java completion: no case enumConstant suggestions where inapplicable (IDEA-168749)

java/java-tests/testData/codeInsight/completion/normal/InsideSwitchCaseWithEnumConstant.java

@@ -0,0 +1,13 @@
+class A extends Base{
+  void foo(B b){
+    switch(b) {
+        case FOO:
+          b.<caret>
+    }
+  }
+}
+
+enum B{
+  FOO, BAR, GOO
+}
+