Add tests for the combination of anonymous labels and a guard

Author: smowton

java/ql/test/library-tests/switch-default-impossible-dispatch/Test.java

@@ -66,6 +66,14 @@ case WrapperWrapper(Wrapper(String s)) -> { }
         i.take(source()); // Can't call C1.take or C2.take (but we don't currently notice, because a multi-pattern case isn't understood as a type test)
     }
 
+    switch(i) {
+      case C1 _, C2 _ when i.toString().equals("abc"):
+        i.take(source()); // Must be either C1.take or C2.take (but we don't currently notice, because neither dominates)
+        break;
+      default: 
+        i.take(source()); // Can't call C1.take or C2.take (but we don't currently notice, because a multi-pattern case isn't understood as a type test)
+    }
+
     switch(i) {
       case C1 _:
       case C2 _:

java/ql/test/library-tests/switch-default-impossible-dispatch/test.expected

@@ -38,9 +38,17 @@
 | Test.java:66:16:66:23 | source(...) | Test.java:8:65:8:65 | x |
 | Test.java:66:16:66:23 | source(...) | Test.java:9:74:9:74 | x |
 | Test.java:66:16:66:23 | source(...) | Test.java:10:82:10:82 | x |
-| Test.java:72:16:72:23 | source(...) | Test.java:7:65:7:65 | x |
-| Test.java:72:16:72:23 | source(...) | Test.java:8:65:8:65 | x |
-| Test.java:72:16:72:23 | source(...) | Test.java:9:74:9:74 | x |
-| Test.java:72:16:72:23 | source(...) | Test.java:10:82:10:82 | x |
-| Test.java:75:16:75:23 | source(...) | Test.java:9:74:9:74 | x |
-| Test.java:75:16:75:23 | source(...) | Test.java:10:82:10:82 | x |
+| Test.java:71:16:71:23 | source(...) | Test.java:7:65:7:65 | x |
+| Test.java:71:16:71:23 | source(...) | Test.java:8:65:8:65 | x |
+| Test.java:71:16:71:23 | source(...) | Test.java:9:74:9:74 | x |
+| Test.java:71:16:71:23 | source(...) | Test.java:10:82:10:82 | x |
+| Test.java:74:16:74:23 | source(...) | Test.java:7:65:7:65 | x |
+| Test.java:74:16:74:23 | source(...) | Test.java:8:65:8:65 | x |
+| Test.java:74:16:74:23 | source(...) | Test.java:9:74:9:74 | x |
+| Test.java:74:16:74:23 | source(...) | Test.java:10:82:10:82 | x |
+| Test.java:80:16:80:23 | source(...) | Test.java:7:65:7:65 | x |
+| Test.java:80:16:80:23 | source(...) | Test.java:8:65:8:65 | x |
+| Test.java:80:16:80:23 | source(...) | Test.java:9:74:9:74 | x |
+| Test.java:80:16:80:23 | source(...) | Test.java:10:82:10:82 | x |
+| Test.java:83:16:83:23 | source(...) | Test.java:9:74:9:74 | x |
+| Test.java:83:16:83:23 | source(...) | Test.java:10:82:10:82 | x |