Be explicit about whether GenericArgCountMismatch arose from a fatal error

Author: varkor

src/librustc_typeck/astconv.rs

@@ -134,7 +134,8 @@ enum GenericArgPosition {
 
 /// A marker denoting that the generic arguments that were
 /// provided did not match the respective generic parameters.
-pub struct GenericArgCountMismatch;
+/// The field indicates whether a fatal error was reported (`Some`), or just a lint (`None`).
+pub struct GenericArgCountMismatch(pub Option<ErrorReported>);
 
 impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
     pub fn ast_region_to_region(
@@ -320,18 +321,19 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         let mut explicit_lifetimes = Ok(());
         if !infer_lifetimes {
             if let Some(span_late) = def.has_late_bound_regions {
-                explicit_lifetimes = Err(GenericArgCountMismatch);
                 let msg = "cannot specify lifetime arguments explicitly \
                            if late bound lifetime parameters are present";
                 let note = "the late bound lifetime parameter is introduced here";
                 let span = args.args[0].span();
                 if position == GenericArgPosition::Value
                     && arg_counts.lifetimes != param_counts.lifetimes
                 {
+                    explicit_lifetimes = Err(GenericArgCountMismatch(Some(ErrorReported)));
                     let mut err = tcx.sess.struct_span_err(span, msg);
                     err.span_note(span_late, note);
                     err.emit();
                 } else {
+                    explicit_lifetimes = Err(GenericArgCountMismatch(None));
                     let mut multispan = MultiSpan::from_span(span);
                     multispan.push_span_label(span_late, note.to_string());
                     tcx.struct_span_lint_hir(
@@ -405,7 +407,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 }
                 err.emit();
 
-                Err(GenericArgCountMismatch)
+                Err(GenericArgCountMismatch(Some(ErrorReported)))
             };
 
         let mut arg_count_correct = explicit_lifetimes;

src/librustc_typeck/check/mod.rs

@@ -5452,11 +5452,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // parameter internally, but we don't allow users to specify the
             // parameter's value explicitly, so we have to do some error-
             // checking here.
-            let suppress_errors = AstConv::check_generic_arg_count_for_call(
-                tcx, span, &generics, &seg, false, // `is_method_call`
-            )
-            .is_err();
-            if suppress_errors {
+            if let Err(GenericArgCountMismatch(Some(ErrorReported))) =
+                AstConv::check_generic_arg_count_for_call(
+                    tcx, span, &generics, &seg, false, // `is_method_call`
+                )
+            {
                 infer_args_for_err.insert(index);
                 self.set_tainted_by_errors(); // See issue #53251.
             }
@@ -5521,7 +5521,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 &[][..],
                 has_self,
                 self_ty,
-                if infer_args_for_err.is_empty() { Ok(()) } else { Err(GenericArgCountMismatch) },
+                if infer_args_for_err.is_empty() {
+                    Ok(())
+                } else {
+                    Err(GenericArgCountMismatch(Some(ErrorReported)))
+                },
                 // Provide the generic args, and whether types should be inferred.
                 |def_id| {
                     if let Some(&PathSeg(_, index)) =