resolve: Adjust hygienic_lexical_parent to account for enum and trait modules

Author: petrochenkov

src/librustc_resolve/lib.rs

@@ -1644,7 +1644,7 @@ impl<'a> Resolver<'a> {
         }
 
         if let ModuleKind::Block(..) = module.kind {
-            return Some(module.parent.unwrap());
+            return Some(module.parent.unwrap().nearest_item_scope());
         }
 
         None

src/test/ui/resolve/block-with-trait-parent.rs

@@ -0,0 +1,14 @@
+// check-pass
+
+trait Trait {
+    fn method(&self) {
+        // Items inside a block turn it into a module internally.
+        struct S;
+        impl Trait for S {}
+
+        // OK, `Trait` is in scope here from method resolution point of view.
+        S.method();
+    }
+}
+
+fn main() {}