false positive in redundant cast: applicable method with inference error (IDEA-186224)

java/java-psi-api/src/com/intellij/psi/util/RedundantCastUtil.java

@@ -402,7 +402,8 @@ public class RedundantCastUtil {
                 (!(newCall instanceof PsiCallExpression) ||
                  oldAnonymousClass != null && newAnonymousClass != null && Comparing.equal(oldAnonymousClass.getBaseClassType(), newAnonymousClass.getBaseClassType()) ||
                  Comparing.equal(PsiUtil.recaptureWildcards(((PsiCallExpression)newCall).getType(), expression), ((PsiCallExpression)expression).getType())) &&
-                newResult.isValidResult()) {
+                newResult.isValidResult() &&
+                !(newResult instanceof MethodCandidateInfo && ((MethodCandidateInfo)newResult).getInferenceErrorMessage() != null)) {
               if (!(newArgs[i] instanceof PsiFunctionalExpression)) {
                 addToResults(cast);
               }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/redundantCast/InferenceErrorForApplicableMethod.java

@@ -0,0 +1,14 @@
+
+import java.util.function.Function;
+
+class Test {
+  static class Node { }
+  static class ValueNode extends Node {}
+
+  static void m(ValueNode v, Node n) {
+    pathToCustomNode((Node)v, current -> n);
+  }
+
+  public static <T> void pathToCustomNode(T node, Function<T, T> getParent) { }
+
+}

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

@@ -82,6 +82,7 @@ public class LambdaRedundantCastTest extends LightDaemonAnalyzerTestCase {
   public void testCastInConditionalBranch() { doTest();}
   public void testCastInsideLambdaReturnExpressionPassedToEnumConstant() { doTest(); }
   public void testGroundTargetTypeDiffersFromCastType() { doTest(); }
+  public void testInferenceErrorForApplicableMethod() { doTest(); }
   public void testRejectReturnTypeChange() {
     doTest();
   }