From 7678df1cbbfa73fcd76e132fd90e5996aed4c9ec Mon Sep 17 00:00:00 2001
From: anna <Anna.Kozlova@jetbrains.com>
Date: Thu, 5 Jul 2012 12:07:47 +0200
Subject: [PATCH] IDEA-87652

---
 .../dataFlow/DfaMemoryStateImpl.java           |  2 +-
 .../NullableProblemThroughCast/expected.xml    |  8 ++++++++
 .../NullableProblemThroughCast/src/Npe.java    | 18 ++++++++++++++++++
 .../codeInspection/DataFlowInspectionTest.java |  1 +
 4 files changed, 28 insertions(+), 1 deletion(-)
 create mode 100644 java/java-tests/testData/inspection/dataFlow/NullableProblemThroughCast/expected.xml
 create mode 100644 java/java-tests/testData/inspection/dataFlow/NullableProblemThroughCast/src/Npe.java

diff --git a/java/java-impl/src/com/intellij/codeInspection/dataFlow/DfaMemoryStateImpl.java b/java/java-impl/src/com/intellij/codeInspection/dataFlow/DfaMemoryStateImpl.java
index 718fc2c8b861..b38fa364fa43 100644
--- a/java/java-impl/src/com/intellij/codeInspection/dataFlow/DfaMemoryStateImpl.java
+++ b/java/java-impl/src/com/intellij/codeInspection/dataFlow/DfaMemoryStateImpl.java
@@ -540,7 +540,7 @@ public class DfaMemoryStateImpl implements DfaMemoryState {
     DfaTypeValue dfaType = (DfaTypeValue)dfaCond.getRightOperand();
 
     final DfaVariableState varState = getVariableState(dfaVar);
-    varState.setNullable(dfaType.isNullable());
+    varState.setNullable(varState.isNullable() || dfaType.isNullable());
     return !isNotNull(dfaVar) || varState.setInstanceofValue(dfaType);
   }
 
diff --git a/java/java-tests/testData/inspection/dataFlow/NullableProblemThroughCast/expected.xml b/java/java-tests/testData/inspection/dataFlow/NullableProblemThroughCast/expected.xml
new file mode 100644
index 000000000000..b7eb5e8e80a8
--- /dev/null
+++ b/java/java-tests/testData/inspection/dataFlow/NullableProblemThroughCast/expected.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<problems>
+  <problem>
+    <file>Npe.java</file>
+    <line>6</line>
+    <description>Method invocation &lt;code&gt;((SomeInterfaceImpl)x).bar()&lt;/code&gt; may produce &lt;code&gt;java.lang.NullPointerException&lt;/code&gt;</description>
+  </problem>
+</problems>
diff --git a/java/java-tests/testData/inspection/dataFlow/NullableProblemThroughCast/src/Npe.java b/java/java-tests/testData/inspection/dataFlow/NullableProblemThroughCast/src/Npe.java
new file mode 100644
index 000000000000..5937591e0b70
--- /dev/null
+++ b/java/java-tests/testData/inspection/dataFlow/NullableProblemThroughCast/src/Npe.java
@@ -0,0 +1,18 @@
+import org.jetbrains.annotations.Nullable;
+
+public class Npe {
+  
+  void foo(@Nullable SomeInterface x) {
+    ((SomeInterfaceImpl)x).bar();
+  }
+
+  interface SomeInterface {
+    void bar();
+  }
+
+  class SomeInterfaceImpl implements SomeInterface {
+    @Override
+    public void bar() {
+    }
+  }
+}
\ No newline at end of file
diff --git a/java/java-tests/testSrc/com/intellij/codeInspection/DataFlowInspectionTest.java b/java/java-tests/testSrc/com/intellij/codeInspection/DataFlowInspectionTest.java
index 6e6ed040da94..7aff8dad846d 100644
--- a/java/java-tests/testSrc/com/intellij/codeInspection/DataFlowInspectionTest.java
+++ b/java/java-tests/testSrc/com/intellij/codeInspection/DataFlowInspectionTest.java
@@ -96,6 +96,7 @@ public class DataFlowInspectionTest extends InspectionTestCase {
 
   public void testNullable() throws Exception { doTest15(); }
   public void testNullableThroughCast() throws Exception { doTest15(); }
+  public void testNullableProblemThroughCast() throws Exception { doTest15(); }
   public void testNullableThroughVariable() throws Exception { doTest15(); }
   public void testNullableThroughVariableShouldNotBeReported() throws Exception { doTest15(); }
   public void testNullableAssignment() throws Exception { doTest15(); }