Rollup of 9 pull requests

compiler/rustc_ast/src/visit.rs

@@ -403,8 +403,8 @@ pub fn walk_ty<'a, V: Visitor<'a>>(visitor: &mut V, typ: &'a Ty) {
             walk_list!(visitor, visit_lifetime, opt_lifetime, LifetimeCtxt::Ref);
             visitor.visit_ty(&mutable_type.ty)
         }
-        TyKind::Tup(tys) => {
-            walk_list!(visitor, visit_ty, tys);
+        TyKind::Tup(tuple_element_types) => {
+            walk_list!(visitor, visit_ty, tuple_element_types);
         }
         TyKind::BareFn(function_declaration) => {
             walk_list!(visitor, visit_generic_param, &function_declaration.generic_params);

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -131,7 +131,7 @@ pub fn print_crate<'a>(
 
         // Currently, in Rust 2018 we don't have `extern crate std;` at the crate
         // root, so this is not needed, and actually breaks things.
-        if edition.rust_2015() {
+        if edition.is_rust_2015() {
             // `#![no_std]`
             let fake_attr = attr::mk_attr_word(g, ast::AttrStyle::Inner, sym::no_std, DUMMY_SP);
             s.print_attribute(&fake_attr);

compiler/rustc_builtin_macros/src/deriving/cmp/partial_eq.rs

@@ -29,16 +29,30 @@ pub fn expand_deriving_partial_eq(
                         cx.span_bug(field.span, "not exactly 2 arguments in `derive(PartialEq)`");
                     };
 
-                    // We received `&T` arguments. Convert them to `T` by
-                    // stripping `&` or adding `*`. This isn't necessary for
-                    // type checking, but it results in much better error
-                    // messages if something goes wrong.
+                    // We received arguments of type `&T`. Convert them to type `T` by stripping
+                    // any leading `&` or adding `*`. This isn't necessary for type checking, but
+                    // it results in better error messages if something goes wrong.
+                    //
+                    // Note: for arguments that look like `&{ x }`, which occur with packed
+                    // structs, this would cause expressions like `{ self.x } == { other.x }`,
+                    // which isn't valid Rust syntax. This wouldn't break compilation because these
+                    // AST nodes are constructed within the compiler. But it would mean that code
+                    // printed by `-Zunpretty=expanded` (or `cargo expand`) would have invalid
+                    // syntax, which would be suboptimal. So we wrap these in parens, giving
+                    // `({ self.x }) == ({ other.x })`, which is valid syntax.
                     let convert = |expr: &P<Expr>| {
                         if let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, inner) =
                             &expr.kind
                         {
-                            inner.clone()
+                            if let ExprKind::Block(..) = &inner.kind {
+                                // `&{ x }` form: remove the `&`, add parens.
+                                cx.expr_paren(field.span, inner.clone())
+                            } else {
+                                // `&x` form: remove the `&`.
+                                inner.clone()
+                            }
                         } else {
+                            // No leading `&`: add a leading `*`.
                             cx.expr_deref(field.span, expr.clone())
                         }
                     };

compiler/rustc_error_messages/locales/en-US/parse.ftl

@@ -203,8 +203,9 @@ parse_inclusive_range_extra_equals = unexpected `=` after inclusive range
     .suggestion_remove_eq = use `..=` instead
     .note = inclusive ranges end with a single equals sign (`..=`)
 
-parse_inclusive_range_match_arrow = unexpected `=>` after open range
-    .suggestion_add_space = add a space between the pattern and `=>`
+parse_inclusive_range_match_arrow = unexpected `>` after inclusive range
+    .label = this is parsed as an inclusive range `..=`
+    .suggestion = add a space between the pattern and `=>`
 
 parse_inclusive_range_no_end = inclusive range with no end
     .suggestion_open_range = use `..` instead

compiler/rustc_expand/src/build.rs

@@ -272,6 +272,10 @@ impl<'a> ExtCtxt<'a> {
         self.expr(sp, ast::ExprKind::AddrOf(ast::BorrowKind::Ref, ast::Mutability::Not, e))
     }
 
+    pub fn expr_paren(&self, sp: Span, e: P<ast::Expr>) -> P<ast::Expr> {
+        self.expr(sp, ast::ExprKind::Paren(e))
+    }
+
     pub fn expr_call(
         &self,
         span: Span,

compiler/rustc_infer/src/infer/error_reporting/mod.rs

@@ -60,7 +60,7 @@ use crate::traits::{
 
 use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
 use rustc_errors::{pluralize, struct_span_err, Diagnostic, ErrorGuaranteed, IntoDiagnosticArg};
-use rustc_errors::{Applicability, DiagnosticBuilder, DiagnosticStyledString, MultiSpan};
+use rustc_errors::{Applicability, DiagnosticBuilder, DiagnosticStyledString};
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, LocalDefId};
@@ -1470,51 +1470,17 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                 for (key, values) in types.iter() {
                     let count = values.len();
                     let kind = key.descr();
-                    let mut returned_async_output_error = false;
                     for &sp in values {
-                        if sp.is_desugaring(DesugaringKind::Async) && !returned_async_output_error {
-                            if [sp] != err.span.primary_spans() {
-                                let mut span: MultiSpan = sp.into();
-                                span.push_span_label(
-                                    sp,
-                                    format!(
-                                        "checked the `Output` of this `async fn`, {}{} {}{}",
-                                        if count > 1 { "one of the " } else { "" },
-                                        target,
-                                        kind,
-                                        pluralize!(count),
-                                    ),
-                                );
-                                err.span_note(
-                                    span,
-                                    "while checking the return type of the `async fn`",
-                                );
-                            } else {
-                                err.span_label(
-                                    sp,
-                                    format!(
-                                        "checked the `Output` of this `async fn`, {}{} {}{}",
-                                        if count > 1 { "one of the " } else { "" },
-                                        target,
-                                        kind,
-                                        pluralize!(count),
-                                    ),
-                                );
-                                err.note("while checking the return type of the `async fn`");
-                            }
-                            returned_async_output_error = true;
-                        } else {
-                            err.span_label(
-                                sp,
-                                format!(
-                                    "{}{} {}{}",
-                                    if count == 1 { "the " } else { "one of the " },
-                                    target,
-                                    kind,
-                                    pluralize!(count),
-                                ),
-                            );
-                        }
+                        err.span_label(
+                            sp,
+                            format!(
+                                "{}{} {}{}",
+                                if count == 1 { "the " } else { "one of the " },
+                                target,
+                                kind,
+                                pluralize!(count),
+                            ),
+                        );
                     }
                 }
             }
@@ -1537,7 +1503,11 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                     //    |
                     //    = note: expected unit type `()`
                     //                 found closure `[closure@$DIR/issue-20862.rs:2:5: 2:14 x:_]`
-                    if !self.ignore_span.overlaps(span) {
+                    //
+                    // Also ignore opaque `Future`s that come from async fns.
+                    if !self.ignore_span.overlaps(span)
+                        && !span.is_desugaring(DesugaringKind::Async)
+                    {
                         self.types.entry(kind).or_default().insert(span);
                     }
                 }

compiler/rustc_parse/src/errors.rs

@@ -667,13 +667,10 @@ pub(crate) struct InclusiveRangeExtraEquals {
 #[diag(parse_inclusive_range_match_arrow)]
 pub(crate) struct InclusiveRangeMatchArrow {
     #[primary_span]
+    pub arrow: Span,
+    #[label]
     pub span: Span,
-    #[suggestion(
-        suggestion_add_space,
-        style = "verbose",
-        code = " ",
-        applicability = "machine-applicable"
-    )]
+    #[suggestion(style = "verbose", code = " ", applicability = "machine-applicable")]
     pub after_pat: Span,
 }
 

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -2394,7 +2394,7 @@ impl<'a> Parser<'a> {
 
     /// Some special error handling for the "top-level" patterns in a match arm,
     /// `for` loop, `let`, &c. (in contrast to subpatterns within such).
-    pub(crate) fn maybe_recover_colon_colon_in_pat_typo_or_anon_enum(
+    pub(crate) fn maybe_recover_colon_colon_in_pat_typo(
         &mut self,
         mut first_pat: P<Pat>,
         expected: Expected,
@@ -2405,41 +2405,26 @@ impl<'a> Parser<'a> {
         if !matches!(first_pat.kind, PatKind::Ident(_, _, None) | PatKind::Path(..))
             || !self.look_ahead(1, |token| token.is_ident() && !token.is_reserved_ident())
         {
-            let mut snapshot_type = self.create_snapshot_for_diagnostic();
-            snapshot_type.bump(); // `:`
-            match snapshot_type.parse_ty() {
-                Err(inner_err) => {
-                    inner_err.cancel();
-                }
-                Ok(ty) => {
-                    let Err(mut err) = self.expected_one_of_not_found(&[], &[]) else {
-                        return first_pat;
-                    };
-                    err.span_label(ty.span, "specifying the type of a pattern isn't supported");
-                    self.restore_snapshot(snapshot_type);
-                    let span = first_pat.span.to(ty.span);
-                    first_pat = self.mk_pat(span, PatKind::Wild);
-                    err.emit();
-                }
-            }
             return first_pat;
         }
         // The pattern looks like it might be a path with a `::` -> `:` typo:
         // `match foo { bar:baz => {} }`
-        let colon_span = self.token.span;
+        let span = self.token.span;
         // We only emit "unexpected `:`" error here if we can successfully parse the
         // whole pattern correctly in that case.
-        let mut snapshot_pat = self.create_snapshot_for_diagnostic();
-        let mut snapshot_type = self.create_snapshot_for_diagnostic();
+        let snapshot = self.create_snapshot_for_diagnostic();
 
         // Create error for "unexpected `:`".
         match self.expected_one_of_not_found(&[], &[]) {
             Err(mut err) => {
-                snapshot_pat.bump(); // Skip the `:`.
-                snapshot_type.bump(); // Skip the `:`.
-                match snapshot_pat.parse_pat_no_top_alt(expected) {
+                self.bump(); // Skip the `:`.
+                match self.parse_pat_no_top_alt(expected) {
                     Err(inner_err) => {
+                        // Carry on as if we had not done anything, callers will emit a
+                        // reasonable error.
                         inner_err.cancel();
+                        err.cancel();
+                        self.restore_snapshot(snapshot);
                     }
                     Ok(mut pat) => {
                         // We've parsed the rest of the pattern.
@@ -2503,33 +2488,22 @@ impl<'a> Parser<'a> {
                             _ => {}
                         }
                         if show_sugg {
-                            err.span_suggestion_verbose(
-                                colon_span.until(self.look_ahead(1, |t| t.span)),
+                            err.span_suggestion(
+                                span,
                                 "maybe write a path separator here",
                                 "::",
                                 Applicability::MaybeIncorrect,
                             );
                         } else {
                             first_pat = self.mk_pat(new_span, PatKind::Wild);
                         }
-                        self.restore_snapshot(snapshot_pat);
+                        err.emit();
                     }
                 }
-                match snapshot_type.parse_ty() {
-                    Err(inner_err) => {
-                        inner_err.cancel();
-                    }
-                    Ok(ty) => {
-                        err.span_label(ty.span, "specifying the type of a pattern isn't supported");
-                        self.restore_snapshot(snapshot_type);
-                        let new_span = first_pat.span.to(ty.span);
-                        first_pat = self.mk_pat(new_span, PatKind::Wild);
-                    }
-                }
-                err.emit();
             }
             _ => {
                 // Carry on as if we had not done anything. This should be unreachable.
+                self.restore_snapshot(snapshot);
             }
         };
         first_pat

compiler/rustc_parse/src/parser/expr.rs

@@ -2716,6 +2716,14 @@ impl<'a> Parser<'a> {
                     );
                     err.emit();
                     this.bump();
+                } else if matches!(
+                    (&this.prev_token.kind, &this.token.kind),
+                    (token::DotDotEq, token::Gt)
+                ) {
+                    // `error_inclusive_range_match_arrow` handles cases like `0..=> {}`,
+                    // so we supress the error here
+                    err.delay_as_bug();
+                    this.bump();
                 } else {
                     return Err(err);
                 }

compiler/rustc_parse/src/parser/item.rs

@@ -2442,7 +2442,7 @@ impl<'a> Parser<'a> {
 
     /// We are parsing `async fn`. If we are on Rust 2015, emit an error.
     fn ban_async_in_2015(&self, span: Span) {
-        if span.rust_2015() {
+        if span.is_rust_2015() {
             let diag = self.diagnostic();
             struct_span_err!(diag, span, E0670, "`async fn` is not permitted in Rust 2015")
                 .span_label(span, "to use `async fn`, switch to Rust 2018 or later")

compiler/rustc_parse/src/parser/pat.rs

@@ -118,8 +118,7 @@ impl<'a> Parser<'a> {
 
             // Check if the user wrote `foo:bar` instead of `foo::bar`.
             if ra == RecoverColon::Yes {
-                first_pat =
-                    self.maybe_recover_colon_colon_in_pat_typo_or_anon_enum(first_pat, expected);
+                first_pat = self.maybe_recover_colon_colon_in_pat_typo(first_pat, expected);
             }
 
             if let Some(leading_vert_span) = leading_vert_span {
@@ -777,7 +776,7 @@ impl<'a> Parser<'a> {
                 self.error_inclusive_range_with_extra_equals(span_with_eq);
             }
             token::Gt if no_space => {
-                self.error_inclusive_range_match_arrow(span);
+                self.error_inclusive_range_match_arrow(span, tok.span);
             }
             _ => self.error_inclusive_range_with_no_end(span),
         }
@@ -787,9 +786,9 @@ impl<'a> Parser<'a> {
         self.sess.emit_err(InclusiveRangeExtraEquals { span });
     }
 
-    fn error_inclusive_range_match_arrow(&self, span: Span) {
+    fn error_inclusive_range_match_arrow(&self, span: Span, arrow: Span) {
         let after_pat = span.with_hi(span.hi() - rustc_span::BytePos(1)).shrink_to_hi();
-        self.sess.emit_err(InclusiveRangeMatchArrow { span, after_pat });
+        self.sess.emit_err(InclusiveRangeMatchArrow { span, arrow, after_pat });
     }
 
     fn error_inclusive_range_with_no_end(&self, span: Span) {
@@ -1013,12 +1012,15 @@ impl<'a> Parser<'a> {
             }
             ate_comma = false;
 
-            if self.check(&token::DotDot) || self.token == token::DotDotDot {
+            if self.check(&token::DotDot)
+                || self.check_noexpect(&token::DotDotDot)
+                || self.check_keyword(kw::Underscore)
+            {
                 etc = true;
                 let mut etc_sp = self.token.span;
 
-                self.recover_one_fewer_dotdot();
-                self.bump(); // `..` || `...`
+                self.recover_bad_dot_dot();
+                self.bump(); // `..` || `...` || `_`
 
                 if self.token == token::CloseDelim(Delimiter::Brace) {
                     etc_span = Some(etc_sp);
@@ -1111,21 +1113,25 @@ impl<'a> Parser<'a> {
         Ok((fields, etc))
     }
 
-    /// Recover on `...` as if it were `..` to avoid further errors.
+    /// Recover on `...` or `_` as if it were `..` to avoid further errors.
     /// See issue #46718.
-    fn recover_one_fewer_dotdot(&self) {
-        if self.token != token::DotDotDot {
+    fn recover_bad_dot_dot(&self) {
+        if self.token == token::DotDot {
             return;
         }
 
-        self.struct_span_err(self.token.span, "expected field pattern, found `...`")
-            .span_suggestion(
-                self.token.span,
-                "to omit remaining fields, use one fewer `.`",
-                "..",
-                Applicability::MachineApplicable,
-            )
-            .emit();
+        let token_str = pprust::token_to_string(&self.token);
+        self.struct_span_err(
+            self.token.span,
+            format!("expected field pattern, found `{token_str}`"),
+        )
+        .span_suggestion_verbose(
+            self.token.span,
+            "to omit remaining fields, use `..`",
+            "..",
+            Applicability::MachineApplicable,
+        )
+        .emit();
     }
 
     fn parse_pat_field(&mut self, lo: Span, attrs: AttrVec) -> PResult<'a, PatField> {