Increase test coverage of use_nested_groups

src/test/ui/use-nested-groups-error.rs

@@ -0,0 +1,27 @@
+// Copyright 2018 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.
+
+#![feature(use_nested_groups)]
+
+mod a {
+    pub mod b1 {
+        pub enum C2 {}
+    }
+
+    pub enum B2 {}
+}
+
+use a::{b1::{C1, C2}, B2};
+//~^ ERROR unresolved import `a::b1::C1`
+
+fn main() {
+    let _: C2;
+    let _: B2;
+}