Add helper methods checking for "#[non_exhaustive] that's active"

A check for `#[non_exhaustive]` is often done in combination with
checking whether the type is local to the crate, in a variety of ways.
Create a helper method and standardize on it as the way to check for
this.

2 files changed, 4 insertions, 5 deletions

diff --git a/compiler/rustc_mir_build/src/builder/matches/match_pair.rs b/compiler/rustc_mir_build/src/builder/matches/match_pair.rs
index c6f3e22e95f..c41538a2817 100644
--- a/compiler/rustc_mir_build/src/builder/matches/match_pair.rs
+++ b/compiler/rustc_mir_build/src/builder/matches/match_pair.rs
@@ -277,8 +277,7 @@ impl<'tcx> MatchPairTree<'tcx> {
                             .inhabited_predicate(cx.tcx, adt_def)
                             .instantiate(cx.tcx, args)
                             .apply_ignore_module(cx.tcx, cx.infcx.typing_env(cx.param_env))
-                }) && (adt_def.did().is_local()
-                    || !adt_def.is_variant_list_non_exhaustive());
+                }) && !adt_def.variant_list_has_applicable_non_exhaustive();
                 if irrefutable { None } else { Some(TestCase::Variant { adt_def, variant_index }) }
             }
 
diff --git a/compiler/rustc_mir_build/src/errors.rs b/compiler/rustc_mir_build/src/errors.rs
index 17b22f25dbb..0e16f871b16 100644
--- a/compiler/rustc_mir_build/src/errors.rs
+++ b/compiler/rustc_mir_build/src/errors.rs
@@ -613,9 +613,9 @@ impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for NonExhaustivePatternsTypeNo
             diag.span_note(span, fluent::mir_build_def_note);
         }
 
-        let is_variant_list_non_exhaustive = matches!(self.ty.kind(),
-            ty::Adt(def, _) if def.is_variant_list_non_exhaustive() && !def.did().is_local());
-        if is_variant_list_non_exhaustive {
+        let is_non_exhaustive = matches!(self.ty.kind(),
+            ty::Adt(def, _) if def.variant_list_has_applicable_non_exhaustive());
+        if is_non_exhaustive {
             diag.note(fluent::mir_build_non_exhaustive_type_note);
         } else {
             diag.note(fluent::mir_build_type_note);