Rollup merge of #93400 - ChayimFriedman2:dont-suggest-using-const-with-bounds-unused...

[rust.git] / compiler / rustc_parse / src / parser / expr.rs

diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index e9aa4adcaf79bae5faddf019378d84bf3f8b5e29..a11cb3f5677c6fb8aeab0df15e86158406aee326 100644 (file)
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -17,7 +17,7 @@
 use rustc_ast::{AnonConst, BinOp, BinOpKind, FnDecl, FnRetTy, MacCall, Param, Ty, TyKind};
 use rustc_ast::{Arm, Async, BlockCheckMode, Expr, ExprKind, Label, Movability, RangeLimits};
 use rustc_ast_pretty::pprust;
-use rustc_errors::{Applicability, DiagnosticBuilder, PResult};
+use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, ErrorReported, PResult};
 use rustc_session::lint::builtin::BREAK_WITH_LABEL_AND_LOOP;
 use rustc_session::lint::BuiltinLintDiagnostics;
 use rustc_span::edition::LATEST_STABLE_EDITION;
@@ -372,10 +372,17 @@ fn should_continue_as_assoc_expr(&mut self, lhs: &Expr) -> bool {
                 self.sess.ambiguous_block_expr_parse.borrow_mut().insert(sp, lhs.span);
                 false
             }
-            (true, Some(AssocOp::LAnd)) => {
+            (true, Some(AssocOp::LAnd)) |
+            (true, Some(AssocOp::LOr)) |
+            (true, Some(AssocOp::BitOr)) => {
                 // `{ 42 } &&x` (#61475) or `{ 42 } && if x { 1 } else { 0 }`. Separated from the
                 // above due to #74233.
                 // These cases are ambiguous and can't be identified in the parser alone.
+                //
+                // Bitwise AND is left out because guessing intent is hard. We can make
+                // suggestions based on the assumption that double-refs are rarely intentional,
+                // and closures are distinct enough that they don't get mixed up with their
+                // return value.
                 let sp = self.sess.source_map().start_point(self.token.span);
                 self.sess.ambiguous_block_expr_parse.borrow_mut().insert(sp, lhs.span);
                 false
@@ -684,7 +691,7 @@ fn parse_assoc_op_cast(
         let parser_snapshot_before_type = self.clone();
         let cast_expr = match self.parse_as_cast_ty() {
             Ok(rhs) => mk_expr(self, lhs, rhs),
-            Err(mut type_err) => {
+            Err(type_err) => {
                 // Rewind to before attempting to parse the type with generics, to recover
                 // from situations like `x as usize < y` in which we first tried to parse
                 // `usize < y` as a type with generic arguments.
@@ -717,7 +724,7 @@ fn parse_assoc_op_cast(
                                     .emit();
                                 return Ok(expr);
                             }
-                            Err(mut err) => {
+                            Err(err) => {
                                 err.cancel();
                                 *self = snapshot;
                             }
@@ -773,7 +780,7 @@ fn parse_assoc_op_cast(
 
                         expr
                     }
-                    Err(mut path_err) => {
+                    Err(path_err) => {
                         // Couldn't parse as a path, return original error and parser state.
                         path_err.cancel();
                         *self = parser_snapshot_after_type;
@@ -1127,7 +1134,7 @@ fn maybe_recover_struct_lit_bad_delims(
         snapshot: Option<(Self, ExprKind)>,
     ) -> Option<P<Expr>> {
         match (seq.as_mut(), snapshot) {
-            (Err(ref mut err), Some((mut snapshot, ExprKind::Path(None, path)))) => {
+            (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, token::Paren) {
@@ -1138,11 +1145,12 @@ fn maybe_recover_struct_lit_bad_delims(
                         let close_paren = self.prev_token.span;
                         let span = lo.to(self.prev_token.span);
                         if !fields.is_empty() {
-                            err.cancel();
-                            let mut err = self.struct_span_err(
+                            let replacement_err = self.struct_span_err(
                                 span,
                                 "invalid `struct` delimiters or `fn` call arguments",
                             );
+                            mem::replace(err, replacement_err).cancel();
+
                             err.multipart_suggestion(
                                 &format!("if `{}` is a struct, use braces as delimiters", name),
                                 vec![
@@ -1166,7 +1174,9 @@ fn maybe_recover_struct_lit_bad_delims(
                         return Some(self.mk_expr_err(span));
                     }
                     Ok(_) => {}
-                    Err(mut err) => err.emit(),
+                    Err(mut err) => {
+                        err.emit();
+                    }
                 }
             }
             _ => {}
@@ -1244,7 +1254,14 @@ fn parse_bottom_expr(&mut self) -> PResult<'a, P<Expr>> {
         } else if self.check(&token::OpenDelim(token::Brace)) {
             self.parse_block_expr(None, lo, BlockCheckMode::Default, attrs)
         } else if self.check(&token::BinOp(token::Or)) || self.check(&token::OrOr) {
-            self.parse_closure_expr(attrs)
+            self.parse_closure_expr(attrs).map_err(|mut err| {
+                // If the input is something like `if a { 1 } else { 2 } | if a { 3 } else { 4 }`
+                // then suggest parens around the lhs.
+                if let Some(sp) = self.sess.ambiguous_block_expr_parse.borrow().get(&lo) {
+                    self.sess.expr_parentheses_needed(&mut err, *sp);
+                }
+                err
+            })
         } else if self.check(&token::OpenDelim(token::Bracket)) {
             self.parse_array_or_repeat_expr(attrs, token::Bracket)
         } else if self.check_path() {
@@ -1622,9 +1639,11 @@ pub(super) fn parse_lit(&mut self) -> PResult<'a, Lit> {
                 };
                 if let Some(expr) = expr {
                     if matches!(expr.kind, ExprKind::Err) {
-                        self.diagnostic()
-                            .delay_span_bug(self.token.span, &"invalid interpolated expression");
-                        return self.diagnostic().struct_dummy();
+                        let mut err = self
+                            .diagnostic()
+                            .struct_span_err(self.token.span, &"invalid interpolated expression");
+                        err.downgrade_to_delayed_bug();
+                        return err;
                     }
                 }
             }
@@ -1667,9 +1686,8 @@ pub(super) fn parse_opt_lit(&mut self) -> Option<Lit> {
             Err(LitError::NotLiteral) => None,
             Err(err) => {
                 let span = token.span;
-                let lit = match token.kind {
-                    token::Literal(lit) => lit,
-                    _ => unreachable!(),
+                let token::Literal(lit) = token.kind else {
+                    unreachable!();
                 };
                 self.bump();
                 self.report_lit_error(err, lit, span);
@@ -1817,6 +1835,7 @@ pub(super) fn expect_no_suffix(&self, sp: Span, kind: &str, suffix: Option<Symbo
                 err
             } else {
                 self.struct_span_err(sp, &format!("suffixes on {} are invalid", kind))
+                    .forget_guarantee()
             };
             err.span_label(sp, format!("invalid suffix `{}`", suf));
             err.emit();
@@ -1877,7 +1896,7 @@ fn maybe_suggest_brackets_instead_of_braces(
                 *self = snapshot;
                 Some(self.mk_expr_err(arr.span))
             }
-            Err(mut e) => {
+            Err(e) => {
                 e.cancel();
                 None
             }
@@ -2098,9 +2117,9 @@ fn parse_if_expr(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
     fn error_missing_if_then_block(
         &self,
         if_span: Span,
-        err: Option<DiagnosticBuilder<'a>>,
+        err: Option<DiagnosticBuilder<'a, ErrorReported>>,
         binop_span: Option<Span>,
-    ) -> DiagnosticBuilder<'a> {
+    ) -> DiagnosticBuilder<'a, ErrorReported> {
         let msg = "this `if` expression has a condition, but no block";
 
         let mut err = if let Some(mut err) = err {
@@ -2380,7 +2399,7 @@ fn parse_arm_body_missing_braces(
                         return Some(err(self, stmts));
                     }
                 }
-                Err(mut err) => {
+                Err(err) => {
                     err.cancel();
                 }
             }
@@ -2397,7 +2416,7 @@ fn parse_arm_body_missing_braces(
                 }
                 // We couldn't parse either yet another statement missing it's
                 // enclosing block nor the next arm's pattern or closing brace.
-                Err(mut stmt_err) => {
+                Err(stmt_err) => {
                     stmt_err.cancel();
                     *self = start_snapshot;
                     break;
@@ -2654,7 +2673,7 @@ pub(super) fn parse_struct_fields(
         let mut base = ast::StructRest::None;
         let mut recover_async = false;
 
-        let mut async_block_err = |e: &mut DiagnosticBuilder<'_>, span: Span| {
+        let mut async_block_err = |e: &mut Diagnostic, span: Span| {
             recover_async = true;
             e.span_label(span, "`async` blocks are only allowed in Rust 2018 or later");
             e.help(&format!("set `edition = \"{}\"` in `Cargo.toml`", LATEST_STABLE_EDITION));