Rollup of 9 pull requests

Cargo.lock

@@ -201,6 +201,7 @@ dependencies = [
  "hex 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "home 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "ignore 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "im-rc 12.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "jobserver 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazycell 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -978,6 +979,15 @@ dependencies = [
  "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "im-rc"
+version = "12.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "rustc_version 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "typenum 1.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "installer"
 version = "0.0.0"
@@ -3038,6 +3048,11 @@ dependencies = [
  "toml 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "typenum"
+version = "1.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "ucd-util"
 version = "0.1.1"
@@ -3331,6 +3346,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum idna 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "38f09e0f0b1fb55fdee1f17470ad800da77af5186a1a76c026b679358b7e844e"
 "checksum if_chain 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "4bac95d9aa0624e7b78187d6fb8ab012b41d9f6f54b1bcb61e61c4845f8357ec"
 "checksum ignore 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3e9faa7c84064f07b40da27044af629f578bc7994b650d3e458d0c29183c1d91"
+"checksum im-rc 12.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d4591152fd573cf453a890b5f9fdc5c328a751a0785539316739d5f85e5c468c"
 "checksum is-match 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7e5b386aef33a1c677be65237cb9d32c3f3ef56bd035949710c4bb13083eb053"
 "checksum itertools 0.7.8 (registry+https://github.com/rust-lang/crates.io-index)" = "f58856976b776fedd95533137617a02fb25719f40e7d9b01c7043cd65474f450"
 "checksum itoa 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "1306f3464951f30e30d12373d31c79fbd52d236e5e896fd92f96ec7babbbe60b"
@@ -3482,6 +3498,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum time 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)" = "d825be0eb33fda1a7e68012d51e9c7f451dc1a69391e7fdc197060bb8c56667b"
 "checksum toml 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)" = "a0263c6c02c4db6c8f7681f9fd35e90de799ebd4cfdeab77a38f4ff6b3d8c0d9"
 "checksum toml-query 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "6854664bfc6df0360c695480836ee90e2d0c965f06db291d10be9344792d43e8"
+"checksum typenum 1.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "612d636f949607bdf9b123b4a6f6d966dedf3ff669f7f045890d3a4a73948169"
 "checksum ucd-util 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "fd2be2d6639d0f8fe6cdda291ad456e23629558d466e2789d2c3e9892bda285d"
 "checksum unicode-bidi 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)" = "49f2bd0c6468a8230e1db229cff8029217cf623c767ea5d60bfbd42729ea54d5"
 "checksum unicode-normalization 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "6a0180bc61fc5a987082bfa111f4cc95c4caff7f9799f3e46df09163a937aa25"

src/libcore/array.rs

@@ -148,6 +148,15 @@ macro_rules! array_impls {
                 }
             }
 
+            #[unstable(feature = "try_from", issue = "33417")]
+            impl<'a, T> TryFrom<&'a [T]> for [T; $N] where T: Copy {
+                type Error = TryFromSliceError;
+
+                fn try_from(slice: &[T]) -> Result<[T; $N], TryFromSliceError> {
+                    <&Self>::try_from(slice).map(|r| *r)
+                }
+            }
+
             #[unstable(feature = "try_from", issue = "33417")]
             impl<'a, T> TryFrom<&'a [T]> for &'a [T; $N] {
                 type Error = TryFromSliceError;

src/libcore/num/mod.rs

@@ -1989,6 +1989,19 @@ big endian.
 ```
 let value = ", stringify!($SelfT), "::from_be_bytes(", $be_bytes, ");
 assert_eq!(value, ", $swap_op, ");
+```
+
+When starting from a slice rather than an array, fallible conversion APIs can be used:
+
+```
+#![feature(try_from)]
+use std::convert::TryInto;
+
+fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {
+    let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());
+    *input = rest;
+    ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())
+}
 ```"),
             #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
             #[rustc_const_unstable(feature = "const_int_conversion")]
@@ -2008,6 +2021,19 @@ little endian.
 ```
 let value = ", stringify!($SelfT), "::from_le_bytes(", $le_bytes, ");
 assert_eq!(value, ", $swap_op, ");
+```
+
+When starting from a slice rather than an array, fallible conversion APIs can be used:
+
+```
+#![feature(try_from)]
+use std::convert::TryInto;
+
+fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {
+    let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());
+    *input = rest;
+    ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())
+}
 ```"),
             #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
             #[rustc_const_unstable(feature = "const_int_conversion")]
@@ -2037,6 +2063,19 @@ let value = ", stringify!($SelfT), "::from_ne_bytes(if cfg!(target_endian = \"bi
         ", $le_bytes, "
     });
 assert_eq!(value, ", $swap_op, ");
+```
+
+When starting from a slice rather than an array, fallible conversion APIs can be used:
+
+```
+#![feature(try_from)]
+use std::convert::TryInto;
+
+fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {
+    let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());
+    *input = rest;
+    ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())
+}
 ```"),
             #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
             #[rustc_const_unstable(feature = "const_int_conversion")]
@@ -3719,6 +3758,19 @@ big endian.
 ```
 let value = ", stringify!($SelfT), "::from_be_bytes(", $be_bytes, ");
 assert_eq!(value, ", $swap_op, ");
+```
+
+When starting from a slice rather than an array, fallible conversion APIs can be used:
+
+```
+#![feature(try_from)]
+use std::convert::TryInto;
+
+fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {
+    let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());
+    *input = rest;
+    ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())
+}
 ```"),
             #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
             #[rustc_const_unstable(feature = "const_int_conversion")]
@@ -3738,6 +3790,19 @@ little endian.
 ```
 let value = ", stringify!($SelfT), "::from_le_bytes(", $le_bytes, ");
 assert_eq!(value, ", $swap_op, ");
+```
+
+When starting from a slice rather than an array, fallible conversion APIs can be used:
+
+```
+#![feature(try_from)]
+use std::convert::TryInto;
+
+fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {
+    let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());
+    *input = rest;
+    ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())
+}
 ```"),
             #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
             #[rustc_const_unstable(feature = "const_int_conversion")]
@@ -3767,6 +3832,19 @@ let value = ", stringify!($SelfT), "::from_ne_bytes(if cfg!(target_endian = \"bi
         ", $le_bytes, "
     });
 assert_eq!(value, ", $swap_op, ");
+```
+
+When starting from a slice rather than an array, fallible conversion APIs can be used:
+
+```
+#![feature(try_from)]
+use std::convert::TryInto;
+
+fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {
+    let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());
+    *input = rest;
+    ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())
+}
 ```"),
             #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
             #[rustc_const_unstable(feature = "const_int_conversion")]

src/libcore/str/lossy.rs

@@ -62,18 +62,15 @@ impl<'a> Iterator for Utf8LossyChunksIter<'a> {
         }
 
         const TAG_CONT_U8: u8 = 128;
-        fn unsafe_get(xs: &[u8], i: usize) -> u8 {
-            unsafe { *xs.get_unchecked(i) }
-        }
         fn safe_get(xs: &[u8], i: usize) -> u8 {
-            if i >= xs.len() { 0 } else { unsafe_get(xs, i) }
+            *xs.get(i).unwrap_or(&0)
         }
 
         let mut i = 0;
         while i < self.source.len() {
             let i_ = i;
 
-            let byte = unsafe_get(self.source, i);
+            let byte = unsafe { *self.source.get_unchecked(i) };
             i += 1;
 
             if byte < 128 {

src/librustc/middle/reachable.rs

@@ -117,8 +117,9 @@ impl<'a, 'tcx> Visitor<'tcx> for ReachableContext<'a, 'tcx> {
                 self.reachable_symbols.insert(node_id);
             }
             Some(def) => {
-                let def_id = def.def_id();
-                if let Some(node_id) = self.tcx.hir.as_local_node_id(def_id) {
+                if let Some((node_id, def_id)) = def.opt_def_id().and_then(|def_id| {
+                    self.tcx.hir.as_local_node_id(def_id).map(|node_id| (node_id, def_id))
+                }) {
                     if self.def_id_represents_local_inlined_item(def_id) {
                         self.worklist.push(node_id);
                     } else {

src/librustc/middle/resolve_lifetime.rs

@@ -1573,7 +1573,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
             .collect();
 
         // ensure that we issue lints in a repeatable order
-        def_ids.sort_by_key(|&def_id| self.tcx.def_path_hash(def_id));
+        def_ids.sort_by_cached_key(|&def_id| self.tcx.def_path_hash(def_id));
 
         for def_id in def_ids {
             debug!(

src/librustc/traits/object_safety.rs

@@ -409,7 +409,7 @@ impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> {
             .collect::<Vec<_>>();
 
         // existential predicates need to be in a specific order
-        associated_types.sort_by_key(|item| self.def_path_hash(item.def_id));
+        associated_types.sort_by_cached_key(|item| self.def_path_hash(item.def_id));
 
         let projection_predicates = associated_types.into_iter().map(|item| {
             ty::ExistentialPredicate::Projection(ty::ExistentialProjection {

src/librustc/util/profiling.rs

@@ -102,7 +102,7 @@ macro_rules! define_categories {
                         };
 
                     json.push_str(&format!(
-                        "{{ \"category\": {}, \"time_ms\": {},
+                        "{{ \"category\": \"{}\", \"time_ms\": {},\
                             \"query_count\": {}, \"query_hits\": {} }},",
                         stringify!($name),
                         self.times.$name / 1_000_000,

src/librustc_mir/build/expr/as_temp.rs

@@ -85,9 +85,15 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
 
         unpack!(block = this.into(&Place::Local(temp), block, expr));
 
-        // In constants, temp_lifetime is None. We should not need to drop
-        // anything because no values with a destructor can be created in
-        // a constant at this time, even if the type may need dropping.
+        // In constants, temp_lifetime is None for temporaries that live for the
+        // 'static lifetime. Thus we do not drop these temporaries and simply leak them.
+        // This is equivalent to what `let x = &foo();` does in functions. The temporary
+        // is lifted to their surrounding scope. In a function that means the temporary lives
+        // until just before the function returns. In constants that means it outlives the
+        // constant's initialization value computation. Anything outliving a constant
+        // must have the `'static` lifetime and live forever.
+        // Anything with a shorter lifetime (e.g the `&foo()` in `bar(&foo())` or anything
+        // within a block will keep the regular drops just like runtime code.
         if let Some(temp_lifetime) = temp_lifetime {
             this.schedule_drop_storage_and_value(
                 expr_span,

src/librustc_mir/hair/pattern/check_match.rs

@@ -234,7 +234,7 @@ impl<'a, 'tcx> MatchVisitor<'a, 'tcx> {
                 if !scrutinee_is_uninhabited {
                     // We know the type is inhabited, so this must be wrong
                     let mut err = create_e0004(self.tcx.sess, scrut.span,
-                                               format!("non-exhaustive patterns: type {} \
+                                               format!("non-exhaustive patterns: type `{}` \
                                                         is non-empty",
                                                        pat_ty));
                     span_help!(&mut err, scrut.span,

src/librustc_mir/monomorphize/partitioning.rs

@@ -985,7 +985,7 @@ fn collect_and_partition_mono_items<'a, 'tcx>(
                 output.push_str(" @@");
                 let mut empty = Vec::new();
                 let cgus = item_to_cgus.get_mut(i).unwrap_or(&mut empty);
-                cgus.as_mut_slice().sort_by_key(|&(ref name, _)| name.clone());
+                cgus.as_mut_slice().sort_by_cached_key(|&(ref name, _)| name.clone());
                 cgus.dedup();
                 for &(ref cgu_name, (linkage, _)) in cgus.iter() {
                     output.push_str(" ");

src/librustc_typeck/check/autoderef.rs

@@ -59,15 +59,15 @@ impl<'a, 'gcx, 'tcx> Iterator for Autoderef<'a, 'gcx, 'tcx> {
         if self.steps.len() >= *tcx.sess.recursion_limit.get() {
             // We've reached the recursion limit, error gracefully.
             let suggested_limit = *tcx.sess.recursion_limit.get() * 2;
-            let msg = format!("reached the recursion limit while auto-dereferencing {:?}",
+            let msg = format!("reached the recursion limit while auto-dereferencing `{:?}`",
                               self.cur_ty);
             let error_id = (DiagnosticMessageId::ErrorId(55), Some(self.span), msg);
             let fresh = tcx.sess.one_time_diagnostics.borrow_mut().insert(error_id);
             if fresh {
                 struct_span_err!(tcx.sess,
                                  self.span,
                                  E0055,
-                                 "reached the recursion limit while auto-dereferencing {:?}",
+                                 "reached the recursion limit while auto-dereferencing `{:?}`",
                                  self.cur_ty)
                     .span_label(self.span, "deref recursion limit reached")
                     .help(&format!(

src/librustc_typeck/diagnostics.rs

@@ -538,7 +538,7 @@ fn main() {
     let foo = Foo;
     let ref_foo = &&Foo;
 
-    // error, reached the recursion limit while auto-dereferencing &&Foo
+    // error, reached the recursion limit while auto-dereferencing `&&Foo`
     ref_foo.foo();
 }
 ```

src/libsyntax/parse/lexer/mod.rs

@@ -60,11 +60,11 @@ pub struct StringReader<'a> {
     // cache a direct reference to the source text, so that we don't have to
     // retrieve it via `self.source_file.src.as_ref().unwrap()` all the time.
     src: Lrc<String>,
-    /// Stack of open delimiters and their spans. Used for error message.
     token: token::Token,
     span: Span,
     /// The raw source span which *does not* take `override_span` into account
     span_src_raw: Span,
+    /// Stack of open delimiters and their spans. Used for error message.
     open_braces: Vec<(token::DelimToken, Span)>,
     /// The type and spans for all braces
     ///
@@ -506,8 +506,7 @@ impl<'a> StringReader<'a> {
         }
     }
 
-    /// Advance the StringReader by one character. If a newline is
-    /// discovered, add it to the SourceFile's list of line start offsets.
+    /// Advance the StringReader by one character.
     crate fn bump(&mut self) {
         let next_src_index = self.src_index(self.next_pos);
         if next_src_index < self.end_src_index {

src/test/ui/did_you_mean/recursion_limit_deref.stderr

@@ -1,4 +1,4 @@
-error[E0055]: reached the recursion limit while auto-dereferencing I
+error[E0055]: reached the recursion limit while auto-dereferencing `I`
   --> $DIR/recursion_limit_deref.rs:60:22
    |
 LL |     let x: &Bottom = &t; //~ ERROR mismatched types

src/test/ui/error-codes/E0004-2.stderr

@@ -1,4 +1,4 @@
-error[E0004]: non-exhaustive patterns: type std::option::Option<i32> is non-empty
+error[E0004]: non-exhaustive patterns: type `std::option::Option<i32>` is non-empty
   --> $DIR/E0004-2.rs:14:11
    |
 LL |     match x { } //~ ERROR E0004

src/test/ui/error-codes/E0055.stderr

@@ -1,4 +1,4 @@
-error[E0055]: reached the recursion limit while auto-dereferencing Foo
+error[E0055]: reached the recursion limit while auto-dereferencing `Foo`
   --> $DIR/E0055.rs:21:13
    |
 LL |     ref_foo.foo();

src/test/ui/infinite/infinite-autoderef.stderr

@@ -7,15 +7,15 @@ LL |         x = box x;
    |             cyclic type of infinite size
    |             help: try using a conversion method: `box x.to_string()`
 
-error[E0055]: reached the recursion limit while auto-dereferencing Foo
+error[E0055]: reached the recursion limit while auto-dereferencing `Foo`
   --> $DIR/infinite-autoderef.rs:35:5
    |
 LL |     Foo.foo;
    |     ^^^^^^^ deref recursion limit reached
    |
    = help: consider adding a `#![recursion_limit="128"]` attribute to your crate
 
-error[E0055]: reached the recursion limit while auto-dereferencing Foo
+error[E0055]: reached the recursion limit while auto-dereferencing `Foo`
   --> $DIR/infinite-autoderef.rs:35:9
    |
 LL |     Foo.foo;
@@ -29,7 +29,7 @@ error[E0609]: no field `foo` on type `Foo`
 LL |     Foo.foo;
    |         ^^^ unknown field
 
-error[E0055]: reached the recursion limit while auto-dereferencing Foo
+error[E0055]: reached the recursion limit while auto-dereferencing `Foo`
   --> $DIR/infinite-autoderef.rs:36:9
    |
 LL |     Foo.bar();

src/test/ui/issues/issue-3096-1.stderr

@@ -1,4 +1,4 @@
-error[E0004]: non-exhaustive patterns: type () is non-empty
+error[E0004]: non-exhaustive patterns: type `()` is non-empty
   --> $DIR/issue-3096-1.rs:12:11
    |
 LL |     match () { } //~ ERROR non-exhaustive

src/test/ui/issues/issue-3096-2.stderr

@@ -1,4 +1,4 @@
-error[E0004]: non-exhaustive patterns: type *const bottom is non-empty
+error[E0004]: non-exhaustive patterns: type `*const bottom` is non-empty
   --> $DIR/issue-3096-2.rs:15:11
    |
 LL |     match x { } //~ ERROR non-exhaustive patterns

src/test/ui/issues/issue-38940.rs

@@ -42,5 +42,5 @@ fn main() {
     let t = Top::new();
     let x: &Bottom = &t;
     //~^ ERROR mismatched types
-    //~| ERROR reached the recursion limit while auto-dereferencing I
+    //~| ERROR reached the recursion limit while auto-dereferencing `I`
 }