!("couldn't open {}: {}", input, e)),
     };
-    match json::from_reader(&mut input) {
+    match json::from_reader(&mut &bytes[..]) {
         Err(s) => Err(format!("{:?}", s)),
         Ok(Json::Object(obj)) => {
             let mut obj = obj;
@@ -495,7 +502,7 @@ fn json_input(input: &str) -> Result<Output, String> {
 /// Outputs the crate/plugin json as a giant json blob at the specified
 /// destination.
 fn json_output(krate: clean::Crate, res: Vec<plugins::PluginJson> ,
-               dst: Path) -> old_io::IoResult<()> {
+               dst: PathBuf) -> io::Result<()> {
     // {
     //   "schema": version,
     //   "crate": { parsed crate ... },
diff --git a/src/librustdoc/markdown.rs b/src/librustdoc/markdown.rs
index d64d9becc0c..7d635c8b232 100644
--- a/src/librustdoc/markdown.rs
+++ b/src/librustdoc/markdown.rs
@@ -8,7 +8,10 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+use std::fs::File;
+use std::io::Write;
 use std::old_io;
+use std::path::{PathBuf, Path};
 
 use core;
 use getopts;
@@ -40,10 +43,10 @@ fn extract_leading_metadata<'a>(s: &'a str) -> (Vec<&'a str>, &'a str) {
 
 /// Render `input` (e.g. "foo.md") into an HTML file in `output`
 /// (e.g. output = "bar" => "bar/foo.html").
-pub fn render(input: &str, mut output: Path, matches: &getopts::Matches,
+pub fn render(input: &str, mut output: PathBuf, matches: &getopts::Matches,
               external_html: &ExternalHtml, include_toc: bool) -> int {
     let input_p = Path::new(input);
-    output.push(input_p.filestem().unwrap());
+    output.push(input_p.file_stem().unwrap());
     output.set_extension("html");
 
     let mut css = String::new();
@@ -59,7 +62,7 @@ pub fn render(input: &str, mut output: Path, matches: &getopts::Matches,
     }
     let playground = playground.unwrap_or("".to_string());
 
-    let mut out = match old_io::File::create(&output) {
+    let mut out = match File::create(&output) {
         Err(e) => {
             let _ = writeln!(&mut old_io::stderr(),
                              "error opening `{}` for writing: {}",
diff --git a/src/librustdoc/test.rs b/src/librustdoc/test.rs
index 43e8f44244e..9fd38ecb136 100644
--- a/src/librustdoc/test.rs
+++ b/src/librustdoc/test.rs
@@ -9,16 +9,20 @@
 // except according to those terms.
 
 use std::cell::RefCell;
-use std::sync::mpsc::channel;
+use std::collections::{HashSet, HashMap};
 use std::dynamic_lib::DynamicLibrary;
-use std::old_io::{Command, TempDir};
+use std::env;
+use std::ffi::OsString;
+use std::fs::TempDir;
 use std::old_io;
-use std::os;
+use std::io;
+use std::path::PathBuf;
+use std::process::Command;
 use std::str;
+use std::sync::mpsc::channel;
 use std::thread;
 use std::thunk::Thunk;
 
-use std::collections::{HashSet, HashMap};
 use testing;
 use rustc_lint;
 use rustc::session::{self, config};
@@ -43,11 +47,12 @@ pub fn run(input: &str,
            mut test_args: Vec<String>,
            crate_name: Option<String>)
            -> int {
-    let input_path = Path::new(input);
+    let input_path = PathBuf::new(input);
     let input = config::Input::File(input_path.clone());
 
     let sessopts = config::Options {
-        maybe_sysroot: Some(os::self_exe_name().unwrap().dir_path().dir_path()),
+        maybe_sysroot: Some(env::current_exe().unwrap().parent().unwrap()
+                                              .parent().unwrap().to_path_buf()),
         search_paths: libs.clone(),
         crate_types: vec!(config::CrateTypeDylib),
         externs: externs.clone(),
@@ -115,7 +120,8 @@ fn runtest(test: &str, cratename: &str, libs: SearchPaths,
     let input = config::Input::Str(test.to_string());
 
     let sessopts = config::Options {
-        maybe_sysroot: Some(os::self_exe_name().unwrap().dir_path().dir_path()),
+        maybe_sysroot: Some(env::current_exe().unwrap().parent().unwrap()
+                                              .parent().unwrap().to_path_buf()),
         search_paths: libs,
         crate_types: vec!(config::CrateTypeExecutable),
         output_types: vec!(config::OutputTypeExe),
@@ -170,7 +176,7 @@ fn runtest(test: &str, cratename: &str, libs: SearchPaths,
     rustc_lint::register_builtins(&mut sess.lint_store.borrow_mut(), Some(&sess));
 
     let outdir = TempDir::new("rustdoctest").ok().expect("rustdoc needs a tempdir");
-    let out = Some(outdir.path().clone());
+    let out = Some(outdir.path().to_path_buf());
     let cfg = config::build_configuration(&sess);
     let libdir = sess.target_filesearch(PathKind::All).get_lib_path();
     let mut control = driver::CompileController::basic();
@@ -187,17 +193,19 @@ fn runtest(test: &str, cratename: &str, libs: SearchPaths,
     // environment to ensure that the target loads the right libraries at
     // runtime. It would be a sad day if the *host* libraries were loaded as a
     // mistake.
-    let mut cmd = Command::new(outdir.path().join("rust-out"));
+    let mut cmd = Command::new(&outdir.path().join("rust-out"));
+    let var = DynamicLibrary::envvar();
     let newpath = {
-        let mut path = DynamicLibrary::search_path();
+        let path = env::var_os(var).unwrap_or(OsString::new());
+        let mut path = env::split_paths(&path).collect::<Vec<_>>();
         path.insert(0, libdir.clone());
-        DynamicLibrary::create_path(&path)
+        env::join_paths(path.iter()).unwrap()
     };
-    cmd.env(DynamicLibrary::envvar(), newpath);
+    cmd.env(var, &newpath);
 
     match cmd.output() {
         Err(e) => panic!("couldn't run the test: {}{}", e,
-                        if e.kind == old_io::PermissionDenied {
+                        if e.kind() == io::ErrorKind::PermissionDenied {
                             " - maybe your tempdir is mounted with noexec?"
                         } else { "" }),
         Ok(out) => {
@@ -205,7 +213,7 @@ fn runtest(test: &str, cratename: &str, libs: SearchPaths,
                 panic!("test executable succeeded when it should have failed");
             } else if !should_fail && !out.status.success() {
                 panic!("test executable failed:\n{:?}",
-                      str::from_utf8(&out.error));
+                      str::from_utf8(&out.stdout));
             }
         }
     }
diff --git a/src/libserialize/lib.rs b/src/libserialize/lib.rs
index d476fd72abc..bfc6b1bf0ef 100644
--- a/src/libserialize/lib.rs
+++ b/src/libserialize/lib.rs
@@ -35,6 +35,7 @@ Core encoding and decoding interfaces.
 #![feature(staged_api)]
 #![feature(std_misc)]
 #![feature(unicode)]
+#![feature(path)]
 #![cfg_attr(test, feature(test))]
 
 // test harness access
diff --git a/src/libserialize/serialize.rs b/src/libserialize/serialize.rs
index 70f0ba4bb23..f287229e083 100644
--- a/src/libserialize/serialize.rs
+++ b/src/libserialize/serialize.rs
@@ -15,6 +15,7 @@ Core encoding and decoding interfaces.
 */
 
 use std::old_path;
+use std::path;
 use std::rc::Rc;
 use std::cell::{Cell, RefCell};
 use std::sync::Arc;
@@ -564,6 +565,19 @@ impl Decodable for old_path::windows::Path {
     }
 }
 
+impl Encodable for path::PathBuf {
+    fn encode<S: Encoder>(&self, e: &mut S) -> Result<(), S::Error> {
+        self.to_str().unwrap().encode(e)
+    }
+}
+
+impl Decodable for path::PathBuf {
+    fn decode<D: Decoder>(d: &mut D) -> Result<path::PathBuf, D::Error> {
+        let bytes: String = try!(Decodable::decode(d));
+        Ok(path::PathBuf::new(&bytes))
+    }
+}
+
 impl<T: Encodable + Copy> Encodable for Cell<T> {
     fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
         self.get().encode(s)
diff --git a/src/libstd/old_io/fs.rs b/src/libstd/old_io/fs.rs
index 4e9c1b36055..9a34ec4b026 100644
--- a/src/libstd/old_io/fs.rs
+++ b/src/libstd/old_io/fs.rs
@@ -82,6 +82,8 @@ use sys_common;
 /// attempted against it for which its underlying file descriptor was not
 /// configured at creation time, via the `FileAccess` parameter to
 /// `File::open_mode()`.
+#[deprecated(since = "1.0.0", reason = "replaced with std::fs::File")]
+#[unstable(feature = "old_io")]
 pub struct File {
     fd: fs_imp::FileDesc,
     path: Path,
@@ -94,6 +96,8 @@ impl sys_common::AsInner<fs_imp::FileDesc> for File {
     }
 }
 
+#[deprecated(since = "1.0.0", reason = "replaced with std::fs")]
+#[unstable(feature = "old_io")]
 impl File {
     /// Open a file at `path` in the mode specified by the `mode` and `access`
     /// arguments
@@ -133,6 +137,8 @@ impl File {
     /// * Attempting to open a file with a `FileAccess` that the user lacks
     ///   permissions for
     /// * Filesystem-level errors (full disk, etc)
+    #[deprecated(since = "1.0.0", reason = "replaced with std::fs::OpenOptions")]
+    #[unstable(feature = "old_io")]
     pub fn open_mode(path: &Path,
                      mode: FileMode,
                      access: FileAccess) -> IoResult<File> {
@@ -174,6 +180,8 @@ impl File {
     ///
     /// let contents = File::open(&Path::new("foo.txt")).read_to_end();
     /// ```
+    #[deprecated(since = "1.0.0", reason = "replaced with std::fs::File::open")]
+    #[unstable(feature = "old_io")]
     pub fn open(path: &Path) -> IoResult<File> {
         File::open_mode(path, Open, Read)
     }
@@ -195,12 +203,16 @@ impl File {
     /// # drop(f);
     /// # ::std::old_io::fs::unlink(&Path::new("foo.txt"));
     /// ```
+    #[deprecated(since = "1.0.0", reason = "replaced with std::fs::File::create")]
+    #[unstable(feature = "old_io")]
     pub fn create(path: &Path) -> IoResult<File> {
         File::open_mode(path, Truncate, Write)
              .update_desc("couldn't create file")
     }
 
     /// Returns the original path that was used to open this file.
+    #[deprecated(since = "1.0.0", reason = "replaced with std::fs")]
+    #[unstable(feature = "old_io")]
     pub fn path<'a>(&'a self) -> &'a Path {
         &self.path
     }
@@ -208,6 +220,8 @@ impl File {
     /// Synchronizes all modifications to this file to its permanent storage
     /// device. This will flush any internal buffers necessary to perform this
     /// operation.
+    #[deprecated(since = "1.0.0", reason = "replaced with std::fs")]
+    #[unstable(feature = "old_io")]
     pub fn fsync(&mut self) -> IoResult<()> {
         self.fd.fsync()
             .update_err("couldn't fsync file",
@@ -218,6 +232,8 @@ impl File {
     /// file metadata to the filesystem. This is intended for use cases that
     /// must synchronize content, but don't need the metadata on disk. The goal
     /// of this method is to reduce disk operations.
+    #[deprecated(since = "1.0.0", reason = "replaced with std::fs")]
+    #[unstable(feature = "old_io")]
     pub fn datasync(&mut self) -> IoResult<()> {
         self.fd.datasync()
             .update_err("couldn't datasync file",
@@ -232,6 +248,8 @@ impl File {
     /// be shrunk. If it is greater than the current file's size, then the file
     /// will be extended to `size` and have all of the intermediate data filled
     /// in with 0s.
+    #[deprecated(since = "1.0.0", reason = "replaced with std::fs")]
+    #[unstable(feature = "old_io")]
     pub fn truncate(&mut self, size: i64) -> IoResult<()> {
         self.fd.truncate(size)
             .update_err("couldn't truncate file", |e|
@@ -247,11 +265,15 @@ impl File {
     /// until you have attempted to read past the end of the file, so if
     /// you've read _exactly_ the number of bytes in the file, this will
     /// return `false`, not `true`.
+    #[deprecated(since = "1.0.0", reason = "replaced with std::fs")]
+    #[unstable(feature = "old_io")]
     pub fn eof(&self) -> bool {
         self.last_nread == 0
     }
 
     /// Queries information about the underlying file.
+    #[deprecated(since = "1.0.0", reason = "replaced with std::fs")]
+    #[unstable(feature = "old_io")]
     pub fn stat(&self) -> IoResult<FileStat> {
         self.fd.fstat()
             .update_err("couldn't fstat file", |e|
@@ -280,6 +302,8 @@ impl File {
 /// This function will return an error if `path` points to a directory, if the
 /// user lacks permissions to remove the file, or if some other filesystem-level
 /// error occurs.
+#[deprecated(since = "1.0.0", reason = "replaced with std::fs::remove_file")]
+#[unstable(feature = "old_io")]
 pub fn unlink(path: &Path) -> IoResult<()> {
     fs_imp::unlink(path)
            .update_err("couldn't unlink path", |e|
@@ -307,6 +331,8 @@ pub fn unlink(path: &Path) -> IoResult<()> {
 /// This function will return an error if the user lacks the requisite permissions
 /// to perform a `stat` call on the given `path` or if there is no entry in the
 /// filesystem at the provided path.
+#[deprecated(since = "1.0.0", reason = "replaced with std::fs::metadata")]
+#[unstable(feature = "old_io")]
 pub fn stat(path: &Path) -> IoResult<FileStat> {
     fs_imp::stat(path)
            .update_err("couldn't stat path", |e|
@@ -321,6 +347,7 @@ pub fn stat(path: &Path) -> IoResult<FileStat> {
 /// # Error
 ///
 /// See `stat`
+#[unstable(feature = "old_fs")]
 pub fn lstat(path: &Path) -> IoResult<FileStat> {
     fs_imp::lstat(path)
            .update_err("couldn't lstat path", |e|
@@ -343,6 +370,8 @@ pub fn lstat(path: &Path) -> IoResult<FileStat> {
 /// This function will return an error if the provided `from` doesn't exist, if
 /// the process lacks permissions to view the contents, or if some other
 /// intermittent I/O error occurs.
+#[deprecated(since = "1.0.0", reason = "replaced with std::fs::rename")]
+#[unstable(feature = "old_io")]
 pub fn rename(from: &Path, to: &Path) -> IoResult<()> {
     fs_imp::rename(from, to)
            .update_err("couldn't rename path", |e|
@@ -377,6 +406,8 @@ pub fn rename(from: &Path, to: &Path) -> IoResult<()> {
 /// Note that this copy is not atomic in that once the destination is
 /// ensured to not exist, there is nothing preventing the destination from
 /// being created and then destroyed by this operation.
+#[deprecated(since = "1.0.0", reason = "replaced with std::fs::copy")]
+#[unstable(feature = "old_io")]
 pub fn copy(from: &Path, to: &Path) -> IoResult<()> {
     fn update_err<T>(result: IoResult<T>, from: &Path, to: &Path) -> IoResult<T> {
         result.update_err("couldn't copy path", |e| {
@@ -421,6 +452,8 @@ pub fn copy(from: &Path, to: &Path) -> IoResult<()> {
 /// This function will return an error if the provided `path` doesn't exist, if
 /// the process lacks permissions to change the attributes of the file, or if
 /// some other I/O error is encountered.
+#[deprecated(since = "1.0.0", reason = "replaced with std::fs::set_permissions")]
+#[unstable(feature = "old_io")]
 pub fn chmod(path: &Path, mode: old_io::FilePermission) -> IoResult<()> {
     fs_imp::chmod(path, mode.bits() as uint)
            .update_err("couldn't chmod path", |e|
@@ -428,6 +461,7 @@ pub fn chmod(path: &Path, mode: old_io::FilePermission) -> IoResult<()> {
 }
 
 /// Change the user and group owners of a file at the specified path.
+#[unstable(feature = "old_fs")]
 pub fn chown(path: &Path, uid: int, gid: int) -> IoResult<()> {
     fs_imp::chown(path, uid, gid)
            .update_err("couldn't chown path", |e|
@@ -437,6 +471,8 @@ pub fn chown(path: &Path, uid: int, gid: int) -> IoResult<()> {
 /// Creates a new hard link on the filesystem. The `dst` path will be a
 /// link pointing to the `src` path. Note that systems often require these
 /// two paths to both be located on the same filesystem.
+#[deprecated(since = "1.0.0", reason = "replaced with std::fs::hard_link")]
+#[unstable(feature = "old_io")]
 pub fn link(src: &Path, dst: &Path) -> IoResult<()> {
     fs_imp::link(src, dst)
            .update_err("couldn't link path", |e|
@@ -445,6 +481,8 @@ pub fn link(src: &Path, dst: &Path) -> IoResult<()> {
 
 /// Creates a new symbolic link on the filesystem. The `dst` path will be a
 /// symlink pointing to the `src` path.
+#[deprecated(since = "1.0.0", reason = "replaced with std::fs::soft_link")]
+#[unstable(feature = "old_io")]
 pub fn symlink(src: &Path, dst: &Path) -> IoResult<()> {
     fs_imp::symlink(src, dst)
            .update_err("couldn't symlink path", |e|
@@ -457,6 +495,8 @@ pub fn symlink(src: &Path, dst: &Path) -> IoResult<()> {
 ///
 /// This function will return an error on failure. Failure conditions include
 /// reading a file that does not exist or reading a file that is not a symlink.
+#[deprecated(since = "1.0.0", reason = "replaced with std::fs::read_link")]
+#[unstable(feature = "old_io")]
 pub fn readlink(path: &Path) -> IoResult<Path> {
     fs_imp::readlink(path)
            .update_err("couldn't resolve symlink for path", |e|
@@ -480,6 +520,7 @@ pub fn readlink(path: &Path) -> IoResult<Path> {
 ///
 /// This function will return an error if the user lacks permissions to make a
 /// new directory at the provided `path`, or if the directory already exists.
+#[unstable(feature = "old_fs")]
 pub fn mkdir(path: &Path, mode: FilePermission) -> IoResult<()> {
     fs_imp::mkdir(path, mode.bits() as uint)
            .update_err("couldn't create directory", |e|
@@ -502,6 +543,8 @@ pub fn mkdir(path: &Path, mode: FilePermission) -> IoResult<()> {
 ///
 /// This function will return an error if the user lacks permissions to remove
 /// the directory at the provided `path`, or if the directory isn't empty.
+#[deprecated(since = "1.0.0", reason = "replaced with std::fs::remove_dir")]
+#[unstable(feature = "old_io")]
 pub fn rmdir(path: &Path) -> IoResult<()> {
     fs_imp::rmdir(path)
            .update_err("couldn't remove directory", |e|
@@ -542,6 +585,8 @@ pub fn rmdir(path: &Path) -> IoResult<()> {
 /// This function will return an error if the provided `path` doesn't exist, if
 /// the process lacks permissions to view the contents or if the `path` points
 /// at a non-directory file
+#[deprecated(since = "1.0.0", reason = "replaced with std::fs::read_dir")]
+#[unstable(feature = "old_io")]
 pub fn readdir(path: &Path) -> IoResult<Vec<Path>> {
     fs_imp::readdir(path)
            .update_err("couldn't read directory",
@@ -552,6 +597,8 @@ pub fn readdir(path: &Path) -> IoResult<Vec<Path>> {
 /// rooted at `path`. The path given will not be iterated over, and this will
 /// perform iteration in some top-down order.  The contents of unreadable
 /// subdirectories are ignored.
+#[deprecated(since = "1.0.0", reason = "replaced with std::fs::walk_dir")]
+#[unstable(feature = "old_io")]
 pub fn walk_dir(path: &Path) -> IoResult<Directories> {
     Ok(Directories {
         stack: try!(readdir(path).update_err("couldn't walk directory",
@@ -561,6 +608,8 @@ pub fn walk_dir(path: &Path) -> IoResult<Directories> {
 
 /// An iterator that walks over a directory
 #[derive(Clone)]
+#[deprecated(since = "1.0.0", reason = "replaced with std::fs::ReadDir")]
+#[unstable(feature = "old_io")]
 pub struct Directories {
     stack: Vec<Path>,
 }
@@ -590,6 +639,7 @@ impl Iterator for Directories {
 /// # Error
 ///
 /// See `fs::mkdir`.
+#[unstable(feature = "old_fs")]
 pub fn mkdir_recursive(path: &Path, mode: FilePermission) -> IoResult<()> {
     // tjc: if directory exists but with different permissions,
     // should we return false?
@@ -627,6 +677,8 @@ pub fn mkdir_recursive(path: &Path, mode: FilePermission) -> IoResult<()> {
 /// # Error
 ///
 /// See `file::unlink` and `fs::readdir`
+#[deprecated(since = "1.0.0", reason = "replaced with std::fs::remove_dir_all")]
+#[unstable(feature = "old_io")]
 pub fn rmdir_recursive(path: &Path) -> IoResult<()> {
     let mut rm_stack = Vec::new();
     rm_stack.push(path.clone());
@@ -689,6 +741,8 @@ pub fn rmdir_recursive(path: &Path) -> IoResult<()> {
 /// `atime` and its modification time set to `mtime`. The times specified should
 /// be in milliseconds.
 // FIXME(#10301) these arguments should not be u64
+#[deprecated(since = "1.0.0", reason = "replaced with std::fs::set_file_times")]
+#[unstable(feature = "old_io")]
 pub fn change_file_times(path: &Path, atime: u64, mtime: u64) -> IoResult<()> {
     fs_imp::utime(path, atime, mtime)
            .update_err("couldn't change_file_times", |e|
@@ -748,6 +802,8 @@ impl Seek for File {
 }
 
 /// Utility methods for paths.
+#[deprecated(since = "1.0.0", reason = "replaced with std::fs::PathExt")]
+#[unstable(feature = "old_io")]
 pub trait PathExtensions {
     /// Get information on the file, directory, etc at this path.
     ///
diff --git a/src/libstd/sys/unix/ext.rs b/src/libstd/sys/unix/ext.rs
index 3f9da6e3c51..45042d6f032 100644
--- a/src/libstd/sys/unix/ext.rs
+++ b/src/libstd/sys/unix/ext.rs
@@ -54,6 +54,7 @@ pub trait AsRawFd {
     fn as_raw_fd(&self) -> Fd;
 }
 
+#[allow(deprecated)]
 impl AsRawFd for old_io::fs::File {
     fn as_raw_fd(&self) -> Fd {
         self.as_inner().fd()
diff --git a/src/libstd/sys/windows/ext.rs b/src/libstd/sys/windows/ext.rs
index ac1006e653f..df18b404f5f 100644
--- a/src/libstd/sys/windows/ext.rs
+++ b/src/libstd/sys/windows/ext.rs
@@ -39,6 +39,7 @@ pub trait AsRawHandle {
     fn as_raw_handle(&self) -> Handle;
 }
 
+#[allow(deprecated)]
 impl AsRawHandle for old_io::fs::File {
     fn as_raw_handle(&self) -> Handle {
         self.as_inner().handle()
diff --git a/src/libstd/sys/windows/process.rs b/src/libstd/sys/windows/process.rs
index 334cafd3eb1..53a037ef07e 100644
--- a/src/libstd/sys/windows/process.rs
+++ b/src/libstd/sys/windows/process.rs
@@ -17,7 +17,7 @@ use hash::Hash;
 use libc::{pid_t, c_void};
 use libc;
 use mem;
-use old_io::fs::PathExtensions;
+#[allow(deprecated)] use old_io::fs::PathExtensions;
 use old_io::process::{ProcessExit, ExitStatus};
 use old_io::{IoResult, IoError};
 use old_io;
diff --git a/src/libsyntax/ast_map/mod.rs b/src/libsyntax/ast_map/mod.rs
index c33158193ce..faa681c0255 100644
--- a/src/libsyntax/ast_map/mod.rs
+++ b/src/libsyntax/ast_map/mod.rs
@@ -25,7 +25,7 @@ use visit::{self, Visitor};
 use arena::TypedArena;
 use std::cell::RefCell;
 use std::fmt;
-use std::old_io::IoResult;
+use std::io;
 use std::iter::{self, repeat};
 use std::mem;
 use std::slice;
@@ -997,11 +997,11 @@ pub fn map_decoded_item<'ast, F: FoldOps>(map: &Map<'ast>,
 }
 
 pub trait NodePrinter {
-    fn print_node(&mut self, node: &Node) -> IoResult<()>;
+    fn print_node(&mut self, node: &Node) -> io::Result<()>;
 }
 
 impl<'a> NodePrinter for pprust::State<'a> {
-    fn print_node(&mut self, node: &Node) -> IoResult<()> {
+    fn print_node(&mut self, node: &Node) -> io::Result<()> {
         match *node {
             NodeItem(a)        => self.print_item(&*a),
             NodeForeignItem(a) => self.print_foreign_item(&*a),
diff --git a/src/libsyntax/ext/source_util.rs b/src/libsyntax/ext/source_util.rs
index ba3743cdb33..62d98be8b85 100644
--- a/src/libsyntax/ext/source_util.rs
+++ b/src/libsyntax/ext/source_util.rs
@@ -20,7 +20,9 @@ use print::pprust;
 use ptr::P;
 use util::small_vector::SmallVector;
 
-use std::old_io::File;
+use std::fs::File;
+use std::io::prelude::*;
+use std::path::{Path, PathBuf};
 use std::rc::Rc;
 
 // These macros all relate to the file system; they either return
@@ -97,7 +99,7 @@ pub fn expand_include<'cx>(cx: &'cx mut ExtCtxt, sp: Span, tts: &[ast::TokenTree
                                         cx.cfg(),
                                         &res_rel_file(cx,
                                                       sp,
-                                                      &Path::new(file)),
+                                                      Path::new(&file)),
                                         true,
                                         None,
                                         sp);
@@ -136,8 +138,10 @@ pub fn expand_include_str(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
         Some(f) => f,
         None => return DummyResult::expr(sp)
     };
-    let file = res_rel_file(cx, sp, &Path::new(file));
-    let bytes = match File::open(&file).read_to_end() {
+    let file = res_rel_file(cx, sp, Path::new(&file));
+    let mut bytes = Vec::new();
+    match File::open(&file).and_then(|mut f| f.read_to_end(&mut bytes)) {
+        Ok(..) => {}
         Err(e) => {
             cx.span_err(sp,
                         &format!("couldn't read {}: {}",
@@ -145,7 +149,6 @@ pub fn expand_include_str(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
                                 e));
             return DummyResult::expr(sp);
         }
-        Ok(bytes) => bytes,
     };
     match String::from_utf8(bytes) {
         Ok(src) => {
@@ -172,15 +175,15 @@ pub fn expand_include_bytes(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
         Some(f) => f,
         None => return DummyResult::expr(sp)
     };
-    let file = res_rel_file(cx, sp, &Path::new(file));
-    match File::open(&file).read_to_end() {
+    let file = res_rel_file(cx, sp, Path::new(&file));
+    let mut bytes = Vec::new();
+    match File::open(&file).and_then(|mut f| f.read_to_end(&mut bytes)) {
         Err(e) => {
             cx.span_err(sp,
                         &format!("couldn't read {}: {}", file.display(), e));
             return DummyResult::expr(sp);
         }
-        Ok(bytes) => {
-            let bytes = bytes.iter().cloned().collect();
+        Ok(..) => {
             base::MacEager::expr(cx.expr_lit(sp, ast::LitBinary(Rc::new(bytes))))
         }
     }
@@ -188,14 +191,18 @@ pub fn expand_include_bytes(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
 
 // resolve a file-system path to an absolute file-system path (if it
 // isn't already)
-fn res_rel_file(cx: &mut ExtCtxt, sp: codemap::Span, arg: &Path) -> Path {
+fn res_rel_file(cx: &mut ExtCtxt, sp: codemap::Span, arg: &Path) -> PathBuf {
     // NB: relative paths are resolved relative to the compilation unit
     if !arg.is_absolute() {
-        let mut cu = Path::new(cx.codemap().span_to_filename(sp));
-        cu.pop();
+        let mut cu = PathBuf::new(&cx.codemap().span_to_filename(sp));
+        if cu.parent().is_some() {
+            cu.pop();
+        } else {
+            cu = PathBuf::new("");
+        }
         cu.push(arg);
         cu
     } else {
-        arg.clone()
+        arg.to_path_buf()
     }
 }
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
index a556b2dfd2a..959e3bdb314 100644
--- a/src/libsyntax/fold.rs
+++ b/src/libsyntax/fold.rs
@@ -1432,7 +1432,7 @@ pub fn noop_fold_stmt<T: Folder>(Spanned {node, span}: Stmt, folder: &mut T)
 
 #[cfg(test)]
 mod test {
-    use std::old_io;
+    use std::io;
     use ast;
     use util::parser_testing::{string_to_crate, matches_codepattern};
     use parse::token;
@@ -1442,7 +1442,7 @@ mod test {
 
     // this version doesn't care about getting comments or docstrings in.
     fn fake_print_crate(s: &mut pprust::State,
-                        krate: &ast::Crate) -> old_io::IoResult<()> {
+                        krate: &ast::Crate) -> io::Result<()> {
         s.print_mod(&krate.module, &krate.attrs)
     }
 
diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index 7acbd10ef03..7bd9cc3b855 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -36,6 +36,9 @@
 #![feature(staged_api)]
 #![feature(std_misc)]
 #![feature(unicode)]
+#![feature(path)]
+#![feature(fs)]
+#![feature(io)]
 
 extern crate arena;
 extern crate fmt_macros;
diff --git a/src/libsyntax/parse/lexer/comments.rs b/src/libsyntax/parse/lexer/comments.rs
index 3ad1d96a45d..fb9e0480ceb 100644
--- a/src/libsyntax/parse/lexer/comments.rs
+++ b/src/libsyntax/parse/lexer/comments.rs
@@ -19,9 +19,8 @@ use parse::lexer::is_block_doc_comment;
 use parse::lexer;
 use print::pprust;
 
-use std::old_io;
+use std::io::Read;
 use std::str;
-use std::string::String;
 use std::usize;
 
 #[derive(Clone, Copy, PartialEq)]
@@ -337,9 +336,10 @@ pub struct Literal {
 // probably not a good thing.
 pub fn gather_comments_and_literals(span_diagnostic: &diagnostic::SpanHandler,
                                     path: String,
-                                    srdr: &mut old_io::Reader)
+                                    srdr: &mut Read)
                                  -> (Vec<Comment>, Vec<Literal>) {
-    let src = srdr.read_to_end().unwrap();
+    let mut src = Vec::new();
+    srdr.read_to_end(&mut src).unwrap();
     let src = String::from_utf8(src).unwrap();
     let cm = CodeMap::new();
     let filemap = cm.new_filemap(path, src);
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index 66589d5e3d1..def5963e6f4 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -18,11 +18,13 @@ use parse::parser::Parser;
 use ptr::P;
 
 use std::cell::{Cell, RefCell};
-use std::old_io::File;
-use std::rc::Rc;
+use std::fs::File;
+use std::io::Read;
+use std::iter;
 use std::num::Int;
+use std::path::{Path, PathBuf};
+use std::rc::Rc;
 use std::str;
-use std::iter;
 
 #[macro_use]
 pub mod parser;
@@ -39,7 +41,7 @@ pub mod obsolete;
 pub struct ParseSess {
     pub span_diagnostic: SpanHandler, // better be the same as the one in the reader!
     /// Used to determine and report recursive mod inclusions
-    included_mod_stack: RefCell<Vec<Path>>,
+    included_mod_stack: RefCell<Vec<PathBuf>>,
     pub node_id: Cell<ast::NodeId>,
 }
 
@@ -250,24 +252,24 @@ pub fn file_to_filemap(sess: &ParseSess, path: &Path, spanopt: Option<Span>)
             None => sess.span_diagnostic.handler().fatal(msg),
         }
     };
-    let bytes = match File::open(path).read_to_end() {
-        Ok(bytes) => bytes,
+    let mut bytes = Vec::new();
+    match File::open(path).and_then(|mut f| f.read_to_end(&mut bytes)) {
+        Ok(..) => {}
         Err(e) => {
-            err(&format!("couldn't read {:?}: {}",
-                        path.display(), e));
-            unreachable!()
+            err(&format!("couldn't read {:?}: {}", path.display(), e));
+            unreachable!();
         }
     };
     match str::from_utf8(&bytes[..]).ok() {
         Some(s) => {
-            return string_to_filemap(sess, s.to_string(),
-                                     path.as_str().unwrap().to_string())
+            string_to_filemap(sess, s.to_string(),
+                              path.to_str().unwrap().to_string())
         }
         None => {
-            err(&format!("{:?} is not UTF-8 encoded", path.display()))
+            err(&format!("{:?} is not UTF-8 encoded", path.display()));
+            unreachable!();
         }
     }
-    unreachable!()
 }
 
 /// Given a session and a string, add the string to
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index c1acee57cf8..88df6d6d4cd 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -78,10 +78,11 @@ use ptr::P;
 use owned_slice::OwnedSlice;
 
 use std::collections::HashSet;
-use std::old_io::fs::PathExtensions;
+use std::io::prelude::*;
 use std::iter;
 use std::mem;
 use std::num::Float;
+use std::path::{Path, PathBuf};
 use std::rc::Rc;
 use std::slice;
 
@@ -5248,14 +5249,23 @@ impl<'a> Parser<'a> {
                     outer_attrs: &[ast::Attribute],
                     id_sp: Span)
                     -> (ast::Item_, Vec<ast::Attribute> ) {
-        let mut prefix = Path::new(self.sess.span_diagnostic.cm.span_to_filename(self.span));
-        prefix.pop();
-        let mod_path = Path::new(".").join_many(&self.mod_path_stack);
-        let dir_path = prefix.join(&mod_path);
+        let mut prefix = PathBuf::new(&self.sess.span_diagnostic.cm
+                                           .span_to_filename(self.span));
+        // FIXME(acrichto): right now "a".pop() == "a", but need to confirm with
+        //                  aturon whether this is expected or not.
+        if prefix.parent().is_some() {
+            prefix.pop();
+        } else {
+            prefix = PathBuf::new("");
+        }
+        let mut dir_path = prefix;
+        for part in &self.mod_path_stack {
+            dir_path.push(&**part);
+        }
         let mod_string = token::get_ident(id);
         let (file_path, owns_directory) = match ::attr::first_attr_value_str_by_name(
                 outer_attrs, "path") {
-            Some(d) => (dir_path.join(d), true),
+            Some(d) => (dir_path.join(&*d), true),
             None => {
                 let mod_name = mod_string.to_string();
                 let default_path_str = format!("{}.rs", mod_name);
@@ -5319,7 +5329,7 @@ impl<'a> Parser<'a> {
     }
 
     fn eval_src_mod_from_path(&mut self,
-                              path: Path,
+                              path: PathBuf,
                               owns_directory: bool,
                               name: String,
                               id_sp: Span) -> (ast::Item_, Vec<ast::Attribute> ) {
@@ -5329,10 +5339,10 @@ impl<'a> Parser<'a> {
                 let mut err = String::from_str("circular modules: ");
                 let len = included_mod_stack.len();
                 for p in &included_mod_stack[i.. len] {
-                    err.push_str(&p.display().as_cow());
+                    err.push_str(&p.to_string_lossy());
                     err.push_str(" -> ");
                 }
-                err.push_str(&path.display().as_cow());
+                err.push_str(&path.to_string_lossy());
                 self.span_fatal(id_sp, &err[..]);
             }
             None => ()
diff --git a/src/libsyntax/print/pp.rs b/src/libsyntax/print/pp.rs
index 4cef7ed469f..640b7d1c91d 100644
--- a/src/libsyntax/print/pp.rs
+++ b/src/libsyntax/print/pp.rs
@@ -59,7 +59,7 @@
 //! line (which it can't) and so naturally place the content on its own line to
 //! avoid combining it with other lines and making matters even worse.
 
-use std::old_io;
+use std::io;
 use std::string;
 use std::iter::repeat;
 
@@ -161,7 +161,7 @@ pub struct PrintStackElem {
 
 const SIZE_INFINITY: isize = 0xffff;
 
-pub fn mk_printer(out: Box<old_io::Writer+'static>, linewidth: usize) -> Printer {
+pub fn mk_printer<'a>(out: Box<io::Write+'a>, linewidth: usize) -> Printer<'a> {
     // Yes 3, it makes the ring buffers big enough to never
     // fall behind.
     let n: usize = 3 * linewidth;
@@ -265,8 +265,8 @@ pub fn mk_printer(out: Box<old_io::Writer+'static>, linewidth: usize) -> Printer
 /// In this implementation (following the paper, again) the SCAN process is
 /// the method called 'pretty_print', and the 'PRINT' process is the method
 /// called 'print'.
-pub struct Printer {
-    pub out: Box<old_io::Writer+'static>,
+pub struct Printer<'a> {
+    pub out: Box<io::Write+'a>,
     buf_len: usize,
     /// Width of lines we're constrained to
     margin: isize,
@@ -303,7 +303,7 @@ pub struct Printer {
     pending_indentation: isize,
 }
 
-impl Printer {
+impl<'a> Printer<'a> {
     pub fn last_token(&mut self) -> Token {
         self.token[self.right].clone()
     }
@@ -311,7 +311,7 @@ impl Printer {
     pub fn replace_last_token(&mut self, t: Token) {
         self.token[self.right] = t;
     }
-    pub fn pretty_print(&mut self, token: Token) -> old_io::IoResult<()> {
+    pub fn pretty_print(&mut self, token: Token) -> io::Result<()> {
         debug!("pp ~[{},{}]", self.left, self.right);
         match token {
           Token::Eof => {
@@ -385,7 +385,7 @@ impl Printer {
           }
         }
     }
-    pub fn check_stream(&mut self) -> old_io::IoResult<()> {
+    pub fn check_stream(&mut self) -> io::Result<()> {
         debug!("check_stream ~[{}, {}] with left_total={}, right_total={}",
                self.left, self.right, self.left_total, self.right_total);
         if self.right_total - self.left_total > self.space {
@@ -445,7 +445,7 @@ impl Printer {
         self.right %= self.buf_len;
         assert!((self.right != self.left));
     }
-    pub fn advance_left(&mut self) -> old_io::IoResult<()> {
+    pub fn advance_left(&mut self) -> io::Result<()> {
         debug!("advance_left ~[{},{}], sizeof({})={}", self.left, self.right,
                self.left, self.size[self.left]);
 
@@ -506,7 +506,7 @@ impl Printer {
             }
         }
     }
-    pub fn print_newline(&mut self, amount: isize) -> old_io::IoResult<()> {
+    pub fn print_newline(&mut self, amount: isize) -> io::Result<()> {
         debug!("NEWLINE {}", amount);
         let ret = write!(self.out, "\n");
         self.pending_indentation = 0;
@@ -529,14 +529,14 @@ impl Printer {
             }
         }
     }
-    pub fn print_str(&mut self, s: &str) -> old_io::IoResult<()> {
+    pub fn print_str(&mut self, s: &str) -> io::Result<()> {
         while self.pending_indentation > 0 {
             try!(write!(self.out, " "));
             self.pending_indentation -= 1;
         }
         write!(self.out, "{}", s)
     }
-    pub fn print(&mut self, token: Token, l: isize) -> old_io::IoResult<()> {
+    pub fn print(&mut self, token: Token, l: isize) -> io::Result<()> {
         debug!("print {} {} (remaining line space={})", tok_str(&token), l,
                self.space);
         debug!("{}", buf_str(&self.token,
@@ -620,61 +620,61 @@ impl Printer {
 // Convenience functions to talk to the printer.
 //
 // "raw box"
-pub fn rbox(p: &mut Printer, indent: usize, b: Breaks) -> old_io::IoResult<()> {
+pub fn rbox(p: &mut Printer, indent: usize, b: Breaks) -> io::Result<()> {
     p.pretty_print(Token::Begin(BeginToken {
         offset: indent as isize,
         breaks: b
     }))
 }
 
-pub fn ibox(p: &mut Printer, indent: usize) -> old_io::IoResult<()> {
+pub fn ibox(p: &mut Printer, indent: usize) -> io::Result<()> {
     rbox(p, indent, Breaks::Inconsistent)
 }
 
-pub fn cbox(p: &mut Printer, indent: usize) -> old_io::IoResult<()> {
+pub fn cbox(p: &mut Printer, indent: usize) -> io::Result<()> {
     rbox(p, indent, Breaks::Consistent)
 }
 
-pub fn break_offset(p: &mut Printer, n: usize, off: isize) -> old_io::IoResult<()> {
+pub fn break_offset(p: &mut Printer, n: usize, off: isize) -> io::Result<()> {
     p.pretty_print(Token::Break(BreakToken {
         offset: off,
         blank_space: n as isize
     }))
 }
 
-pub fn end(p: &mut Printer) -> old_io::IoResult<()> {
+pub fn end(p: &mut Printer) -> io::Result<()> {
     p.pretty_print(Token::End)
 }
 
-pub fn eof(p: &mut Printer) -> old_io::IoResult<()> {
+pub fn eof(p: &mut Printer) -> io::Result<()> {
     p.pretty_print(Token::Eof)
 }
 
-pub fn word(p: &mut Printer, wrd: &str) -> old_io::IoResult<()> {
+pub fn word(p: &mut Printer, wrd: &str) -> io::Result<()> {
     p.pretty_print(Token::String(/* bad */ wrd.to_string(), wrd.len() as isize))
 }
 
-pub fn huge_word(p: &mut Printer, wrd: &str) -> old_io::IoResult<()> {
+pub fn huge_word(p: &mut Printer, wrd: &str) -> io::Result<()> {
     p.pretty_print(Token::String(/* bad */ wrd.to_string(), SIZE_INFINITY))
 }
 
-pub fn zero_word(p: &mut Printer, wrd: &str) -> old_io::IoResult<()> {
+pub fn zero_word(p: &mut Printer, wrd: &str) -> io::Result<()> {
     p.pretty_print(Token::String(/* bad */ wrd.to_string(), 0))
 }
 
-pub fn spaces(p: &mut Printer, n: usize) -> old_io::IoResult<()> {
+pub fn spaces(p: &mut Printer, n: usize) -> io::Result<()> {
     break_offset(p, n, 0)
 }
 
-pub fn zerobreak(p: &mut Printer) -> old_io::IoResult<()> {
+pub fn zerobreak(p: &mut Printer) -> io::Result<()> {
     spaces(p, 0)
 }
 
-pub fn space(p: &mut Printer) -> old_io::IoResult<()> {
+pub fn space(p: &mut Printer) -> io::Result<()> {
     spaces(p, 1)
 }
 
-pub fn hardbreak(p: &mut Printer) -> old_io::IoResult<()> {
+pub fn hardbreak(p: &mut Printer) -> io::Result<()> {
     spaces(p, SIZE_INFINITY as usize)
 }
 
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index af16e19c9f0..883c2295a36 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -30,7 +30,7 @@ use ptr::P;
 use std_inject;
 
 use std::{ascii, mem};
-use std::old_io::{self, IoResult};
+use std::io::{self, Write, Read};
 use std::iter;
 
 pub enum AnnNode<'a> {
@@ -43,8 +43,8 @@ pub enum AnnNode<'a> {
 }
 
 pub trait PpAnn {
-    fn pre(&self, _state: &mut State, _node: AnnNode) -> IoResult<()> { Ok(()) }
-    fn post(&self, _state: &mut State, _node: AnnNode) -> IoResult<()> { Ok(()) }
+    fn pre(&self, _state: &mut State, _node: AnnNode) -> io::Result<()> { Ok(()) }
+    fn post(&self, _state: &mut State, _node: AnnNode) -> io::Result<()> { Ok(()) }
 }
 
 #[derive(Copy)]
@@ -59,7 +59,7 @@ pub struct CurrentCommentAndLiteral {
 }
 
 pub struct State<'a> {
-    pub s: pp::Printer,
+    pub s: pp::Printer<'a>,
     cm: Option<&'a CodeMap>,
     comments: Option<Vec<comments::Comment> >,
     literals: Option<Vec<comments::Literal> >,
@@ -69,12 +69,12 @@ pub struct State<'a> {
     encode_idents_with_hygiene: bool,
 }
 
-pub fn rust_printer(writer: Box<old_io::Writer+'static>) -> State<'static> {
+pub fn rust_printer<'a>(writer: Box<Write+'a>) -> State<'a> {
     static NO_ANN: NoAnn = NoAnn;
     rust_printer_annotated(writer, &NO_ANN)
 }
 
-pub fn rust_printer_annotated<'a>(writer: Box<old_io::Writer+'static>,
+pub fn rust_printer_annotated<'a>(writer: Box<Write+'a>,
                                   ann: &'a PpAnn) -> State<'a> {
     State {
         s: pp::mk_printer(writer, default_columns),
@@ -104,10 +104,10 @@ pub fn print_crate<'a>(cm: &'a CodeMap,
                        span_diagnostic: &diagnostic::SpanHandler,
                        krate: &ast::Crate,
                        filename: String,
-                       input: &mut old_io::Reader,
-                       out: Box<old_io::Writer+'static>,
+                       input: &mut Read,
+                       out: Box<Write+'a>,
                        ann: &'a PpAnn,
-                       is_expanded: bool) -> IoResult<()> {
+                       is_expanded: bool) -> io::Result<()> {
     let mut s = State::new_from_input(cm,
                                       span_diagnostic,
                                       filename,
@@ -143,8 +143,8 @@ impl<'a> State<'a> {
     pub fn new_from_input(cm: &'a CodeMap,
                           span_diagnostic: &diagnostic::SpanHandler,
                           filename: String,
-                          input: &mut old_io::Reader,
-                          out: Box<old_io::Writer+'static>,
+                          input: &mut Read,
+                          out: Box<Write+'a>,
                           ann: &'a PpAnn,
                           is_expanded: bool) -> State<'a> {
         let (cmnts, lits) = comments::gather_comments_and_literals(
@@ -164,7 +164,7 @@ impl<'a> State<'a> {
     }
 
     pub fn new(cm: &'a CodeMap,
-               out: Box<old_io::Writer+'static>,
+               out: Box<Write+'a>,
                ann: &'a PpAnn,
                comments: Option<Vec<comments::Comment>>,
                literals: Option<Vec<comments::Literal>>) -> State<'a> {
@@ -185,14 +185,14 @@ impl<'a> State<'a> {
 }
 
 pub fn to_string<F>(f: F) -> String where
-    F: FnOnce(&mut State) -> IoResult<()>,
+    F: FnOnce(&mut State) -> io::Result<()>,
 {
     use std::raw::TraitObject;
     let mut s = rust_printer(box Vec::new());
     f(&mut s).unwrap();
     eof(&mut s.s).unwrap();
     let wr = unsafe {
-        // FIXME(pcwalton): A nasty function to extract the string from an `old_io::Writer`
+        // FIXME(pcwalton): A nasty function to extract the string from an `Write`
         // that we "know" to be a `Vec<u8>` that works around the lack of checked
         // downcasts.
         let obj: &TraitObject = mem::transmute(&s.s.out);
@@ -440,13 +440,13 @@ thing_to_string_impls! { to_string }
 pub mod with_hygiene {
     use abi;
     use ast;
-    use std::old_io::IoResult;
+    use std::io;
     use super::indent_unit;
 
     // This function is the trick that all the rest of the routines
     // hang on.
     pub fn to_string_hyg<F>(f: F) -> String where
-        F: FnOnce(&mut super::State) -> IoResult<()>,
+        F: FnOnce(&mut super::State) -> io::Result<()>,
     {
         super::to_string(move |s| {
             s.encode_idents_with_hygiene = true;
@@ -474,44 +474,44 @@ fn needs_parentheses(expr: &ast::Expr) -> bool {
 }
 
 impl<'a> State<'a> {
-    pub fn ibox(&mut self, u: usize) -> IoResult<()> {
+    pub fn ibox(&mut self, u: usize) -> io::Result<()> {
         self.boxes.push(pp::Breaks::Inconsistent);
         pp::ibox(&mut self.s, u)
     }
 
-    pub fn end(&mut self) -> IoResult<()> {
+    pub fn end(&mut self) -> io::Result<()> {
         self.boxes.pop().unwrap();
         pp::end(&mut self.s)
     }
 
-    pub fn cbox(&mut self, u: usize) -> IoResult<()> {
+    pub fn cbox(&mut self, u: usize) -> io::Result<()> {
         self.boxes.push(pp::Breaks::Consistent);
         pp::cbox(&mut self.s, u)
     }
 
     // "raw box"
-    pub fn rbox(&mut self, u: usize, b: pp::Breaks) -> IoResult<()> {
+    pub fn rbox(&mut self, u: usize, b: pp::Breaks) -> io::Result<()> {
         self.boxes.push(b);
         pp::rbox(&mut self.s, u, b)
     }
 
-    pub fn nbsp(&mut self) -> IoResult<()> { word(&mut self.s, " ") }
+    pub fn nbsp(&mut self) -> io::Result<()> { word(&mut self.s, " ") }
 
-    pub fn word_nbsp(&mut self, w: &str) -> IoResult<()> {
+    pub fn word_nbsp(&mut self, w: &str) -> io::Result<()> {
         try!(word(&mut self.s, w));
         self.nbsp()
     }
 
-    pub fn word_space(&mut self, w: &str) -> IoResult<()> {
+    pub fn word_space(&mut self, w: &str) -> io::Result<()> {
         try!(word(&mut self.s, w));
         space(&mut self.s)
     }
 
-    pub fn popen(&mut self) -> IoResult<()> { word(&mut self.s, "(") }
+    pub fn popen(&mut self) -> io::Result<()> { word(&mut self.s, "(") }
 
-    pub fn pclose(&mut self) -> IoResult<()> { word(&mut self.s, ")") }
+    pub fn pclose(&mut self) -> io::Result<()> { word(&mut self.s, ")") }
 
-    pub fn head(&mut self, w: &str) -> IoResult<()> {
+    pub fn head(&mut self, w: &str) -> io::Result<()> {
         // outer-box is consistent
         try!(self.cbox(indent_unit));
         // head-box is inconsistent
@@ -523,17 +523,17 @@ impl<'a> State<'a> {
         Ok(())
     }
 
-    pub fn bopen(&mut self) -> IoResult<()> {
+    pub fn bopen(&mut self) -> io::Result<()> {
         try!(word(&mut self.s, "{"));
         self.end() // close the head-box
     }
 
     pub fn bclose_(&mut self, span: codemap::Span,
-                   indented: usize) -> IoResult<()> {
+                   indented: usize) -> io::Result<()> {
         self.bclose_maybe_open(span, indented, true)
     }
     pub fn bclose_maybe_open (&mut self, span: codemap::Span,
-                              indented: usize, close_box: bool) -> IoResult<()> {
+                              indented: usize, close_box: bool) -> io::Result<()> {
         try!(self.maybe_print_comment(span.hi));
         try!(self.break_offset_if_not_bol(1, -(indented as isize)));
         try!(word(&mut self.s, "}"));
@@ -542,7 +542,7 @@ impl<'a> State<'a> {
         }
         Ok(())
     }
-    pub fn bclose(&mut self, span: codemap::Span) -> IoResult<()> {
+    pub fn bclose(&mut self, span: codemap::Span) -> io::Result<()> {
         self.bclose_(span, indent_unit)
     }
 
@@ -572,18 +572,18 @@ impl<'a> State<'a> {
         }
     }
 
-    pub fn hardbreak_if_not_bol(&mut self) -> IoResult<()> {
+    pub fn hardbreak_if_not_bol(&mut self) -> io::Result<()> {
         if !self.is_bol() {
             try!(hardbreak(&mut self.s))
         }
         Ok(())
     }
-    pub fn space_if_not_bol(&mut self) -> IoResult<()> {
+    pub fn space_if_not_bol(&mut self) -> io::Result<()> {
         if !self.is_bol() { try!(space(&mut self.s)); }
         Ok(())
     }
     pub fn break_offset_if_not_bol(&mut self, n: usize,
-                                   off: isize) -> IoResult<()> {
+                                   off: isize) -> io::Result<()> {
         if !self.is_bol() {
             break_offset(&mut self.s, n, off)
         } else {
@@ -599,7 +599,7 @@ impl<'a> State<'a> {
 
     // Synthesizes a comment that was not textually present in the original source
     // file.
-    pub fn synth_comment(&mut self, text: String) -> IoResult<()> {
+    pub fn synth_comment(&mut self, text: String) -> io::Result<()> {
         try!(word(&mut self.s, "/*"));
         try!(space(&mut self.s));
         try!(word(&mut self.s, &text[..]));
@@ -607,8 +607,8 @@ impl<'a> State<'a> {
         word(&mut self.s, "*/")
     }
 
-    pub fn commasep<T, F>(&mut self, b: Breaks, elts: &[T], mut op: F) -> IoResult<()> where
-        F: FnMut(&mut State, &T) -> IoResult<()>,
+    pub fn commasep<T, F>(&mut self, b: Breaks, elts: &[T], mut op: F) -> io::Result<()> where
+        F: FnMut(&mut State, &T) -> io::Result<()>,
     {
         try!(self.rbox(0, b));
         let mut first = true;
@@ -624,8 +624,8 @@ impl<'a> State<'a> {
                                   b: Breaks,
                                   elts: &[T],
                                   mut op: F,
-                                  mut get_span: G) -> IoResult<()> where
-        F: FnMut(&mut State, &T) -> IoResult<()>,
+                                  mut get_span: G) -> io::Result<()> where
+        F: FnMut(&mut State, &T) -> io::Result<()>,
         G: FnMut(&T) -> codemap::Span,
     {
         try!(self.rbox(0, b));
@@ -646,12 +646,12 @@ impl<'a> State<'a> {
     }
 
     pub fn commasep_exprs(&mut self, b: Breaks,
-                          exprs: &[P<ast::Expr>]) -> IoResult<()> {
+                          exprs: &[P<ast::Expr>]) -> io::Result<()> {
         self.commasep_cmnt(b, exprs, |s, e| s.print_expr(&**e), |e| e.span)
     }
 
     pub fn print_mod(&mut self, _mod: &ast::Mod,
-                     attrs: &[ast::Attribute]) -> IoResult<()> {
+                     attrs: &[ast::Attribute]) -> io::Result<()> {
         try!(self.print_inner_attributes(attrs));
         for item in &_mod.items {
             try!(self.print_item(&**item));
@@ -660,7 +660,7 @@ impl<'a> State<'a> {
     }
 
     pub fn print_foreign_mod(&mut self, nmod: &ast::ForeignMod,
-                             attrs: &[ast::Attribute]) -> IoResult<()> {
+                             attrs: &[ast::Attribute]) -> io::Result<()> {
         try!(self.print_inner_attributes(attrs));
         for item in &nmod.items {
             try!(self.print_foreign_item(&**item));
@@ -669,7 +669,7 @@ impl<'a> State<'a> {
     }
 
     pub fn print_opt_lifetime(&mut self,
-                              lifetime: &Option<ast::Lifetime>) -> IoResult<()> {
+                              lifetime: &Option<ast::Lifetime>) -> io::Result<()> {
         if let Some(l) = *lifetime {
             try!(self.print_lifetime(&l));
             try!(self.nbsp());
@@ -677,7 +677,7 @@ impl<'a> State<'a> {
         Ok(())
     }
 
-    pub fn print_type(&mut self, ty: &ast::Ty) -> IoResult<()> {
+    pub fn print_type(&mut self, ty: &ast::Ty) -> io::Result<()> {
         try!(self.maybe_print_comment(ty.span.lo));
         try!(self.ibox(0));
         match ty.node {
@@ -762,7 +762,7 @@ impl<'a> State<'a> {
     }
 
     pub fn print_foreign_item(&mut self,
-                              item: &ast::ForeignItem) -> IoResult<()> {
+                              item: &ast::ForeignItem) -> io::Result<()> {
         try!(self.hardbreak_if_not_bol());
         try!(self.maybe_print_comment(item.span.lo));
         try!(self.print_outer_attributes(&item.attrs));
@@ -791,7 +791,7 @@ impl<'a> State<'a> {
     }
 
     fn print_associated_type(&mut self, typedef: &ast::AssociatedType)
-                             -> IoResult<()>
+                             -> io::Result<()>
     {
         try!(self.print_outer_attributes(&typedef.attrs));
         try!(self.word_space("type"));
@@ -799,7 +799,7 @@ impl<'a> State<'a> {
         word(&mut self.s, ";")
     }
 
-    fn print_typedef(&mut self, typedef: &ast::Typedef) -> IoResult<()> {
+    fn print_typedef(&mut self, typedef: &ast::Typedef) -> io::Result<()> {
         try!(self.word_space("type"));
         try!(self.print_ident(typedef.ident));
         try!(space(&mut self.s));
@@ -809,7 +809,7 @@ impl<'a> State<'a> {
     }
 
     /// Pretty-print an item
-    pub fn print_item(&mut self, item: &ast::Item) -> IoResult<()> {
+    pub fn print_item(&mut self, item: &ast::Item) -> io::Result<()> {
         try!(self.hardbreak_if_not_bol());
         try!(self.maybe_print_comment(item.span.lo));
         try!(self.print_outer_attributes(&item.attrs));
@@ -1032,11 +1032,11 @@ impl<'a> State<'a> {
         self.ann.post(self, NodeItem(item))
     }
 
-    fn print_trait_ref(&mut self, t: &ast::TraitRef) -> IoResult<()> {
+    fn print_trait_ref(&mut self, t: &ast::TraitRef) -> io::Result<()> {
         self.print_path(&t.path, false, 0)
     }
 
-    fn print_formal_lifetime_list(&mut self, lifetimes: &[ast::LifetimeDef]) -> IoResult<()> {
+    fn print_formal_lifetime_list(&mut self, lifetimes: &[ast::LifetimeDef]) -> io::Result<()> {
         if !lifetimes.is_empty() {
             try!(word(&mut self.s, "for<"));
             let mut comma = false;
@@ -1052,7 +1052,7 @@ impl<'a> State<'a> {
         Ok(())
     }
 
-    fn print_poly_trait_ref(&mut self, t: &ast::PolyTraitRef) -> IoResult<()> {
+    fn print_poly_trait_ref(&mut self, t: &ast::PolyTraitRef) -> io::Result<()> {
         try!(self.print_formal_lifetime_list(&t.bound_lifetimes));
         self.print_trait_ref(&t.trait_ref)
     }
@@ -1060,7 +1060,7 @@ impl<'a> State<'a> {
     pub fn print_enum_def(&mut self, enum_definition: &ast::EnumDef,
                           generics: &ast::Generics, ident: ast::Ident,
                           span: codemap::Span,
-                          visibility: ast::Visibility) -> IoResult<()> {
+                          visibility: ast::Visibility) -> io::Result<()> {
         try!(self.head(&visibility_qualified(visibility, "enum")));
         try!(self.print_ident(ident));
         try!(self.print_generics(generics));
@@ -1071,7 +1071,7 @@ impl<'a> State<'a> {
 
     pub fn print_variants(&mut self,
                           variants: &[P<ast::Variant>],
-                          span: codemap::Span) -> IoResult<()> {
+                          span: codemap::Span) -> io::Result<()> {
         try!(self.bopen());
         for v in variants {
             try!(self.space_if_not_bol());
@@ -1086,7 +1086,7 @@ impl<'a> State<'a> {
         self.bclose(span)
     }
 
-    pub fn print_visibility(&mut self, vis: ast::Visibility) -> IoResult<()> {
+    pub fn print_visibility(&mut self, vis: ast::Visibility) -> io::Result<()> {
         match vis {
             ast::Public => self.word_nbsp("pub"),
             ast::Inherited => Ok(())
@@ -1097,7 +1097,7 @@ impl<'a> State<'a> {
                         struct_def: &ast::StructDef,
                         generics: &ast::Generics,
                         ident: ast::Ident,
-                        span: codemap::Span) -> IoResult<()> {
+                        span: codemap::Span) -> io::Result<()> {
         try!(self.print_ident(ident));
         try!(self.print_generics(generics));
         if ast_util::struct_def_is_tuple_like(struct_def) {
@@ -1155,7 +1155,7 @@ impl<'a> State<'a> {
     /// appropriate macro, transcribe back into the grammar we just parsed from,
     /// and then pretty-print the resulting AST nodes (so, e.g., we print
     /// expression arguments as expressions). It can be done! I think.
-    pub fn print_tt(&mut self, tt: &ast::TokenTree) -> IoResult<()> {
+    pub fn print_tt(&mut self, tt: &ast::TokenTree) -> io::Result<()> {
         match *tt {
             ast::TtToken(_, ref tk) => {
                 try!(word(&mut self.s, &token_to_string(tk)));
@@ -1193,7 +1193,7 @@ impl<'a> State<'a> {
         }
     }
 
-    pub fn print_tts(&mut self, tts: &[ast::TokenTree]) -> IoResult<()> {
+    pub fn print_tts(&mut self, tts: &[ast::TokenTree]) -> io::Result<()> {
         try!(self.ibox(0));
         let mut suppress_space = false;
         for (i, tt) in tts.iter().enumerate() {
@@ -1213,7 +1213,7 @@ impl<'a> State<'a> {
         self.end()
     }
 
-    pub fn print_variant(&mut self, v: &ast::Variant) -> IoResult<()> {
+    pub fn print_variant(&mut self, v: &ast::Variant) -> io::Result<()> {
         try!(self.print_visibility(v.node.vis));
         match v.node.kind {
             ast::TupleVariantKind(ref args) => {
@@ -1242,7 +1242,7 @@ impl<'a> State<'a> {
         }
     }
 
-    pub fn print_ty_method(&mut self, m: &ast::TypeMethod) -> IoResult<()> {
+    pub fn print_ty_method(&mut self, m: &ast::TypeMethod) -> io::Result<()> {
         try!(self.hardbreak_if_not_bol());
         try!(self.maybe_print_comment(m.span.lo));
         try!(self.print_outer_attributes(&m.attrs));
@@ -1256,7 +1256,7 @@ impl<'a> State<'a> {
     }
 
     pub fn print_trait_method(&mut self,
-                              m: &ast::TraitItem) -> IoResult<()> {
+                              m: &ast::TraitItem) -> io::Result<()> {
         match *m {
             RequiredMethod(ref ty_m) => self.print_ty_method(ty_m),
             ProvidedMethod(ref m) => self.print_method(&**m),
@@ -1264,14 +1264,14 @@ impl<'a> State<'a> {
         }
     }
 
-    pub fn print_impl_item(&mut self, ii: &ast::ImplItem) -> IoResult<()> {
+    pub fn print_impl_item(&mut self, ii: &ast::ImplItem) -> io::Result<()> {
         match *ii {
             MethodImplItem(ref m) => self.print_method(&**m),
             TypeImplItem(ref td) => self.print_typedef(&**td),
         }
     }
 
-    pub fn print_method(&mut self, meth: &ast::Method) -> IoResult<()> {
+    pub fn print_method(&mut self, meth: &ast::Method) -> io::Result<()> {
         try!(self.hardbreak_if_not_bol());
         try!(self.maybe_print_comment(meth.span.lo));
         try!(self.print_outer_attributes(&meth.attrs));
@@ -1310,7 +1310,7 @@ impl<'a> State<'a> {
     }
 
     pub fn print_outer_attributes(&mut self,
-                                  attrs: &[ast::Attribute]) -> IoResult<()> {
+                                  attrs: &[ast::Attribute]) -> io::Result<()> {
         let mut count = 0;
         for attr in attrs {
             match attr.node.style {
@@ -1328,7 +1328,7 @@ impl<'a> State<'a> {
     }
 
     pub fn print_inner_attributes(&mut self,
-                                  attrs: &[ast::Attribute]) -> IoResult<()> {
+                                  attrs: &[ast::Attribute]) -> io::Result<()> {
         let mut count = 0;
         for attr in attrs {
             match attr.node.style {
@@ -1345,7 +1345,7 @@ impl<'a> State<'a> {
         Ok(())
     }
 
-    pub fn print_attribute(&mut self, attr: &ast::Attribute) -> IoResult<()> {
+    pub fn print_attribute(&mut self, attr: &ast::Attribute) -> io::Result<()> {
         try!(self.hardbreak_if_not_bol());
         try!(self.maybe_print_comment(attr.span.lo));
         if attr.node.is_sugared_doc {
@@ -1361,7 +1361,7 @@ impl<'a> State<'a> {
     }
 
 
-    pub fn print_stmt(&mut self, st: &ast::Stmt) -> IoResult<()> {
+    pub fn print_stmt(&mut self, st: &ast::Stmt) -> io::Result<()> {
         try!(self.maybe_print_comment(st.span.lo));
         match st.node {
             ast::StmtDecl(ref decl, _) => {
@@ -1395,22 +1395,22 @@ impl<'a> State<'a> {
         self.maybe_print_trailing_comment(st.span, None)
     }
 
-    pub fn print_block(&mut self, blk: &ast::Block) -> IoResult<()> {
+    pub fn print_block(&mut self, blk: &ast::Block) -> io::Result<()> {
         self.print_block_with_attrs(blk, &[])
     }
 
-    pub fn print_block_unclosed(&mut self, blk: &ast::Block) -> IoResult<()> {
+    pub fn print_block_unclosed(&mut self, blk: &ast::Block) -> io::Result<()> {
         self.print_block_unclosed_indent(blk, indent_unit)
     }
 
     pub fn print_block_unclosed_indent(&mut self, blk: &ast::Block,
-                                       indented: usize) -> IoResult<()> {
+                                       indented: usize) -> io::Result<()> {
         self.print_block_maybe_unclosed(blk, indented, &[], false)
     }
 
     pub fn print_block_with_attrs(&mut self,
                                   blk: &ast::Block,
-                                  attrs: &[ast::Attribute]) -> IoResult<()> {
+                                  attrs: &[ast::Attribute]) -> io::Result<()> {
         self.print_block_maybe_unclosed(blk, indent_unit, attrs, true)
     }
 
@@ -1418,7 +1418,7 @@ impl<'a> State<'a> {
                                       blk: &ast::Block,
                                       indented: usize,
                                       attrs: &[ast::Attribute],
-                                      close_box: bool) -> IoResult<()> {
+                                      close_box: bool) -> io::Result<()> {
         match blk.rules {
             ast::UnsafeBlock(..) => try!(self.word_space("unsafe")),
             ast::DefaultBlock => ()
@@ -1444,7 +1444,7 @@ impl<'a> State<'a> {
         self.ann.post(self, NodeBlock(blk))
     }
 
-    fn print_else(&mut self, els: Option<&ast::Expr>) -> IoResult<()> {
+    fn print_else(&mut self, els: Option<&ast::Expr>) -> io::Result<()> {
         match els {
             Some(_else) => {
                 match _else.node {
@@ -1489,7 +1489,7 @@ impl<'a> State<'a> {
     }
 
     pub fn print_if(&mut self, test: &ast::Expr, blk: &ast::Block,
-                    elseopt: Option<&ast::Expr>) -> IoResult<()> {
+                    elseopt: Option<&ast::Expr>) -> io::Result<()> {
         try!(self.head("if"));
         try!(self.print_expr(test));
         try!(space(&mut self.s));
@@ -1498,7 +1498,7 @@ impl<'a> State<'a> {
     }
 
     pub fn print_if_let(&mut self, pat: &ast::Pat, expr: &ast::Expr, blk: &ast::Block,
-                        elseopt: Option<&ast::Expr>) -> IoResult<()> {
+                        elseopt: Option<&ast::Expr>) -> io::Result<()> {
         try!(self.head("if let"));
         try!(self.print_pat(pat));
         try!(space(&mut self.s));
@@ -1510,7 +1510,7 @@ impl<'a> State<'a> {
     }
 
     pub fn print_mac(&mut self, m: &ast::Mac, delim: token::DelimToken)
-                     -> IoResult<()> {
+                     -> io::Result<()> {
         match m.node {
             // I think it's reasonable to hide the ctxt here:
             ast::MacInvocTT(ref pth, ref tts, _) => {
@@ -1532,13 +1532,13 @@ impl<'a> State<'a> {
     }
 
 
-    fn print_call_post(&mut self, args: &[P<ast::Expr>]) -> IoResult<()> {
+    fn print_call_post(&mut self, args: &[P<ast::Expr>]) -> io::Result<()> {
         try!(self.popen());
         try!(self.commasep_exprs(Inconsistent, args));
         self.pclose()
     }
 
-    pub fn print_expr_maybe_paren(&mut self, expr: &ast::Expr) -> IoResult<()> {
+    pub fn print_expr_maybe_paren(&mut self, expr: &ast::Expr) -> io::Result<()> {
         let needs_par = needs_parentheses(expr);
         if needs_par {
             try!(self.popen());
@@ -1552,7 +1552,7 @@ impl<'a> State<'a> {
 
     fn print_expr_box(&mut self,
                       place: &Option<P<ast::Expr>>,
-                      expr: &ast::Expr) -> IoResult<()> {
+                      expr: &ast::Expr) -> io::Result<()> {
         try!(word(&mut self.s, "box"));
         try!(word(&mut self.s, "("));
         try!(place.as_ref().map_or(Ok(()), |e|self.print_expr(&**e)));
@@ -1560,7 +1560,7 @@ impl<'a> State<'a> {
         self.print_expr(expr)
     }
 
-    fn print_expr_vec(&mut self, exprs: &[P<ast::Expr>]) -> IoResult<()> {
+    fn print_expr_vec(&mut self, exprs: &[P<ast::Expr>]) -> io::Result<()> {
         try!(self.ibox(indent_unit));
         try!(word(&mut self.s, "["));
         try!(self.commasep_exprs(Inconsistent, &exprs[..]));
@@ -1570,7 +1570,7 @@ impl<'a> State<'a> {
 
     fn print_expr_repeat(&mut self,
                          element: &ast::Expr,
-                         count: &ast::Expr) -> IoResult<()> {
+                         count: &ast::Expr) -> io::Result<()> {
         try!(self.ibox(indent_unit));
         try!(word(&mut self.s, "["));
         try!(self.print_expr(element));
@@ -1583,7 +1583,7 @@ impl<'a> State<'a> {
     fn print_expr_struct(&mut self,
                          path: &ast::Path,
                          fields: &[ast::Field],
-                         wth: &Option<P<ast::Expr>>) -> IoResult<()> {
+                         wth: &Option<P<ast::Expr>>) -> io::Result<()> {
         try!(self.print_path(path, true, 0));
         if !(fields.is_empty() && wth.is_none()) {
             try!(word(&mut self.s, "{"));
@@ -1616,7 +1616,7 @@ impl<'a> State<'a> {
         Ok(())
     }
 
-    fn print_expr_tup(&mut self, exprs: &[P<ast::Expr>]) -> IoResult<()> {
+    fn print_expr_tup(&mut self, exprs: &[P<ast::Expr>]) -> io::Result<()> {
         try!(self.popen());
         try!(self.commasep_exprs(Inconsistent, &exprs[..]));
         if exprs.len() == 1 {
@@ -1627,7 +1627,7 @@ impl<'a> State<'a> {
 
     fn print_expr_call(&mut self,
                        func: &ast::Expr,
-                       args: &[P<ast::Expr>]) -> IoResult<()> {
+                       args: &[P<ast::Expr>]) -> io::Result<()> {
         try!(self.print_expr_maybe_paren(func));
         self.print_call_post(args)
     }
@@ -1635,7 +1635,7 @@ impl<'a> State<'a> {
     fn print_expr_method_call(&mut self,
                               ident: ast::SpannedIdent,
                               tys: &[P<ast::Ty>],
-                              args: &[P<ast::Expr>]) -> IoResult<()> {
+                              args: &[P<ast::Expr>]) -> io::Result<()> {
         let base_args = &args[1..];
         try!(self.print_expr(&*args[0]));
         try!(word(&mut self.s, "."));
@@ -1652,7 +1652,7 @@ impl<'a> State<'a> {
     fn print_expr_binary(&mut self,
                          op: ast::BinOp,
                          lhs: &ast::Expr,
-                         rhs: &ast::Expr) -> IoResult<()> {
+                         rhs: &ast::Expr) -> io::Result<()> {
         try!(self.print_expr(lhs));
         try!(space(&mut self.s));
         try!(self.word_space(ast_util::binop_to_string(op.node)));
@@ -1661,20 +1661,20 @@ impl<'a> State<'a> {
 
     fn print_expr_unary(&mut self,
                         op: ast::UnOp,
-                        expr: &ast::Expr) -> IoResult<()> {
+                        expr: &ast::Expr) -> io::Result<()> {
         try!(word(&mut self.s, ast_util::unop_to_string(op)));
         self.print_expr_maybe_paren(expr)
     }
 
     fn print_expr_addr_of(&mut self,
                           mutability: ast::Mutability,
-                          expr: &ast::Expr) -> IoResult<()> {
+                          expr: &ast::Expr) -> io::Result<()> {
         try!(word(&mut self.s, "&"));
         try!(self.print_mutability(mutability));
         self.print_expr_maybe_paren(expr)
     }
 
-    pub fn print_expr(&mut self, expr: &ast::Expr) -> IoResult<()> {
+    pub fn print_expr(&mut self, expr: &ast::Expr) -> io::Result<()> {
         try!(self.maybe_print_comment(expr.span.lo));
         try!(self.ibox(indent_unit));
         try!(self.ann.pre(self, NodeExpr(expr)));
@@ -1958,7 +1958,7 @@ impl<'a> State<'a> {
         self.end()
     }
 
-    pub fn print_local_decl(&mut self, loc: &ast::Local) -> IoResult<()> {
+    pub fn print_local_decl(&mut self, loc: &ast::Local) -> io::Result<()> {
         try!(self.print_pat(&*loc.pat));
         if let Some(ref ty) = loc.ty {
             try!(self.word_space(":"));
@@ -1967,7 +1967,7 @@ impl<'a> State<'a> {
         Ok(())
     }
 
-    pub fn print_decl(&mut self, decl: &ast::Decl) -> IoResult<()> {
+    pub fn print_decl(&mut self, decl: &ast::Decl) -> io::Result<()> {
         try!(self.maybe_print_comment(decl.span.lo));
         match decl.node {
             ast::DeclLocal(ref loc) => {
@@ -1989,7 +1989,7 @@ impl<'a> State<'a> {
         }
     }
 
-    pub fn print_ident(&mut self, ident: ast::Ident) -> IoResult<()> {
+    pub fn print_ident(&mut self, ident: ast::Ident) -> io::Result<()> {
         if self.encode_idents_with_hygiene {
             let encoded = ident.encode_with_hygiene();
             try!(word(&mut self.s, &encoded[..]))
@@ -1999,17 +1999,17 @@ impl<'a> State<'a> {
         self.ann.post(self, NodeIdent(&ident))
     }
 
-    pub fn print_usize(&mut self, i: usize) -> IoResult<()> {
+    pub fn print_usize(&mut self, i: usize) -> io::Result<()> {
         word(&mut self.s, &i.to_string())
     }
 
-    pub fn print_name(&mut self, name: ast::Name) -> IoResult<()> {
+    pub fn print_name(&mut self, name: ast::Name) -> io::Result<()> {
         try!(word(&mut self.s, &token::get_name(name)));
         self.ann.post(self, NodeName(&name))
     }
 
     pub fn print_for_decl(&mut self, loc: &ast::Local,
-                          coll: &ast::Expr) -> IoResult<()> {
+                          coll: &ast::Expr) -> io::Result<()> {
         try!(self.print_local_decl(loc));
         try!(space(&mut self.s));
         try!(self.word_space("in"));
@@ -2020,7 +2020,7 @@ impl<'a> State<'a> {
                   path: &ast::Path,
                   colons_before_params: bool,
                   depth: usize)
-                  -> IoResult<()>
+                  -> io::Result<()>
     {
         try!(self.maybe_print_comment(path.span.lo));
 
@@ -2044,7 +2044,7 @@ impl<'a> State<'a> {
                    path: &ast::Path,
                    qself: &ast::QSelf,
                    colons_before_params: bool)
-                   -> IoResult<()>
+                   -> io::Result<()>
     {
         try!(word(&mut self.s, "<"));
         try!(self.print_type(&qself.ty));
@@ -2064,7 +2064,7 @@ impl<'a> State<'a> {
     fn print_path_parameters(&mut self,
                              parameters: &ast::PathParameters,
                              colons_before_params: bool)
-                             -> IoResult<()>
+                             -> io::Result<()>
     {
         if parameters.is_empty() {
             return Ok(());
@@ -2134,7 +2134,7 @@ impl<'a> State<'a> {
         Ok(())
     }
 
-    pub fn print_pat(&mut self, pat: &ast::Pat) -> IoResult<()> {
+    pub fn print_pat(&mut self, pat: &ast::Pat) -> io::Result<()> {
         try!(self.maybe_print_comment(pat.span.lo));
         try!(self.ann.pre(self, NodePat(pat)));
         /* Pat isn't normalized, but the beauty of it
@@ -2253,7 +2253,7 @@ impl<'a> State<'a> {
         self.ann.post(self, NodePat(pat))
     }
 
-    fn print_arm(&mut self, arm: &ast::Arm) -> IoResult<()> {
+    fn print_arm(&mut self, arm: &ast::Arm) -> io::Result<()> {
         // I have no idea why this check is necessary, but here it
         // is :(
         if arm.attrs.is_empty() {
@@ -2302,7 +2302,7 @@ impl<'a> State<'a> {
     // Returns whether it printed anything
     fn print_explicit_self(&mut self,
                            explicit_self: &ast::ExplicitSelf_,
-                           mutbl: ast::Mutability) -> IoResult<bool> {
+                           mutbl: ast::Mutability) -> io::Result<bool> {
         try!(self.print_mutability(mutbl));
         match *explicit_self {
             ast::SelfStatic => { return Ok(false); }
@@ -2331,7 +2331,7 @@ impl<'a> State<'a> {
                     name: ast::Ident,
                     generics: &ast::Generics,
                     opt_explicit_self: Option<&ast::ExplicitSelf_>,
-                    vis: ast::Visibility) -> IoResult<()> {
+                    vis: ast::Visibility) -> io::Result<()> {
         try!(self.head(""));
         try!(self.print_fn_header_info(unsafety, abi, vis));
         try!(self.nbsp());
@@ -2343,7 +2343,7 @@ impl<'a> State<'a> {
 
     pub fn print_fn_args(&mut self, decl: &ast::FnDecl,
                          opt_explicit_self: Option<&ast::ExplicitSelf_>)
-        -> IoResult<()> {
+        -> io::Result<()> {
         // It is unfortunate to duplicate the commasep logic, but we want the
         // self type and the args all in the same box.
         try!(self.rbox(0, Inconsistent));
@@ -2376,7 +2376,7 @@ impl<'a> State<'a> {
 
     pub fn print_fn_args_and_ret(&mut self, decl: &ast::FnDecl,
                                  opt_explicit_self: Option<&ast::ExplicitSelf_>)
-        -> IoResult<()> {
+        -> io::Result<()> {
         try!(self.popen());
         try!(self.print_fn_args(decl, opt_explicit_self));
         if decl.variadic {
@@ -2390,7 +2390,7 @@ impl<'a> State<'a> {
     pub fn print_fn_block_args(
             &mut self,
             decl: &ast::FnDecl)
-            -> IoResult<()> {
+            -> io::Result<()> {
         try!(word(&mut self.s, "|"));
         try!(self.print_fn_args(decl, None));
         try!(word(&mut self.s, "|"));
@@ -2415,7 +2415,7 @@ impl<'a> State<'a> {
     }
 
     pub fn print_capture_clause(&mut self, capture_clause: ast::CaptureClause)
-                                -> IoResult<()> {
+                                -> io::Result<()> {
         match capture_clause {
             ast::CaptureByValue => self.word_space("move"),
             ast::CaptureByRef => Ok(()),
@@ -2425,7 +2425,7 @@ impl<'a> State<'a> {
     pub fn print_bounds(&mut self,
                         prefix: &str,
                         bounds: &[ast::TyParamBound])
-                        -> IoResult<()> {
+                        -> io::Result<()> {
         if !bounds.is_empty() {
             try!(word(&mut self.s, prefix));
             let mut first = true;
@@ -2458,14 +2458,14 @@ impl<'a> State<'a> {
 
     pub fn print_lifetime(&mut self,
                           lifetime: &ast::Lifetime)
-                          -> IoResult<()>
+                          -> io::Result<()>
     {
         self.print_name(lifetime.name)
     }
 
     pub fn print_lifetime_def(&mut self,
                               lifetime: &ast::LifetimeDef)
-                              -> IoResult<()>
+                              -> io::Result<()>
     {
         try!(self.print_lifetime(&lifetime.lifetime));
         let mut sep = ":";
@@ -2479,7 +2479,7 @@ impl<'a> State<'a> {
 
     pub fn print_generics(&mut self,
                           generics: &ast::Generics)
-                          -> IoResult<()>
+                          -> io::Result<()>
     {
         let total = generics.lifetimes.len() + generics.ty_params.len();
         if total == 0 {
@@ -2508,7 +2508,7 @@ impl<'a> State<'a> {
         Ok(())
     }
 
-    pub fn print_ty_param(&mut self, param: &ast::TyParam) -> IoResult<()> {
+    pub fn print_ty_param(&mut self, param: &ast::TyParam) -> io::Result<()> {
         try!(self.print_ident(param.ident));
         try!(self.print_bounds(":", &param.bounds));
         match param.default {
@@ -2522,7 +2522,7 @@ impl<'a> State<'a> {
     }
 
     pub fn print_where_clause(&mut self, generics: &ast::Generics)
-                              -> IoResult<()> {
+                              -> io::Result<()> {
         if generics.where_clause.predicates.len() == 0 {
             return Ok(())
         }
@@ -2573,7 +2573,7 @@ impl<'a> State<'a> {
         Ok(())
     }
 
-    pub fn print_meta_item(&mut self, item: &ast::MetaItem) -> IoResult<()> {
+    pub fn print_meta_item(&mut self, item: &ast::MetaItem) -> io::Result<()> {
         try!(self.ibox(indent_unit));
         match item.node {
             ast::MetaWord(ref name) => {
@@ -2596,7 +2596,7 @@ impl<'a> State<'a> {
         self.end()
     }
 
-    pub fn print_view_path(&mut self, vp: &ast::ViewPath) -> IoResult<()> {
+    pub fn print_view_path(&mut self, vp: &ast::ViewPath) -> io::Result<()> {
         match vp.node {
             ast::ViewPathSimple(ident, ref path) => {
                 try!(self.print_path(path, false, 0));
@@ -2640,19 +2640,19 @@ impl<'a> State<'a> {
     }
 
     pub fn print_mutability(&mut self,
-                            mutbl: ast::Mutability) -> IoResult<()> {
+                            mutbl: ast::Mutability) -> io::Result<()> {
         match mutbl {
             ast::MutMutable => self.word_nbsp("mut"),
             ast::MutImmutable => Ok(()),
         }
     }
 
-    pub fn print_mt(&mut self, mt: &ast::MutTy) -> IoResult<()> {
+    pub fn print_mt(&mut self, mt: &ast::MutTy) -> io::Result<()> {
         try!(self.print_mutability(mt.mutbl));
         self.print_type(&*mt.ty)
     }
 
-    pub fn print_arg(&mut self, input: &ast::Arg) -> IoResult<()> {
+    pub fn print_arg(&mut self, input: &ast::Arg) -> io::Result<()> {
         try!(self.ibox(indent_unit));
         match input.ty.node {
             ast::TyInfer => try!(self.print_pat(&*input.pat)),
@@ -2675,7 +2675,7 @@ impl<'a> State<'a> {
         self.end()
     }
 
-    pub fn print_fn_output(&mut self, decl: &ast::FnDecl) -> IoResult<()> {
+    pub fn print_fn_output(&mut self, decl: &ast::FnDecl) -> io::Result<()> {
         if let ast::DefaultReturn(..) = decl.output {
             return Ok(());
         }
@@ -2705,7 +2705,7 @@ impl<'a> State<'a> {
                        id: Option<ast::Ident>,
                        generics: &ast::Generics,
                        opt_explicit_self: Option<&ast::ExplicitSelf_>)
-                       -> IoResult<()> {
+                       -> io::Result<()> {
         try!(self.ibox(indent_unit));
         try!(self.print_fn_header_info(Some(unsafety), abi, ast::Inherited));
 
@@ -2726,7 +2726,7 @@ impl<'a> State<'a> {
 
     pub fn maybe_print_trailing_comment(&mut self, span: codemap::Span,
                                         next_pos: Option<BytePos>)
-        -> IoResult<()> {
+        -> io::Result<()> {
         let cm = match self.cm {
             Some(cm) => cm,
             _ => return Ok(())
@@ -2749,7 +2749,7 @@ impl<'a> State<'a> {
         Ok(())
     }
 
-    pub fn print_remaining_comments(&mut self) -> IoResult<()> {
+    pub fn print_remaining_comments(&mut self) -> io::Result<()> {
         // If there aren't any remaining comments, then we need to manually
         // make sure there is a line break at the end.
         if self.next_comment().is_none() {
@@ -2767,7 +2767,7 @@ impl<'a> State<'a> {
         Ok(())
     }
 
-    pub fn print_literal(&mut self, lit: &ast::Lit) -> IoResult<()> {
+    pub fn print_literal(&mut self, lit: &ast::Lit) -> io::Result<()> {
         try!(self.maybe_print_comment(lit.span.lo));
         match self.next_lit(lit.span.lo) {
             Some(ref ltrl) => {
@@ -2848,7 +2848,7 @@ impl<'a> State<'a> {
         }
     }
 
-    pub fn maybe_print_comment(&mut self, pos: BytePos) -> IoResult<()> {
+    pub fn maybe_print_comment(&mut self, pos: BytePos) -> io::Result<()> {
         loop {
             match self.next_comment() {
                 Some(ref cmnt) => {
@@ -2864,7 +2864,7 @@ impl<'a> State<'a> {
     }
 
     pub fn print_comment(&mut self,
-                         cmnt: &comments::Comment) -> IoResult<()> {
+                         cmnt: &comments::Comment) -> io::Result<()> {
         match cmnt.style {
             comments::Mixed => {
                 assert_eq!(cmnt.lines.len(), 1);
@@ -2915,7 +2915,7 @@ impl<'a> State<'a> {
     }
 
     pub fn print_string(&mut self, st: &str,
-                        style: ast::StrStyle) -> IoResult<()> {
+                        style: ast::StrStyle) -> io::Result<()> {
         let st = match style {
             ast::CookedStr => {
                 (format!("\"{}\"", st.escape_default()))
@@ -2943,7 +2943,7 @@ impl<'a> State<'a> {
     }
 
     pub fn print_opt_unsafety(&mut self,
-                            opt_unsafety: Option<ast::Unsafety>) -> IoResult<()> {
+                            opt_unsafety: Option<ast::Unsafety>) -> io::Result<()> {
         match opt_unsafety {
             Some(unsafety) => self.print_unsafety(unsafety),
             None => Ok(())
@@ -2952,7 +2952,7 @@ impl<'a> State<'a> {
 
     pub fn print_opt_abi_and_extern_if_nondefault(&mut self,
                                                   opt_abi: Option<abi::Abi>)
-        -> IoResult<()> {
+        -> io::Result<()> {
         match opt_abi {
             Some(abi::Rust) => Ok(()),
             Some(abi) => {
@@ -2964,7 +2964,7 @@ impl<'a> State<'a> {
     }
 
     pub fn print_extern_opt_abi(&mut self,
-                                opt_abi: Option<abi::Abi>) -> IoResult<()> {
+                                opt_abi: Option<abi::Abi>) -> io::Result<()> {
         match opt_abi {
             Some(abi) => {
                 try!(self.word_nbsp("extern"));
@@ -2977,7 +2977,7 @@ impl<'a> State<'a> {
     pub fn print_fn_header_info(&mut self,
                                 opt_unsafety: Option<ast::Unsafety>,
                                 abi: abi::Abi,
-                                vis: ast::Visibility) -> IoResult<()> {
+                                vis: ast::Visibility) -> io::Result<()> {
         try!(word(&mut self.s, &visibility_qualified(vis, "")));
         try!(self.print_opt_unsafety(opt_unsafety));
 
@@ -2989,7 +2989,7 @@ impl<'a> State<'a> {
         word(&mut self.s, "fn")
     }
 
-    pub fn print_unsafety(&mut self, s: ast::Unsafety) -> IoResult<()> {
+    pub fn print_unsafety(&mut self, s: ast::Unsafety) -> io::Result<()> {
         match s {
             ast::Unsafety::Normal => Ok(()),
             ast::Unsafety::Unsafe => self.word_nbsp("unsafe"),
diff --git a/src/libterm/lib.rs b/src/libterm/lib.rs
index 756d67b5db1..ba9860ee31f 100644
--- a/src/libterm/lib.rs
+++ b/src/libterm/lib.rs
@@ -52,14 +52,15 @@
 
 #![feature(box_syntax)]
 #![feature(collections)]
+#![feature(fs)]
 #![feature(int_uint)]
+#![feature(io)]
 #![feature(old_io)]
-#![feature(old_path)]
+#![feature(path)]
 #![feature(rustc_private)]
 #![feature(staged_api)]
-#![feature(unicode)]
 #![feature(std_misc)]
-#![feature(os)]
+#![feature(unicode)]
 #![cfg_attr(windows, feature(libc))]
 
 #[macro_use] extern crate log;
diff --git a/src/libterm/terminfo/parser/compiled.rs b/src/libterm/terminfo/parser/compiled.rs
index c147e6aa056..cc9a2880b5d 100644
--- a/src/libterm/terminfo/parser/compiled.rs
+++ b/src/libterm/terminfo/parser/compiled.rs
@@ -13,7 +13,8 @@
 //! ncurses-compatible compiled terminfo format parsing (term(5))
 
 use std::collections::HashMap;
-use std::old_io;
+use std::io::prelude::*;
+use std::io;
 use super::super::TermInfo;
 
 // These are the orders ncurses uses in its compiled format (as of 5.9). Not sure if portable.
@@ -158,7 +159,7 @@ pub static stringnames: &'static[&'static str] = &[ "cbt", "_", "cr", "csr", "tb
     "box1"];
 
 /// Parse a compiled terminfo entry, using long capability names if `longnames` is true
-pub fn parse(file: &mut old_io::Reader, longnames: bool)
+pub fn parse(file: &mut Read, longnames: bool)
              -> Result<Box<TermInfo>, String> {
     macro_rules! try { ($e:expr) => (
         match $e {
@@ -182,17 +183,17 @@ pub fn parse(file: &mut old_io::Reader, longnames: bool)
     }
 
     // Check magic number
-    let magic = try!(file.read_le_u16());
+    let magic = try!(read_le_u16(file));
     if magic != 0x011A {
         return Err(format!("invalid magic number: expected {:x}, found {:x}",
                            0x011A as usize, magic as usize));
     }
 
-    let names_bytes          = try!(file.read_le_i16()) as int;
-    let bools_bytes          = try!(file.read_le_i16()) as int;
-    let numbers_count        = try!(file.read_le_i16()) as int;
-    let string_offsets_count = try!(file.read_le_i16()) as int;
-    let string_table_bytes   = try!(file.read_le_i16()) as int;
+    let names_bytes          = try!(read_le_u16(file)) as int;
+    let bools_bytes          = try!(read_le_u16(file)) as int;
+    let numbers_count        = try!(read_le_u16(file)) as int;
+    let string_offsets_count = try!(read_le_u16(file)) as int;
+    let string_table_bytes   = try!(read_le_u16(file)) as int;
 
     assert!(names_bytes          > 0);
 
@@ -212,7 +213,7 @@ pub fn parse(file: &mut old_io::Reader, longnames: bool)
     }
 
     // don't read NUL
-    let bytes = try!(file.read_exact(names_bytes as uint - 1));
+    let bytes = try!(read_exact(file, names_bytes as uint - 1));
     let names_str = match String::from_utf8(bytes) {
         Ok(s)  => s,
         Err(_) => return Err("input not utf-8".to_string()),
@@ -222,12 +223,12 @@ pub fn parse(file: &mut old_io::Reader, longnames: bool)
                                            .map(|s| s.to_string())
                                            .collect();
 
-    try!(file.read_byte()); // consume NUL
+    try!(read_byte(file)); // consume NUL
 
     let mut bools_map = HashMap::new();
     if bools_bytes != 0 {
         for i in 0..bools_bytes {
-            let b = try!(file.read_byte());
+            let b = try!(read_byte(file));
             if b == 1 {
                 bools_map.insert(bnames[i as uint].to_string(), true);
             }
@@ -235,13 +236,13 @@ pub fn parse(file: &mut old_io::Reader, longnames: bool)
     }
 
     if (bools_bytes + names_bytes) % 2 == 1 {
-        try!(file.read_byte()); // compensate for padding
+        try!(read_byte(file)); // compensate for padding
     }
 
     let mut numbers_map = HashMap::new();
     if numbers_count != 0 {
         for i in 0..numbers_count {
-            let n = try!(file.read_le_u16());
+            let n = try!(read_le_u16(file));
             if n != 0xFFFF {
                 numbers_map.insert(nnames[i as uint].to_string(), n);
             }
@@ -253,10 +254,10 @@ pub fn parse(file: &mut old_io::Reader, longnames: bool)
     if string_offsets_count != 0 {
         let mut string_offsets = Vec::with_capacity(10);
         for _ in 0..string_offsets_count {
-            string_offsets.push(try!(file.read_le_u16()));
+            string_offsets.push(try!(read_le_u16(file)));
         }
 
-        let string_table = try!(file.read_exact(string_table_bytes as uint));
+        let string_table = try!(read_exact(file, string_table_bytes as usize));
 
         if string_table.len() != string_table_bytes as uint {
             return Err("error: hit EOF before end of string \
@@ -309,6 +310,25 @@ pub fn parse(file: &mut old_io::Reader, longnames: bool)
     })
 }
 
+fn read_le_u16<R: Read + ?Sized>(r: &mut R) -> io::Result<u16> {
+    let mut b = [0; 2];
+    assert_eq!(try!(r.read(&mut b)), 2);
+    Ok((b[0] as u16) | ((b[1] as u16) << 8))
+}
+
+fn read_byte<R: Read + ?Sized>(r: &mut R) -> io::Result<u8> {
+    let mut b = [0; 1];
+    assert_eq!(try!(r.read(&mut b)), 1);
+    Ok(b[0])
+}
+
+fn read_exact<R: Read + ?Sized>(r: &mut R, sz: usize) -> io::Result<Vec<u8>> {
+    let mut v = Vec::with_capacity(sz);
+    try!(r.take(sz as u64).read_to_end(&mut v));
+    assert_eq!(v.len(), sz);
+    Ok(v)
+}
+
 /// Create a dummy TermInfo struct for msys terminals
 pub fn msys_terminfo() -> Box<TermInfo> {
     let mut strings = HashMap::new();
diff --git a/src/libterm/terminfo/searcher.rs b/src/libterm/terminfo/searcher.rs
index 15f7f3884ec..f47921cbf5e 100644
--- a/src/libterm/terminfo/searcher.rs
+++ b/src/libterm/terminfo/searcher.rs
@@ -12,26 +12,27 @@
 //!
 //! Does not support hashed database, only filesystem!
 
-use std::old_io::File;
-use std::old_io::fs::PathExtensions;
 use std::env;
+use std::fs::File;
+use std::io::prelude::*;
+use std::path::PathBuf;
 
 /// Return path to database entry for `term`
 #[allow(deprecated)]
-pub fn get_dbpath_for_term(term: &str) -> Option<Box<Path>> {
+pub fn get_dbpath_for_term(term: &str) -> Option<Box<PathBuf>> {
     if term.len() == 0 {
         return None;
     }
 
-    let homedir = ::std::os::homedir();
+    let homedir = env::home_dir();
 
     let mut dirs_to_search = Vec::new();
     let first_char = term.char_at(0);
 
     // Find search directory
-    match env::var("TERMINFO") {
-        Ok(dir) => dirs_to_search.push(Path::new(dir)),
-        Err(..) => {
+    match env::var_os("TERMINFO") {
+        Some(dir) => dirs_to_search.push(PathBuf::new(&dir)),
+        None => {
             if homedir.is_some() {
                 // ncurses compatibility;
                 dirs_to_search.push(homedir.unwrap().join(".terminfo"))
@@ -39,9 +40,9 @@ pub fn get_dbpath_for_term(term: &str) -> Option<Box<Path>> {
             match env::var("TERMINFO_DIRS") {
                 Ok(dirs) => for i in dirs.split(':') {
                     if i == "" {
-                        dirs_to_search.push(Path::new("/usr/share/terminfo"));
+                        dirs_to_search.push(PathBuf::new("/usr/share/terminfo"));
                     } else {
-                        dirs_to_search.push(Path::new(i));
+                        dirs_to_search.push(PathBuf::new(i));
                     }
                 },
                 // Found nothing in TERMINFO_DIRS, use the default paths:
@@ -49,9 +50,9 @@ pub fn get_dbpath_for_term(term: &str) -> Option<Box<Path>> {
                 // ~/.terminfo, ncurses will search /etc/terminfo, then
                 // /lib/terminfo, and eventually /usr/share/terminfo.
                 Err(..) => {
-                    dirs_to_search.push(Path::new("/etc/terminfo"));
-                    dirs_to_search.push(Path::new("/lib/terminfo"));
-                    dirs_to_search.push(Path::new("/usr/share/terminfo"));
+                    dirs_to_search.push(PathBuf::new("/etc/terminfo"));
+                    dirs_to_search.push(PathBuf::new("/lib/terminfo"));
+                    dirs_to_search.push(PathBuf::new("/usr/share/terminfo"));
                 }
             }
         }
@@ -61,13 +62,13 @@ pub fn get_dbpath_for_term(term: &str) -> Option<Box<Path>> {
     for p in &dirs_to_search {
         if p.exists() {
             let f = first_char.to_string();
-            let newp = p.join_many(&[&f[..], term]);
+            let newp = p.join(&f).join(term);
             if newp.exists() {
                 return Some(box newp);
             }
             // on some installations the dir is named after the hex of the char (e.g. OS X)
             let f = format!("{:x}", first_char as uint);
-            let newp = p.join_many(&[&f[..], term]);
+            let newp = p.join(&f).join(term);
             if newp.exists() {
                 return Some(box newp);
             }
@@ -100,7 +101,7 @@ fn test_get_dbpath_for_term() {
     // FIXME (#9639): This needs to handle non-utf8 paths
     fn x(t: &str) -> String {
         let p = get_dbpath_for_term(t).expect("no terminfo entry found");
-        p.as_str().unwrap().to_string()
+        p.to_str().unwrap().to_string()
     };
     assert!(x("screen") == "/usr/share/terminfo/s/screen");
     assert!(get_dbpath_for_term("") == None);
diff --git a/src/libtest/lib.rs b/src/libtest/lib.rs
index 3fbb07d03a8..e309e7a6c22 100644
--- a/src/libtest/lib.rs
+++ b/src/libtest/lib.rs
@@ -38,10 +38,12 @@
 #![feature(core)]
 #![feature(int_uint)]
 #![feature(old_io)]
-#![feature(old_path)]
+#![feature(path)]
+#![feature(fs)]
 #![feature(rustc_private)]
 #![feature(staged_api)]
 #![feature(std_misc)]
+#![feature(io)]
 
 extern crate getopts;
 extern crate serialize;
@@ -65,13 +67,16 @@ use term::color::{Color, RED, YELLOW, GREEN, CYAN};
 use std::any::Any;
 use std::cmp;
 use std::collections::BTreeMap;
+use std::env;
 use std::fmt;
-use std::old_io::stdio::StdWriter;
-use std::old_io::{File, ChanReader, ChanWriter};
-use std::old_io;
+use std::fs::File;
+use std::io::{self, Write};
 use std::iter::repeat;
 use std::num::{Float, Int};
-use std::env;
+use std::old_io::stdio::StdWriter;
+use std::old_io::{ChanReader, ChanWriter};
+use std::old_io;
+use std::path::{PathBuf};
 use std::sync::mpsc::{channel, Sender};
 use std::thread;
 use std::thunk::{Thunk, Invoke};
@@ -287,7 +292,7 @@ pub struct TestOpts {
     pub run_ignored: bool,
     pub run_tests: bool,
     pub run_benchmarks: bool,
-    pub logfile: Option<Path>,
+    pub logfile: Option<PathBuf>,
     pub nocapture: bool,
     pub color: ColorConfig,
 }
@@ -376,7 +381,7 @@ pub fn parse_opts(args: &[String]) -> Option<OptRes> {
     let run_ignored = matches.opt_present("ignored");
 
     let logfile = matches.opt_str("logfile");
-    let logfile = logfile.map(|s| Path::new(s));
+    let logfile = logfile.map(|s| PathBuf::new(&s));
 
     let run_benchmarks = matches.opt_present("bench");
     let run_tests = ! run_benchmarks ||
@@ -446,11 +451,19 @@ struct ConsoleTestState<T> {
     max_name_len: uint, // number of columns to fill when aligning names
 }
 
+fn new2old(new: io::Error) -> old_io::IoError {
+    old_io::IoError {
+        kind: old_io::OtherIoError,
+        desc: "other error",
+        detail: Some(new.to_string()),
+    }
+}
+
 impl<T: Writer> ConsoleTestState<T> {
     pub fn new(opts: &TestOpts,
                _: Option<T>) -> old_io::IoResult<ConsoleTestState<StdWriter>> {
         let log_out = match opts.logfile {
-            Some(ref path) => Some(try!(File::create(path))),
+            Some(ref path) => Some(try!(File::create(path).map_err(new2old))),
             None => None
         };
         let out = match term::stdout() {
@@ -560,7 +573,7 @@ impl<T: Writer> ConsoleTestState<T> {
     }
 
     pub fn write_log(&mut self, test: &TestDesc,
-                     result: &TestResult) -> old_io::IoResult<()> {
+                     result: &TestResult) -> io::Result<()> {
         match self.log_out {
             None => Ok(()),
             Some(ref mut o) => {
@@ -646,7 +659,7 @@ pub fn run_tests_console(opts: &TestOpts, tests: Vec<TestDescAndFn> ) -> old_io:
             TeFiltered(ref filtered_tests) => st.write_run_start(filtered_tests.len()),
             TeWait(ref test, padding) => st.write_test_start(test, padding),
             TeResult(test, result, stdout) => {
-                try!(st.write_log(&test, &result));
+                try!(st.write_log(&test, &result).map_err(new2old));
                 try!(st.write_result(&result));
                 match result {
                     TrOk => st.passed += 1,
diff --git a/src/rustbook/book.rs b/src/rustbook/book.rs
index 8900b60d191..ac7f2f824cb 100644
--- a/src/rustbook/book.rs
+++ b/src/rustbook/book.rs
@@ -10,14 +10,16 @@
 
 //! Basic data structures for representing a book.
 
-use std::old_io::BufferedReader;
+use std::io::prelude::*;
+use std::io::BufReader;
 use std::iter;
 use std::iter::AdditiveIterator;
+use std::path::{Path, PathBuf};
 
 pub struct BookItem {
     pub title: String,
-    pub path: Path,
-    pub path_to_root: Path,
+    pub path: PathBuf,
+    pub path_to_root: PathBuf,
     pub children: Vec<BookItem>,
 }
 
@@ -76,7 +78,7 @@ impl Book {
 }
 
 /// Construct a book by parsing a summary (markdown table of contents).
-pub fn parse_summary<R: Reader>(input: R, src: &Path) -> Result<Book, Vec<String>> {
+pub fn parse_summary(input: &mut Read, src: &Path) -> Result<Book, Vec<String>> {
     fn collapse(stack: &mut Vec<BookItem>,
                 top_items: &mut Vec<BookItem>,
                 to_level: usize) {
@@ -100,16 +102,16 @@ pub fn parse_summary<R: Reader>(input: R, src: &Path) -> Result<Book, Vec<String
     // always include the introduction
     top_items.push(BookItem {
         title: "Introduction".to_string(),
-        path: Path::new("README.md"),
-        path_to_root: Path::new("."),
+        path: PathBuf::new("README.md"),
+        path_to_root: PathBuf::new("."),
         children: vec!(),
     });
 
-    for line_result in BufferedReader::new(input).lines() {
+    for line_result in BufReader::new(input).lines() {
         let line = match line_result {
             Ok(line) => line,
             Err(err) => {
-                errors.push(err.desc.to_string()); // FIXME: include detail
+                errors.push(err.to_string());
                 return Err(errors);
             }
         };
@@ -125,16 +127,16 @@ pub fn parse_summary<R: Reader>(input: R, src: &Path) -> Result<Book, Vec<String
         let title = line[start_bracket + 1..end_bracket].to_string();
         let indent = &line[..star_idx];
 
-        let path_from_root = match src.join(given_path).path_relative_from(src) {
-            Some(p) => p,
+        let path_from_root = match src.join(given_path).relative_from(src) {
+            Some(p) => p.to_path_buf(),
             None => {
                 errors.push(format!("paths in SUMMARY.md must be relative, \
                                      but path '{}' for section '{}' is not.",
                                      given_path, title));
-                Path::new("")
+                PathBuf::new("")
             }
         };
-        let path_to_root = Path::new(iter::repeat("../")
+        let path_to_root = PathBuf::new(&iter::repeat("../")
                                          .take(path_from_root.components().count() - 1)
                                          .collect::<String>());
         let item = BookItem {
diff --git a/src/rustbook/build.rs b/src/rustbook/build.rs
index f36d97d6d12..1fb30e15400 100644
--- a/src/rustbook/build.rs
+++ b/src/rustbook/build.rs
@@ -11,13 +11,14 @@
 //! Implementation of the `build` subcommand, used to compile a book.
 
 use std::env;
-use std::os;
-use std::old_io;
-use std::old_io::{fs, File, BufferedWriter, TempDir, IoResult};
+use std::fs::{self, File, TempDir};
+use std::io::prelude::*;
+use std::io::{self, BufWriter};
+use std::path::{Path, PathBuf};
 
 use subcommand::Subcommand;
 use term::Term;
-use error::{Error, CliResult, CommandResult};
+use error::{err, CliResult, CommandResult};
 use book;
 use book::{Book, BookItem};
 use css;
@@ -29,17 +30,17 @@ struct Build;
 
 pub fn parse_cmd(name: &str) -> Option<Box<Subcommand>> {
     if name == "build" {
-        Some(box Build as Box<Subcommand>)
+        Some(Box::new(Build))
     } else {
         None
     }
 }
 
-fn write_toc(book: &Book, path_to_root: &Path, out: &mut Writer) -> IoResult<()> {
+fn write_toc(book: &Book, path_to_root: &Path, out: &mut Write) -> io::Result<()> {
     fn walk_items(items: &[BookItem],
                   section: &str,
                   path_to_root: &Path,
-                  out: &mut Writer) -> IoResult<()> {
+                  out: &mut Write) -> io::Result<()> {
         for (i, item) in items.iter().enumerate() {
             try!(walk_item(item, &format!("{}{}.", section, i + 1)[..], path_to_root, out));
         }
@@ -48,9 +49,9 @@ fn write_toc(book: &Book, path_to_root: &Path, out: &mut Writer) -> IoResult<()>
     fn walk_item(item: &BookItem,
                  section: &str,
                  path_to_root: &Path,
-                 out: &mut Writer) -> IoResult<()> {
+                 out: &mut Write) -> io::Result<()> {
         try!(writeln!(out, "<li><a href='{}'><b>{}</b> {}</a>",
-                 path_to_root.join(item.path.with_extension("html")).display(),
+                 path_to_root.join(&item.path.with_extension("html")).display(),
                  section,
                  item.title));
         if !item.children.is_empty() {
@@ -75,30 +76,35 @@ fn write_toc(book: &Book, path_to_root: &Path, out: &mut Writer) -> IoResult<()>
 fn render(book: &Book, tgt: &Path) -> CliResult<()> {
     let tmp = try!(TempDir::new("rust-book"));
 
-    for (section, item) in book.iter() {
-        println!("{} {}", section, item.title);
-
-        let out_path = tgt.join(item.path.dirname());
+    for (_section, item) in book.iter() {
+        let out_path = match item.path.parent() {
+            Some(p) => tgt.join(p),
+            None => tgt.to_path_buf(),
+        };
 
         let src;
         if env::args().len() < 3 {
-            src = os::getcwd().unwrap().clone();
+            src = env::current_dir().unwrap().clone();
         } else {
-            src = Path::new(env::args().nth(2).unwrap().clone());
+            src = PathBuf::new(&env::args().nth(2).unwrap());
         }
         // preprocess the markdown, rerouting markdown references to html references
-        let markdown_data = try!(File::open(&src.join(&item.path)).read_to_string());
-        let preprocessed_path = tmp.path().join(item.path.filename().unwrap());
+        let mut markdown_data = String::new();
+        try!(File::open(&src.join(&item.path)).and_then(|mut f| {
+            f.read_to_string(&mut markdown_data)
+        }));
+        let preprocessed_path = tmp.path().join(item.path.file_name().unwrap());
         {
             let urls = markdown_data.replace(".md)", ".html)");
-            try!(File::create(&preprocessed_path)
-                      .write_str(&urls[..]));
+            try!(File::create(&preprocessed_path).and_then(|mut f| {
+                f.write_all(urls.as_bytes())
+            }));
         }
 
         // write the prelude to a temporary HTML file for rustdoc inclusion
         let prelude = tmp.path().join("prelude.html");
         {
-            let mut toc = BufferedWriter::new(try!(File::create(&prelude)));
+            let mut toc = BufWriter::new(try!(File::create(&prelude)));
             try!(writeln!(&mut toc, r#"<div id="nav">
                 <button id="toggle-nav">
                   <span class="sr-only">Toggle navigation</span>
@@ -115,12 +121,12 @@ fn render(book: &Book, tgt: &Path) -> CliResult<()> {
         // write the postlude to a temporary HTML file for rustdoc inclusion
         let postlude = tmp.path().join("postlude.html");
         {
-            let mut toc = BufferedWriter::new(try!(File::create(&postlude)));
-            try!(toc.write_str(javascript::JAVASCRIPT));
+            let mut toc = BufWriter::new(try!(File::create(&postlude)));
+            try!(toc.write_all(javascript::JAVASCRIPT.as_bytes()));
             try!(writeln!(&mut toc, "</div></div>"));
         }
 
-        try!(fs::mkdir_recursive(&out_path, old_io::USER_DIR));
+        try!(fs::create_dir_all(&out_path));
 
         let rustdoc_args: &[String] = &[
             "".to_string(),
@@ -135,7 +141,7 @@ fn render(book: &Book, tgt: &Path) -> CliResult<()> {
         if output_result != 0 {
             let message = format!("Could not execute `rustdoc` with {:?}: {}",
                                   rustdoc_args, output_result);
-            return Err(box message as Box<Error>);
+            return Err(err(&message));
         }
     }
 
@@ -150,28 +156,30 @@ impl Subcommand for Build {
     }
     fn usage(&self) {}
     fn execute(&mut self, term: &mut Term) -> CommandResult<()> {
-        let cwd = os::getcwd().unwrap();
+        let cwd = env::current_dir().unwrap();
         let src;
         let tgt;
 
         if env::args().len() < 3 {
             src = cwd.clone();
         } else {
-            src = Path::new(env::args().nth(2).unwrap().clone());
+            src = PathBuf::new(&env::args().nth(2).unwrap());
         }
 
         if env::args().len() < 4 {
             tgt = cwd.join("_book");
         } else {
-            tgt = Path::new(env::args().nth(3).unwrap().clone());
+            tgt = PathBuf::new(&env::args().nth(3).unwrap());
         }
 
-        try!(fs::mkdir(&tgt, old_io::USER_DIR));
+        try!(fs::create_dir(&tgt));
 
-        try!(File::create(&tgt.join("rust-book.css")).write_str(css::STYLE));
+        try!(File::create(&tgt.join("rust-book.css")).and_then(|mut f| {
+            f.write_all(css::STYLE.as_bytes())
+        }));
 
-        let summary = try!(File::open(&src.join("SUMMARY.md")));
-        match book::parse_summary(summary, &src) {
+        let mut summary = try!(File::open(&src.join("SUMMARY.md")));
+        match book::parse_summary(&mut summary, &src) {
             Ok(book) => {
                 // execute rustdoc on the whole book
                 render(&book, &tgt)
@@ -182,7 +190,7 @@ impl Subcommand for Build {
                     term.err(&format!("error: {}", err)[..]);
                 }
 
-                Err(box format!("{} errors occurred", n) as Box<Error>)
+                Err(err(&format!("{} errors occurred", n)))
             }
         }
     }
diff --git a/src/rustbook/error.rs b/src/rustbook/error.rs
index 43c882c7d5b..294b4e55669 100644
--- a/src/rustbook/error.rs
+++ b/src/rustbook/error.rs
@@ -10,10 +10,8 @@
 
 //! Error handling utilities. WIP.
 
+use std::error::Error;
 use std::fmt;
-use std::fmt::{Debug, Formatter};
-
-use std::old_io::IoError;
 
 pub type CliError = Box<Error + 'static>;
 pub type CliResult<T> = Result<T, CliError>;
@@ -21,63 +19,17 @@ pub type CliResult<T> = Result<T, CliError>;
 pub type CommandError = Box<Error + 'static>;
 pub type CommandResult<T> = Result<T, CommandError>;
 
-pub trait Error {
-    fn description(&self) -> &str;
-
-    fn detail(&self) -> Option<&str> { None }
-    fn cause(&self) -> Option<&Error> { None }
-}
-
-pub trait FromError<E> {
-    fn from_err(err: E) -> Self;
-}
-
-impl Debug for Box<Error + 'static> {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        write!(f, "{}", self.description())
-    }
-}
-
-impl<E: Error + 'static> FromError<E> for Box<Error + 'static> {
-    fn from_err(err: E) -> Box<Error + 'static> {
-        box err as Box<Error>
-    }
-}
+pub fn err(s: &str) -> CliError {
+    struct E(String);
 
-impl<'a> Error for &'a str {
-    fn description<'b>(&'b self) -> &'b str {
-        *self
+    impl Error for E {
+        fn description(&self) -> &str { &self.0 }
     }
-}
-
-impl Error for String {
-    fn description<'a>(&'a self) -> &'a str {
-        &self[..]
+    impl fmt::Display for E {
+        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+            self.0.fmt(f)
+        }
     }
-}
-
-impl<'a> Error for Box<Error + 'a> {
-    fn description(&self) -> &str { (**self).description() }
-    fn detail(&self) -> Option<&str> { (**self).detail() }
-    fn cause(&self) -> Option<&Error> { (**self).cause() }
-}
-
-impl FromError<()> for () {
-    fn from_err(_: ()) -> () { () }
-}
 
-impl FromError<IoError> for IoError {
-    fn from_err(error: IoError) -> IoError { error }
+    Box::new(E(s.to_string()))
 }
-
-impl Error for IoError {
-    fn description(&self) -> &str {
-        self.desc
-    }
-    fn detail(&self) -> Option<&str> {
-        self.detail.as_ref().map(|s| &s[..])
-    }
-}
-
-
-//fn iter_map_err<T, U, E, I: Iterator<Result<T,E>>>(iter: I,
diff --git a/src/rustbook/help.rs b/src/rustbook/help.rs
index 7fd8214f731..995d2f2494a 100644
--- a/src/rustbook/help.rs
+++ b/src/rustbook/help.rs
@@ -19,7 +19,7 @@ struct Help;
 
 pub fn parse_cmd(name: &str) -> Option<Box<Subcommand>> {
     match name {
-        "help" | "--help" | "-h" | "-?" => Some(box Help as Box<Subcommand>),
+        "help" | "--help" | "-h" | "-?" => Some(Box::new(Help)),
         _ => None
     }
 }
diff --git a/src/rustbook/main.rs b/src/rustbook/main.rs
index b9fc011e8b9..848f960839e 100644
--- a/src/rustbook/main.rs
+++ b/src/rustbook/main.rs
@@ -8,31 +8,24 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(box_syntax)]
-#![feature(collections)]
+#![deny(warnings)]
+
 #![feature(core)]
+#![feature(exit_status)]
+#![feature(fs)]
+#![feature(io)]
 #![feature(old_io)]
-#![feature(env)]
-#![feature(os)]
-#![feature(old_path)]
+#![feature(path)]
 #![feature(rustdoc)]
+#![feature(tempdir)]
 
 extern crate rustdoc;
 
 use std::env;
+use std::error::Error;
 use subcommand::Subcommand;
 use term::Term;
 
-macro_rules! try (
-    ($expr:expr) => ({
-        use error;
-        match $expr {
-            Ok(val) => val,
-            Err(err) => return Err(error::FromError::from_err(err))
-        }
-    })
-);
-
 mod term;
 mod error;
 mod book;
@@ -56,15 +49,12 @@ fn main() {
     } else {
         match subcommand::parse_name(&cmd[1][..]) {
             Some(mut subcmd) => {
-                match subcmd.parse_args(cmd.tail()) {
+                match subcmd.parse_args(&cmd[..cmd.len()-1]) {
                     Ok(_) => {
                         match subcmd.execute(&mut term) {
                             Ok(_) => (),
                             Err(err) => {
-                                term.err(&format!("error: {}", err.description())[..]);
-                                err.detail().map(|detail| {
-                                    term.err(&format!("detail: {}", detail)[..]);
-                                });
+                                term.err(&format!("error: {}", err));
                             }
                         }
                     }
diff --git a/src/rustbook/serve.rs b/src/rustbook/serve.rs
index 808527dcef9..2fa7b7eed7b 100644
--- a/src/rustbook/serve.rs
+++ b/src/rustbook/serve.rs
@@ -19,7 +19,7 @@ struct Serve;
 
 pub fn parse_cmd(name: &str) -> Option<Box<Subcommand>> {
     if name == "serve" {
-        Some(box Serve as Box<Subcommand>)
+        Some(Box::new(Serve))
     } else {
         None
     }
diff --git a/src/rustbook/term.rs b/src/rustbook/term.rs
index 98aa3fca184..06595cb0455 100644
--- a/src/rustbook/term.rs
+++ b/src/rustbook/term.rs
@@ -21,7 +21,7 @@ pub struct Term {
 impl Term {
     pub fn new() -> Term {
         Term {
-            err: box stdio::stderr() as Box<Writer>,
+            err: Box::new(stdio::stderr())
         }
     }
 
diff --git a/src/rustbook/test.rs b/src/rustbook/test.rs
index 727a385a8f0..72df0768e7b 100644
--- a/src/rustbook/test.rs
+++ b/src/rustbook/test.rs
@@ -11,19 +11,19 @@
 //! Implementation of the `test` subcommand. Just a stub for now.
 
 use subcommand::Subcommand;
-use error::CliResult;
-use error::CommandResult;
-use error::Error;
+use error::{err, CliResult, CommandResult};
 use term::Term;
 use book;
-use std::old_io::{Command, File};
-use std::os;
+
+use std::fs::File;
+use std::env;
+use std::process::Command;
 
 struct Test;
 
 pub fn parse_cmd(name: &str) -> Option<Box<Subcommand>> {
     if name == "test" {
-        Some(box Test as Box<Subcommand>)
+        Some(Box::new(Test))
     } else {
         None
     }
@@ -35,11 +35,11 @@ impl Subcommand for Test {
     }
     fn usage(&self) {}
     fn execute(&mut self, term: &mut Term) -> CommandResult<()> {
-        let cwd = os::getcwd().unwrap();
+        let cwd = env::current_dir().unwrap();
         let src = cwd.clone();
 
-        let summary = File::open(&src.join("SUMMARY.md"));
-        match book::parse_summary(summary, &src) {
+        let mut summary = try!(File::open(&src.join("SUMMARY.md")));
+        match book::parse_summary(&mut summary, &src) {
             Ok(book) => {
                 for (_, item) in book.iter() {
                     let output_result = Command::new("rustdoc")
@@ -50,15 +50,15 @@ impl Subcommand for Test {
                         Ok(output) => {
                             if !output.status.success() {
                                 term.err(&format!("{}\n{}",
-                                         String::from_utf8_lossy(&output.output[..]),
-                                         String::from_utf8_lossy(&output.error[..]))[..]);
-                                return Err(box "Some tests failed." as Box<Error>);
+                                         String::from_utf8_lossy(&output.stdout),
+                                         String::from_utf8_lossy(&output.stderr)));
+                                return Err(err("some tests failed"));
                             }
 
                         }
                         Err(e) => {
-                            let message = format!("Could not execute `rustdoc`: {}", e);
-                            return Err(box message as Box<Error>);
+                            let message = format!("could not execute `rustdoc`: {}", e);
+                            return Err(err(&message))
                         }
                     }
                 }
@@ -67,7 +67,7 @@ impl Subcommand for Test {
                 for err in errors {
                     term.err(&err[..]);
                 }
-                return Err(box "There was an error." as Box<Error>);
+                return Err(err("there was an error"))
             }
         }
         Ok(()) // lol
diff --git a/src/test/compile-fail/empty-extern-arg.rs b/src/test/compile-fail/empty-extern-arg.rs
index 9b7df81a5dc..8791481d9e7 100644
--- a/src/test/compile-fail/empty-extern-arg.rs
+++ b/src/test/compile-fail/empty-extern-arg.rs
@@ -9,6 +9,6 @@
 // except according to those terms.
 
 // compile-flags: --extern std=
-// error-pattern: is not a file
+// error-pattern: can't find crate for `std`
 
 fn main() {}
diff --git a/src/test/parse-fail/circular_modules_main.rs b/src/test/parse-fail/circular_modules_main.rs
index ac5ec1236ff..3e548981f1e 100644
--- a/src/test/parse-fail/circular_modules_main.rs
+++ b/src/test/parse-fail/circular_modules_main.rs
@@ -9,10 +9,10 @@
 // except according to those terms.
 
 #[path = "circular_modules_hello.rs"]
-mod circular_modules_hello; //~ERROR: circular modules
+mod circular_modules_hello; //~ ERROR: circular modules
 
 pub fn hi_str() -> String {
-  "Hi!".to_string()
+    "Hi!".to_string()
 }
 
 fn main() {
diff --git a/src/test/parse-fail/issue-5806.rs b/src/test/parse-fail/issue-5806.rs
index 597366a1b35..b2608cc0b92 100644
--- a/src/test/parse-fail/issue-5806.rs
+++ b/src/test/parse-fail/issue-5806.rs
@@ -8,15 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
+// ignore-windows
+// ignore-freebsd
 
 #[path = "../compile-fail"]
 mod foo; //~ ERROR: a directory
diff --git a/src/test/run-make/issue-19371/foo.rs b/src/test/run-make/issue-19371/foo.rs
index cff4d44910b..1ed816ed729 100644
--- a/src/test/run-make/issue-19371/foo.rs
+++ b/src/test/run-make/issue-19371/foo.rs
@@ -18,6 +18,8 @@ use rustc::session::config::{basic_options, build_configuration, Input, OutputTy
 use rustc_driver::driver::{compile_input, CompileController};
 use syntax::diagnostics::registry::Registry;
 
+use std::path::PathBuf;
+
 fn main() {
     let src = r#"
     fn main() {}
@@ -29,9 +31,9 @@ fn main() {
         panic!("expected rustc path");
     }
 
-    let tmpdir = Path::new(&args[1]);
+    let tmpdir = PathBuf::new(&args[1]);
 
-    let mut sysroot = Path::new(&args[3]);
+    let mut sysroot = PathBuf::new(&args[3]);
     sysroot.pop();
     sysroot.pop();
 
@@ -40,7 +42,7 @@ fn main() {
     compile(src.to_string(), tmpdir.join("out"), sysroot.clone());
 }
 
-fn basic_sess(sysroot: Path) -> Session {
+fn basic_sess(sysroot: PathBuf) -> Session {
     let mut opts = basic_options();
     opts.output_types = vec![OutputTypeExe];
     opts.maybe_sysroot = Some(sysroot);
@@ -51,7 +53,7 @@ fn basic_sess(sysroot: Path) -> Session {
     sess
 }
 
-fn compile(code: String, output: Path, sysroot: Path) {
+fn compile(code: String, output: PathBuf, sysroot: PathBuf) {
     let sess = basic_sess(sysroot);
     let cfg = build_configuration(&sess);
     let control = CompileController::basic();
diff --git a/src/test/run-pass-fulldeps/compiler-calls.rs b/src/test/run-pass-fulldeps/compiler-calls.rs
index 9e164522d77..75a968c3f81 100644
--- a/src/test/run-pass-fulldeps/compiler-calls.rs
+++ b/src/test/run-pass-fulldeps/compiler-calls.rs
@@ -25,6 +25,7 @@ use rustc::session::config::{self, Input};
 use rustc_driver::{driver, CompilerCalls, Compilation};
 use syntax::diagnostics;
 
+use std::path::PathBuf;
 
 struct TestCalls {
     count: u32
@@ -43,14 +44,15 @@ impl<'a> CompilerCalls<'a> for TestCalls {
                      _: &getopts::Matches,
                      _: &Session,
                      _: &Input,
-                     _: &Option<Path>,
-                     _: &Option<Path>)
+                     _: &Option<PathBuf>,
+                     _: &Option<PathBuf>)
                      -> Compilation {
         self.count *= 3;
         Compilation::Stop
     }
 
-    fn some_input(&mut self, input: Input, input_path: Option<Path>) -> (Input, Option<Path>) {
+    fn some_input(&mut self, input: Input, input_path: Option<PathBuf>)
+                  -> (Input, Option<PathBuf>) {
         self.count *= 5;
         (input, input_path)
     }
@@ -58,10 +60,10 @@ impl<'a> CompilerCalls<'a> for TestCalls {
     fn no_input(&mut self,
                 _: &getopts::Matches,
                 _: &config::Options,
-                _: &Option<Path>,
-                _: &Option<Path>,
+                _: &Option<PathBuf>,
+                _: &Option<PathBuf>,
                 _: &diagnostics::registry::Registry)
-                -> Option<(Input, Option<Path>)> {
+                -> Option<(Input, Option<PathBuf>)> {
         panic!("This shouldn't happen");
     }