IDEA-136580 "Contract violation" warnings are reported for manual method contract

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

@@ -625,7 +625,7 @@ public class DfaMemoryStateImpl implements DfaMemoryState {
       applyEquivalenceRelation(dfaRelation, dfaLeft, dfaRight);
       return isNegated;
     }
-    if (canBeNaN(dfaLeft) || canBeNaN(dfaRight)) {
+    if (canBeNaN(dfaLeft) && canBeNaN(dfaRight)) {
       applyEquivalenceRelation(dfaRelation, dfaLeft, dfaRight);
       return true;
     }

java/java-tests/testData/inspection/dataFlow/contractCheck/DoubleParameter.java

@@ -0,0 +1,11 @@
+import org.jetbrains.annotations.Contract;
+
+class Zoo {
+  @Contract("null, _ -> null; !null, _ -> !null")
+  public static Double testContract_1(Double value1, int value2) {
+    if (value1 == null) {
+      return null;
+    }
+    return 0.0;
+  }
+}

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

@@ -41,4 +41,5 @@ public class ContractCheckTest extends LightCodeInsightFixtureTestCase {
 
   public void testSignatureIssues() { doTest(); }
   public void testVarargInferred() { doTest(); }
+  public void testDoubleParameter() { doTest(); }
 }