From 1b4d301a50d57439767cc5ceea9139ab51ca8c56 Mon Sep 17 00:00:00 2001
From: peter <peter@jetbrains.com>
Date: Mon, 8 Dec 2014 17:29:01 +0100
Subject: [PATCH] treat lambdas as notnull in dfa & nullity inference
 (IDEA-134045)

---
 .../codeInspection/dataFlow/NullityInference.java   | 13 +++++++++++--
 .../dataFlow/value/DfaExpressionFactory.java        |  2 +-
 .../NullityInferenceFromSourceTestCase.groovy       |  4 ++++
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/NullityInference.java b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/NullityInference.java
index e77a9478334b..dbf8a4569bbf 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/NullityInference.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/NullityInference.java
@@ -83,14 +83,15 @@ public class NullityInference {
               hasNotNulls.set(true);
             }
           }
-          else if (value.getType() instanceof PsiPrimitiveType) {
+          else if (value instanceof PsiLambdaExpression || value.getType() instanceof PsiPrimitiveType) {
             hasNotNulls.set(true);
           }
           else if (value instanceof PsiMethodCallExpression) {
             PsiMethod target = ((PsiMethodCallExpression)value).resolveMethod();
             if (target == null) {
               hasUnknowns.set(true);
-            } else {
+            }
+            else {
               delegates.add(target);
             }
           }
@@ -100,6 +101,14 @@ public class NullityInference {
           super.visitReturnStatement(statement);
         }
 
+        @Override
+        public void visitClass(PsiClass aClass) {
+        }
+
+        @Override
+        public void visitLambdaExpression(PsiLambdaExpression expression) {
+        }
+
         @Override
         public void visitErrorElement(PsiErrorElement element) {
           hasErrors.set(true);
diff --git a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/value/DfaExpressionFactory.java b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/value/DfaExpressionFactory.java
index bbc5de57df94..92df8c858229 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/value/DfaExpressionFactory.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/value/DfaExpressionFactory.java
@@ -94,7 +94,7 @@ public class DfaExpressionFactory {
       return myFactory.createLiteralValue((PsiLiteralExpression)expression);
     }
 
-    if (expression instanceof PsiNewExpression) {
+    if (expression instanceof PsiNewExpression || expression instanceof PsiLambdaExpression) {
       return myFactory.createTypeValue(expression.getType(), Nullness.NOT_NULL);
     }
 
diff --git a/java/java-tests/testSrc/com/intellij/codeInspection/NullityInferenceFromSourceTestCase.groovy b/java/java-tests/testSrc/com/intellij/codeInspection/NullityInferenceFromSourceTestCase.groovy
index c6b6bfd65149..66c31010bc70 100644
--- a/java/java-tests/testSrc/com/intellij/codeInspection/NullityInferenceFromSourceTestCase.groovy
+++ b/java/java-tests/testSrc/com/intellij/codeInspection/NullityInferenceFromSourceTestCase.groovy
@@ -73,6 +73,10 @@ String bar() { return "z"; }
     assert inferNullity(parse('Object foo() { return 1; }')) == NOT_NULL
   }
 
+  void "test null inside lambda"() {
+    assert inferNullity(parse('Object foo() { return () -> { return null; }; }')) == NOT_NULL
+  }
+
   protected abstract Nullness inferNullity(PsiMethod method)
 
   protected PsiMethod parse(String method) {