Add alt-pattern-lit.rs test.

Author: graydon

src/test/run-pass/alt-pattern-lit.rs

@@ -0,0 +1,17 @@
+fn altlit(int f) -> int {
+  alt (f) {
+    case (10) {
+      log "case 10";
+      ret 20;
+    }
+    case (11) {
+      log "case 11";
+      ret 22;
+    }
+  }
+}
+
+fn main() {
+  check (altlit(10) == 20);
+  check (altlit(11) == 22);
+}