Emit clearer diagnostics for parens around `for` loop heads

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

diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index cdc1d1cf99f3c842b1615488cc0f2a050c3f1c57..ab7478c7e5faab52fdc65295c0dcf25f8c9861cb 100644 (file)
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -446,11 +446,13 @@ pub fn maybe_suggest_struct_literal(
                         )
                         .emit();
                     *self = snapshot;
-                    Ok(self.mk_block(
+                    let mut tail = self.mk_block(
                         vec![self.mk_stmt_err(expr.span)],
                         s,
                         lo.to(self.prev_token.span),
-                    ))
+                    );
+                    tail.could_be_bare_literal = true;
+                    Ok(tail)
                 }
                 (Err(mut err), Ok(tail)) => {
                     // We have a block tail that contains a somehow valid type ascription expr.
@@ -463,7 +465,10 @@ pub fn maybe_suggest_struct_literal(
                     self.consume_block(token::Brace, ConsumeClosingDelim::Yes);
                     Err(err)
                 }
-                (Ok(_), Ok(tail)) => Ok(tail),
+                (Ok(_), Ok(mut tail)) => {
+                    tail.could_be_bare_literal = true;
+                    Ok(tail)
+                }
             });
         }
         None
@@ -1341,8 +1346,9 @@ pub(super) fn recover_parens_around_for_head(
                     .span_to_snippet(pat.span.trim_start(begin_par_sp).unwrap())
                     .unwrap_or_else(|_| pprust::pat_to_string(&pat));
 
-                self.struct_span_err(self.prev_token.span, "unexpected closing `)`")
-                    .span_label(begin_par_sp, "opening `(`")
+                let sp = MultiSpan::from_spans(vec![begin_par_sp, self.prev_token.span]);
+
+                self.struct_span_err(sp, "unexpected parenthesis surrounding `for` loop head")
                     .span_suggestion(
                         begin_par_sp.to(self.prev_token.span),
                         "remove parenthesis in `for` loop",
@@ -1628,50 +1634,57 @@ pub(super) fn parameter_without_type(
         {
             let rfc_note = "anonymous parameters are removed in the 2018 edition (see RFC 1685)";
 
-            let (ident, self_sugg, param_sugg, type_sugg) = match pat.kind {
-                PatKind::Ident(_, ident, _) => (
-                    ident,
-                    format!("self: {}", ident),
-                    format!("{}: TypeName", ident),
-                    format!("_: {}", ident),
-                ),
-                // Also catches `fn foo(&a)`.
-                PatKind::Ref(ref pat, mutab)
-                    if matches!(pat.clone().into_inner().kind, PatKind::Ident(..)) =>
-                {
-                    match pat.clone().into_inner().kind {
-                        PatKind::Ident(_, ident, _) => {
-                            let mutab = mutab.prefix_str();
-                            (
-                                ident,
-                                format!("self: &{}{}", mutab, ident),
-                                format!("{}: &{}TypeName", ident, mutab),
-                                format!("_: &{}{}", mutab, ident),
-                            )
+            let (ident, self_sugg, param_sugg, type_sugg, self_span, param_span, type_span) =
+                match pat.kind {
+                    PatKind::Ident(_, ident, _) => (
+                        ident,
+                        "self: ".to_string(),
+                        ": TypeName".to_string(),
+                        "_: ".to_string(),
+                        pat.span.shrink_to_lo(),
+                        pat.span.shrink_to_hi(),
+                        pat.span.shrink_to_lo(),
+                    ),
+                    // Also catches `fn foo(&a)`.
+                    PatKind::Ref(ref inner_pat, mutab)
+                        if matches!(inner_pat.clone().into_inner().kind, PatKind::Ident(..)) =>
+                    {
+                        match inner_pat.clone().into_inner().kind {
+                            PatKind::Ident(_, ident, _) => {
+                                let mutab = mutab.prefix_str();
+                                (
+                                    ident,
+                                    "self: ".to_string(),
+                                    format!("{}: &{}TypeName", ident, mutab),
+                                    "_: ".to_string(),
+                                    pat.span.shrink_to_lo(),
+                                    pat.span,
+                                    pat.span.shrink_to_lo(),
+                                )
+                            }
+                            _ => unreachable!(),
                         }
-                        _ => unreachable!(),
-                    }
-                }
-                _ => {
-                    // Otherwise, try to get a type and emit a suggestion.
-                    if let Some(ty) = pat.to_ty() {
-                        err.span_suggestion_verbose(
-                            pat.span,
-                            "explicitly ignore the parameter name",
-                            format!("_: {}", pprust::ty_to_string(&ty)),
-                            Applicability::MachineApplicable,
-                        );
-                        err.note(rfc_note);
                     }
+                    _ => {
+                        // Otherwise, try to get a type and emit a suggestion.
+                        if let Some(ty) = pat.to_ty() {
+                            err.span_suggestion_verbose(
+                                pat.span,
+                                "explicitly ignore the parameter name",
+                                format!("_: {}", pprust::ty_to_string(&ty)),
+                                Applicability::MachineApplicable,
+                            );
+                            err.note(rfc_note);
+                        }
 
-                    return None;
-                }
-            };
+                        return None;
+                    }
+                };
 
             // `fn foo(a, b) {}`, `fn foo(a<x>, b<y>) {}` or `fn foo(usize, usize) {}`
             if first_param {
                 err.span_suggestion(
-                    pat.span,
+                    self_span,
                     "if this is a `self` type, give it a parameter name",
                     self_sugg,
                     Applicability::MaybeIncorrect,
@@ -1681,14 +1694,14 @@ pub(super) fn parameter_without_type(
             // `fn foo(HashMap: TypeName<u32>)`.
             if self.token != token::Lt {
                 err.span_suggestion(
-                    pat.span,
+                    param_span,
                     "if this is a parameter name, give it a type",
                     param_sugg,
                     Applicability::HasPlaceholders,
                 );
             }
             err.span_suggestion(
-                pat.span,
+                type_span,
                 "if this is a type, explicitly ignore the parameter name",
                 type_sugg,
                 Applicability::MachineApplicable,