Merge pull request #19826 from lnicola/sync-from-rust

minor: Sync from downstream

5 files changed, 70 insertions, 17 deletions

diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index 23c8db7bca7..6277dde7c97 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -41,8 +41,9 @@ use crate::errors::{
     IncorrectSemicolon, IncorrectUseOfAwait, IncorrectUseOfUse, PatternMethodParamWithoutBody,
     QuestionMarkInType, QuestionMarkInTypeSugg, SelfParamNotFirst, StructLiteralBodyWithoutPath,
     StructLiteralBodyWithoutPathSugg, SuggAddMissingLetStmt, SuggEscapeIdentifier, SuggRemoveComma,
-    TernaryOperator, UnexpectedConstInGenericParam, UnexpectedConstParamDeclaration,
-    UnexpectedConstParamDeclarationSugg, UnmatchedAngleBrackets, UseEqInstead, WrapType,
+    TernaryOperator, TernaryOperatorSuggestion, UnexpectedConstInGenericParam,
+    UnexpectedConstParamDeclaration, UnexpectedConstParamDeclarationSugg, UnmatchedAngleBrackets,
+    UseEqInstead, WrapType,
 };
 use crate::parser::attr::InnerAttrPolicy;
 use crate::{exp, fluent_generated as fluent};
@@ -497,7 +498,7 @@ impl<'a> Parser<'a> {
             // If the user is trying to write a ternary expression, recover it and
             // return an Err to prevent a cascade of irrelevant diagnostics.
             if self.prev_token == token::Question
-                && let Err(e) = self.maybe_recover_from_ternary_operator()
+                && let Err(e) = self.maybe_recover_from_ternary_operator(None)
             {
                 return Err(e);
             }
@@ -1602,12 +1603,18 @@ impl<'a> Parser<'a> {
     /// Rust has no ternary operator (`cond ? then : else`). Parse it and try
     /// to recover from it if `then` and `else` are valid expressions. Returns
     /// an err if this appears to be a ternary expression.
-    pub(super) fn maybe_recover_from_ternary_operator(&mut self) -> PResult<'a, ()> {
+    /// If we have the span of the condition, we can provide a better error span
+    /// and code suggestion.
+    pub(super) fn maybe_recover_from_ternary_operator(
+        &mut self,
+        cond: Option<Span>,
+    ) -> PResult<'a, ()> {
         if self.prev_token != token::Question {
             return PResult::Ok(());
         }
 
-        let lo = self.prev_token.span.lo();
+        let question = self.prev_token.span;
+        let lo = cond.unwrap_or(question).lo();
         let snapshot = self.create_snapshot_for_diagnostic();
 
         if match self.parse_expr() {
@@ -1620,11 +1627,20 @@ impl<'a> Parser<'a> {
             }
         } {
             if self.eat_noexpect(&token::Colon) {
+                let colon = self.prev_token.span;
                 match self.parse_expr() {
-                    Ok(_) => {
-                        return Err(self
-                            .dcx()
-                            .create_err(TernaryOperator { span: self.token.span.with_lo(lo) }));
+                    Ok(expr) => {
+                        let sugg = cond.map(|cond| TernaryOperatorSuggestion {
+                            before_cond: cond.shrink_to_lo(),
+                            question,
+                            colon,
+                            end: expr.span.shrink_to_hi(),
+                        });
+                        return Err(self.dcx().create_err(TernaryOperator {
+                            span: self.prev_token.span.with_lo(lo),
+                            sugg,
+                            no_sugg: sugg.is_none(),
+                        }));
                     }
                     Err(err) => {
                         err.cancel();
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index f3b53971b29..2a7910a6af4 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -3828,7 +3828,7 @@ impl<'a> Parser<'a> {
         // Convert `label` -> `'label`,
         // so that nameres doesn't complain about non-existing label
         let label = format!("'{}", ident.name);
-        let ident = Ident { name: Symbol::intern(&label), span: ident.span };
+        let ident = Ident::new(Symbol::intern(&label), ident.span);
 
         self.dcx().emit_err(errors::ExpectedLabelFoundIdent {
             span: ident.span,
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index 4be8a90368d..babc55ccc0f 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -2894,7 +2894,7 @@ impl<'a> Parser<'a> {
         let (mut params, _) = self.parse_paren_comma_seq(|p| {
             p.recover_vcs_conflict_marker();
             let snapshot = p.create_snapshot_for_diagnostic();
-            let param = p.parse_param_general(req_name, first_param).or_else(|e| {
+            let param = p.parse_param_general(req_name, first_param, true).or_else(|e| {
                 let guar = e.emit();
                 // When parsing a param failed, we should check to make the span of the param
                 // not contain '(' before it.
@@ -2922,7 +2922,13 @@ impl<'a> Parser<'a> {
     /// Parses a single function parameter.
     ///
     /// - `self` is syntactically allowed when `first_param` holds.
-    fn parse_param_general(&mut self, req_name: ReqName, first_param: bool) -> PResult<'a, Param> {
+    /// - `recover_arg_parse` is used to recover from a failed argument parse.
+    pub(super) fn parse_param_general(
+        &mut self,
+        req_name: ReqName,
+        first_param: bool,
+        recover_arg_parse: bool,
+    ) -> PResult<'a, Param> {
         let lo = self.token.span;
         let attrs = self.parse_outer_attributes()?;
         self.collect_tokens(None, attrs, ForceCollect::No, |this, attrs| {
@@ -2990,12 +2996,13 @@ impl<'a> Parser<'a> {
                     // If this is a C-variadic argument and we hit an error, return the error.
                     Err(err) if this.token == token::DotDotDot => return Err(err),
                     Err(err) if this.unmatched_angle_bracket_count > 0 => return Err(err),
-                    // Recover from attempting to parse the argument as a type without pattern.
-                    Err(err) => {
+                    Err(err) if recover_arg_parse => {
+                        // Recover from attempting to parse the argument as a type without pattern.
                         err.cancel();
                         this.restore_snapshot(parser_snapshot_before_ty);
                         this.recover_arg_parse()?
                     }
+                    Err(err) => return Err(err),
                 }
             };
 
diff --git a/compiler/rustc_parse/src/parser/path.rs b/compiler/rustc_parse/src/parser/path.rs
index 1093e4f4af0..9bce2fa74ca 100644
--- a/compiler/rustc_parse/src/parser/path.rs
+++ b/compiler/rustc_parse/src/parser/path.rs
@@ -15,7 +15,11 @@ use tracing::debug;
 
 use super::ty::{AllowPlus, RecoverQPath, RecoverReturnSign};
 use super::{Parser, Restrictions, TokenType};
-use crate::errors::{self, PathSingleColon, PathTripleColon};
+use crate::ast::{PatKind, TyKind};
+use crate::errors::{
+    self, FnPathFoundNamedParams, PathFoundAttributeInParams, PathFoundCVariadicParams,
+    PathSingleColon, PathTripleColon,
+};
 use crate::exp;
 use crate::parser::{CommaRecoveryMode, RecoverColon, RecoverComma};
 
@@ -396,7 +400,28 @@ impl<'a> Parser<'a> {
                         snapshot = Some(self.create_snapshot_for_diagnostic());
                     }
 
-                    let (inputs, _) = match self.parse_paren_comma_seq(|p| p.parse_ty()) {
+                    let dcx = self.dcx();
+                    let parse_params_result = self.parse_paren_comma_seq(|p| {
+                        let param = p.parse_param_general(|_| false, false, false);
+                        param.map(move |param| {
+                            if !matches!(param.pat.kind, PatKind::Missing) {
+                                dcx.emit_err(FnPathFoundNamedParams {
+                                    named_param_span: param.pat.span,
+                                });
+                            }
+                            if matches!(param.ty.kind, TyKind::CVarArgs) {
+                                dcx.emit_err(PathFoundCVariadicParams { span: param.pat.span });
+                            }
+                            if !param.attrs.is_empty() {
+                                dcx.emit_err(PathFoundAttributeInParams {
+                                    span: param.attrs[0].span,
+                                });
+                            }
+                            param.ty
+                        })
+                    });
+
+                    let (inputs, _) = match parse_params_result {
                         Ok(output) => output,
                         Err(mut error) if prev_token_before_parsing == token::PathSep => {
                             error.span_label(
diff --git a/compiler/rustc_parse/src/parser/stmt.rs b/compiler/rustc_parse/src/parser/stmt.rs
index 885a65d4de7..396ded96bde 100644
--- a/compiler/rustc_parse/src/parser/stmt.rs
+++ b/compiler/rustc_parse/src/parser/stmt.rs
@@ -879,7 +879,12 @@ impl<'a> Parser<'a> {
             {
                 // Just check for errors and recover; do not eat semicolon yet.
 
-                let expect_result = self.expect_one_of(&[], &[exp!(Semi), exp!(CloseBrace)]);
+                let expect_result =
+                    if let Err(e) = self.maybe_recover_from_ternary_operator(Some(expr.span)) {
+                        Err(e)
+                    } else {
+                        self.expect_one_of(&[], &[exp!(Semi), exp!(CloseBrace)])
+                    };
 
                 // Try to both emit a better diagnostic, and avoid further errors by replacing
                 // the `expr` with `ExprKind::Err`.