java: single underscore variables highlighting for Java 8

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/highlighting/Underscores.java

@@ -0,0 +1,16 @@
+class C {
+  void test() {
+    {
+      I <warning descr="Use of '_' as an identifier might not be supported in releases after Java 8">_</warning> = new I() { public void f(int i) { } };
+      accept(_);
+    }
+
+    {
+      accept(<error descr="Use of '_' as a lambda parameter name is not allowed">_</error> -> System.out.println(_));
+      accept((int <error descr="Use of '_' as a lambda parameter name is not allowed">_</error>) -> System.out.println(_));
+    }
+  }
+
+  interface I { void f(int i); }
+  void accept(I i) { i.f(42); }
+}