From fbf500d2d4f616edd250413a89a1426ef8aa6bc9 Mon Sep 17 00:00:00 2001
From: "Anna.Kozlova" <anna.kozlova@jetbrains.com>
Date: Wed, 26 Apr 2017 16:21:52 +0200
Subject: [PATCH] inference: skip standalone expressions in lambda returns
 (IDEA-171922)

---
 .../ExpressionCompatibilityConstraint.java         |  3 +++
 ...oneExpressionsInLambdaReturnForNestedCalls.java | 14 ++++++++++++++
 .../daemon/lambda/NewLambdaHighlightingTest.java   |  1 +
 3 files changed, 18 insertions(+)
 create mode 100644 java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newLambda/IgnoreStandaloneExpressionsInLambdaReturnForNestedCalls.java

diff --git a/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/constraints/ExpressionCompatibilityConstraint.java b/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/constraints/ExpressionCompatibilityConstraint.java
index 4a6ef5c74700..86d104a2af2c 100644
--- a/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/constraints/ExpressionCompatibilityConstraint.java
+++ b/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/constraints/ExpressionCompatibilityConstraint.java
@@ -129,6 +129,9 @@ public class ExpressionCompatibilityConstraint extends InputOutputConstraintForm
                                                                          PsiExpression expression,
                                                                          PsiType targetType,
                                                                          boolean registerErrorOnFailure) {
+    if (!PsiPolyExpressionUtil.isPolyExpression(expression)) {
+      return session;
+    }
     final PsiExpressionList argumentList = ((PsiCall)expression).getArgumentList();
     if (argumentList != null) {
       final MethodCandidateInfo.CurrentCandidateProperties candidateProperties = MethodCandidateInfo.getCurrentMethod(argumentList);
diff --git a/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newLambda/IgnoreStandaloneExpressionsInLambdaReturnForNestedCalls.java b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newLambda/IgnoreStandaloneExpressionsInLambdaReturnForNestedCalls.java
new file mode 100644
index 000000000000..0f57ae5cde70
--- /dev/null
+++ b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newLambda/IgnoreStandaloneExpressionsInLambdaReturnForNestedCalls.java
@@ -0,0 +1,14 @@
+
+import java.util.ArrayList;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collector;
+import java.util.stream.Collectors;
+
+
+class Foo {
+  private static void foo(final Function<String, ?> compose) {
+    Collector<String, ?, ? extends Map<?, ArrayList<String>>> stringMapCollector =
+      Collectors.groupingBy(compose, Collector.of(() -> new ArrayList<String>(), null, null, s -> new ArrayList<>(s)));
+  }
+}
\ No newline at end of file
diff --git a/java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/NewLambdaHighlightingTest.java b/java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/NewLambdaHighlightingTest.java
index a0fa43720372..2edb5879a2b0 100644
--- a/java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/NewLambdaHighlightingTest.java
+++ b/java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/NewLambdaHighlightingTest.java
@@ -155,6 +155,7 @@ public class NewLambdaHighlightingTest extends LightDaemonAnalyzerTestCase {
   public void testGroundTargetTypeWhenAbstractMethodInSuperclass() { doTest(); }
   public void testNestedLambdasWithInferenceOfReturnTypeInTheLatestLambda() { doTest(); }
   public void testCapturedWildcardNotOpenedDuringInference() { doTest(); }
+  public void testIgnoreStandaloneExpressionsInLambdaReturnForNestedCalls() { doTest(); }
 
   private void doTest() {
     IdeaTestUtil.setTestVersion(JavaSdkVersion.JDK_1_8, getModule(), getTestRootDisposable());