From 12553cb3de5333cb5472c7071c0c6ef555419b1b Mon Sep 17 00:00:00 2001
From: peter <peter@jetbrains.com>
Date: Mon, 22 Sep 2014 12:38:11 +0200
Subject: [PATCH] IDEA-130111 "Constant conditions & exceptions" inspection:
 false positive for possible NPE

---
 .../dataFlow/DfaMemoryStateImpl.java          | 17 ++++++--------
 .../dataFlow/fixture/EnumConstantNotNull.java | 23 +++++++++++++++++++
 .../DataFlowInspectionTest.java               |  1 +
 3 files changed, 31 insertions(+), 10 deletions(-)
 create mode 100644 java/java-tests/testData/inspection/dataFlow/fixture/EnumConstantNotNull.java

diff --git a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/DfaMemoryStateImpl.java b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/DfaMemoryStateImpl.java
index 6790be21f52a..e1ec00c16c91 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/DfaMemoryStateImpl.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/DfaMemoryStateImpl.java
@@ -464,8 +464,6 @@ public class DfaMemoryStateImpl implements DfaMemoryState {
 
   @Override
   public boolean isNull(DfaValue dfaValue) {
-    if (dfaValue instanceof DfaTypeValue && ((DfaTypeValue)dfaValue).isNotNull()) return false;
-    
     if (dfaValue instanceof DfaConstValue) return ((DfaConstValue)dfaValue).getValue() == null;
 
     if (dfaValue instanceof DfaVariableValue) {
@@ -478,14 +476,13 @@ public class DfaMemoryStateImpl implements DfaMemoryState {
 
   @Override
   public boolean isNotNull(DfaValue dfaVar) {
-    if (dfaVar instanceof DfaVariableValue && getVariableState((DfaVariableValue)dfaVar).isNotNull()) {
-      return true;
-    }
-    if (dfaVar instanceof DfaConstValue && ((DfaConstValue)dfaVar).getValue() != null) {
-      return true;
-    }
-    if (dfaVar instanceof DfaTypeValue && ((DfaTypeValue)dfaVar).isNotNull()) {
-      return true;
+    if (dfaVar instanceof DfaConstValue) return ((DfaConstValue)dfaVar).getValue() != null;
+    if (dfaVar instanceof DfaTypeValue) return ((DfaTypeValue)dfaVar).isNotNull();
+    if (dfaVar instanceof DfaVariableValue) {
+      if (getVariableState((DfaVariableValue)dfaVar).isNotNull()) return true;
+
+      DfaConstValue constantValue = getConstantValue((DfaVariableValue)dfaVar);
+      if (constantValue != null && constantValue.getValue() != null) return true;
     }
 
     DfaConstValue dfaNull = myFactory.getConstFactory().getNull();
diff --git a/java/java-tests/testData/inspection/dataFlow/fixture/EnumConstantNotNull.java b/java/java-tests/testData/inspection/dataFlow/fixture/EnumConstantNotNull.java
new file mode 100644
index 000000000000..c9b2f78b2a96
--- /dev/null
+++ b/java/java-tests/testData/inspection/dataFlow/fixture/EnumConstantNotNull.java
@@ -0,0 +1,23 @@
+import org.jetbrains.annotations.Nullable;
+
+class FooWithComments {
+  void unimportantMethod() {
+    AnEnum ae = nullableGetter();
+    if (ae != null) {
+      if (ae == AnEnum.ENUM_VALUE) {
+        anotherMethod(ae.name());       // IDEA warns that ae.name() could cause NPE
+      } else {
+        // do something else
+      }
+    }
+  }
+
+  private native void anotherMethod(String name);
+
+  @Nullable
+  private native AnEnum nullableGetter();
+
+  enum AnEnum {
+    ENUM_VALUE, FOO2
+  }
+}
diff --git a/java/java-tests/testSrc/com/intellij/codeInspection/DataFlowInspectionTest.java b/java/java-tests/testSrc/com/intellij/codeInspection/DataFlowInspectionTest.java
index 92465cf858bc..85478517138d 100644
--- a/java/java-tests/testSrc/com/intellij/codeInspection/DataFlowInspectionTest.java
+++ b/java/java-tests/testSrc/com/intellij/codeInspection/DataFlowInspectionTest.java
@@ -91,6 +91,7 @@ public class DataFlowInspectionTest extends LightCodeInsightFixtureTestCase {
   public void testVisitFinallyOnce() throws Throwable { doTest(); }
   public void testNotEqualsDoesntImplyNotNullity() throws Throwable { doTest(); }
   public void testEqualsEnumConstant() throws Throwable { doTest(); }
+  public void testEnumConstantNotNull() throws Throwable { doTest(); }
   public void testEqualsConstant() throws Throwable { doTest(); }
   public void testFinalLoopVariableInstanceof() throws Throwable { doTest(); }
   public void testGreaterIsNotEquals() throws Throwable { doTest(); }