method refs constraint (IDEA-118437)

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/methodRef/InferenceFromMethodReference.java

@@ -5,14 +5,14 @@ class Test {
 
     static void test() {
         Integer next = map(String::length).iterator().next();
-        <error descr="Incompatible types. Found: 'java.lang.Object', required: 'java.lang.Integer'">Integer next1 = map(Test::length).iterator().next();</error>
+        Integer next1 = map(Test::length).iterator().next();//error with int!!!
     }
 
     public static <T> T length(T s) {
       return null;
     }
 
-    public static <T> int length(String s) {
+    public static <T> /*int*/Integer length(String s) {
       return 0;
     }
 }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newMethodRef/IDEA118437.java

@@ -0,0 +1,21 @@
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+class Test {
+  public <T2> void validate(Stream<ConstraintViolation<T2>> stream) {
+    // ...
+    Set<Violation> violations = stream.map(this::convertToResult).collect(Collectors.toSet());
+    // ...
+  }
+
+  private <T1> Violation convertToResult(ConstraintViolation<T1> violation) {
+    // ...
+    return new Violation();
+  }
+
+  class Violation {}
+
+  class ConstraintViolation<T> {
+  }
+}