Add test for #7950

Closes #7950

src/test/compile-fail/issue-7950.rs

@@ -0,0 +1,17 @@
+// Copyright 2015 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.
+
+// tests the good error message, not "missing module Foo" or something else unexpected
+
+struct Foo;
+
+fn main() {
+    Foo::bar(); //~ ERROR type `Foo` does not implement any method in scope named `bar`
+}