Rollup of 10 pull requests

compiler/rustc_ast/src/util/classify.rs

@@ -2,7 +2,7 @@
 
 // Predicates on exprs and stmts that the pretty-printer and parser use
 
-use crate::ast;
+use crate::{ast, token::Delimiter};
 
 /// Does this expression require a semicolon to be treated
 /// as a statement? The negation of this: 'can this expression
@@ -59,8 +59,12 @@ pub fn expr_trailing_brace(mut expr: &ast::Expr) -> Option<&ast::Expr> {
             | While(..)
             | ConstBlock(_) => break Some(expr),
 
-            // FIXME: These can end in `}`, but changing these would break stable code.
-            InlineAsm(_) | OffsetOf(_, _) | MacCall(_) | IncludedBytes(_) | FormatArgs(_) => {
+            MacCall(mac) => {
+                break (mac.args.delim == Delimiter::Brace).then_some(expr);
+            }
+
+            InlineAsm(_) | OffsetOf(_, _) | IncludedBytes(_) | FormatArgs(_) => {
+                // These should have been denied pre-expansion.
                 break None;
             }
 

compiler/rustc_expand/src/base.rs

@@ -664,8 +664,8 @@ pub enum SyntaxExtensionKind {
     /// A token-based attribute macro.
     Attr(
         /// An expander with signature (TokenStream, TokenStream) -> TokenStream.
-        /// The first TokenSteam is the attribute itself, the second is the annotated item.
-        /// The produced TokenSteam replaces the input TokenSteam.
+        /// The first TokenStream is the attribute itself, the second is the annotated item.
+        /// The produced TokenStream replaces the input TokenStream.
         Box<dyn AttrProcMacro + sync::DynSync + sync::DynSend>,
     ),
 
@@ -685,7 +685,7 @@ pub enum SyntaxExtensionKind {
     /// A token-based derive macro.
     Derive(
         /// An expander with signature TokenStream -> TokenStream.
-        /// The produced TokenSteam is appended to the input TokenSteam.
+        /// The produced TokenStream is appended to the input TokenStream.
         ///
         /// FIXME: The text above describes how this should work. Currently it
         /// is handled identically to `LegacyDerive`. It should be migrated to

compiler/rustc_parse/messages.ftl

@@ -724,6 +724,8 @@ parse_sugg_turbofish_syntax = use `::<...>` instead of `<...>` to specify lifeti
 
 parse_sugg_wrap_expression_in_parentheses = wrap the expression in parentheses
 
+parse_sugg_wrap_macro_in_parentheses = use parentheses instead of braces for this macro
+
 parse_sugg_wrap_pattern_in_parens = wrap the pattern in parentheses
 
 parse_switch_mut_let_order =

compiler/rustc_parse/src/errors.rs

@@ -722,19 +722,32 @@ pub(crate) struct LabeledLoopInBreak {
     #[primary_span]
     pub span: Span,
     #[subdiagnostic]
-    pub sub: WrapExpressionInParentheses,
+    pub sub: WrapInParentheses,
 }
 
 #[derive(Subdiagnostic)]
-#[multipart_suggestion(
-    parse_sugg_wrap_expression_in_parentheses,
-    applicability = "machine-applicable"
-)]
-pub(crate) struct WrapExpressionInParentheses {
-    #[suggestion_part(code = "(")]
-    pub left: Span,
-    #[suggestion_part(code = ")")]
-    pub right: Span,
+
+pub(crate) enum WrapInParentheses {
+    #[multipart_suggestion(
+        parse_sugg_wrap_expression_in_parentheses,
+        applicability = "machine-applicable"
+    )]
+    Expression {
+        #[suggestion_part(code = "(")]
+        left: Span,
+        #[suggestion_part(code = ")")]
+        right: Span,
+    },
+    #[multipart_suggestion(
+        parse_sugg_wrap_macro_in_parentheses,
+        applicability = "machine-applicable"
+    )]
+    MacroArgs {
+        #[suggestion_part(code = "(")]
+        left: Span,
+        #[suggestion_part(code = ")")]
+        right: Span,
+    },
 }
 
 #[derive(Diagnostic)]
@@ -936,7 +949,7 @@ pub(crate) struct InvalidExpressionInLetElse {
     pub span: Span,
     pub operator: &'static str,
     #[subdiagnostic]
-    pub sugg: WrapExpressionInParentheses,
+    pub sugg: WrapInParentheses,
 }
 
 #[derive(Diagnostic)]
@@ -945,7 +958,7 @@ pub(crate) struct InvalidCurlyInLetElse {
     #[primary_span]
     pub span: Span,
     #[subdiagnostic]
-    pub sugg: WrapExpressionInParentheses,
+    pub sugg: WrapInParentheses,
 }
 
 #[derive(Diagnostic)]

compiler/rustc_parse/src/parser/expr.rs

@@ -1844,7 +1844,7 @@ impl<'a> Parser<'a> {
             let lexpr = self.parse_expr_labeled(label, true)?;
             self.dcx().emit_err(errors::LabeledLoopInBreak {
                 span: lexpr.span,
-                sub: errors::WrapExpressionInParentheses {
+                sub: errors::WrapInParentheses::Expression {
                     left: lexpr.span.shrink_to_lo(),
                     right: lexpr.span.shrink_to_hi(),
                 },

compiler/rustc_parse/src/parser/stmt.rs

@@ -389,7 +389,7 @@ impl<'a> Parser<'a> {
                 self.dcx().emit_err(errors::InvalidExpressionInLetElse {
                     span: init.span,
                     operator: op.node.as_str(),
-                    sugg: errors::WrapExpressionInParentheses {
+                    sugg: errors::WrapInParentheses::Expression {
                         left: init.span.shrink_to_lo(),
                         right: init.span.shrink_to_hi(),
                     },
@@ -400,12 +400,19 @@ impl<'a> Parser<'a> {
 
     fn check_let_else_init_trailing_brace(&self, init: &ast::Expr) {
         if let Some(trailing) = classify::expr_trailing_brace(init) {
-            self.dcx().emit_err(errors::InvalidCurlyInLetElse {
-                span: trailing.span.with_lo(trailing.span.hi() - BytePos(1)),
-                sugg: errors::WrapExpressionInParentheses {
+            let sugg = match &trailing.kind {
+                ExprKind::MacCall(mac) => errors::WrapInParentheses::MacroArgs {
+                    left: mac.args.dspan.open,
+                    right: mac.args.dspan.close,
+                },
+                _ => errors::WrapInParentheses::Expression {
                     left: trailing.span.shrink_to_lo(),
                     right: trailing.span.shrink_to_hi(),
                 },
+            };
+            self.dcx().emit_err(errors::InvalidCurlyInLetElse {
+                span: trailing.span.with_lo(trailing.span.hi() - BytePos(1)),
+                sugg,
             });
         }
     }

compiler/rustc_passes/src/dead.rs

@@ -57,7 +57,7 @@ struct MarkSymbolVisitor<'tcx> {
     tcx: TyCtxt<'tcx>,
     maybe_typeck_results: Option<&'tcx ty::TypeckResults<'tcx>>,
     live_symbols: LocalDefIdSet,
-    repr_has_repr_c: bool,
+    repr_unconditionally_treats_fields_as_live: bool,
     repr_has_repr_simd: bool,
     in_pat: bool,
     ignore_variant_stack: Vec<DefId>,
@@ -365,15 +365,17 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
             return;
         }
 
-        let had_repr_c = self.repr_has_repr_c;
+        let unconditionally_treated_fields_as_live =
+            self.repr_unconditionally_treats_fields_as_live;
         let had_repr_simd = self.repr_has_repr_simd;
-        self.repr_has_repr_c = false;
+        self.repr_unconditionally_treats_fields_as_live = false;
         self.repr_has_repr_simd = false;
         match node {
             Node::Item(item) => match item.kind {
                 hir::ItemKind::Struct(..) | hir::ItemKind::Union(..) => {
                     let def = self.tcx.adt_def(item.owner_id);
-                    self.repr_has_repr_c = def.repr().c();
+                    self.repr_unconditionally_treats_fields_as_live =
+                        def.repr().c() || def.repr().transparent();
                     self.repr_has_repr_simd = def.repr().simd();
 
                     intravisit::walk_item(self, item)
@@ -411,7 +413,7 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
             _ => {}
         }
         self.repr_has_repr_simd = had_repr_simd;
-        self.repr_has_repr_c = had_repr_c;
+        self.repr_unconditionally_treats_fields_as_live = unconditionally_treated_fields_as_live;
     }
 
     fn mark_as_used_if_union(&mut self, adt: ty::AdtDef<'tcx>, fields: &[hir::ExprField<'_>]) {
@@ -435,11 +437,11 @@ impl<'tcx> Visitor<'tcx> for MarkSymbolVisitor<'tcx> {
 
     fn visit_variant_data(&mut self, def: &'tcx hir::VariantData<'tcx>) {
         let tcx = self.tcx;
-        let has_repr_c = self.repr_has_repr_c;
+        let unconditionally_treat_fields_as_live = self.repr_unconditionally_treats_fields_as_live;
         let has_repr_simd = self.repr_has_repr_simd;
         let live_fields = def.fields().iter().filter_map(|f| {
             let def_id = f.def_id;
-            if has_repr_c || (f.is_positional() && has_repr_simd) {
+            if unconditionally_treat_fields_as_live || (f.is_positional() && has_repr_simd) {
                 return Some(def_id);
             }
             if !tcx.visibility(f.hir_id.owner.def_id).is_public() {
@@ -741,7 +743,7 @@ fn live_symbols_and_ignored_derived_traits(
         tcx,
         maybe_typeck_results: None,
         live_symbols: Default::default(),
-        repr_has_repr_c: false,
+        repr_unconditionally_treats_fields_as_live: false,
         repr_has_repr_simd: false,
         in_pat: false,
         ignore_variant_stack: vec![],

library/alloc/src/boxed/thin.rs

@@ -171,7 +171,6 @@ struct WithHeader<H>(NonNull<u8>, PhantomData<H>);
 /// An opaque representation of `WithHeader<H>` to avoid the
 /// projection invariance of `<T as Pointee>::Metadata`.
 #[repr(transparent)]
-#[allow(dead_code)] // Field only used through `WithHeader` type above.
 struct WithOpaqueHeader(NonNull<u8>);
 
 impl WithOpaqueHeader {

library/alloc/src/vec/mod.rs

@@ -358,7 +358,7 @@ mod spec_extend;
 ///
 /// `vec![x; n]`, `vec![a, b, c, d]`, and
 /// [`Vec::with_capacity(n)`][`Vec::with_capacity`], will all produce a `Vec`
-/// with exactly the requested capacity. If <code>[len] == [capacity]</code>,
+/// with at least the requested capacity. If <code>[len] == [capacity]</code>,
 /// (as is the case for the [`vec!`] macro), then a `Vec<T>` can be converted to
 /// and from a [`Box<[T]>`][owned slice] without reallocating or moving the elements.
 ///
@@ -1023,8 +1023,11 @@ impl<T, A: Allocator> Vec<T, A> {
 
     /// Shrinks the capacity of the vector as much as possible.
     ///
-    /// It will drop down as close as possible to the length but the allocator
-    /// may still inform the vector that there is space for a few more elements.
+    /// The behavior of this method depends on the allocator, which may either shrink the vector
+    /// in-place or reallocate. The resulting vector might still have some excess capacity, just as
+    /// is the case for [`with_capacity`]. See [`Allocator::shrink`] for more details.
+    ///
+    /// [`with_capacity`]: Vec::with_capacity
     ///
     /// # Examples
     ///
@@ -1074,10 +1077,10 @@ impl<T, A: Allocator> Vec<T, A> {
 
     /// Converts the vector into [`Box<[T]>`][owned slice].
     ///
-    /// If the vector has excess capacity, its items will be moved into a
-    /// newly-allocated buffer with exactly the right capacity.
+    /// Before doing the conversion, this method discards excess capacity like [`shrink_to_fit`].
     ///
     /// [owned slice]: Box
+    /// [`shrink_to_fit`]: Vec::shrink_to_fit
     ///
     /// # Examples
     ///
@@ -3290,8 +3293,10 @@ impl<T, A: Allocator> From<Box<[T], A>> for Vec<T, A> {
 impl<T, A: Allocator> From<Vec<T, A>> for Box<[T], A> {
     /// Convert a vector into a boxed slice.
     ///
-    /// If `v` has excess capacity, its items will be moved into a
-    /// newly-allocated buffer with exactly the right capacity.
+    /// Before doing the conversion, this method discards excess capacity like [`Vec::shrink_to_fit`].
+    ///
+    /// [owned slice]: Box
+    /// [`Vec::shrink_to_fit`]: Vec::shrink_to_fit
     ///
     /// # Examples
     ///