java 8: resolve conflicts choosing more specific return type (IDEA-98845)

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

@@ -0,0 +1,30 @@
+class IntStream {
+  private void foo(IntStream s) {
+    s.map(i -> 1 << i);
+    s.map(i -> 1);
+    s.map(i -> i);
+  }
+
+  public static void main(String[] args) {
+    new IntStream().foo(null);
+  }
+
+  private IntStream map(IntUnaryOperator mapper) {
+    System.out.println(mapper);
+    return null;
+  }
+
+  private <T> IntStream <warning descr="Private method 'map(ObjIntFunction<T>)' is never used">map</warning>(ObjIntFunction<T> mapper) {
+    System.out.println(mapper);
+    return null;
+  }
+}
+
+interface IntUnaryOperator {
+  public int applyAsInt(int operand);
+}
+
+interface ObjIntFunction<T> {
+  public T apply(int i);
+}
+