Add a test for uninhabitedness changes

src/test/ui/always-inhabited-union-ref.rs

@@ -0,0 +1,29 @@
+#![feature(exhaustive_patterns)]
+#![feature(never_type)]
+
+#![allow(dead_code)]
+#![allow(unreachable_code)]
+
+pub union Foo {
+    foo: !,
+}
+
+fn uninhab_ref() -> &'static ! {
+    unimplemented!()
+}
+
+fn uninhab_union() -> Foo {
+    unimplemented!()
+}
+
+fn match_on_uninhab() {
+    match uninhab_ref() {
+        //~^ ERROR non-exhaustive patterns: type &'static ! is non-empty
+    }
+
+    match uninhab_union() {
+        //~^ ERROR non-exhaustive patterns: type Foo is non-empty
+    }
+}
+
+fn main() {}

src/test/ui/always-inhabited-union-ref.stderr

@@ -0,0 +1,27 @@
+error[E0004]: non-exhaustive patterns: type &'static ! is non-empty
+  --> $DIR/always-inhabited-union-ref.rs:20:11
+   |
+LL |     match uninhab_ref() {
+   |           ^^^^^^^^^^^^^
+   |
+help: ensure that all possible cases are being handled, possibly by adding wildcards or more match arms
+  --> $DIR/always-inhabited-union-ref.rs:20:11
+   |
+LL |     match uninhab_ref() {
+   |           ^^^^^^^^^^^^^
+
+error[E0004]: non-exhaustive patterns: type Foo is non-empty
+  --> $DIR/always-inhabited-union-ref.rs:24:11
+   |
+LL |     match uninhab_union() {
+   |           ^^^^^^^^^^^^^^^
+   |
+help: ensure that all possible cases are being handled, possibly by adding wildcards or more match arms
+  --> $DIR/always-inhabited-union-ref.rs:24:11
+   |
+LL |     match uninhab_union() {
+   |           ^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0004`.

src/test/ui/inhabitedness-infinite-loop.rs

@@ -1,26 +0,0 @@
-// Copyright 2012-2014 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.
-
-// error-pattern:reached recursion limit
-
-#![feature(never_type)]
-#![feature(exhaustive_patterns)]
-
-struct Foo<'a, T: 'a> {
-    ph: std::marker::PhantomData<T>,
-    foo: &'a Foo<'a, (T, T)>,
-}
-
-fn wub(f: Foo<!>) {
-    match f {}
-}
-
-fn main() {}
-