most specific check: ensure that functional types are specifically checked when method is not generics (IDEA-136287)

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/mostSpecific/FunctionalTypeComparisonWhenMethodsAreNotGeneric.java

@@ -0,0 +1,30 @@
+class ATest {
+
+  private void test(Function<ATest, String> nameF) {
+    Function<ATest, String> aTestStringFunction  = nameF.andThen(ATest::withUnderscore);
+    Function<ATest, String> aTestStringFunction1 = nameF.andThen((s) -> {return ATest.withUnderscore(s);});
+    Function<ATest, String> aTestStringFunction2 = nameF.andThen((String s) -> ATest.withUnderscore(s));
+
+    System.out.println(aTestStringFunction);
+    System.out.println(aTestStringFunction1);
+    System.out.println(aTestStringFunction2);
+  }
+
+  static String withUnderscore(String s) {
+    return "";
+  }
+}
+
+@FunctionalInterface
+interface Function<A, R> {
+
+  R apply(A a);
+
+  default <C> Function<A, C> andThen(Function<R, ? extends C> g) { return null;}
+  default Function1V<A> andThen(Function1V<R> g) {return null;}
+}
+
+@FunctionalInterface
+interface Function1V<A> {
+  void apply(A a);
+}