Mostly parser: Eliminate code that's been dead / semi-dead since the removal of type ascription syntax

compiler/rustc_ast/src/ast.rs

@@ -545,14 +545,6 @@ pub struct Block {
     pub rules: BlockCheckMode,
     pub span: Span,
     pub tokens: Option<LazyAttrTokenStream>,
-    /// The following *isn't* a parse error, but will cause multiple errors in following stages.
-    /// ```compile_fail
-    /// let x = {
-    ///     foo: var
-    /// };
-    /// ```
-    /// #34255
-    pub could_be_bare_literal: bool,
 }
 
 /// A match pattern.

compiler/rustc_ast/src/mut_visit.rs

@@ -1225,7 +1225,7 @@ fn walk_mt<T: MutVisitor>(vis: &mut T, MutTy { ty, mutbl: _ }: &mut MutTy) {
 }
 
 pub fn walk_block<T: MutVisitor>(vis: &mut T, block: &mut P<Block>) {
-    let Block { id, stmts, rules: _, span, tokens, could_be_bare_literal: _ } = block.deref_mut();
+    let Block { id, stmts, rules: _, span, tokens } = block.deref_mut();
     vis.visit_id(id);
     stmts.flat_map_in_place(|stmt| vis.flat_map_stmt(stmt));
     visit_lazy_tts(vis, tokens);

compiler/rustc_ast/src/visit.rs

@@ -1035,7 +1035,7 @@ pub fn walk_field_def<'a, V: Visitor<'a>>(visitor: &mut V, field: &'a FieldDef)
 }
 
 pub fn walk_block<'a, V: Visitor<'a>>(visitor: &mut V, block: &'a Block) -> V::Result {
-    let Block { stmts, id: _, rules: _, span: _, tokens: _, could_be_bare_literal: _ } = block;
+    let Block { stmts, id: _, rules: _, span: _, tokens: _ } = block;
     walk_list!(visitor, visit_stmt, stmts);
     V::Result::output()
 }

compiler/rustc_builtin_macros/src/autodiff.rs

@@ -395,7 +395,6 @@ mod llvm_enzyme {
             tokens: None,
             rules: unsf,
             span,
-            could_be_bare_literal: false,
         };
         let unsf_expr = ecx.expr_block(P(unsf_block));
         let blackbox_call_expr = ecx.expr_path(ecx.path(span, blackbox_path));

compiler/rustc_builtin_macros/src/deriving/mod.rs

@@ -110,7 +110,6 @@ fn call_unreachable(cx: &ExtCtxt<'_>, span: Span) -> P<ast::Expr> {
         rules: ast::BlockCheckMode::Unsafe(ast::CompilerGenerated),
         span,
         tokens: None,
-        could_be_bare_literal: false,
     }))
 }
 

compiler/rustc_expand/src/build.rs

@@ -286,7 +286,6 @@ impl<'a> ExtCtxt<'a> {
             rules: BlockCheckMode::Default,
             span,
             tokens: None,
-            could_be_bare_literal: false,
         })
     }
 

compiler/rustc_parse/messages.ftl

@@ -757,10 +757,6 @@ parse_struct_literal_body_without_path =
     struct literal body without path
     .suggestion = you might have forgotten to add the struct literal inside the block
 
-parse_struct_literal_needing_parens =
-    invalid struct literal
-    .suggestion = you might need to surround the struct literal with parentheses
-
 parse_struct_literal_not_allowed_here = struct literals are not allowed here
     .suggestion = surround the struct literal with parentheses
 

compiler/rustc_parse/src/errors.rs

@@ -1272,24 +1272,6 @@ pub(crate) struct StructLiteralBodyWithoutPathSugg {
     pub after: Span,
 }
 
-#[derive(Diagnostic)]
-#[diag(parse_struct_literal_needing_parens)]
-pub(crate) struct StructLiteralNeedingParens {
-    #[primary_span]
-    pub span: Span,
-    #[subdiagnostic]
-    pub sugg: StructLiteralNeedingParensSugg,
-}
-
-#[derive(Subdiagnostic)]
-#[multipart_suggestion(parse_suggestion, applicability = "machine-applicable")]
-pub(crate) struct StructLiteralNeedingParensSugg {
-    #[suggestion_part(code = "(")]
-    pub before: Span,
-    #[suggestion_part(code = ")")]
-    pub after: Span,
-}
-
 #[derive(Diagnostic)]
 #[diag(parse_unmatched_angle_brackets)]
 pub(crate) struct UnmatchedAngleBrackets {

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -40,9 +40,8 @@ use crate::errors::{
     HelpIdentifierStartsWithNumber, HelpUseLatestEdition, InInTypo, IncorrectAwait,
     IncorrectSemicolon, IncorrectUseOfAwait, IncorrectUseOfUse, PatternMethodParamWithoutBody,
     QuestionMarkInType, QuestionMarkInTypeSugg, SelfParamNotFirst, StructLiteralBodyWithoutPath,
-    StructLiteralBodyWithoutPathSugg, StructLiteralNeedingParens, StructLiteralNeedingParensSugg,
-    SuggAddMissingLetStmt, SuggEscapeIdentifier, SuggRemoveComma, TernaryOperator,
-    UnexpectedConstInGenericParam, UnexpectedConstParamDeclaration,
+    StructLiteralBodyWithoutPathSugg, SuggAddMissingLetStmt, SuggEscapeIdentifier, SuggRemoveComma,
+    TernaryOperator, UnexpectedConstInGenericParam, UnexpectedConstParamDeclaration,
     UnexpectedConstParamDeclarationSugg, UnmatchedAngleBrackets, UseEqInstead, WrapType,
 };
 use crate::parser::attr::InnerAttrPolicy;
@@ -949,7 +948,6 @@ impl<'a> Parser<'a> {
         lo: Span,
         s: BlockCheckMode,
         maybe_struct_name: token::Token,
-        can_be_struct_literal: bool,
     ) -> Option<PResult<'a, P<Block>>> {
         if self.token.is_ident() && self.look_ahead(1, |t| t == &token::Colon) {
             // We might be having a struct literal where people forgot to include the path:
@@ -975,47 +973,23 @@ impl<'a> Parser<'a> {
                     // fn foo() -> Foo { Path {
                     //     field: value,
                     // } }
-                    let guar = err.delay_as_bug();
+                    err.cancel();
                     self.restore_snapshot(snapshot);
-                    let mut tail = self.mk_block(
+                    let guar = self.dcx().emit_err(StructLiteralBodyWithoutPath {
+                        span: expr.span,
+                        sugg: StructLiteralBodyWithoutPathSugg {
+                            before: expr.span.shrink_to_lo(),
+                            after: expr.span.shrink_to_hi(),
+                        },
+                    });
+                    Ok(self.mk_block(
                         thin_vec![self.mk_stmt_err(expr.span, guar)],
                         s,
                         lo.to(self.prev_token.span),
-                    );
-                    tail.could_be_bare_literal = true;
-                    if maybe_struct_name.is_ident() && can_be_struct_literal {
-                        // Account for `if Example { a: one(), }.is_pos() {}`.
-                        // expand `before` so that we take care of module path such as:
-                        // `foo::Bar { ... } `
-                        // we expect to suggest `(foo::Bar { ... })` instead of `foo::(Bar { ... })`
-                        let sm = self.psess.source_map();
-                        let before = maybe_struct_name.span.shrink_to_lo();
-                        if let Ok(extend_before) = sm.span_extend_prev_while(before, |t| {
-                            t.is_alphanumeric() || t == ':' || t == '_'
-                        }) {
-                            Err(self.dcx().create_err(StructLiteralNeedingParens {
-                                span: maybe_struct_name.span.to(expr.span),
-                                sugg: StructLiteralNeedingParensSugg {
-                                    before: extend_before.shrink_to_lo(),
-                                    after: expr.span.shrink_to_hi(),
-                                },
-                            }))
-                        } else {
-                            return None;
-                        }
-                    } else {
-                        self.dcx().emit_err(StructLiteralBodyWithoutPath {
-                            span: expr.span,
-                            sugg: StructLiteralBodyWithoutPathSugg {
-                                before: expr.span.shrink_to_lo(),
-                                after: expr.span.shrink_to_hi(),
-                            },
-                        });
-                        Ok(tail)
-                    }
+                    ))
                 }
                 (Err(err), Ok(tail)) => {
-                    // We have a block tail that contains a somehow valid type ascription expr.
+                    // We have a block tail that contains a somehow valid expr.
                     err.cancel();
                     Ok(tail)
                 }
@@ -1025,10 +999,7 @@ impl<'a> Parser<'a> {
                     self.consume_block(exp!(OpenBrace), exp!(CloseBrace), ConsumeClosingDelim::Yes);
                     Err(err)
                 }
-                (Ok(_), Ok(mut tail)) => {
-                    tail.could_be_bare_literal = true;
-                    Ok(tail)
-                }
+                (Ok(_), Ok(tail)) => Ok(tail),
             });
         }
         None

compiler/rustc_parse/src/parser/expr.rs

@@ -2296,7 +2296,7 @@ impl<'a> Parser<'a> {
             });
         }
 
-        let (attrs, blk) = self.parse_block_common(lo, blk_mode, true, None)?;
+        let (attrs, blk) = self.parse_block_common(lo, blk_mode, None)?;
         Ok(self.mk_expr_with_attrs(blk.span, ExprKind::Block(blk, opt_label), attrs))
     }
 
@@ -3474,19 +3474,9 @@ impl<'a> Parser<'a> {
     }
 
     fn is_certainly_not_a_block(&self) -> bool {
+        // `{ ident, ` and `{ ident: ` cannot start a block.
         self.look_ahead(1, |t| t.is_ident())
-            && (
-                // `{ ident, ` cannot start a block.
-                self.look_ahead(2, |t| t == &token::Comma)
-                    || self.look_ahead(2, |t| t == &token::Colon)
-                        && (
-                            // `{ ident: token, ` cannot start a block.
-                            self.look_ahead(4, |t| t == &token::Comma)
-                                // `{ ident: ` cannot start a block unless it's a type ascription
-                                // `ident: Type`.
-                                || self.look_ahead(3, |t| !t.can_begin_type())
-                        )
-            )
+            && self.look_ahead(2, |t| t == &token::Comma || t == &token::Colon)
     }
 
     fn maybe_parse_struct_expr(

compiler/rustc_parse/src/parser/item.rs

@@ -2529,7 +2529,7 @@ impl<'a> Parser<'a> {
             *sig_hi = self.prev_token.span;
             (AttrVec::new(), None)
         } else if self.check(exp!(OpenBrace)) || self.token.is_whole_block() {
-            self.parse_block_common(self.token.span, BlockCheckMode::Default, false, None)
+            self.parse_block_common(self.token.span, BlockCheckMode::Default, None)
                 .map(|(attrs, body)| (attrs, Some(body)))?
         } else if self.token == token::Eq {
             // Recover `fn foo() = $expr;`.

compiler/rustc_parse/src/parser/stmt.rs

@@ -668,7 +668,7 @@ impl<'a> Parser<'a> {
         &mut self,
         loop_header: Option<Span>,
     ) -> PResult<'a, (AttrVec, P<Block>)> {
-        self.parse_block_common(self.token.span, BlockCheckMode::Default, true, loop_header)
+        self.parse_block_common(self.token.span, BlockCheckMode::Default, loop_header)
     }
 
     /// Parses a block. Inner attributes are allowed, block labels are not.
@@ -679,7 +679,6 @@ impl<'a> Parser<'a> {
         &mut self,
         lo: Span,
         blk_mode: BlockCheckMode,
-        can_be_struct_literal: bool,
         loop_header: Option<Span>,
     ) -> PResult<'a, (AttrVec, P<Block>)> {
         maybe_whole!(self, NtBlock, |block| (AttrVec::new(), block));
@@ -691,12 +690,7 @@ impl<'a> Parser<'a> {
         }
 
         let attrs = self.parse_inner_attributes()?;
-        let tail = match self.maybe_suggest_struct_literal(
-            lo,
-            blk_mode,
-            maybe_ident,
-            can_be_struct_literal,
-        ) {
+        let tail = match self.maybe_suggest_struct_literal(lo, blk_mode, maybe_ident) {
             Some(tail) => tail?,
             None => self.parse_block_tail(lo, blk_mode, AttemptLocalParseRecovery::Yes)?,
         };
@@ -1043,14 +1037,7 @@ impl<'a> Parser<'a> {
         rules: BlockCheckMode,
         span: Span,
     ) -> P<Block> {
-        P(Block {
-            stmts,
-            id: DUMMY_NODE_ID,
-            rules,
-            span,
-            tokens: None,
-            could_be_bare_literal: false,
-        })
+        P(Block { stmts, id: DUMMY_NODE_ID, rules, span, tokens: None })
     }
 
     pub(super) fn mk_stmt(&self, span: Span, kind: StmtKind) -> Stmt {

compiler/rustc_resolve/src/late.rs

@@ -674,11 +674,6 @@ struct DiagMetadata<'ast> {
     /// they are used (in a `break` or `continue` statement)
     unused_labels: FxHashMap<NodeId, Span>,
 
-    /// Only used for better errors on `let x = { foo: bar };`.
-    /// In the case of a parse error with `let x = { foo: bar, };`, this isn't needed, it's only
-    /// needed for cases where this parses as a correct type ascription.
-    current_block_could_be_bare_struct_literal: Option<Span>,
-
     /// Only used for better errors on `let <pat>: <expr, not type>;`.
     current_let_binding: Option<(Span, Option<Span>, Option<Span>)>,
 
@@ -4650,13 +4645,6 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
             self.ribs[ValueNS].push(Rib::new(RibKind::Normal));
         }
 
-        let prev = self.diag_metadata.current_block_could_be_bare_struct_literal.take();
-        if let (true, [Stmt { kind: StmtKind::Expr(expr), .. }]) =
-            (block.could_be_bare_literal, &block.stmts[..])
-            && let ExprKind::Type(..) = expr.kind
-        {
-            self.diag_metadata.current_block_could_be_bare_struct_literal = Some(block.span);
-        }
         // Descend into the block.
         for stmt in &block.stmts {
             if let StmtKind::Item(ref item) = stmt.kind
@@ -4670,7 +4658,6 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
 
             self.visit_stmt(stmt);
         }
-        self.diag_metadata.current_block_could_be_bare_struct_literal = prev;
 
         // Move back up.
         self.parent_scope.module = orig_module;

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -450,7 +450,6 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
             err.span_suggestion_verbose(sugg.0, sugg.1, &sugg.2, Applicability::MaybeIncorrect);
         }
 
-        self.suggest_bare_struct_literal(&mut err);
         self.suggest_changing_type_to_const_param(&mut err, res, source, span);
         self.explain_functions_in_pattern(&mut err, res, source);
 
@@ -1281,19 +1280,6 @@ impl<'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
         }
     }
 
-    fn suggest_bare_struct_literal(&mut self, err: &mut Diag<'_>) {
-        if let Some(span) = self.diag_metadata.current_block_could_be_bare_struct_literal {
-            err.multipart_suggestion(
-                "you might have meant to write a `struct` literal",
-                vec![
-                    (span.shrink_to_lo(), "{ SomeStruct ".to_string()),
-                    (span.shrink_to_hi(), "}".to_string()),
-                ],
-                Applicability::HasPlaceholders,
-            );
-        }
-    }
-
     fn explain_functions_in_pattern(
         &mut self,
         err: &mut Diag<'_>,

src/tools/rustfmt/src/closures.rs

@@ -176,7 +176,6 @@ fn rewrite_closure_with_block(
             .first()
             .map(|attr| attr.span.to(body.span))
             .unwrap_or(body.span),
-        could_be_bare_literal: false,
     };
     let block = crate::expr::rewrite_block_with_visitor(
         context,

src/tools/rustfmt/src/macros.rs

@@ -423,7 +423,6 @@ fn rewrite_empty_macro_def_body(
         rules: ast::BlockCheckMode::Default,
         span,
         tokens: None,
-        could_be_bare_literal: false,
     };
     block.rewrite_result(context, shape)
 }

src/tools/tidy/src/issues.txt

@@ -3189,7 +3189,6 @@ ui/parser/issues/issue-108495-dec.rs
 ui/parser/issues/issue-110014.rs
 ui/parser/issues/issue-111148.rs
 ui/parser/issues/issue-111416.rs
-ui/parser/issues/issue-111692.rs
 ui/parser/issues/issue-112188.rs
 ui/parser/issues/issue-112458.rs
 ui/parser/issues/issue-113110-non-item-at-module-root.rs

tests/ui-fulldeps/pprust-expr-roundtrip.rs

@@ -114,7 +114,6 @@ fn iter_exprs(depth: usize, f: &mut dyn FnMut(P<Expr>)) {
                     rules: BlockCheckMode::Default,
                     span: DUMMY_SP,
                     tokens: None,
-                    could_be_bare_literal: false,
                 });
                 iter_exprs(depth - 1, &mut |e| g(ExprKind::If(e, block.clone(), None)));
             }