Auto merge of rust-lang#116408 - matthiaskrgr:rollup-hmolg4m, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - rust-lang#115961 (Replace 'mutex' with 'lock' in RwLock documentation)
 - rust-lang#116146 (Clarify `arg` and `args` documentation)
 - rust-lang#116363 (Adapt `todo!` documentation to mention displaying custom values)
 - rust-lang#116365 (bootstrap: make copying linker binaries conditional)
 - rust-lang#116388 (rustdoc: fix & clean up handling of cross-crate higher-ranked parameters)
 - rust-lang#116393 (Emit feature gate *warning* for `auto` traits pre-expansion)
 - rust-lang#116395 (Mark myself as vacation or whatever)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

Diff for: compiler/rustc_ast_passes/src/feature_gate.rs

@@ -603,6 +603,7 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
         "exclusive range pattern syntax is experimental"
     );
     gate_all_legacy_dont_use!(try_blocks, "`try` blocks are unstable");
+    gate_all_legacy_dont_use!(auto_traits, "`auto` traits are unstable");
 
     visit::walk_crate(&mut visitor, krate);
 }

Diff for: compiler/rustc_parse/src/parser/item.rs

@@ -813,7 +813,12 @@ impl<'a> Parser<'a> {
     fn parse_item_trait(&mut self, attrs: &mut AttrVec, lo: Span) -> PResult<'a, ItemInfo> {
         let unsafety = self.parse_unsafety(Case::Sensitive);
         // Parse optional `auto` prefix.
-        let is_auto = if self.eat_keyword(kw::Auto) { IsAuto::Yes } else { IsAuto::No };
+        let is_auto = if self.eat_keyword(kw::Auto) {
+            self.sess.gated_spans.gate(sym::auto_traits, self.prev_token.span);
+            IsAuto::Yes
+        } else {
+            IsAuto::No
+        };
 
         self.expect_keyword(kw::Trait)?;
         let ident = self.parse_ident()?;

Diff for: library/core/src/macros/mod.rs

@@ -719,7 +719,8 @@ macro_rules! unreachable {
 /// The difference between `unimplemented!` and [`todo!`] is that while `todo!`
 /// conveys an intent of implementing the functionality later and the message is "not yet
 /// implemented", `unimplemented!` makes no such claims. Its message is "not implemented".
-/// Also some IDEs will mark `todo!`s.
+///
+/// Also, some IDEs will mark `todo!`s.
 ///
 /// # Panics
 ///
@@ -805,50 +806,63 @@ macro_rules! unimplemented {
 /// The difference between [`unimplemented!`] and `todo!` is that while `todo!` conveys
 /// an intent of implementing the functionality later and the message is "not yet
 /// implemented", `unimplemented!` makes no such claims. Its message is "not implemented".
-/// Also some IDEs will mark `todo!`s.
+///
+/// Also, some IDEs will mark `todo!`s.
 ///
 /// # Panics
 ///
-/// This will always [`panic!`].
+/// This will always [`panic!`] because `todo!` is just a shorthand for `panic!` with a
+/// fixed, specific message.
+///
+/// Like `panic!`, this macro has a second form for displaying custom values.
 ///
 /// # Examples
 ///
 /// Here's an example of some in-progress code. We have a trait `Foo`:
 ///
 /// ```
 /// trait Foo {
-///     fn bar(&self);
+///     fn bar(&self) -> u8;
 ///     fn baz(&self);
+///     fn qux(&self) -> Result<u64, ()>;
 /// }
 /// ```
 ///
 /// We want to implement `Foo` on one of our types, but we also want to work on
 /// just `bar()` first. In order for our code to compile, we need to implement
-/// `baz()`, so we can use `todo!`:
+/// `baz()` and `qux()`, so we can use `todo!`:
 ///
 /// ```
 /// # trait Foo {
-/// #     fn bar(&self);
+/// #     fn bar(&self) -> u8;
 /// #     fn baz(&self);
+/// #     fn qux(&self) -> Result<u64, ()>;
 /// # }
 /// struct MyStruct;
 ///
 /// impl Foo for MyStruct {
-///     fn bar(&self) {
-///         // implementation goes here
+///     fn bar(&self) -> u8 {
+///         1 + 1
 ///     }
 ///
 ///     fn baz(&self) {
-///         // let's not worry about implementing baz() for now
+///         // Let's not worry about implementing baz() for now
 ///         todo!();
 ///     }
+///
+///     fn qux(&self) -> Result<u64, ()> {
+///         // We can add a message to todo! to display our omission.
+///         // This will display:
+///         // "thread 'main' panicked at 'not yet implemented: MyStruct is not yet quxable'".
+///         todo!("MyStruct is not yet quxable");
+///     }
 /// }
 ///
 /// fn main() {
 ///     let s = MyStruct;
 ///     s.bar();
 ///
-///     // we aren't even using baz(), so this is fine.
+///     // We aren't even using baz() or qux(), so this is fine.
 /// }
 /// ```
 #[macro_export]

Diff for: library/std/src/process.rs

@@ -607,7 +607,7 @@ impl Command {
     ///
     /// Note that the argument is not passed through a shell, but given
     /// literally to the program. This means that shell syntax like quotes,
-    /// escaped characters, word splitting, glob patterns, substitution, etc.
+    /// escaped characters, word splitting, glob patterns, variable substitution, etc.
     /// have no effect.
     ///
     /// # Examples
@@ -637,7 +637,7 @@ impl Command {
     ///
     /// Note that the arguments are not passed through a shell, but given
     /// literally to the program. This means that shell syntax like quotes,
-    /// escaped characters, word splitting, glob patterns, substitution, etc.
+    /// escaped characters, word splitting, glob patterns, variable substitution, etc.
     /// have no effect.
     ///
     /// # Examples

Diff for: library/std/src/sync/rwlock.rs

@@ -380,7 +380,7 @@ impl<T: ?Sized> RwLock<T> {
     ///
     /// If the lock is poisoned, it will remain poisoned until this function is called. This allows
     /// recovering from a poisoned state and marking that it has recovered. For example, if the
-    /// value is overwritten by a known-good value, then the mutex can be marked as un-poisoned. Or
+    /// value is overwritten by a known-good value, then the lock can be marked as un-poisoned. Or
     /// possibly, the value could be inspected to determine if it is in a consistent state, and if
     /// so the poison is removed.
     ///
@@ -397,7 +397,7 @@ impl<T: ?Sized> RwLock<T> {
     ///
     /// let _ = thread::spawn(move || {
     ///     let _lock = c_lock.write().unwrap();
-    ///     panic!(); // the mutex gets poisoned
+    ///     panic!(); // the lock gets poisoned
     /// }).join();
     ///
     /// assert_eq!(lock.is_poisoned(), true);

Diff for: src/bootstrap/compile.rs

@@ -167,12 +167,14 @@ impl Step for Std {
                 .rustc_snapshot_sysroot()
                 .join("lib")
                 .join("rustlib")
-                .join(&compiler.host.triple)
+                .join(compiler.host.triple)
                 .join("bin");
-            let target_sysroot_bin =
-                builder.sysroot_libdir(compiler, target).parent().unwrap().join("bin");
-            t!(fs::create_dir_all(&target_sysroot_bin));
-            builder.cp_r(&src_sysroot_bin, &target_sysroot_bin);
+            if src_sysroot_bin.exists() {
+                let target_sysroot_bin =
+                    builder.sysroot_libdir(compiler, target).parent().unwrap().join("bin");
+                t!(fs::create_dir_all(&target_sysroot_bin));
+                builder.cp_r(&src_sysroot_bin, &target_sysroot_bin);
+            }
         }
 
         let mut cargo = builder.cargo(compiler, Mode::Std, SourceType::InTree, target, "build");

Diff for: src/librustdoc/clean/auto_trait.rs

@@ -551,8 +551,8 @@ where
                 WherePredicate::RegionPredicate { lifetime, bounds } => {
                     lifetime_to_bounds.entry(lifetime).or_default().extend(bounds);
                 }
-                WherePredicate::EqPredicate { lhs, rhs, bound_params } => {
-                    match *lhs {
+                WherePredicate::EqPredicate { lhs, rhs } => {
+                    match lhs {
                         Type::QPath(box QPathData {
                             ref assoc,
                             ref self_type,
@@ -590,14 +590,13 @@ where
                                 GenericArgs::AngleBracketed { ref mut bindings, .. } => {
                                     bindings.push(TypeBinding {
                                         assoc: assoc.clone(),
-                                        kind: TypeBindingKind::Equality { term: *rhs },
+                                        kind: TypeBindingKind::Equality { term: rhs },
                                     });
                                 }
                                 GenericArgs::Parenthesized { .. } => {
                                     existing_predicates.push(WherePredicate::EqPredicate {
                                         lhs: lhs.clone(),
                                         rhs,
-                                        bound_params,
                                     });
                                     continue; // If something other than a Fn ends up
                                     // with parentheses, leave it alone

Diff for: src/librustdoc/clean/inline.rs

@@ -18,9 +18,9 @@ use rustc_span::hygiene::MacroKind;
 use rustc_span::symbol::{kw, sym, Symbol};
 
 use crate::clean::{
-    self, clean_fn_decl_from_did_and_sig, clean_generics, clean_impl_item, clean_middle_assoc_item,
-    clean_middle_field, clean_middle_ty, clean_trait_ref_with_bindings, clean_ty,
-    clean_ty_alias_inner_type, clean_ty_generics, clean_variant_def, utils, Attributes,
+    self, clean_bound_vars, clean_fn_decl_from_did_and_sig, clean_generics, clean_impl_item,
+    clean_middle_assoc_item, clean_middle_field, clean_middle_ty, clean_trait_ref_with_bindings,
+    clean_ty, clean_ty_alias_inner_type, clean_ty_generics, clean_variant_def, utils, Attributes,
     AttributesExt, ImplKind, ItemId, Type,
 };
 use crate::core::DocContext;
@@ -239,20 +239,13 @@ pub(crate) fn build_external_trait(cx: &mut DocContext<'_>, did: DefId) -> clean
 
 fn build_external_function<'tcx>(cx: &mut DocContext<'tcx>, did: DefId) -> Box<clean::Function> {
     let sig = cx.tcx.fn_sig(did).instantiate_identity();
-
-    let late_bound_regions = sig.bound_vars().into_iter().filter_map(|var| match var {
-        ty::BoundVariableKind::Region(ty::BrNamed(_, name)) if name != kw::UnderscoreLifetime => {
-            Some(clean::GenericParamDef::lifetime(name))
-        }
-        _ => None,
-    });
-
     let predicates = cx.tcx.explicit_predicates_of(did);
+
     let (generics, decl) = clean::enter_impl_trait(cx, |cx| {
         // NOTE: generics need to be cleaned before the decl!
         let mut generics = clean_ty_generics(cx, cx.tcx.generics_of(did), predicates);
         // FIXME: This does not place parameters in source order (late-bound ones come last)
-        generics.params.extend(late_bound_regions);
+        generics.params.extend(clean_bound_vars(sig.bound_vars()));
         let decl = clean_fn_decl_from_did_and_sig(cx, Some(did), sig);
         (generics, decl)
     });