IDEA-104754 Good code yellow: Unboxing

java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/DfaMemoryStateImpl.java

@@ -292,6 +292,9 @@ public class DfaMemoryStateImpl implements DfaMemoryState {
       if (value instanceof DfaVariableValue) {
         myVariableStates.put(var, getVariableState((DfaVariableValue)value).clone());
       }
+      else if (value instanceof DfaBoxedValue) {
+        getVariableState(var).setNullable(false);
+      }
     }
 
     if (getVariableState(var).isNotNull()) {

java/java-tests/testData/inspection/dataFlow/fixture/BoxingImpliesNotNull.java

@@ -0,0 +1,14 @@
+import org.jetbrains.annotations.Nullable;
+
+class Baz {
+  Integer bar() { return 2; }
+
+  void g() {
+    @Nullable Integer foo = bar();
+    if (foo == null) {
+      foo = 0;
+    }
+    System.out.println(foo.intValue());
+  }
+
+}

java/java-tests/testSrc/com/intellij/codeInspection/DataFlowInspectionTest.java

@@ -278,4 +278,5 @@ public class DataFlowInspectionTest extends LightCodeInsightFixtureTestCase {
   }
 
   public void testContractAnnotation() { doTest(); }
+  public void testBoxingImpliesNotNull() { doTest(); }
 }