2 files changed, 8 insertions, 3 deletions
diff --git a/compiler/rustc_hir_analysis/src/astconv/mod.rs b/compiler/rustc_hir_analysis/src/astconv/mod.rs
index 78740ac33ca..9f4f1413650 100644
--- a/compiler/rustc_hir_analysis/src/astconv/mod.rs
+++ b/compiler/rustc_hir_analysis/src/astconv/mod.rs
@@ -2659,7 +2659,11 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                         self.suggest_trait_fn_ty_for_impl_fn_infer(hir_id, Some(i))
                     {
                         infer_replacements.push((a.span, suggested_ty.to_string()));
-                        return suggested_ty;
+                        return Ty::new_error_with_message(
+                            self.tcx(),
+                            a.span,
+                            suggested_ty.to_string(),
+                        );
                     }
                 }
 
@@ -2677,7 +2681,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                         self.suggest_trait_fn_ty_for_impl_fn_infer(hir_id, None)
                 {
                     infer_replacements.push((output.span, suggested_ty.to_string()));
-                    suggested_ty
+                    Ty::new_error_with_message(self.tcx(), output.span, suggested_ty.to_string())
                 } else {
                     visitor.visit_ty(output);
                     self.ast_ty_to_ty(output)
diff --git a/compiler/rustc_hir_analysis/src/lib.rs b/compiler/rustc_hir_analysis/src/lib.rs
index dfc54ac5b23..d4f08b12a18 100644
--- a/compiler/rustc_hir_analysis/src/lib.rs
+++ b/compiler/rustc_hir_analysis/src/lib.rs
@@ -116,7 +116,8 @@ use rustc_hir::def::DefKind;
 rustc_fluent_macro::fluent_messages! { "../messages.ftl" }
 
 fn require_c_abi_if_c_variadic(tcx: TyCtxt<'_>, decl: &hir::FnDecl<'_>, abi: Abi, span: Span) {
-    const CONVENTIONS_UNSTABLE: &str = "`C`, `cdecl`, `aapcs`, `win64`, `sysv64` or `efiapi`";
+    const CONVENTIONS_UNSTABLE: &str =
+        "`C`, `cdecl`, `system`, `aapcs`, `win64`, `sysv64` or `efiapi`";
     const CONVENTIONS_STABLE: &str = "`C` or `cdecl`";
     const UNSTABLE_EXPLAIN: &str =
         "using calling conventions other than `C` or `cdecl` for varargs functions is unstable";