auto merge of #14253 : alexcrichton/rust/issue-14221, r=pcwalton

This plugs a leak where resolve was treating enums defined in parent modules as
in-scope for all children modules when resolving a pattern identifier. This
eliminates the code path in resolve entirely.

If this breaks any existing code, then it indicates that the variants need to be
explicitly imported into the module.

Closes #14221

src/test/compile-fail/issue-14221.rs

@@ -0,0 +1,25 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+pub enum E {
+    A,
+    B,
+}
+
+pub mod b {
+    pub fn key(e: ::E) -> &'static str {
+        match e {
+            A => "A",
+            B => "B", //~ ERROR: unreachable pattern
+        }
+    }
+}
+
+fn main() {}