Auto merge of #23796 - alexcrichton:rollup, r=alexcrichton

16 files changed, 97 insertions, 245 deletions

diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index fec67c7aef4..f815e8e7843 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -1249,29 +1249,15 @@ pub enum ImplItem_ {
     MacImplItem(Mac),
 }
 
-#[derive(Clone, Eq, RustcEncodable, RustcDecodable, Hash, Copy)]
+#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Copy)]
 pub enum IntTy {
-    TyIs(bool /* is this deprecated `int`? */),
+    TyIs,
     TyI8,
     TyI16,
     TyI32,
     TyI64,
 }
 
-impl PartialEq for IntTy {
-    fn eq(&self, other: &IntTy) -> bool {
-        match (*self, *other) {
-            // true/false need to compare the same, so this can't be derived
-            (TyIs(_), TyIs(_)) |
-            (TyI8, TyI8) |
-            (TyI16, TyI16) |
-            (TyI32, TyI32) |
-            (TyI64, TyI64) => true,
-            _ => false
-        }
-    }
-}
-
 impl fmt::Debug for IntTy {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         fmt::Display::fmt(self, f)
@@ -1287,41 +1273,25 @@ impl fmt::Display for IntTy {
 impl IntTy {
     pub fn suffix_len(&self) -> usize {
         match *self {
-            TyIs(true) /* i */ => 1,
-            TyIs(false) /* is */ | TyI8 => 2,
+            TyIs | TyI8 => 2,
             TyI16 | TyI32 | TyI64  => 3,
         }
     }
 }
 
-#[derive(Clone, Eq, RustcEncodable, RustcDecodable, Hash, Copy)]
+#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Copy)]
 pub enum UintTy {
-    TyUs(bool /* is this deprecated uint? */),
+    TyUs,
     TyU8,
     TyU16,
     TyU32,
     TyU64,
 }
 
-impl PartialEq for UintTy {
-    fn eq(&self, other: &UintTy) -> bool {
-        match (*self, *other) {
-            // true/false need to compare the same, so this can't be derived
-            (TyUs(_), TyUs(_)) |
-            (TyU8, TyU8) |
-            (TyU16, TyU16) |
-            (TyU32, TyU32) |
-            (TyU64, TyU64) => true,
-            _ => false
-        }
-    }
-}
-
 impl UintTy {
     pub fn suffix_len(&self) -> usize {
         match *self {
-            TyUs(true) /* u */ => 1,
-            TyUs(false) /* us */ | TyU8 => 2,
+            TyUs | TyU8 => 2,
             TyU16 | TyU32 | TyU64  => 3,
         }
     }
diff --git a/src/libsyntax/ast_util.rs b/src/libsyntax/ast_util.rs
index cec824e79ff..b7aa2aebbfa 100644
--- a/src/libsyntax/ast_util.rs
+++ b/src/libsyntax/ast_util.rs
@@ -140,7 +140,7 @@ pub fn is_path(e: P<Expr>) -> bool {
 /// We want to avoid "45int" and "-3int" in favor of "45" and "-3"
 pub fn int_ty_to_string(t: IntTy, val: Option<i64>) -> String {
     let s = match t {
-        TyIs(_) => "isize",
+        TyIs => "isize",
         TyI8 => "i8",
         TyI16 => "i16",
         TyI32 => "i32",
@@ -160,7 +160,7 @@ pub fn int_ty_max(t: IntTy) -> u64 {
     match t {
         TyI8 => 0x80,
         TyI16 => 0x8000,
-        TyIs(_) | TyI32 => 0x80000000, // actually ni about TyIs
+        TyIs | TyI32 => 0x80000000, // actually ni about TyIs
         TyI64 => 0x8000000000000000
     }
 }
@@ -169,7 +169,7 @@ pub fn int_ty_max(t: IntTy) -> u64 {
 /// We want to avoid "42u" in favor of "42us". "42uint" is right out.
 pub fn uint_ty_to_string(t: UintTy, val: Option<u64>) -> String {
     let s = match t {
-        TyUs(_) => "usize",
+        TyUs => "usize",
         TyU8 => "u8",
         TyU16 => "u16",
         TyU32 => "u32",
@@ -186,7 +186,7 @@ pub fn uint_ty_max(t: UintTy) -> u64 {
     match t {
         TyU8 => 0xff,
         TyU16 => 0xffff,
-        TyUs(_) | TyU32 => 0xffffffff, // actually ni about TyUs
+        TyUs | TyU32 => 0xffffffff, // actually ni about TyUs
         TyU64 => 0xffffffffffffffff
     }
 }
diff --git a/src/libsyntax/attr.rs b/src/libsyntax/attr.rs
index 1c7930b9bc9..2d8484e95bb 100644
--- a/src/libsyntax/attr.rs
+++ b/src/libsyntax/attr.rs
@@ -565,10 +565,8 @@ fn int_type_of_word(s: &str) -> Option<IntType> {
         "u32" => Some(UnsignedInt(ast::TyU32)),
         "i64" => Some(SignedInt(ast::TyI64)),
         "u64" => Some(UnsignedInt(ast::TyU64)),
-        "int" => Some(SignedInt(ast::TyIs(true))),
-        "uint" => Some(UnsignedInt(ast::TyUs(true))),
-        "isize" => Some(SignedInt(ast::TyIs(false))),
-        "usize" => Some(UnsignedInt(ast::TyUs(false))),
+        "isize" => Some(SignedInt(ast::TyIs)),
+        "usize" => Some(UnsignedInt(ast::TyUs)),
         _ => None
     }
 }
@@ -612,7 +610,7 @@ impl IntType {
             SignedInt(ast::TyI16) | UnsignedInt(ast::TyU16) |
             SignedInt(ast::TyI32) | UnsignedInt(ast::TyU32) |
             SignedInt(ast::TyI64) | UnsignedInt(ast::TyU64) => true,
-            SignedInt(ast::TyIs(_)) | UnsignedInt(ast::TyUs(_)) => false
+            SignedInt(ast::TyIs) | UnsignedInt(ast::TyUs) => false
         }
     }
 }
diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index d916651b056..5d0853761ee 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -696,10 +696,10 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
         self.expr(sp, ast::ExprLit(P(respan(sp, lit))))
     }
     fn expr_usize(&self, span: Span, i: usize) -> P<ast::Expr> {
-        self.expr_lit(span, ast::LitInt(i as u64, ast::UnsignedIntLit(ast::TyUs(false))))
+        self.expr_lit(span, ast::LitInt(i as u64, ast::UnsignedIntLit(ast::TyUs)))
     }
     fn expr_int(&self, sp: Span, i: isize) -> P<ast::Expr> {
-        self.expr_lit(sp, ast::LitInt(i as u64, ast::SignedIntLit(ast::TyIs(false),
+        self.expr_lit(sp, ast::LitInt(i as u64, ast::SignedIntLit(ast::TyIs,
                                                                   ast::Sign::new(i))))
     }
     fn expr_u32(&self, sp: Span, u: u32) -> P<ast::Expr> {
diff --git a/src/libsyntax/ext/deriving/generic/mod.rs b/src/libsyntax/ext/deriving/generic/mod.rs
index 0c5e4d67642..397775fdbfe 100644
--- a/src/libsyntax/ext/deriving/generic/mod.rs
+++ b/src/libsyntax/ext/deriving/generic/mod.rs
@@ -1163,7 +1163,7 @@ impl<'a> MethodDef<'a> {
             let arms: Vec<ast::Arm> = variants.iter().enumerate()
                 .map(|(index, variant)| {
                     let pat = variant_to_pat(cx, sp, type_ident, &**variant);
-                    let lit = ast::LitInt(index as u64, ast::UnsignedIntLit(ast::TyUs(false)));
+                    let lit = ast::LitInt(index as u64, ast::UnsignedIntLit(ast::TyUs));
                     cx.arm(sp, vec![pat], cx.expr_lit(sp, lit))
                 }).collect();
 
diff --git a/src/libsyntax/ext/quote.rs b/src/libsyntax/ext/quote.rs
index 5bbcdea879d..87299721fb3 100644
--- a/src/libsyntax/ext/quote.rs
+++ b/src/libsyntax/ext/quote.rs
@@ -264,7 +264,6 @@ pub mod rt {
         (unsigned, $t:ty, $tag:expr) => (
             impl ToSource for $t {
                 fn to_source(&self) -> String {
-                    #![allow(trivial_numeric_casts)]
                     let lit = ast::LitInt(*self as u64, ast::UnsignedIntLit($tag));
                     pprust::lit_to_string(&dummy_spanned(lit))
                 }
@@ -277,13 +276,13 @@ pub mod rt {
         );
     }
 
-    impl_to_source_int! { signed, int, ast::TyIs(false) }
+    impl_to_source_int! { signed, isize, ast::TyIs }
     impl_to_source_int! { signed, i8,  ast::TyI8 }
     impl_to_source_int! { signed, i16, ast::TyI16 }
     impl_to_source_int! { signed, i32, ast::TyI32 }
     impl_to_source_int! { signed, i64, ast::TyI64 }
 
-    impl_to_source_int! { unsigned, uint, ast::TyUs(false) }
+    impl_to_source_int! { unsigned, usize, ast::TyUs }
     impl_to_source_int! { unsigned, u8,   ast::TyU8 }
     impl_to_source_int! { unsigned, u16,  ast::TyU16 }
     impl_to_source_int! { unsigned, u32,  ast::TyU32 }
@@ -332,12 +331,12 @@ pub mod rt {
     impl_to_tokens! { () }
     impl_to_tokens! { char }
     impl_to_tokens! { bool }
-    impl_to_tokens! { int }
+    impl_to_tokens! { isize }
     impl_to_tokens! { i8 }
     impl_to_tokens! { i16 }
     impl_to_tokens! { i32 }
     impl_to_tokens! { i64 }
-    impl_to_tokens! { uint }
+    impl_to_tokens! { usize }
     impl_to_tokens! { u8 }
     impl_to_tokens! { u16 }
     impl_to_tokens! { u32 }
diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index 60f81dac1e9..c6e6e749860 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -54,7 +54,6 @@ const KNOWN_FEATURES: &'static [(&'static str, &'static str, Status)] = &[
     ("non_ascii_idents", "1.0.0", Active),
     ("thread_local", "1.0.0", Active),
     ("link_args", "1.0.0", Active),
-    ("phase", "1.0.0", Removed),
     ("plugin_registrar", "1.0.0", Active),
     ("log_syntax", "1.0.0", Active),
     ("trace_macros", "1.0.0", Active),
@@ -74,6 +73,7 @@ const KNOWN_FEATURES: &'static [(&'static str, &'static str, Status)] = &[
 
     ("rustc_diagnostic_macros", "1.0.0", Active),
     ("unboxed_closures", "1.0.0", Active),
+    ("reflect", "1.0.0", Active),
     ("import_shadowing", "1.0.0", Removed),
     ("advanced_slice_patterns", "1.0.0", Active),
     ("tuple_indexing", "1.0.0", Accepted),
@@ -102,15 +102,9 @@ const KNOWN_FEATURES: &'static [(&'static str, &'static str, Status)] = &[
     // A way to temporarily opt out of the new orphan rules. This will *never* be accepted.
     ("old_orphan_check", "1.0.0", Deprecated),
 
-    // A way to temporarily opt out of the new impl rules. This will *never* be accepted.
-    ("old_impl_check", "1.0.0", Deprecated),
-
     // OIBIT specific features
     ("optin_builtin_traits", "1.0.0", Active),
 
-    // int and uint are now deprecated
-    ("int_uint", "1.0.0", Active),
-
     // macro reexport needs more discussion and stabilization
     ("macro_reexport", "1.0.0", Active),
 
@@ -153,6 +147,9 @@ const KNOWN_FEATURES: &'static [(&'static str, &'static str, Status)] = &[
     // below (it has to be checked before expansion possibly makes
     // macros disappear).
     ("allow_internal_unstable", "1.0.0", Active),
+
+    // #23121. Array patterns have some hazards yet.
+    ("slice_patterns", "1.0.0", Active),
 ];
 // (changing above list without updating src/doc/reference.md makes @cmr sad)
 
@@ -201,7 +198,6 @@ pub const KNOWN_ATTRIBUTES: &'static [(&'static str, AttributeType)] = &[
     ("no_mangle", Normal),
     ("no_link", Normal),
     ("derive", Normal),
-    ("should_fail", Normal),
     ("should_panic", Normal),
     ("ignore", Normal),
     ("no_implicit_prelude", Normal),
@@ -280,8 +276,11 @@ pub const KNOWN_ATTRIBUTES: &'static [(&'static str, AttributeType)] = &[
 
     // FIXME: #19470 this shouldn't be needed forever
     ("old_orphan_check", Whitelisted),
-    ("old_impl_check", Whitelisted),
-    ("rustc_paren_sugar", Whitelisted), // FIXME: #18101 temporary unboxed closure hack
+
+    ("rustc_paren_sugar", Gated("unboxed_closures",
+                                "unboxed_closures are still evolving")),
+    ("rustc_reflect_like", Gated("reflect",
+                                 "defining reflective traits is still evolving")),
 
     // Crate level attributes
     ("crate_name", CrateLevel),
@@ -360,7 +359,6 @@ struct Context<'a> {
     features: Vec<&'static str>,
     span_handler: &'a SpanHandler,
     cm: &'a CodeMap,
-    do_warnings: bool,
 }
 
 impl<'a> Context<'a> {
@@ -371,12 +369,6 @@ impl<'a> Context<'a> {
             emit_feature_err(self.span_handler, feature, span, explain);
         }
     }
-
-    fn warn_feature(&self, feature: &str, span: Span, explain: &str) {
-        if !self.has_feature(feature) && self.do_warnings {
-            emit_feature_warn(self.span_handler, feature, span, explain);
-        }
-    }
     fn has_feature(&self, feature: &str) -> bool {
         self.features.iter().any(|&n| n == feature)
     }
@@ -595,13 +587,6 @@ impl<'a, 'v> Visitor<'v> for PostExpansionVisitor<'a> {
                         i.span,
                         "the new orphan check rules will eventually be strictly enforced");
                 }
-
-                if attr::contains_name(&i.attrs[..],
-                                       "old_impl_check") {
-                    self.gate_feature("old_impl_check",
-                                      i.span,
-                                      "`#[old_impl_check]` will be removed in the future");
-                }
             }
 
             _ => {}
@@ -624,35 +609,6 @@ impl<'a, 'v> Visitor<'v> for PostExpansionVisitor<'a> {
         visit::walk_foreign_item(self, i)
     }
 
-    fn visit_ty(&mut self, t: &ast::Ty) {
-        match t.node {
-            ast::TyPath(None, ref p) => {
-                match &*p.segments {
-
-                    [ast::PathSegment { identifier, .. }] => {
-                        let name = token::get_ident(identifier);
-                        let msg = if name == "int" {
-                            Some("the `int` type is deprecated; \
-                                  use `isize` or a fixed-sized integer")
-                        } else if name == "uint" {
-                            Some("the `uint` type is deprecated; \
-                                  use `usize` or a fixed-sized integer")
-                        } else {
-                            None
-                        };
-
-                        if let Some(msg) = msg {
-                            self.context.warn_feature("int_uint", t.span, msg)
-                        }
-                    }
-                    _ => {}
-                }
-            }
-            _ => {}
-        }
-        visit::walk_ty(self, t);
-    }
-
     fn visit_expr(&mut self, e: &ast::Expr) {
         match e.node {
             ast::ExprBox(..) | ast::ExprUnary(ast::UnOp::UnUniq, _) => {
@@ -661,25 +617,6 @@ impl<'a, 'v> Visitor<'v> for PostExpansionVisitor<'a> {
                                   "box expression syntax is experimental; \
                                    you can call `Box::new` instead.");
             }
-            ast::ExprLit(ref lit) => {
-                match lit.node {
-                    ast::LitInt(_, ty) => {
-                        let msg = if let ast::SignedIntLit(ast::TyIs(true), _) = ty {
-                            Some("the `i` and `is` suffixes on integers are deprecated; \
-                                  use `isize` or one of the fixed-sized suffixes")
-                        } else if let ast::UnsignedIntLit(ast::TyUs(true)) = ty {
-                            Some("the `u` and `us` suffixes on integers are deprecated; \
-                                  use `usize` or one of the fixed-sized suffixes")
-                        } else {
-                            None
-                        };
-                        if let Some(msg) = msg {
-                            self.context.warn_feature("int_uint", e.span, msg);
-                        }
-                    }
-                    _ => {}
-                }
-            }
             _ => {}
         }
         visit::walk_expr(self, e);
@@ -694,6 +631,11 @@ impl<'a, 'v> Visitor<'v> for PostExpansionVisitor<'a> {
                                    but at the end of a slice (e.g. \
                                    `[0, ..xs, 0]` are experimental")
             }
+            ast::PatVec(..) => {
+                self.gate_feature("slice_patterns",
+                                  pattern.span,
+                                  "slice pattern syntax is experimental");
+            }
             ast::PatBox(..) => {
                 self.gate_feature("box_patterns",
                                   pattern.span,
@@ -722,8 +664,8 @@ impl<'a, 'v> Visitor<'v> for PostExpansionVisitor<'a> {
     }
 }
 
-fn check_crate_inner<F>(cm: &CodeMap, span_handler: &SpanHandler, krate: &ast::Crate,
-                        do_warnings: bool,
+fn check_crate_inner<F>(cm: &CodeMap, span_handler: &SpanHandler,
+                        krate: &ast::Crate,
                         check: F)
                        -> Features
     where F: FnOnce(&mut Context, &ast::Crate)
@@ -731,7 +673,6 @@ fn check_crate_inner<F>(cm: &CodeMap, span_handler: &SpanHandler, krate: &ast::C
     let mut cx = Context {
         features: Vec::new(),
         span_handler: span_handler,
-        do_warnings: do_warnings,
         cm: cm,
     };
 
@@ -812,14 +753,14 @@ fn check_crate_inner<F>(cm: &CodeMap, span_handler: &SpanHandler, krate: &ast::C
 
 pub fn check_crate_macros(cm: &CodeMap, span_handler: &SpanHandler, krate: &ast::Crate)
 -> Features {
-    check_crate_inner(cm, span_handler, krate, true,
+    check_crate_inner(cm, span_handler, krate,
                       |ctx, krate| visit::walk_crate(&mut MacroVisitor { context: ctx }, krate))
 }
 
-pub fn check_crate(cm: &CodeMap, span_handler: &SpanHandler, krate: &ast::Crate,
-                   do_warnings: bool) -> Features
+pub fn check_crate(cm: &CodeMap, span_handler: &SpanHandler, krate: &ast::Crate)
+                   -> Features
 {
-    check_crate_inner(cm, span_handler, krate, do_warnings,
+    check_crate_inner(cm, span_handler, krate,
                       |ctx, krate| visit::walk_crate(&mut PostExpansionVisitor { context: ctx },
                                                      krate))
 }
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
index 105a61d0857..d4451cc7b71 100644
--- a/src/libsyntax/fold.rs
+++ b/src/libsyntax/fold.rs
@@ -40,7 +40,7 @@ impl<T> MoveMap<T> for Vec<T> {
         for p in &mut self {
             unsafe {
                 // FIXME(#5016) this shouldn't need to zero to be safe.
-                ptr::write(p, f(ptr::read_and_zero(p)));
+                ptr::write(p, f(ptr::read_and_drop(p)));
             }
         }
         self
diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index 72498afa320..c471d9e3179 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -29,7 +29,6 @@
 #![feature(box_syntax)]
 #![feature(collections)]
 #![feature(core)]
-#![feature(int_uint)]
 #![feature(libc)]
 #![feature(old_path)]
 #![feature(quote, unsafe_destructor)]
@@ -40,6 +39,7 @@
 #![feature(str_char)]
 #![feature(convert)]
 #![feature(into_cow)]
+#![feature(slice_patterns)]
 
 extern crate arena;
 extern crate fmt_macros;
@@ -49,7 +49,7 @@ extern crate libc;
 #[macro_use] extern crate log;
 #[macro_use] #[no_link] extern crate rustc_bitflags;
 
-extern crate "serialize" as rustc_serialize; // used by deriving
+extern crate serialize as rustc_serialize; // used by deriving
 
 pub mod util {
     pub mod interner;
diff --git a/src/libsyntax/parse/lexer/mod.rs b/src/libsyntax/parse/lexer/mod.rs
index 0843713681b..e11e9f62a5b 100644
--- a/src/libsyntax/parse/lexer/mod.rs
+++ b/src/libsyntax/parse/lexer/mod.rs
@@ -742,6 +742,7 @@ impl<'a> StringReader<'a> {
         let start_bpos = self.last_pos;
         let mut accum_int = 0;
 
+        let mut valid = true;
         for _ in 0..n_digits {
             if self.is_eof() {
                 let last_bpos = self.last_pos;
@@ -750,6 +751,7 @@ impl<'a> StringReader<'a> {
             if self.curr_is(delim) {
                 let last_bpos = self.last_pos;
                 self.err_span_(start_bpos, last_bpos, "numeric character escape is too short");
+                valid = false;
                 break;
             }
             let c = self.curr.unwrap_or('\x00');
@@ -757,6 +759,8 @@ impl<'a> StringReader<'a> {
             accum_int += c.to_digit(16).unwrap_or_else(|| {
                 self.err_span_char(self.last_pos, self.pos,
                               "illegal character in numeric character escape", c);
+
+                valid = false;
                 0
             });
             self.bump();
@@ -767,10 +771,11 @@ impl<'a> StringReader<'a> {
                            self.last_pos,
                            "this form of character escape may only be used \
                             with characters in the range [\\x00-\\x7f]");
+            valid = false;
         }
 
         match char::from_u32(accum_int) {
-            Some(_) => true,
+            Some(_) => valid,
             None => {
                 let last_bpos = self.last_pos;
                 self.err_span_(start_bpos, last_bpos, "illegal numeric character escape");
@@ -799,7 +804,18 @@ impl<'a> StringReader<'a> {
                             'n' | 'r' | 't' | '\\' | '\'' | '"' | '0' => true,
                             'x' => self.scan_byte_escape(delim, !ascii_only),
                             'u' if self.curr_is('{') => {
-                                self.scan_unicode_escape(delim)
+                            let valid = self.scan_unicode_escape(delim);
+                            if valid && ascii_only {
+                                self.err_span_(
+                                    escaped_pos,
+                                    self.last_pos,
+                                    "unicode escape sequences cannot be used as a byte or in \
+                                    a byte string"
+                                );
+                                false
+                            } else {
+                               valid
+                            }
                             }
                             '\n' if delim == '"' => {
                                 self.consume_whitespace();
@@ -869,6 +885,7 @@ impl<'a> StringReader<'a> {
         let start_bpos = self.last_pos;
         let mut count = 0;
         let mut accum_int = 0;
+        let mut valid = true;
 
         while !self.curr_is('}') && count <= 6 {
             let c = match self.curr {
@@ -884,29 +901,30 @@ impl<'a> StringReader<'a> {
                     self.fatal_span_(self.last_pos, self.pos,
                                      "unterminated unicode escape (needed a `}`)");
                 } else {
-                    self.fatal_span_char(self.last_pos, self.pos,
+                    self.err_span_char(self.last_pos, self.pos,
                                    "illegal character in unicode escape", c);
                 }
+                valid = false;
+                0
             });
             self.bump();
             count += 1;
         }
 
         if count > 6 {
-            self.fatal_span_(start_bpos, self.last_pos,
+            self.err_span_(start_bpos, self.last_pos,
                           "overlong unicode escape (can have at most 6 hex digits)");
+            valid = false;
         }
 
         self.bump(); // past the ending }
 
-        let mut valid = count >= 1 && count <= 6;
-        if char::from_u32(accum_int).is_none() {
-            valid = false;
+        if valid && (char::from_u32(accum_int).is_none() || count == 0) {
+            self.err_span_(start_bpos, self.last_pos, "illegal unicode character escape");
+            valid= false;
         }
 
-        if !valid {
-            self.fatal_span_(start_bpos, self.last_pos, "illegal unicode character escape");
-        }
+
         valid
     }
 
@@ -1330,7 +1348,7 @@ impl<'a> StringReader<'a> {
                 "unterminated byte constant".to_string());
         }
 
-        let id = if valid { self.name_from(start) } else { token::intern("??") };
+        let id = if valid { self.name_from(start) } else { token::intern("?") };
         self.bump(); // advance curr past token
         return token::Byte(id);
     }
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index 4e851761212..bea42a88bf5 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -700,18 +700,18 @@ pub fn integer_lit(s: &str, suffix: Option<&str>, sd: &SpanHandler, sp: Span) ->
     if let Some(suf) = suffix {
         if suf.is_empty() { sd.span_bug(sp, "found empty literal suffix in Some")}
         ty = match suf {
-            "isize" => ast::SignedIntLit(ast::TyIs(false), ast::Plus),
+            "isize" => ast::SignedIntLit(ast::TyIs, ast::Plus),
             "i8"  => ast::SignedIntLit(ast::TyI8, ast::Plus),
             "i16" => ast::SignedIntLit(ast::TyI16, ast::Plus),
             "i32" => ast::SignedIntLit(ast::TyI32, ast::Plus),
             "i64" => ast::SignedIntLit(ast::TyI64, ast::Plus),
-            "usize" => ast::UnsignedIntLit(ast::TyUs(false)),
+            "usize" => ast::UnsignedIntLit(ast::TyUs),
             "u8"  => ast::UnsignedIntLit(ast::TyU8),
             "u16" => ast::UnsignedIntLit(ast::TyU16),
             "u32" => ast::UnsignedIntLit(ast::TyU32),
             "u64" => ast::UnsignedIntLit(ast::TyU64),
-            "i" | "is" => ast::SignedIntLit(ast::TyIs(true), ast::Plus),
-            "u" | "us" => ast::UnsignedIntLit(ast::TyUs(true)),
+            "is" => ast::SignedIntLit(ast::TyIs, ast::Plus),
+            "us" => ast::UnsignedIntLit(ast::TyUs),
             _ => {
                 // i<digits> and u<digits> look like widths, so lets
                 // give an error message along those lines
diff --git a/src/libsyntax/parse/obsolete.rs b/src/libsyntax/parse/obsolete.rs
index 276be73823a..bb9b586bb3f 100644
--- a/src/libsyntax/parse/obsolete.rs
+++ b/src/libsyntax/parse/obsolete.rs
@@ -23,7 +23,6 @@ use ptr::P;
 #[derive(Copy, PartialEq, Eq, Hash)]
 pub enum ObsoleteSyntax {
     ClosureKind,
-    EmptyIndex,
     ExternCrateString,
 }
 
@@ -52,11 +51,6 @@ impl<'a> ParserObsoleteMethods for parser::Parser<'a> {
                 "rely on inference instead",
                 true,
             ),
-            ObsoleteSyntax::EmptyIndex => (
-                "[]",
-                "write `[..]` instead",
-                false, // warning for now
-            ),
             ObsoleteSyntax::ExternCrateString => (
                 "\"crate-name\"",
                 "use an identifier not in quotes instead",
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 786970ce252..b287093bf19 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -2312,46 +2312,13 @@ impl<'a> Parser<'a> {
               // expr[...]
               // Could be either an index expression or a slicing expression.
               token::OpenDelim(token::Bracket) => {
-                let bracket_pos = self.span.lo;
                 self.bump();
 
-                if self.eat(&token::CloseDelim(token::Bracket)) {
-                    // No expression, expand to a RangeFull
-                    // FIXME(#20516) It would be better to use a lang item or
-                    // something for RangeFull.
-                    hi = self.last_span.hi;
-
-                    let idents = vec![token::str_to_ident("std"),
-                                      token::str_to_ident("ops"),
-                                      token::str_to_ident("RangeFull")];
-                    let segments = idents.into_iter().map(|ident| {
-                        ast::PathSegment {
-                            identifier: ident,
-                            parameters: ast::PathParameters::none(),
-                        }
-                    }).collect();
-                    let span = mk_sp(lo, hi);
-                    let path = ast::Path {
-                        span: span,
-                        global: true,
-                        segments: segments,
-                    };
-
-                    let range = ExprStruct(path, vec![], None);
-                    let ix = self.mk_expr(bracket_pos, hi, range);
-                    let index = self.mk_index(e, ix);
-                    e = self.mk_expr(lo, hi, index);
-
-                    let obsolete_span = mk_sp(bracket_pos, hi);
-                    self.obsolete(obsolete_span, ObsoleteSyntax::EmptyIndex);
-                } else {
-                    let ix = self.parse_expr();
-                    hi = self.span.hi;
-                    self.commit_expr_expecting(&*ix, token::CloseDelim(token::Bracket));
-                    let index = self.mk_index(e, ix);
-                    e = self.mk_expr(lo, hi, index)
-                }
-
+                let ix = self.parse_expr();
+                hi = self.span.hi;
+                self.commit_expr_expecting(&*ix, token::CloseDelim(token::Bracket));
+                let index = self.mk_index(e, ix);
+                e = self.mk_expr(lo, hi, index)
               }
               _ => return e
             }
@@ -4984,46 +4951,19 @@ impl<'a> Parser<'a> {
     ///
     /// # Examples
     ///
-    /// extern crate url;
-    /// extern crate foo = "bar"; //deprecated
-    /// extern crate "bar" as foo;
+    /// extern crate foo;
+    /// extern crate bar as foo;
     fn parse_item_extern_crate(&mut self,
-                                lo: BytePos,
-                                visibility: Visibility,
-                                attrs: Vec<Attribute>)
+                               lo: BytePos,
+                               visibility: Visibility,
+                               attrs: Vec<Attribute>)
                                 -> P<Item> {
 
-        let (maybe_path, ident) = match self.token {
-            token::Ident(..) => {
-                let crate_name = self.parse_ident();
-                if self.eat_keyword(keywords::As) {
-                    (Some(crate_name.name), self.parse_ident())
-                } else {
-                    (None, crate_name)
-                }
-            },
-            token::Literal(token::Str_(..), suf) |
-            token::Literal(token::StrRaw(..), suf) => {
-                let sp = self.span;
-                self.expect_no_suffix(sp, "extern crate name", suf);
-                // forgo the internal suffix check of `parse_str` to
-                // avoid repeats (this unwrap will always succeed due
-                // to the restriction of the `match`)
-                let (s, _, _) = self.parse_optional_str().unwrap();
-                self.expect_keyword(keywords::As);
-                let the_ident = self.parse_ident();
-                self.obsolete(sp, ObsoleteSyntax::ExternCrateString);
-                let s = token::intern(&s);
-                (Some(s), the_ident)
-            },
-            _ => {
-                let span = self.span;
-                let token_str = self.this_token_to_string();
-                self.span_fatal(span,
-                                &format!("expected extern crate name but \
-                                         found `{}`",
-                                        token_str));
-            }
+        let crate_name = self.parse_ident();
+        let (maybe_path, ident) = if self.eat_keyword(keywords::As) {
+            (Some(crate_name.name), self.parse_ident())
+        } else {
+            (None, crate_name)
         };
         self.expect(&token::Semi);
 
diff --git a/src/libsyntax/ptr.rs b/src/libsyntax/ptr.rs
index ca3a1848c3a..7e0bcd3e1dc 100644
--- a/src/libsyntax/ptr.rs
+++ b/src/libsyntax/ptr.rs
@@ -71,8 +71,8 @@ impl<T: 'static> P<T> {
     {
         unsafe {
             let p = &mut *self.ptr;
-            // FIXME(#5016) this shouldn't need to zero to be safe.
-            ptr::write(p, f(ptr::read_and_zero(p)));
+            // FIXME(#5016) this shouldn't need to drop-fill to be safe.
+            ptr::write(p, f(ptr::read_and_drop(p)));
         }
         self
     }
diff --git a/src/libsyntax/std_inject.rs b/src/libsyntax/std_inject.rs
index 0fa7e4f902c..021ec4738ed 100644
--- a/src/libsyntax/std_inject.rs
+++ b/src/libsyntax/std_inject.rs
@@ -52,7 +52,7 @@ struct StandardLibraryInjector {
 impl fold::Folder for StandardLibraryInjector {
     fn fold_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
 
-        // The name to use in `extern crate "name" as std;`
+        // The name to use in `extern crate name as std;`
         let actual_crate_name = match self.alt_std_name {
             Some(ref s) => token::intern(&s),
             None => token::intern("std"),
diff --git a/src/libsyntax/test.rs b/src/libsyntax/test.rs
index 2a47a696b1c..fbee11ee657 100644
--- a/src/libsyntax/test.rs
+++ b/src/libsyntax/test.rs
@@ -134,7 +134,7 @@ impl<'a> fold::Folder for TestHarnessGenerator<'a> {
                         path: self.cx.path.clone(),
                         bench: is_bench_fn(&self.cx, &*i),
                         ignore: is_ignored(&*i),
-                        should_panic: should_panic(&*i, self.cx.span_diagnostic)
+                        should_panic: should_panic(&*i)
                     };
                     self.cx.testfns.push(test);
                     self.tests.push(i.ident);
@@ -386,16 +386,8 @@ fn is_ignored(i: &ast::Item) -> bool {
     i.attrs.iter().any(|attr| attr.check_name("ignore"))
 }
 
-fn should_panic(i: &ast::Item, diag: &diagnostic::SpanHandler) -> ShouldPanic {
-    match i.attrs.iter().find(|attr| {
-        if attr.check_name("should_panic") { return true; }
-        if attr.check_name("should_fail") {
-            diag.span_warn(attr.span, "`#[should_fail]` is deprecated. Use `#[should_panic]` \
-                                       instead");
-            return true;
-        }
-        false
-    }) {
+fn should_panic(i: &ast::Item) -> ShouldPanic {
+    match i.attrs.iter().find(|attr| attr.check_name("should_panic")) {
         Some(attr) => {
             let msg = attr.meta_item_list()
                 .and_then(|list| list.iter().find(|mi| mi.check_name("expected")))