Auto merge of rust-lang#92927 - matthiaskrgr:rollup-pgzwfcm, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - rust-lang#92747 (Simplification of BigNum::bit_length)
 - rust-lang#92767 (Use the new language identifier for Rust in the PDB debug format)
 - rust-lang#92775 (Inline std::os::unix::ffi::OsStringExt methods)
 - rust-lang#92863 (Remove `&mut` from `io::read_to_string` signature)
 - rust-lang#92865 (Ignore static lifetimes for GATs outlives lint)
 - rust-lang#92873 (Generate more precise generator names)
 - rust-lang#92879 (Add Sync bound to allocator parameter in vec::IntoIter)
 - rust-lang#92892 (Do not fail evaluation in const blocks)

Failed merges:

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

Author: bors

compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs

@@ -519,12 +519,18 @@ fn push_unqualified_item_name(
             output.push_str(tcx.crate_name(def_id.krate).as_str());
         }
         DefPathData::ClosureExpr if tcx.generator_kind(def_id).is_some() => {
+            let key = match tcx.generator_kind(def_id).unwrap() {
+                hir::GeneratorKind::Async(hir::AsyncGeneratorKind::Block) => "async_block",
+                hir::GeneratorKind::Async(hir::AsyncGeneratorKind::Closure) => "async_closure",
+                hir::GeneratorKind::Async(hir::AsyncGeneratorKind::Fn) => "async_fn",
+                hir::GeneratorKind::Gen => "generator",
+            };
             // Generators look like closures, but we want to treat them differently
             // in the debug info.
             if cpp_like_debuginfo(tcx) {
-                write!(output, "generator${}", disambiguated_data.disambiguator).unwrap();
+                write!(output, "{}${}", key, disambiguated_data.disambiguator).unwrap();
             } else {
-                write!(output, "{{generator#{}}}", disambiguated_data.disambiguator).unwrap();
+                write!(output, "{{{}#{}}}", key, disambiguated_data.disambiguator).unwrap();
             }
         }
         _ => match disambiguated_data.data.name() {

compiler/rustc_typeck/src/check/expr.rs

@@ -1226,7 +1226,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let body = self.tcx.hir().body(anon_const.body);
 
         // Create a new function context.
-        let fcx = FnCtxt::new(self, self.param_env, body.value.hir_id);
+        let fcx = FnCtxt::new(self, self.param_env.with_const(), body.value.hir_id);
         crate::check::GatherLocalsVisitor::new(&fcx).visit_body(body);
 
         let ty = fcx.check_expr_with_expectation(&body.value, expected);

compiler/rustc_typeck/src/check/wfcheck.rs

@@ -14,8 +14,9 @@ use rustc_hir::lang_items::LangItem;
 use rustc_hir::ItemKind;
 use rustc_infer::infer::outlives::env::OutlivesEnvironment;
 use rustc_infer::infer::outlives::obligations::TypeOutlives;
-use rustc_infer::infer::TyCtxtInferExt;
-use rustc_infer::infer::{self, RegionckMode, SubregionOrigin};
+use rustc_infer::infer::region_constraints::GenericKind;
+use rustc_infer::infer::{self, RegionckMode};
+use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
 use rustc_middle::hir::map as hir_map;
 use rustc_middle::ty::subst::{GenericArgKind, InternalSubsts, Subst};
 use rustc_middle::ty::trait_def::TraitSpecializationKind;
@@ -332,6 +333,12 @@ fn check_gat_where_clauses(
         // outlives relationship (`Self: 'a`), then we want to ensure that is
         // reflected in a where clause on the GAT itself.
         for (region, region_idx) in &regions {
+            // Ignore `'static` lifetimes for the purpose of this lint: it's
+            // because we know it outlives everything and so doesn't give meaninful
+            // clues
+            if let ty::ReStatic = region {
+                continue;
+            }
             for (ty, ty_idx) in &types {
                 // In our example, requires that Self: 'a
                 if ty_known_to_outlive(tcx, id, param_env, &wf_tys, *ty, *region) {
@@ -371,10 +378,19 @@ fn check_gat_where_clauses(
         // outlives relationship, then we want to ensure that is
         // reflected in a where clause on the GAT itself.
         for (region_a, region_a_idx) in &regions {
+            // Ignore `'static` lifetimes for the purpose of this lint: it's
+            // because we know it outlives everything and so doesn't give meaninful
+            // clues
+            if let ty::ReStatic = region_a {
+                continue;
+            }
             for (region_b, region_b_idx) in &regions {
                 if region_a == region_b {
                     continue;
                 }
+                if let ty::ReStatic = region_b {
+                    continue;
+                }
 
                 if region_known_to_outlive(tcx, id, param_env, &wf_tys, *region_a, *region_b) {
                     debug!(?region_a_idx, ?region_b_idx);
@@ -502,8 +518,6 @@ fn check_gat_where_clauses(
     }
 }
 
-// FIXME(jackh726): refactor some of the shared logic between the two functions below
-
 /// Given a known `param_env` and a set of well formed types, can we prove that
 /// `ty` outlives `region`.
 fn ty_known_to_outlive<'tcx>(
@@ -514,54 +528,49 @@ fn ty_known_to_outlive<'tcx>(
     ty: Ty<'tcx>,
     region: ty::Region<'tcx>,
 ) -> bool {
-    // Unfortunately, we have to use a new `InferCtxt` each call, because
-    // region constraints get added and solved there and we need to test each
-    // call individually.
-    tcx.infer_ctxt().enter(|infcx| {
-        let mut outlives_environment = OutlivesEnvironment::new(param_env);
-        outlives_environment.add_implied_bounds(&infcx, wf_tys.clone(), id, DUMMY_SP);
-        outlives_environment.save_implied_bounds(id);
-        let region_bound_pairs = outlives_environment.region_bound_pairs_map().get(&id).unwrap();
-
-        let cause = ObligationCause::new(DUMMY_SP, id, ObligationCauseCode::MiscObligation);
-
-        let sup_type = ty;
-        let sub_region = region;
-
-        let origin = SubregionOrigin::from_obligation_cause(&cause, || {
-            infer::RelateParamBound(cause.span, sup_type, None)
-        });
-
+    resolve_regions_with_wf_tys(tcx, id, param_env, &wf_tys, |infcx, region_bound_pairs| {
+        let origin = infer::RelateParamBound(DUMMY_SP, ty, None);
         let outlives = &mut TypeOutlives::new(
-            &infcx,
+            infcx,
             tcx,
-            &region_bound_pairs,
+            region_bound_pairs,
             Some(infcx.tcx.lifetimes.re_root_empty),
             param_env,
         );
-        outlives.type_must_outlive(origin, sup_type, sub_region);
-
-        let errors = infcx.resolve_regions(
-            id.expect_owner().to_def_id(),
-            &outlives_environment,
-            RegionckMode::default(),
-        );
-
-        debug!(?errors, "errors");
-
-        // If we were able to prove that the type outlives the region without
-        // an error, it must be because of the implied or explicit bounds...
-        errors.is_empty()
+        outlives.type_must_outlive(origin, ty, region);
     })
 }
 
+/// Given a known `param_env` and a set of well formed types, can we prove that
+/// `region_a` outlives `region_b`
 fn region_known_to_outlive<'tcx>(
     tcx: TyCtxt<'tcx>,
     id: hir::HirId,
     param_env: ty::ParamEnv<'tcx>,
     wf_tys: &FxHashSet<Ty<'tcx>>,
     region_a: ty::Region<'tcx>,
     region_b: ty::Region<'tcx>,
+) -> bool {
+    resolve_regions_with_wf_tys(tcx, id, param_env, &wf_tys, |mut infcx, _| {
+        use rustc_infer::infer::outlives::obligations::TypeOutlivesDelegate;
+        let origin = infer::RelateRegionParamBound(DUMMY_SP);
+        // `region_a: region_b` -> `region_b <= region_a`
+        infcx.push_sub_region_constraint(origin, region_b, region_a);
+    })
+}
+
+/// Given a known `param_env` and a set of well formed types, set up an
+/// `InferCtxt`, call the passed function (to e.g. set up region constraints
+/// to be tested), then resolve region and return errors
+fn resolve_regions_with_wf_tys<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    id: hir::HirId,
+    param_env: ty::ParamEnv<'tcx>,
+    wf_tys: &FxHashSet<Ty<'tcx>>,
+    add_constraints: impl for<'a> FnOnce(
+        &'a InferCtxt<'a, 'tcx>,
+        &'a Vec<(&'tcx ty::RegionKind, GenericKind<'tcx>)>,
+    ),
 ) -> bool {
     // Unfortunately, we have to use a new `InferCtxt` each call, because
     // region constraints get added and solved there and we need to test each
@@ -570,16 +579,9 @@ fn region_known_to_outlive<'tcx>(
         let mut outlives_environment = OutlivesEnvironment::new(param_env);
         outlives_environment.add_implied_bounds(&infcx, wf_tys.clone(), id, DUMMY_SP);
         outlives_environment.save_implied_bounds(id);
+        let region_bound_pairs = outlives_environment.region_bound_pairs_map().get(&id).unwrap();
 
-        let cause = ObligationCause::new(DUMMY_SP, id, ObligationCauseCode::MiscObligation);
-
-        let origin = SubregionOrigin::from_obligation_cause(&cause, || {
-            infer::RelateRegionParamBound(cause.span)
-        });
-
-        use rustc_infer::infer::outlives::obligations::TypeOutlivesDelegate;
-        // `region_a: region_b` -> `region_b <= region_a`
-        (&infcx).push_sub_region_constraint(origin, region_b, region_a);
+        add_constraints(&infcx, region_bound_pairs);
 
         let errors = infcx.resolve_regions(
             id.expect_owner().to_def_id(),

library/alloc/src/vec/into_iter.rs

@@ -125,7 +125,7 @@ impl<T, A: Allocator> AsRef<[T]> for IntoIter<T, A> {
 #[stable(feature = "rust1", since = "1.0.0")]
 unsafe impl<T: Send, A: Allocator + Send> Send for IntoIter<T, A> {}
 #[stable(feature = "rust1", since = "1.0.0")]
-unsafe impl<T: Sync, A: Allocator> Sync for IntoIter<T, A> {}
+unsafe impl<T: Sync, A: Allocator + Sync> Sync for IntoIter<T, A> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T, A: Allocator> Iterator for IntoIter<T, A> {

library/core/src/num/bignum.rs

@@ -158,24 +158,15 @@ macro_rules! define_bignum {
             /// Returns the number of bits necessary to represent this value. Note that zero
             /// is considered to need 0 bits.
             pub fn bit_length(&self) -> usize {
-                // Skip over the most significant digits which are zero.
+                let digitbits = <$ty>::BITS as usize;
                 let digits = self.digits();
-                let zeros = digits.iter().rev().take_while(|&&x| x == 0).count();
-                let end = digits.len() - zeros;
-                let nonzero = &digits[..end];
-
-                if nonzero.is_empty() {
+                // Find the most significant non-zero digit.
+                let msd = digits.iter().rposition(|&x| x != 0);
+                match msd {
+                    Some(msd) => msd * digitbits + digits[msd].log2() as usize + 1,
                     // There are no non-zero digits, i.e., the number is zero.
-                    return 0;
-                }
-                // This could be optimized with leading_zeros() and bit shifts, but that's
-                // probably not worth the hassle.
-                let digitbits = <$ty>::BITS as usize;
-                let mut i = nonzero.len() * digitbits - 1;
-                while self.get_bit(i) == 0 {
-                    i -= 1;
+                    _ => 0,
                 }
-                i + 1
             }
 
             /// Adds `other` to itself and returns its own mutable reference.

library/core/tests/num/bignum.rs

@@ -1,4 +1,5 @@
 use core::num::bignum::tests::Big8x3 as Big;
+use core::num::bignum::Big32x40;
 
 #[test]
 #[should_panic]
@@ -215,6 +216,16 @@ fn test_get_bit_out_of_range() {
 
 #[test]
 fn test_bit_length() {
+    for i in 0..8 * 3 {
+        // 010000...000
+        assert_eq!(Big::from_small(1).mul_pow2(i).bit_length(), i + 1);
+    }
+    for i in 1..8 * 3 - 1 {
+        // 010000...001
+        assert_eq!(Big::from_small(1).mul_pow2(i).add(&Big::from_small(1)).bit_length(), i + 1);
+        // 110000...000
+        assert_eq!(Big::from_small(3).mul_pow2(i).bit_length(), i + 2);
+    }
     assert_eq!(Big::from_small(0).bit_length(), 0);
     assert_eq!(Big::from_small(1).bit_length(), 1);
     assert_eq!(Big::from_small(5).bit_length(), 3);
@@ -223,6 +234,30 @@ fn test_bit_length() {
     assert_eq!(Big::from_u64(0xffffff).bit_length(), 24);
 }
 
+#[test]
+fn test_bit_length_32x40() {
+    for i in 0..32 * 40 {
+        // 010000...000
+        assert_eq!(Big32x40::from_small(1).mul_pow2(i).bit_length(), i + 1);
+    }
+    for i in 1..32 * 40 - 1 {
+        // 010000...001
+        assert_eq!(
+            Big32x40::from_small(1).mul_pow2(i).add(&Big32x40::from_small(1)).bit_length(),
+            i + 1
+        );
+        // 110000...000
+        assert_eq!(Big32x40::from_small(3).mul_pow2(i).bit_length(), i + 2);
+    }
+    assert_eq!(Big32x40::from_small(0).bit_length(), 0);
+    assert_eq!(Big32x40::from_small(1).bit_length(), 1);
+    assert_eq!(Big32x40::from_small(5).bit_length(), 3);
+    assert_eq!(Big32x40::from_small(0x18).bit_length(), 5);
+    assert_eq!(Big32x40::from_u64(0x4073).bit_length(), 15);
+    assert_eq!(Big32x40::from_u64(0xffffff).bit_length(), 24);
+    assert_eq!(Big32x40::from_u64(0xffffffffffffffff).bit_length(), 64);
+}
+
 #[test]
 fn test_ord() {
     assert!(Big::from_u64(0) < Big::from_u64(0xffffff));

library/std/src/io/mod.rs

@@ -1031,14 +1031,14 @@ pub trait Read {
 ///
 /// # use std::io;
 /// fn main() -> io::Result<()> {
-///     let stdin = io::read_to_string(&mut io::stdin())?;
+///     let stdin = io::read_to_string(io::stdin())?;
 ///     println!("Stdin was:");
 ///     println!("{}", stdin);
 ///     Ok(())
 /// }
 /// ```
 #[unstable(feature = "io_read_to_string", issue = "80218")]
-pub fn read_to_string<R: Read>(reader: &mut R) -> Result<String> {
+pub fn read_to_string<R: Read>(mut reader: R) -> Result<String> {
     let mut buf = String::new();
     reader.read_to_string(&mut buf)?;
     Ok(buf)

library/std/src/os/unix/ffi/os_str.rs

@@ -28,9 +28,11 @@ pub trait OsStringExt: Sealed {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl OsStringExt for OsString {
+    #[inline]
     fn from_vec(vec: Vec<u8>) -> OsString {
         FromInner::from_inner(Buf { inner: vec })
     }
+    #[inline]
     fn into_vec(self) -> Vec<u8> {
         self.into_inner().inner
     }

src/llvm-project

@@ -17,7 +17,7 @@ async fn async_fn_test() {
 // FIXME: No way to reliably check the filename.
 
 // CHECK-DAG:  [[ASYNC_FN:!.*]] = !DINamespace(name: "async_fn_test"
-// CHECK-DAG:  [[GEN:!.*]] = !DICompositeType(tag: DW_TAG_union_type, name: "generator$0"
+// CHECK-DAG:  [[GEN:!.*]] = !DICompositeType(tag: DW_TAG_union_type, name: "async_fn$0"
 // CHECK:      {{!.*}} = !DIDerivedType(tag: DW_TAG_member, name: "variant0", scope: [[GEN]],
 // For brevity, we only check the struct name and members of the last variant.
 // CHECK-SAME: file: [[FILE:![0-9]*]], line: 11,

src/test/codegen/async-fn-debug-msvc.rs

@@ -17,7 +17,7 @@ async fn async_fn_test() {
 // FIXME: No way to reliably check the filename.
 
 // CHECK-DAG:  [[ASYNC_FN:!.*]] = !DINamespace(name: "async_fn_test"
-// CHECK-DAG:  [[GEN:!.*]] = !DICompositeType(tag: DW_TAG_structure_type, name: "{generator#0}", scope: [[ASYNC_FN]]
+// CHECK-DAG:  [[GEN:!.*]] = !DICompositeType(tag: DW_TAG_structure_type, name: "{async_fn#0}", scope: [[ASYNC_FN]]
 // CHECK:      [[VARIANT:!.*]] = !DICompositeType(tag: DW_TAG_variant_part, scope: [[ASYNC_FN]],
 // CHECK-NOT:  flags: DIFlagArtificial
 // CHECK-SAME: discriminator: [[DISC:![0-9]*]]

src/test/codegen/async-fn-debug.rs

@@ -0,0 +1,17 @@
+#![allow(unused)]
+#![feature(const_fn_trait_bound, const_trait_impl, inline_const)]
+
+const fn f<T: ~const Drop>(x: T) {}
+
+struct UnconstDrop;
+
+impl Drop for UnconstDrop {
+    fn drop(&mut self) {}
+}
+
+fn main() {
+    const {
+        f(UnconstDrop);
+        //~^ ERROR the trait bound `UnconstDrop: Drop` is not satisfied
+    }
+}

src/test/ui/consts/const-block-const-bound.rs

@@ -0,0 +1,21 @@
+error[E0277]: the trait bound `UnconstDrop: Drop` is not satisfied
+  --> $DIR/const-block-const-bound.rs:14:11
+   |
+LL |         f(UnconstDrop);
+   |         - ^^^^^^^^^^^ the trait `Drop` is not implemented for `UnconstDrop`
+   |         |
+   |         required by a bound introduced by this call
+   |
+note: required by a bound in `f`
+  --> $DIR/const-block-const-bound.rs:4:15
+   |
+LL | const fn f<T: ~const Drop>(x: T) {}
+   |               ^^^^^^^^^^^ required by this bound in `f`
+help: consider introducing a `where` bound, but there might be an alternative better way to express this requirement
+   |
+LL | fn main() where UnconstDrop: Drop {
+   |           +++++++++++++++++++++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.

src/test/ui/consts/const-block-const-bound.stderr

@@ -189,4 +189,17 @@ trait Trait: 'static {
     fn make_assoc(_: &u32) -> Self::Assoc<'_>;
 }
 
+// We ignore `'static` lifetimes for any lints
+trait StaticReturn<'a> {
+    type Y<'b>;
+    fn foo(&self) -> Self::Y<'static>;
+}
+
+// Same as above, but with extra method that takes GAT - just make sure this works
+trait StaticReturnAndTakes<'a> {
+    type Y<'b>;
+    fn foo(&self) -> Self::Y<'static>;
+    fn bar<'b>(&self, arg: Self::Y<'b>);
+}
+
 fn main() {}