From c20dfc0165dc177206afe11d6c3778688c6206b8 Mon Sep 17 00:00:00 2001
From: "Anna.Kozlova" <anna.kozlova@jetbrains.com>
Date: Thu, 28 Nov 2019 09:56:31 +0100
Subject: [PATCH] java inference: ignore method reference constraints when
 starting from them

EA-209460 - IAE: ObjectUtils.$$$reportNull$$$

GitOrigin-RevId: 8476b832fcc1c85c10aed6ea56f65645bfd02b03
---
 .../graphInference/InferenceSession.java      |  4 +--
 ...reateMethodFromMethodRefApplicability.java | 29 +++++++++++++++++++
 .../lambda/NewMethodRefHighlightingTest.java  |  1 +
 3 files changed, 32 insertions(+), 2 deletions(-)
 create mode 100644 java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newMethodRef/CreateMethodFromMethodRefApplicability.java

diff --git a/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java b/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java
index 74af44e228fe..fa5f387541fd 100644
--- a/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java
+++ b/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java
@@ -393,7 +393,7 @@ public class InferenceSession {
         final PsiType parameterType = nestedSubstitutor.substitute(getParameterType(parameters, i, siteSubstitutor, varargs));
         if (!isPertinentToApplicability(arg, parentMethod)) {
           ExpressionCompatibilityConstraint compatibilityConstraint = new ExpressionCompatibilityConstraint(arg, parameterType);
-          if (arg instanceof PsiLambdaExpression && ignoreLambdaConstraintTree(arg) || dependsOnIgnoredConstraint(ignoredConstraints, compatibilityConstraint)) {
+          if (arg instanceof PsiFunctionalExpression && ignoreLambdaConstraintTree(arg) || dependsOnIgnoredConstraint(ignoredConstraints, compatibilityConstraint)) {
             ignoredConstraints.add(compatibilityConstraint);
             continue;
           }
@@ -440,7 +440,7 @@ public class InferenceSession {
   
   public static boolean ignoreLambdaConstraintTree(PsiExpression arg) {
     for (PsiElement expr : MethodCandidateInfo.ourOverloadGuard.currentStack()) {
-      if (PsiTreeUtil.getParentOfType(expr, PsiLambdaExpression.class) == arg) {
+      if (PsiTreeUtil.getParentOfType(expr, PsiFunctionalExpression.class, false) == arg) {
         return true;
       }
     }
diff --git a/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newMethodRef/CreateMethodFromMethodRefApplicability.java b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newMethodRef/CreateMethodFromMethodRefApplicability.java
new file mode 100644
index 000000000000..4ce8a26f649d
--- /dev/null
+++ b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newMethodRef/CreateMethodFromMethodRefApplicability.java
@@ -0,0 +1,29 @@
+
+import java.util.*;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+class DemoApplicationTests {
+
+  void test2() {
+    var a = Stream.of("")
+      .map(s -> s.substring(1))
+      .map(s -> s.length())
+      .map(l1 -> String.valueOf(l1)).collect(Collectors.toList());
+
+    Stream.of("")
+      .map(l -> a.get(l.length()))
+      .map(s -> new DemoApplicationTests()).findAny()
+      .map(d -> d.foo(this::<error descr="Cannot resolve method 'bar'">ba<caret>r</error>));
+  }
+
+  <T> void foo(Consumer<T> c) {}
+
+  <T, R> void foo(Function<T, R> c) {}
+
+  void bar(long j) {}
+
+  void bar(int i) {}
+}
diff --git a/java/java-tests/testSrc/com/intellij/java/codeInsight/daemon/lambda/NewMethodRefHighlightingTest.java b/java/java-tests/testSrc/com/intellij/java/codeInsight/daemon/lambda/NewMethodRefHighlightingTest.java
index ee12c15f1d3a..918418cb3aa2 100644
--- a/java/java-tests/testSrc/com/intellij/java/codeInsight/daemon/lambda/NewMethodRefHighlightingTest.java
+++ b/java/java-tests/testSrc/com/intellij/java/codeInsight/daemon/lambda/NewMethodRefHighlightingTest.java
@@ -196,6 +196,7 @@ public class NewMethodRefHighlightingTest extends LightDaemonAnalyzerTestCase {
   public void testDontIgnoreIncompatibilitiesDuringFirstApplicabilityCheck() { doTest(); }
   public void testCaptureOnDedicatedParameterOfSecondSearch() { doTest(); }
   public void testVoidConflict() { doTest(); }
+  public void testCreateMethodFromMethodRefApplicability() { doTest(); }
   public void testErrorMessageOnTopCallWhenFunctionalInterfaceIsNotInferred() { doTest(); }
 
   private void doTest() {