Rollup of 6 pull requests

compiler/rustc_ast/src/ast.rs

@@ -1616,7 +1616,7 @@ pub enum StrStyle {
     /// A raw string, like `r##"foo"##`.
     ///
     /// The value is the number of `#` symbols used.
-    Raw(u16),
+    Raw(u8),
 }
 
 /// An AST literal.

compiler/rustc_ast/src/token.rs

@@ -59,9 +59,9 @@ pub enum LitKind {
     Integer,
     Float,
     Str,
-    StrRaw(u16), // raw string delimited by `n` hash symbols
+    StrRaw(u8), // raw string delimited by `n` hash symbols
     ByteStr,
-    ByteStrRaw(u16), // raw byte string delimited by `n` hash symbols
+    ByteStrRaw(u8), // raw byte string delimited by `n` hash symbols
     Err,
 }
 

compiler/rustc_ast_lowering/src/expr.rs

@@ -618,9 +618,9 @@ impl<'hir> LoweringContext<'_, 'hir> {
     /// Desugar `<expr>.await` into:
     /// ```rust
     /// match ::std::future::IntoFuture::into_future(<expr>) {
-    ///     mut pinned => loop {
+    ///     mut __awaitee => loop {
     ///         match unsafe { ::std::future::Future::poll(
-    ///             <::std::pin::Pin>::new_unchecked(&mut pinned),
+    ///             <::std::pin::Pin>::new_unchecked(&mut __awaitee),
     ///             ::std::future::get_context(task_context),
     ///         ) } {
     ///             ::std::task::Poll::Ready(result) => break result,
@@ -657,21 +657,24 @@ impl<'hir> LoweringContext<'_, 'hir> {
         let expr = self.lower_expr_mut(expr);
         let expr_hir_id = expr.hir_id;
 
-        let pinned_ident = Ident::with_dummy_span(sym::pinned);
-        let (pinned_pat, pinned_pat_hid) =
-            self.pat_ident_binding_mode(span, pinned_ident, hir::BindingAnnotation::Mutable);
+        // Note that the name of this binding must not be changed to something else because
+        // debuggers and debugger extensions expect it to be called `__awaitee`. They use
+        // this name to identify what is being awaited by a suspended async functions.
+        let awaitee_ident = Ident::with_dummy_span(sym::__awaitee);
+        let (awaitee_pat, awaitee_pat_hid) =
+            self.pat_ident_binding_mode(span, awaitee_ident, hir::BindingAnnotation::Mutable);
 
         let task_context_ident = Ident::with_dummy_span(sym::_task_context);
 
         // unsafe {
         //     ::std::future::Future::poll(
-        //         ::std::pin::Pin::new_unchecked(&mut pinned),
+        //         ::std::pin::Pin::new_unchecked(&mut __awaitee),
         //         ::std::future::get_context(task_context),
         //     )
         // }
         let poll_expr = {
-            let pinned = self.expr_ident(span, pinned_ident, pinned_pat_hid);
-            let ref_mut_pinned = self.expr_mut_addr_of(span, pinned);
+            let awaitee = self.expr_ident(span, awaitee_ident, awaitee_pat_hid);
+            let ref_mut_awaitee = self.expr_mut_addr_of(span, awaitee);
             let task_context = if let Some(task_context_hid) = self.task_context {
                 self.expr_ident_mut(span, task_context_ident, task_context_hid)
             } else {
@@ -681,7 +684,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             let new_unchecked = self.expr_call_lang_item_fn_mut(
                 span,
                 hir::LangItem::PinNewUnchecked,
-                arena_vec![self; ref_mut_pinned],
+                arena_vec![self; ref_mut_awaitee],
                 Some(expr_hir_id),
             );
             let get_context = self.expr_call_lang_item_fn_mut(
@@ -782,8 +785,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
             span: self.lower_span(span),
         });
 
-        // mut pinned => loop { ... }
-        let pinned_arm = self.arm(pinned_pat, loop_expr);
+        // mut __awaitee => loop { ... }
+        let awaitee_arm = self.arm(awaitee_pat, loop_expr);
 
         // `match ::std::future::IntoFuture::into_future(<expr>) { ... }`
         let into_future_span = self.mark_span_with_reason(
@@ -799,11 +802,11 @@ impl<'hir> LoweringContext<'_, 'hir> {
         );
 
         // match <into_future_expr> {
-        //     mut pinned => loop { .. }
+        //     mut __awaitee => loop { .. }
         // }
         hir::ExprKind::Match(
             into_future_expr,
-            arena_vec![self; pinned_arm],
+            arena_vec![self; awaitee_arm],
             hir::MatchSource::AwaitDesugar,
         )
     }

compiler/rustc_lexer/src/lib.rs

@@ -161,15 +161,15 @@ pub enum LiteralKind {
     /// "b"abc"", "b"abc"
     ByteStr { terminated: bool },
     /// "r"abc"", "r#"abc"#", "r####"ab"###"c"####", "r#"a"
-    RawStr { n_hashes: u16, err: Option<RawStrError> },
+    RawStr { n_hashes: u8, err: Option<RawStrError> },
     /// "br"abc"", "br#"abc"#", "br####"ab"###"c"####", "br#"a"
-    RawByteStr { n_hashes: u16, err: Option<RawStrError> },
+    RawByteStr { n_hashes: u8, err: Option<RawStrError> },
 }
 
 /// Error produced validating a raw string. Represents cases like:
 /// - `r##~"abcde"##`: `InvalidStarter`
 /// - `r###"abcde"##`: `NoTerminator { expected: 3, found: 2, possible_terminator_offset: Some(11)`
-/// - Too many `#`s (>65535): `TooManyDelimiters`
+/// - Too many `#`s (>255): `TooManyDelimiters`
 // perf note: It doesn't matter that this makes `Token` 36 bytes bigger. See #77629
 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
 pub enum RawStrError {
@@ -178,7 +178,7 @@ pub enum RawStrError {
     /// The string was never terminated. `possible_terminator_offset` is the number of characters after `r` or `br` where they
     /// may have intended to terminate it.
     NoTerminator { expected: usize, found: usize, possible_terminator_offset: Option<usize> },
-    /// More than 65535 `#`s exist.
+    /// More than 255 `#`s exist.
     TooManyDelimiters { found: usize },
 }
 
@@ -698,12 +698,12 @@ impl Cursor<'_> {
     }
 
     /// Eats the double-quoted string and returns `n_hashes` and an error if encountered.
-    fn raw_double_quoted_string(&mut self, prefix_len: usize) -> (u16, Option<RawStrError>) {
+    fn raw_double_quoted_string(&mut self, prefix_len: usize) -> (u8, Option<RawStrError>) {
         // Wrap the actual function to handle the error with too many hashes.
         // This way, it eats the whole raw string.
         let (n_hashes, err) = self.raw_string_unvalidated(prefix_len);
-        // Only up to 65535 `#`s are allowed in raw strings
-        match u16::try_from(n_hashes) {
+        // Only up to 255 `#`s are allowed in raw strings
+        match u8::try_from(n_hashes) {
             Ok(num) => (num, err),
             // We lie about the number of hashes here :P
             Err(_) => (0, Some(RawStrError::TooManyDelimiters { found: n_hashes })),

compiler/rustc_lexer/src/tests.rs

@@ -2,7 +2,7 @@ use super::*;
 
 use expect_test::{expect, Expect};
 
-fn check_raw_str(s: &str, expected_hashes: u16, expected_err: Option<RawStrError>) {
+fn check_raw_str(s: &str, expected_hashes: u8, expected_err: Option<RawStrError>) {
     let s = &format!("r{}", s);
     let mut cursor = Cursor::new(s);
     cursor.bump();
@@ -68,13 +68,13 @@ fn test_unterminated_no_pound() {
 
 #[test]
 fn test_too_many_hashes() {
-    let max_count = u16::MAX;
+    let max_count = u8::MAX;
     let mut hashes: String = "#".repeat(max_count.into());
 
-    // Valid number of hashes (65535 = 2^16 - 1), but invalid string.
+    // Valid number of hashes (255 = 2^8 - 1 = u8::MAX), but invalid string.
     check_raw_str(&hashes, max_count, Some(RawStrError::InvalidStarter { bad_char: '\u{0}' }));
 
-    // One more hash sign (65536 = 2^16) becomes too many.
+    // One more hash sign (256 = 2^8) becomes too many.
     hashes.push('#');
     check_raw_str(
         &hashes,

compiler/rustc_parse/src/lexer/mod.rs

@@ -597,15 +597,13 @@ impl<'a> StringReader<'a> {
         }
     }
 
-    /// Note: It was decided to not add a test case, because it would be too big.
-    /// <https://github.com/rust-lang/rust/pull/50296#issuecomment-392135180>
     fn report_too_many_hashes(&self, start: BytePos, found: usize) -> ! {
         self.fatal_span_(
             start,
             self.pos,
             &format!(
                 "too many `#` symbols: raw strings may be delimited \
-                by up to 65535 `#` symbols, but found {}",
+                by up to 255 `#` symbols, but found {}",
                 found
             ),
         )

compiler/rustc_span/src/symbol.rs

@@ -272,6 +272,7 @@ symbols! {
         __D,
         __H,
         __S,
+        __awaitee,
         __try_var,
         _d,
         _e,
@@ -1018,7 +1019,6 @@ symbols! {
         pattern_parentheses,
         phantom_data,
         pin,
-        pinned,
         platform_intrinsics,
         plugin,
         plugin_registrar,

compiler/rustc_trait_selection/src/traits/codegen.rs

@@ -19,6 +19,7 @@ use rustc_middle::ty::{self, TyCtxt};
 /// obligations *could be* resolved if we wanted to.
 ///
 /// This also expects that `trait_ref` is fully normalized.
+#[instrument(level = "debug", skip(tcx))]
 pub fn codegen_fulfill_obligation<'tcx>(
     tcx: TyCtxt<'tcx>,
     (param_env, trait_ref): (ty::ParamEnv<'tcx>, ty::PolyTraitRef<'tcx>),
@@ -27,11 +28,6 @@ pub fn codegen_fulfill_obligation<'tcx>(
     let trait_ref = tcx.erase_regions(trait_ref);
     // We expect the input to be fully normalized.
     debug_assert_eq!(trait_ref, tcx.normalize_erasing_regions(param_env, trait_ref));
-    debug!(
-        "codegen_fulfill_obligation(trait_ref={:?}, def_id={:?})",
-        (param_env, trait_ref),
-        trait_ref.def_id()
-    );
 
     // Do the initial selection for the obligation. This yields the
     // shallow result we are looking for -- that is, what specific impl.
@@ -80,25 +76,22 @@ pub fn codegen_fulfill_obligation<'tcx>(
             }
         };
 
-        debug!("fulfill_obligation: selection={:?}", selection);
+        debug!(?selection);
 
         // Currently, we use a fulfillment context to completely resolve
         // all nested obligations. This is because they can inform the
         // inference of the impl's type parameters.
         let mut fulfill_cx = FulfillmentContext::new();
         let impl_source = selection.map(|predicate| {
-            debug!("fulfill_obligation: register_predicate_obligation {:?}", predicate);
             fulfill_cx.register_predicate_obligation(&infcx, predicate);
         });
         let impl_source = drain_fulfillment_cx_or_panic(&infcx, &mut fulfill_cx, impl_source);
 
-        // There should be no opaque types during codegen, they all get revealed.
-        let opaque_types = infcx.inner.borrow_mut().opaque_type_storage.take_opaque_types();
-        if !opaque_types.is_empty() {
-            bug!("{:#?}", opaque_types);
-        }
+        // Opaque types may have gotten their hidden types constrained, but we can ignore them safely
+        // as they will get constrained elsewhere, too.
+        let _opaque_types = infcx.inner.borrow_mut().opaque_type_storage.take_opaque_types();
 
-        debug!("Cache miss: {:?} => {:?}", trait_ref, impl_source);
+        debug!("Cache miss: {trait_ref:?} => {impl_source:?}");
         Ok(&*tcx.arena.alloc(impl_source))
     })
 }

library/alloc/src/vec/into_iter.rs

@@ -8,7 +8,8 @@ use core::iter::{
     FusedIterator, InPlaceIterable, SourceIter, TrustedLen, TrustedRandomAccessNoCoerce,
 };
 use core::marker::PhantomData;
-use core::mem::{self};
+use core::mem::{self, ManuallyDrop};
+use core::ops::Deref;
 use core::ptr::{self, NonNull};
 use core::slice::{self};
 
@@ -32,7 +33,9 @@ pub struct IntoIter<
     pub(super) buf: NonNull<T>,
     pub(super) phantom: PhantomData<T>,
     pub(super) cap: usize,
-    pub(super) alloc: A,
+    // the drop impl reconstructs a RawVec from buf, cap and alloc
+    // to avoid dropping the allocator twice we need to wrap it into ManuallyDrop
+    pub(super) alloc: ManuallyDrop<A>,
     pub(super) ptr: *const T,
     pub(super) end: *const T,
 }
@@ -295,11 +298,11 @@ where
 impl<T: Clone, A: Allocator + Clone> Clone for IntoIter<T, A> {
     #[cfg(not(test))]
     fn clone(&self) -> Self {
-        self.as_slice().to_vec_in(self.alloc.clone()).into_iter()
+        self.as_slice().to_vec_in(self.alloc.deref().clone()).into_iter()
     }
     #[cfg(test)]
     fn clone(&self) -> Self {
-        crate::slice::to_vec(self.as_slice(), self.alloc.clone()).into_iter()
+        crate::slice::to_vec(self.as_slice(), self.alloc.deref().clone()).into_iter()
     }
 }
 
@@ -311,8 +314,8 @@ unsafe impl<#[may_dangle] T, A: Allocator> Drop for IntoIter<T, A> {
         impl<T, A: Allocator> Drop for DropGuard<'_, T, A> {
             fn drop(&mut self) {
                 unsafe {
-                    // `IntoIter::alloc` is not used anymore after this
-                    let alloc = ptr::read(&self.0.alloc);
+                    // `IntoIter::alloc` is not used anymore after this and will be dropped by RawVec
+                    let alloc = ManuallyDrop::take(&mut self.0.alloc);
                     // RawVec handles deallocation
                     let _ = RawVec::from_raw_parts_in(self.0.buf.as_ptr(), self.0.cap, alloc);
                 }

library/alloc/src/vec/mod.rs

@@ -2579,7 +2579,7 @@ impl<T, A: Allocator> IntoIterator for Vec<T, A> {
     fn into_iter(self) -> IntoIter<T, A> {
         unsafe {
             let mut me = ManuallyDrop::new(self);
-            let alloc = ptr::read(me.allocator());
+            let alloc = ManuallyDrop::new(ptr::read(me.allocator()));
             let begin = me.as_mut_ptr();
             let end = if mem::size_of::<T>() == 0 {
                 arith_offset(begin as *const i8, me.len() as isize) as *const T

library/alloc/tests/vec.rs

@@ -1,3 +1,6 @@
+use core::alloc::{Allocator, Layout};
+use core::ptr::NonNull;
+use std::alloc::System;
 use std::assert_matches::assert_matches;
 use std::borrow::Cow;
 use std::cell::Cell;
@@ -991,6 +994,31 @@ fn test_into_iter_advance_by() {
     assert_eq!(i.len(), 0);
 }
 
+#[test]
+fn test_into_iter_drop_allocator() {
+    struct ReferenceCountedAllocator<'a>(DropCounter<'a>);
+
+    unsafe impl Allocator for ReferenceCountedAllocator<'_> {
+        fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, core::alloc::AllocError> {
+            System.allocate(layout)
+        }
+
+        unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) {
+            System.deallocate(ptr, layout)
+        }
+    }
+
+    let mut drop_count = 0;
+
+    let allocator = ReferenceCountedAllocator(DropCounter { count: &mut drop_count });
+    let _ = Vec::<u32, _>::new_in(allocator);
+    assert_eq!(drop_count, 1);
+
+    let allocator = ReferenceCountedAllocator(DropCounter { count: &mut drop_count });
+    let _ = Vec::<u32, _>::new_in(allocator).into_iter();
+    assert_eq!(drop_count, 2);
+}
+
 #[test]
 fn test_from_iter_specialization() {
     let src: Vec<usize> = vec![0usize; 1];