Don't unnecessarily stringify paths in diagnostics

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

@@ -165,13 +165,13 @@ parser_use_empty_block_not_semi = expected { "`{}`" }, found `;`
     .suggestion = try using { "`{}`" } instead
 
 parser_comparison_interpreted_as_generic =
-    `<` is interpreted as a start of generic arguments for `{$typename}`, not a comparison
+    `<` is interpreted as a start of generic arguments for `{$type}`, not a comparison
     .label_args = interpreted as generic arguments
     .label_comparison = not interpreted as comparison
     .suggestion = try comparing the cast value
 
 parser_shift_interpreted_as_generic =
-    `<<` is interpreted as a start of generic arguments for `{$typename}`, not a shift
+    `<<` is interpreted as a start of generic arguments for `{$type}`, not a shift
     .label_args = interpreted as generic arguments
     .label_comparison = not interpreted as shift
     .suggestion = try shifting the cast value
@@ -184,8 +184,8 @@ parser_leading_plus_not_supported = leading `+` is not supported
     .suggestion_remove_plus = try removing the `+`
 
 parser_parentheses_with_struct_fields = invalid `struct` delimiters or `fn` call arguments
-    .suggestion_braces_for_struct = if `{$name}` is a struct, use braces as delimiters
+    .suggestion_braces_for_struct = if `{$type}` is a struct, use braces as delimiters
-    .suggestion_no_fields_for_fn = if `{$name}` is a function, use the arguments directly
+    .suggestion_no_fields_for_fn = if `{$type}` is a function, use the arguments directly
 
 parser_labeled_loop_in_break = parentheses are required around this expression to avoid confusion with a labeled break expression
 

compiler/rustc_parse/src/errors.rs

@@ -1,3 +1,4 @@
+use rustc_ast::Path;
 use rustc_errors::{fluent, AddToDiagnostic, Applicability, EmissionGuarantee, IntoDiagnostic};
 use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_session::errors::ExprParenthesesNeeded;
@@ -536,7 +537,7 @@ pub(crate) struct ComparisonInterpretedAsGeneric {
     #[primary_span]
     #[label(parser::label_comparison)]
     pub comparison: Span,
-    pub typename: String,
+    pub r#type: Path,
     #[label(parser::label_args)]
     pub args: Span,
     #[subdiagnostic]
@@ -549,7 +550,7 @@ pub(crate) struct ShiftInterpretedAsGeneric {
     #[primary_span]
     #[label(parser::label_comparison)]
     pub shift: Span,
-    pub typename: String,
+    pub r#type: Path,
     #[label(parser::label_args)]
     pub args: Span,
     #[subdiagnostic]
@@ -597,7 +598,7 @@ pub(crate) struct LeadingPlusNotSupported {
 pub(crate) struct ParenthesesWithStructFields {
     #[primary_span]
     pub span: Span,
-    pub name: String,
+    pub r#type: Path,
     #[subdiagnostic]
     pub braces_for_struct: BracesForStructLiteral,
     #[subdiagnostic]

compiler/rustc_parse/src/parser/expr.rs

@@ -756,11 +756,12 @@ impl<'a> Parser<'a> {
 
                 match self.parse_path(PathStyle::Expr) {
                     Ok(path) => {
-                        let typename = pprust::path_to_string(&path);
-
                         let span_after_type = parser_snapshot_after_type.token.span;
-                        let expr =
+                        let expr = mk_expr(
-                            mk_expr(self, lhs, self.mk_ty(path.span, TyKind::Path(None, path)));
+                            self,
+                            lhs,
+                            self.mk_ty(path.span, TyKind::Path(None, path.clone())),
+                        );
 
                         let args_span = self.look_ahead(1, |t| t.span).to(span_after_type);
                         let suggestion = ComparisonOrShiftInterpretedAsGenericSugg {
@@ -771,14 +772,14 @@ impl<'a> Parser<'a> {
                         match self.token.kind {
                             token::Lt => self.sess.emit_err(ComparisonInterpretedAsGeneric {
                                 comparison: self.token.span,
-                                typename,
+                                r#type: path,
                                 args: args_span,
                                 suggestion,
                             }),
                             token::BinOp(token::Shl) => {
                                 self.sess.emit_err(ShiftInterpretedAsGeneric {
                                     shift: self.token.span,
-                                    typename,
+                                    r#type: path,
                                     args: args_span,
                                     suggestion,
                                 })
@@ -1197,9 +1198,8 @@ impl<'a> Parser<'a> {
     ) -> Option<P<Expr>> {
         match (seq.as_mut(), snapshot) {
             (Err(err), Some((mut snapshot, ExprKind::Path(None, path)))) => {
-                let name = pprust::path_to_string(&path);
                 snapshot.bump(); // `(`
-                match snapshot.parse_struct_fields(path, false, Delimiter::Parenthesis) {
+                match snapshot.parse_struct_fields(path.clone(), false, Delimiter::Parenthesis) {
                     Ok((fields, ..))
                         if snapshot.eat(&token::CloseDelim(Delimiter::Parenthesis)) =>
                     {
@@ -1211,7 +1211,7 @@ impl<'a> Parser<'a> {
                         if !fields.is_empty() {
                             let mut replacement_err = ParenthesesWithStructFields {
                                 span,
-                                name,
+                                r#type: path,
                                 braces_for_struct: BracesForStructLiteral {
                                     first: open_paren,
                                     second: close_paren,