warn about compilable code which would lead to runtime ClassCastException in addition to unchecked warning which nobody understands (IDEA-154345)

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting7/RuntimeClassCast.java

@@ -0,0 +1,10 @@
+class Test {
+  <S extends Runnable> S f() {
+    return null;
+  }
+
+  {
+    String m  <warning descr="Though assignment is formal correct, it could lead to ClassCastException at runtime. Expected: 'String', actual: 'Runnable & String'">=</warning> f();
+    System.out.println(m);
+  }
+}