5 files changed, 10 insertions, 9 deletions
diff --git a/src/libstd/Cargo.toml b/src/libstd/Cargo.toml
index 5348c9a0f34..bcdd1b4b088 100644
--- a/src/libstd/Cargo.toml
+++ b/src/libstd/Cargo.toml
@@ -25,7 +25,7 @@ profiler_builtins = { path = "../libprofiler_builtins", optional = true }
 unwind = { path = "../libunwind" }
 
 [dev-dependencies]
-rand = "0.4"
+rand = "0.5"
 
 [target.x86_64-apple-darwin.dependencies]
 rustc_asan = { path = "../librustc_asan" }
diff --git a/src/libstd/fs.rs b/src/libstd/fs.rs
index 7632fbc41f5..e177d4a988a 100644
--- a/src/libstd/fs.rs
+++ b/src/libstd/fs.rs
@@ -2076,7 +2076,7 @@ mod tests {
     use fs::{self, File, OpenOptions};
     use io::{ErrorKind, SeekFrom};
     use path::Path;
-    use rand::{StdRng, Rng};
+    use rand::{StdRng, FromEntropy, RngCore};
     use str;
     use sys_common::io::test::{TempDir, tmpdir};
     use thread;
@@ -3110,7 +3110,7 @@ mod tests {
     #[test]
     fn binary_file() {
         let mut bytes = [0; 1024];
-        StdRng::new().unwrap().fill_bytes(&mut bytes);
+        StdRng::from_entropy().fill_bytes(&mut bytes);
 
         let tmpdir = tmpdir();
 
@@ -3123,7 +3123,7 @@ mod tests {
     #[test]
     fn write_then_read() {
         let mut bytes = [0; 1024];
-        StdRng::new().unwrap().fill_bytes(&mut bytes);
+        StdRng::from_entropy().fill_bytes(&mut bytes);
 
         let tmpdir = tmpdir();
 
diff --git a/src/libstd/sync/rwlock.rs b/src/libstd/sync/rwlock.rs
index e3db60cff84..ed3a3865a6c 100644
--- a/src/libstd/sync/rwlock.rs
+++ b/src/libstd/sync/rwlock.rs
@@ -597,7 +597,7 @@ mod tests {
             thread::spawn(move || {
                 let mut rng = rand::thread_rng();
                 for _ in 0..M {
-                    if rng.gen_weighted_bool(N) {
+                    if rng.gen_bool(1.0 / (N as f64)) {
                         drop(r.write().unwrap());
                     } else {
                         drop(r.read().unwrap());
diff --git a/src/libstd/sys_common/io.rs b/src/libstd/sys_common/io.rs
index ab23936358e..a96fb192139 100644
--- a/src/libstd/sys_common/io.rs
+++ b/src/libstd/sys_common/io.rs
@@ -14,7 +14,7 @@ pub const DEFAULT_BUF_SIZE: usize = 8 * 1024;
 pub mod test {
     use path::{Path, PathBuf};
     use env;
-    use rand::{self, Rng};
+    use rand::{self, RngCore};
     use fs;
 
     pub struct TempDir(PathBuf);
diff --git a/src/libstd/tests/env.rs b/src/libstd/tests/env.rs
index 8acb8a46d7b..7302a794480 100644
--- a/src/libstd/tests/env.rs
+++ b/src/libstd/tests/env.rs
@@ -13,11 +13,12 @@ extern crate rand;
 use std::env::*;
 use std::ffi::{OsString, OsStr};
 
-use rand::Rng;
+use rand::{thread_rng, Rng};
+use rand::distributions::Alphanumeric;
 
 fn make_rand_name() -> OsString {
-    let mut rng = rand::thread_rng();
-    let n = format!("TEST{}", rng.gen_ascii_chars().take(10)
+    let mut rng = thread_rng();
+    let n = format!("TEST{}", rng.sample_iter(&Alphanumeric).take(10)
                                  .collect::<String>());
     let n = OsString::from(n);
     assert!(var_os(&n).is_none());