enum variant ctor inherits stability of variant

compiler/rustc_passes/src/stability.rs

@@ -460,7 +460,7 @@ fn visit_variant(&mut self, var: &'tcx Variant<'tcx>) {
                         AnnotationKind::Required,
                         InheritDeprecation::Yes,
                         InheritConstStability::No,
-                        InheritStability::No,
+                        InheritStability::Yes,
                         |_| {},
                     );
                 }

src/test/ui/stability-attribute/auxiliary/ctor-stability.rs

@@ -0,0 +1,8 @@
+#![crate_type = "lib"]
+#![feature(staged_api)]
+#![stable(feature = "none", since = "1.0")]
+
+#[stable(feature = "none", since = "1.0")]
+pub enum Foo {
+    A,
+}

src/test/ui/stability-attribute/ctor-stability.rs

@@ -0,0 +1,8 @@
+// aux-build:ctor-stability.rs
+// check-pass
+
+extern crate ctor_stability;
+
+fn main() {
+    let _ = ctor_stability::Foo::A;
+}