Auto merge of #77524 - Patryk27:fixes/66228, r=estebank

Rework diagnostics for wrong number of generic args (fixes #66228 and #71924)

This PR reworks the `wrong number of {} arguments` message, so that it provides more details and contextual hints.

1 files changed, 2 insertions, 1 deletions

diff --git a/compiler/rustc_parse/src/parser/path.rs b/compiler/rustc_parse/src/parser/path.rs
index 43dee391c17..dd36122f6a1 100644
--- a/compiler/rustc_parse/src/parser/path.rs
+++ b/compiler/rustc_parse/src/parser/path.rs
@@ -230,10 +230,11 @@ impl<'a> Parser<'a> {
                 } else {
                     // `(T, U) -> R`
                     let (inputs, _) = self.parse_paren_comma_seq(|p| p.parse_ty())?;
+                    let inputs_span = lo.to(self.prev_token.span);
                     let span = ident.span.to(self.prev_token.span);
                     let output =
                         self.parse_ret_ty(AllowPlus::No, RecoverQPath::No, RecoverReturnSign::No)?;
-                    ParenthesizedArgs { inputs, output, span }.into()
+                    ParenthesizedArgs { span, inputs, inputs_span, output }.into()
                 };
 
                 PathSegment { ident, args, id: ast::DUMMY_NODE_ID }