method references: don't infer Object when no constraint exist for 'raw' reference (IDEA-171922)

java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/constraints/PsiMethodReferenceCompatibilityConstraint.java

@@ -252,6 +252,10 @@ public class PsiMethodReferenceCompatibilityConstraint implements ConstraintForm
           LOG.assertTrue(paramTypes.length == signature.getParameterTypes().length, "expr: " + methodReferenceExpression + "; " +
                                                                                     paramTypes.length + "; " +
                                                                                     Arrays.toString(signature.getParameterTypes()));
+          if (Arrays.deepEquals(signature.getParameterTypes(), paramTypes)) {
+            return PsiSubstitutor.EMPTY;
+          }
+
           psiSubstitutor = helper.inferTypeArguments(PsiTypesUtil.filterUnusedTypeParameters(qContainingClass.getTypeParameters(), paramTypes),
                                                      paramTypes,
                                                      signature.getParameterTypes(),

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

@@ -0,0 +1,18 @@
+
+import java.util.List;
+import java.util.function.Function;
+
+
+class Foo<T extends Comparable<T>> {
+
+  public Foo(final Foo<T> tuple) { }
+
+  {
+    List<Foo<T>> l = bar(Foo::new);
+  }
+
+  public<U> List<U> bar(Function<Foo<T>, U> mapper) {
+    return null;
+  }
+
+}

java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/NewMethodRefHighlightingTest.java

@@ -172,6 +172,7 @@ public class NewMethodRefHighlightingTest extends LightDaemonAnalyzerTestCase {
   public void testIncludeOnlyTypeParametersUsedInParameterTypesExcludeThoseUsedInReturnOnly() { doTest(); }
   public void testMethodREfToContainingMethodWithGenericParam() { doTest(); }
   public void testDistinguishCapturedWildcardsByDifferentParameters() throws Exception { doTest(); }
+  public void testConstructorRefOnClassWithRecursiveTypeParameter() throws Exception { doTest(); }
 
   private void doTest() {
     doTest(false);