skip inference for incompatible method references

EA-103416 - assert: PsiMethodReferenceCompatibilityConstraint.getSubstitutor

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

@@ -249,10 +249,11 @@ public class PsiMethodReferenceCompatibilityConstraint implements ConstraintForm
           final PsiResolveHelper helper = JavaPsiFacade.getInstance(methodReferenceExpression.getProject()).getResolveHelper();
           final PsiType[] paramTypes =
             member instanceof PsiMethod ? ((PsiMethod)member).getSignature(PsiSubstitutor.EMPTY).getParameterTypes() : PsiType.EMPTY_ARRAY;
-          LOG.assertTrue(paramTypes.length == signature.getParameterTypes().length || 
-                         member instanceof PsiMethod && ((PsiMethod)member).isVarArgs(), "expr: " + methodReferenceExpression + "; " +
-                                                                                    paramTypes.length + "; " +
-                                                                                    Arrays.toString(signature.getParameterTypes()));
+
+          if (paramTypes.length != signature.getParameterTypes().length && !(member instanceof PsiMethod && ((PsiMethod)member).isVarArgs())) {
+            //inapplicable method reference
+            return PsiSubstitutor.EMPTY;
+          }
           if (Arrays.deepEquals(signature.getParameterTypes(), paramTypes)) {
             return PsiSubstitutor.EMPTY;
           }

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

@@ -0,0 +1,10 @@
+import java.util.function.IntFunction;
+
+class Outer<K> {
+  public Outer() { }
+
+  {
+    //wrong number of parameters as well as a wrong expected type
+    final IntFunction<Outer[]> aNew = <error descr="Bad return type in method reference: cannot convert Outer to Outer[]">Outer::new</error>;
+  }
+}

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

@@ -179,6 +179,7 @@ public class NewMethodRefHighlightingTest extends LightDaemonAnalyzerTestCase {
   public void testConstructorReferenceWithVarargsParameters() { doTest(); }
   public void testMethodReferenceSwallowedErrors() { doTest(); }
   public void testConflictingVarargsFromFirstSearchWithNArityOfTheSecondSearch() { doTest(); }
+  public void testSkipInferenceForInapplicableMethodReference() { doTest(); }
 
   public void testPreferErrorOnTopLevelToFailedSubstitutorOnNestedLevel() { doTest(); }