Rollup of 12 pull requests

config.toml.example

@@ -243,19 +243,36 @@
 # =============================================================================
 [rust]
 
-# Indicates that the build should be optimized for debugging Rust. Note that
-# this is typically not what you want as it takes an incredibly large amount of
-# time to have a debug-mode rustc compile any code (notably libstd). If this
-# value is set to `true` it will affect a number of configuration options below
-# as well, if unconfigured.
-#debug = false
-
-# Whether or not to optimize the compiler and standard library
+# Whether or not to optimize the compiler and standard library.
+#
 # Note: the slowness of the non optimized compiler compiling itself usually
 #       outweighs the time gains in not doing optimizations, therefore a
-#       full bootstrap takes much more time with optimize set to false.
+#       full bootstrap takes much more time with `optimize` set to false.
 #optimize = true
 
+# Indicates that the build should be configured for debugging Rust. A
+# `debug`-enabled compiler and standard library will be somewhat
+# slower (due to e.g. checking of debug assertions) but should remain
+# usable.
+#
+# Note: If this value is set to `true`, it will affect a number of
+#       configuration options below as well, if they have been left
+#       unconfigured in this file.
+#
+# Note: changes to the `debug` setting do *not* affect `optimize`
+#       above. In theory, a "maximally debuggable" environment would
+#       set `optimize` to `false` above to assist the introspection
+#       facilities of debuggers like lldb and gdb. To recreate such an
+#       environment, explicitly set `optimize` to `false` and `debug`
+#       to `true`. In practice, everyone leaves `optimize` set to
+#       `true`, because an unoptimized rustc with debugging
+#       enabled becomes *unusably slow* (e.g. rust-lang/rust#24840
+#       reported a 25x slowdown) and bootstrapping the supposed
+#       "maximally debuggable" environment (notably libstd) takes
+#       hours to build.
+#
+#debug = false
+
 # Number of codegen units to use for each compiler invocation. A value of 0
 # means "the number of cores on this machine", and 1+ is passed through to the
 # compiler.

src/Cargo.lock

@@ -1269,7 +1269,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "minifier"
-version = "0.0.19"
+version = "0.0.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "macro-utils 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2484,7 +2484,7 @@ dependencies = [
 name = "rustdoc"
 version = "0.0.0"
 dependencies = [
- "minifier 0.0.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "minifier 0.0.20 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "pulldown-cmark 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "tempfile 3.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3289,7 +3289,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum memchr 2.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "a3b4142ab8738a78c51896f704f83c11df047ff1bda9a92a661aa6361552d93d"
 "checksum memmap 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e2ffa2c986de11a9df78620c01eeaaf27d94d3ff02bf81bfcca953102dd0c6ff"
 "checksum memoffset 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "0f9dc261e2b62d7a622bf416ea3c5245cdd5d9a7fcc428c0d06804dfce1775b3"
-"checksum minifier 0.0.19 (registry+https://github.com/rust-lang/crates.io-index)" = "9908ed7c62f990c21ab41fdca53a864a3ada0da69d8729c4de727b397e27bc11"
+"checksum minifier 0.0.20 (registry+https://github.com/rust-lang/crates.io-index)" = "96c269bb45c39b333392b2b18ad71760b34ac65666591386b0e959ed58b3f474"
 "checksum miniz-sys 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)" = "609ce024854aeb19a0ef7567d348aaa5a746b32fb72e336df7fcc16869d7e2b4"
 "checksum miow 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "396aa0f2003d7df8395cb93e09871561ccc3e785f0acb369170e8cc74ddf9226"
 "checksum new_debug_unreachable 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "0cdc457076c78ab54d5e0d6fa7c47981757f1e34dc39ff92787f217dede586c4"

src/bootstrap/config.rs

@@ -628,6 +628,9 @@ impl Config {
         let default = false;
         config.llvm_assertions = llvm_assertions.unwrap_or(default);
 
+        let default = true;
+        config.rust_optimize = optimize.unwrap_or(default);
+
         let default = match &config.channel[..] {
             "stable" | "beta" | "nightly" => true,
             _ => false,
@@ -640,7 +643,6 @@ impl Config {
         config.debug_jemalloc = debug_jemalloc.unwrap_or(default);
         config.rust_debuginfo = debuginfo.unwrap_or(default);
         config.rust_debug_assertions = debug_assertions.unwrap_or(default);
-        config.rust_optimize = optimize.unwrap_or(!default);
 
         let default = config.channel == "dev";
         config.ignore_git = ignore_git.unwrap_or(default);

src/doc/rustc/src/lints/listing/warn-by-default.md

@@ -279,7 +279,7 @@ warning: functions generic over types must be mangled
 1 |   #[no_mangle]
   |   ------------ help: remove this attribute
 2 | / fn foo<T>(t: T) {
-3 | |     
+3 | |
 4 | | }
   | |_^
   |
@@ -513,7 +513,7 @@ This will produce:
 warning: borrow of packed field requires unsafe function or block (error E0133)
   --> src/main.rs:11:13
    |
-11 |     let y = &x.data.0; 
+11 |     let y = &x.data.0;
    |             ^^^^^^^^^
    |
    = note: #[warn(safe_packed_borrows)] on by default
@@ -874,7 +874,7 @@ fn main() {
 This will produce:
 
 ```text
-warning: unused `std::result::Result` which must be used
+warning: unused `std::result::Result` that must be used
  --> src/main.rs:6:5
   |
 6 |     returns_result();

src/liballoc/vec.rs

@@ -120,11 +120,17 @@ use raw_vec::RawVec;
 /// assert_eq!(vec, [1, 2, 3, 4]);
 /// ```
 ///
-/// It can also initialize each element of a `Vec<T>` with a given value:
+/// It can also initialize each element of a `Vec<T>` with a given value.
+/// This may be more efficient than performing allocation and initialization
+/// in separate steps, especially when initializing a vector of zeros:
 ///
 /// ```
 /// let vec = vec![0; 5];
 /// assert_eq!(vec, [0, 0, 0, 0, 0]);
+///
+/// // The following is equivalent, but potentially slower:
+/// let mut vec1 = Vec::with_capacity(5);
+/// vec1.resize(5, 0);
 /// ```
 ///
 /// Use a `Vec<T>` as an efficient stack:

src/libcore/iter/mod.rs

@@ -253,7 +253,7 @@
 //! using it. The compiler will warn us about this kind of behavior:
 //!
 //! ```text
-//! warning: unused result which must be used: iterator adaptors are lazy and
+//! warning: unused result that must be used: iterator adaptors are lazy and
 //! do nothing unless consumed
 //! ```
 //!

src/libcore/option.rs

@@ -867,8 +867,6 @@ impl<T> Option<T> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(option_replace)]
-    ///
     /// let mut x = Some(2);
     /// let old = x.replace(5);
     /// assert_eq!(x, Some(5));
@@ -880,7 +878,7 @@ impl<T> Option<T> {
     /// assert_eq!(old, None);
     /// ```
     #[inline]
-    #[unstable(feature = "option_replace", issue = "51998")]
+    #[stable(feature = "option_replace", since = "1.31.0")]
     pub fn replace(&mut self, value: T) -> Option<T> {
         mem::replace(self, Some(value))
     }

src/libcore/tests/lib.rs

@@ -39,7 +39,6 @@
 #![feature(reverse_bits)]
 #![feature(inner_deref)]
 #![feature(slice_internals)]
-#![feature(option_replace)]
 #![feature(slice_partition_dedup)]
 #![feature(copy_within)]
 

src/librustc/hir/lowering.rs

@@ -3953,6 +3953,7 @@ impl<'a> LoweringContext<'a> {
                             constraint: out.constraint.clone(),
                             is_rw: out.is_rw,
                             is_indirect: out.is_indirect,
+                            span: out.expr.span,
                         })
                         .collect(),
                     asm: asm.asm.clone(),

src/librustc/hir/mod.rs

@@ -1812,6 +1812,7 @@ pub struct InlineAsmOutput {
     pub constraint: Symbol,
     pub is_rw: bool,
     pub is_indirect: bool,
+    pub span: Span,
 }
 
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]

src/librustc/ich/impls_hir.rs

@@ -983,7 +983,8 @@ impl<'a> ToStableHashKey<StableHashingContext<'a>> for hir::BodyId {
 impl_stable_hash_for!(struct hir::InlineAsmOutput {
     constraint,
     is_rw,
-    is_indirect
+    is_indirect,
+    span
 });
 
 impl_stable_hash_for!(struct hir::GlobalAsm {

src/librustc/lint/levels.rs

@@ -18,11 +18,10 @@ use lint::context::CheckLintNameResult;
 use lint::{self, Lint, LintId, Level, LintSource};
 use rustc_data_structures::stable_hasher::{HashStable, ToStableHashKey,
                                            StableHasher, StableHasherResult};
-use session::{config::nightly_options, Session};
+use session::Session;
 use syntax::ast;
 use syntax::attr;
 use syntax::source_map::MultiSpan;
-use syntax::feature_gate;
 use syntax::symbol::Symbol;
 use util::nodemap::FxHashMap;
 
@@ -228,28 +227,14 @@ impl<'a> LintLevelsBuilder<'a> {
                     }
                 };
                 let tool_name = if let Some(lint_tool) = word.is_scoped() {
-                    let gate_feature = !self.sess.features_untracked().tool_lints;
-                    let known_tool = attr::is_known_lint_tool(lint_tool);
-                    if gate_feature {
-                        feature_gate::emit_feature_err(
-                            &sess.parse_sess,
-                            "tool_lints",
-                            word.span,
-                            feature_gate::GateIssue::Language,
-                            &format!("scoped lint `{}` is experimental", word.ident),
-                        );
-                    }
-                    if !known_tool {
+                    if !attr::is_known_lint_tool(lint_tool) {
                         span_err!(
                             sess,
                             lint_tool.span,
                             E0710,
                             "an unknown tool name found in scoped lint: `{}`",
                             word.ident
                         );
-                    }
-
-                    if gate_feature || !known_tool {
                         continue;
                     }
 
@@ -299,13 +284,7 @@ impl<'a> LintLevelsBuilder<'a> {
                                     "change it to",
                                     new_lint_name.to_string(),
                                     Applicability::MachineApplicable,
-                                );
-
-                                if nightly_options::is_nightly_build() {
-                                    err.emit();
-                                } else {
-                                    err.cancel();
-                                }
+                                ).emit();
 
                                 let src = LintSource::Node(Symbol::intern(&new_lint_name), li.span);
                                 for id in ids {

src/librustc/middle/expr_use_visitor.rs

@@ -364,11 +364,12 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
     }
 
     fn mutate_expr(&mut self,
+                   span: Span,
                    assignment_expr: &hir::Expr,
                    expr: &hir::Expr,
                    mode: MutateMode) {
         let cmt = return_if_err!(self.mc.cat_expr(expr));
-        self.delegate.mutate(assignment_expr.id, assignment_expr.span, &cmt, mode);
+        self.delegate.mutate(assignment_expr.id, span, &cmt, mode);
         self.walk_expr(expr);
     }
 
@@ -472,12 +473,16 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
                     if o.is_indirect {
                         self.consume_expr(output);
                     } else {
-                        self.mutate_expr(expr, output,
-                                         if o.is_rw {
-                                             MutateMode::WriteAndRead
-                                         } else {
-                                             MutateMode::JustWrite
-                                         });
+                        self.mutate_expr(
+                            output.span,
+                            expr,
+                            output,
+                            if o.is_rw {
+                                MutateMode::WriteAndRead
+                            } else {
+                                MutateMode::JustWrite
+                            },
+                        );
                     }
                 }
                 self.consume_exprs(inputs);
@@ -515,7 +520,7 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
             }
 
             hir::ExprKind::Assign(ref lhs, ref rhs) => {
-                self.mutate_expr(expr, &lhs, MutateMode::JustWrite);
+                self.mutate_expr(expr.span, expr, &lhs, MutateMode::JustWrite);
                 self.consume_expr(&rhs);
             }
 
@@ -527,7 +532,7 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
                 if self.mc.tables.is_method_call(expr) {
                     self.consume_expr(lhs);
                 } else {
-                    self.mutate_expr(expr, &lhs, MutateMode::WriteAndRead);
+                    self.mutate_expr(expr.span, expr, &lhs, MutateMode::WriteAndRead);
                 }
                 self.consume_expr(&rhs);
             }

src/librustc_driver/lib.rs

@@ -21,7 +21,6 @@
 #![feature(box_syntax)]
 #![cfg_attr(unix, feature(libc))]
 #![feature(nll)]
-#![feature(option_replace)]
 #![feature(quote)]
 #![feature(rustc_diagnostic_macros)]
 #![feature(slice_sort_by_cached_key)]

src/librustc_lint/unused.rs

@@ -135,7 +135,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
 
         if let Some(must_use_op) = must_use_op {
             cx.span_lint(UNUSED_MUST_USE, expr.span,
-                         &format!("unused {} which must be used", must_use_op));
+                         &format!("unused {} that must be used", must_use_op));
             op_warned = true;
         }
 
@@ -146,7 +146,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
         fn check_must_use(cx: &LateContext, def_id: DefId, sp: Span, describe_path: &str) -> bool {
             for attr in cx.tcx.get_attrs(def_id).iter() {
                 if attr.check_name("must_use") {
-                    let msg = format!("unused {}`{}` which must be used",
+                    let msg = format!("unused {}`{}` that must be used",
                                           describe_path, cx.tcx.item_path_str(def_id));
                     let mut err = cx.struct_span_lint(UNUSED_MUST_USE, sp, &msg);
                     // check for #[must_use = "..."]
@@ -233,7 +233,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedAttributes {
                 .find(|&&(builtin, ty, _)| name == builtin && ty == AttributeType::CrateLevel)
                 .is_some();
 
-            // Has a plugin registered this attribute as one which must be used at
+            // Has a plugin registered this attribute as one that must be used at
             // the crate level?
             let plugin_crate = plugin_attributes.iter()
                 .find(|&&(ref x, t)| name == &**x && AttributeType::CrateLevel == t)