A few tests for infinite loops

src/test/compile-fail/loop-does-not-diverge.rs

@@ -0,0 +1,13 @@
+// error-pattern:some control paths may return
+/* Make sure a loop{} with a break in it can't be
+   the tailexpr in the body of a diverging function */
+fn forever() -> ! {
+  loop {
+    break;
+  }
+  ret 42;
+}
+
+fn main() {
+  if (1 == 2) { forever(); }
+}

src/test/run-pass/loop-diverges.rs

@@ -0,0 +1,10 @@
+/* Make sure a loop{} can be the tailexpr in the body
+of a diverging function */
+
+fn forever() -> ! {
+  loop{}
+}
+
+fn main() {
+  if (1 == 2) { forever(); }
+}