Auto merge of #91361 - Mark-Simulacrum:stable-next, r=Mark-Simulacrum

[stable] 1.57.0 artifacts

This is the standard beta->stable promotion, and includes a last-minute backports of:

* #90044 via inclusion of #91220.
*  [beta] Don't treat unnormalized function arguments as well-formed #91242

r? `@Mark-Simulacrum`

RELEASES.md

@@ -1,3 +1,117 @@
+Version 1.57.0 (2021-12-02)
+==========================
+
+Language
+--------
+
+- [Macro attributes may follow `#[derive]` and will see the original (pre-`cfg`) input.][87220]
+- [Accept curly-brace macros in expressions, like `m!{ .. }.method()` and `m!{ .. }?`.][88690]
+- [Allow panicking in constant evaluation.][89508]
+
+Compiler
+--------
+
+- [Create more accurate debuginfo for vtables.][89597]
+- [Add `armv6k-nintendo-3ds` at Tier 3\*.][88529]
+- [Add `armv7-unknown-linux-uclibceabihf` at Tier 3\*.][88952]
+- [Add `m68k-unknown-linux-gnu` at Tier 3\*.][88321]
+- [Add SOLID targets at Tier 3\*:][86191] `aarch64-kmc-solid_asp3`, `armv7a-kmc-solid_asp3-eabi`, `armv7a-kmc-solid_asp3-eabihf`
+
+\* Refer to Rust's [platform support page][platform-support-doc] for more
+   information on Rust's tiered platform support.
+
+Libraries
+---------
+
+- [Avoid allocations and copying in `Vec::leak`][89337]
+- [Add `#[repr(i8)]` to `Ordering`][89507]
+- [Optimize `File::read_to_end` and `read_to_string`][89582]
+- [Update to Unicode 14.0][89614]
+- [Many more functions are marked `#[must_use]`][89692], producing a warning
+  when ignoring their return value. This helps catch mistakes such as expecting
+  a function to mutate a value in place rather than return a new value.
+
+Stabilised APIs
+---------------
+
+- [`[T; N]::as_mut_slice`][`array::as_mut_slice`]
+- [`[T; N]::as_slice`][`array::as_slice`]
+- [`collections::TryReserveError`]
+- [`HashMap::try_reserve`]
+- [`HashSet::try_reserve`]
+- [`String::try_reserve`]
+- [`String::try_reserve_exact`]
+- [`Vec::try_reserve`]
+- [`Vec::try_reserve_exact`]
+- [`VecDeque::try_reserve`]
+- [`VecDeque::try_reserve_exact`]
+- [`Iterator::map_while`]
+- [`iter::MapWhile`]
+- [`proc_macro::is_available`]
+- [`Command::get_program`]
+- [`Command::get_args`]
+- [`Command::get_envs`]
+- [`Command::get_current_dir`]
+- [`CommandArgs`]
+- [`CommandEnvs`]
+
+These APIs are now usable in const contexts:
+
+- [`hint::unreachable_unchecked`]
+
+Cargo
+-----
+
+- [Stabilize custom profiles][cargo/9943]
+
+Compatibility notes
+-------------------
+
+Internal changes
+----------------
+These changes provide no direct user facing benefits, but represent significant
+improvements to the internals and overall performance of rustc
+and related tools.
+
+- [Added an experimental backend for codegen with `libgccjit`.][87260]
+
+[86191]: https://github.com/rust-lang/rust/pull/86191/
+[87220]: https://github.com/rust-lang/rust/pull/87220/
+[87260]: https://github.com/rust-lang/rust/pull/87260/
+[88243]: https://github.com/rust-lang/rust/pull/88243/
+[88321]: https://github.com/rust-lang/rust/pull/88321/
+[88529]: https://github.com/rust-lang/rust/pull/88529/
+[88690]: https://github.com/rust-lang/rust/pull/88690/
+[88952]: https://github.com/rust-lang/rust/pull/88952/
+[89337]: https://github.com/rust-lang/rust/pull/89337/
+[89507]: https://github.com/rust-lang/rust/pull/89507/
+[89508]: https://github.com/rust-lang/rust/pull/89508/
+[89582]: https://github.com/rust-lang/rust/pull/89582/
+[89597]: https://github.com/rust-lang/rust/pull/89597/
+[89614]: https://github.com/rust-lang/rust/pull/89614/
+[89692]: https://github.com/rust-lang/rust/issues/89692/
+[cargo/9943]: https://github.com/rust-lang/cargo/pull/9943/
+[`array::as_mut_slice`]: https://doc.rust-lang.org/std/primitive.array.html#method.as_mut_slice
+[`array::as_slice`]: https://doc.rust-lang.org/std/primitive.array.html#method.as_slice
+[`collections::TryReserveError`]: https://doc.rust-lang.org/std/collections/struct.TryReserveError.html
+[`HashMap::try_reserve`]: https://doc.rust-lang.org/std/collections/hash_map/struct.HashMap.html#method.try_reserve
+[`HashSet::try_reserve`]: https://doc.rust-lang.org/std/collections/hash_set/struct.HashSet.html#method.try_reserve
+[`String::try_reserve`]: https://doc.rust-lang.org/alloc/string/struct.String.html#method.try_reserve
+[`String::try_reserve_exact`]: https://doc.rust-lang.org/alloc/string/struct.String.html#method.try_reserve_exact
+[`Vec::try_reserve`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.try_reserve
+[`Vec::try_reserve_exact`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.try_reserve_exact
+[`VecDeque::try_reserve`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.try_reserve
+[`VecDeque::try_reserve_exact`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.try_reserve_exact
+[`Iterator::map_while`]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.map_while
+[`iter::MapWhile`]: https://doc.rust-lang.org/std/iter/struct.MapWhile.html
+[`proc_macro::is_available`]: https://doc.rust-lang.org/proc_macro/fn.is_available.html
+[`Command::get_program`]: https://doc.rust-lang.org/std/process/struct.Command.html#method.get_program
+[`Command::get_args`]: https://doc.rust-lang.org/std/process/struct.Command.html#method.get_args
+[`Command::get_envs`]: https://doc.rust-lang.org/std/process/struct.Command.html#method.get_envs
+[`Command::get_current_dir`]: https://doc.rust-lang.org/std/process/struct.Command.html#method.get_current_dir
+[`CommandArgs`]: https://doc.rust-lang.org/std/process/struct.CommandArgs.html
+[`CommandEnvs`]: https://doc.rust-lang.org/std/process/struct.CommandEnvs.html
+
 Version 1.56.1 (2021-11-01)
 ===========================
 
@@ -85,7 +199,7 @@ Cargo
 - [Cargo supports specifying a minimum supported Rust version in Cargo.toml.][`rust-version`]
   This has no effect at present on dependency version selection.
   We encourage crates to specify their minimum supported Rust version, and we encourage CI systems
-  that support Rust code to include a crate's specified minimum version in the text matrix for that
+  that support Rust code to include a crate's specified minimum version in the test matrix for that
   crate by default.
 
 Compatibility notes

compiler/rustc_borrowck/src/type_check/free_region_relations.rs

@@ -258,7 +258,6 @@ impl UniversalRegionRelationsBuilder<'cx, 'tcx> {
                 debug!("build: input_or_output={:?}", ty);
                 // We add implied bounds from both the unnormalized and normalized ty
                 // See issue #87748
-                let constraints_implied_1 = self.add_implied_bounds(ty);
                 let TypeOpOutput { output: norm_ty, constraints: constraints1, .. } = self
                     .param_env
                     .and(type_op::normalize::Normalize::new(ty))
@@ -286,10 +285,9 @@ impl UniversalRegionRelationsBuilder<'cx, 'tcx> {
                 // }
                 // ```
                 // Both &Self::Bar and &() are WF
-                let constraints_implied_2 =
-                    if ty != norm_ty { self.add_implied_bounds(norm_ty) } else { None };
+                let constraints_implied = self.add_implied_bounds(norm_ty);
                 normalized_inputs_and_output.push(norm_ty);
-                constraints1.into_iter().chain(constraints_implied_1).chain(constraints_implied_2)
+                constraints1.into_iter().chain(constraints_implied)
             })
             .collect();
 

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -417,7 +417,10 @@ pub fn llvm_global_features(sess: &Session) -> Vec<String> {
     features.extend(sess.opts.cg.target_feature.split(',').flat_map(&filter));
 
     // FIXME: Move outline-atomics to target definition when earliest supported LLVM is 12.
-    if get_version() >= (12, 0, 0) && sess.target.llvm_target.contains("aarch64-unknown-linux") {
+    if get_version() >= (12, 0, 0)
+        && sess.target.llvm_target.contains("aarch64-unknown-linux")
+        && sess.target.llvm_target != "aarch64-unknown-linux-musl"
+    {
         features.push("+outline-atomics".to_string());
     }
 

compiler/rustc_typeck/src/check/compare_method.rs

@@ -266,14 +266,9 @@ fn compare_predicate_entailment<'tcx>(
         // First liberate late bound regions and subst placeholders
         let trait_sig = tcx.liberate_late_bound_regions(impl_m.def_id, tcx.fn_sig(trait_m.def_id));
         let trait_sig = trait_sig.subst(tcx, trait_to_placeholder_substs);
-        // Next, add all inputs and output as well-formed tys. Importantly,
-        // we have to do this before normalization, since the normalized ty may
-        // not contain the input parameters. See issue #87748.
-        wf_tys.extend(trait_sig.inputs_and_output.iter());
         let trait_sig =
             inh.normalize_associated_types_in(impl_m_span, impl_m_hir_id, param_env, trait_sig);
-        // Also add the resulting inputs and output as well-formed.
-        // This probably isn't strictly necessary.
+        // Add the resulting inputs and output as well-formed.
         wf_tys.extend(trait_sig.inputs_and_output.iter());
         let trait_fty = tcx.mk_fn_ptr(ty::Binder::dummy(trait_sig));
 

compiler/rustc_typeck/src/check/mod.rs

@@ -391,7 +391,6 @@ fn typeck_with_fallback<'tcx>(
             let mut wf_tys = FxHashSet::default();
             // Compute the fty from point of view of inside the fn.
             let fn_sig = tcx.liberate_late_bound_regions(def_id.to_def_id(), fn_sig);
-            wf_tys.extend(fn_sig.inputs_and_output.iter());
             let fn_sig = inh.normalize_associated_types_in(
                 body.value.span,
                 body_id.hir_id,

compiler/rustc_typeck/src/check/wfcheck.rs

@@ -960,11 +960,6 @@ fn check_fn_or_method<'fcx, 'tcx>(
 ) {
     let sig = fcx.tcx.liberate_late_bound_regions(def_id, sig);
 
-    // Unnormalized types in signature are WF too
-    implied_bounds.extend(sig.inputs());
-    // FIXME(#27579) return types should not be implied bounds
-    implied_bounds.insert(sig.output());
-
     // Normalize the input and output types one at a time, using a different
     // `WellFormedLoc` for each. We cannot call `normalize_associated_types`
     // on the entire `FnSig`, since this would use the same `WellFormedLoc`

src/ci/channel

@@ -1 +1 @@
-beta
+stable

src/test/ui/fn/implied-bounds-unnorm-associated-type.nll.stderr

@@ -0,0 +1,14 @@
+error: lifetime may not live long enough
+  --> $DIR/implied-bounds-unnorm-associated-type.rs:14:5
+   |
+LL | fn f<'a, 'b>(s: &'b str, _: <&'a &'b () as Trait>::Type) -> &'a str {
+   |      --  -- lifetime `'b` defined here
+   |      |
+   |      lifetime `'a` defined here
+LL |     s
+   |     ^ returning this value requires that `'b` must outlive `'a`
+   |
+   = help: consider adding the following bound: `'b: 'a`
+
+error: aborting due to previous error
+

src/test/ui/fn/implied-bounds-unnorm-associated-type.rs

@@ -0,0 +1,22 @@
+// check-fail
+// See issue #91068. Types in the substs of an associated type can't be implied
+// to be WF, since they don't actually have to be constructed.
+
+trait Trait {
+    type Type;
+}
+
+impl<T> Trait for T {
+    type Type = ();
+}
+
+fn f<'a, 'b>(s: &'b str, _: <&'a &'b () as Trait>::Type) -> &'a str {
+    s //~ ERROR lifetime mismatch [E0623]
+}
+
+fn main() {
+    let x = String::from("Hello World!");
+    let y = f(&x, ());
+    drop(x);
+    println!("{}", y);
+}

src/test/ui/fn/implied-bounds-unnorm-associated-type.stderr

@@ -0,0 +1,13 @@
+error[E0623]: lifetime mismatch
+  --> $DIR/implied-bounds-unnorm-associated-type.rs:14:5
+   |
+LL | fn f<'a, 'b>(s: &'b str, _: <&'a &'b () as Trait>::Type) -> &'a str {
+   |                 -------      ----------
+   |                 |
+   |                 these two types are declared with different lifetimes...
+LL |     s
+   |     ^ ...but data from `s` flows here
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0623`.

src/test/ui/generic-associated-types/issue-87748.rs

@@ -1,30 +0,0 @@
-// Checks that we properly add implied bounds from unnormalized projections in
-// inputs when typechecking functions.
-
-// check-pass
-
-#![feature(generic_associated_types)]
-
-trait MyTrait {
-    type Assoc<'a, 'b> where 'b: 'a;
-    fn do_sth(arg: Self::Assoc<'_, '_>);
-}
-
-struct A;
-struct B;
-struct C;
-
-impl MyTrait for A {
-    type Assoc<'a, 'b> where 'b: 'a = u32;
-    fn do_sth(_: u32) {}
-}
-impl MyTrait for B {
-    type Assoc<'a, 'b> where 'b: 'a = u32;
-    fn do_sth(_: Self::Assoc<'_, '_>) {}
-}
-impl MyTrait for C {
-    type Assoc<'a, 'b> where 'b: 'a = u32;
-    fn do_sth(_: Self::Assoc<'static, 'static>) {}
-}
-
-fn main () {}