IDEA-117297 @Contract doesn't play nice with @NotNull/@Nullable

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

@@ -1417,7 +1417,7 @@ public class ControlFlowAnalyzer extends JavaElementVisitor {
     for (MethodContract contract : contracts) {
       handleContract(expression, contract);
     }
-    pushUnknown(); // goto here if all contracts are false
+    pushUnknownReturnValue(expression); // goto here if all contracts are false
     return true;
   }
   
@@ -1451,7 +1451,7 @@ public class ControlFlowAnalyzer extends JavaElementVisitor {
     // if contract is true
     switch (contract.returnValue) {
       case ANY_VALUE:
-        pushUnknown();
+        pushUnknownReturnValue(expression);
         addInstruction(new GotoInstruction(exitPoint));
         break;
       case NULL_VALUE:
@@ -1482,6 +1482,17 @@ public class ControlFlowAnalyzer extends JavaElementVisitor {
     }
   }
 
+  private void pushUnknownReturnValue(PsiMethodCallExpression expression) {
+    PsiMethod method = expression.resolveMethod();
+    if (method != null) {
+      PsiType type = expression.getType();
+      addInstruction(new PushInstruction(myFactory.createTypeValue(type, DfaPsiUtil.getElementNullability(type, method)), null));
+    }
+    else {
+      pushUnknown();
+    }
+  }
+
   private static List<MethodContract> getCallContracts(PsiMethodCallExpression expression) {
     PsiMethod resolved = expression.resolveMethod();
     if (resolved != null) {

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

@@ -12,5 +12,32 @@ public class Foo {
   @Nullable
   Object foo(Object a) { return a; }
 
+  @NotNull
+  Object notNull() {
+    return <warning descr="Expression 'nullable(false)' might evaluate to null but is returned by the method declared as @NotNull">nullable(false)</warning>;
+  }
+
+  @NotNull
+  Object notNull2() {
+    return <warning descr="Expression 'nullable2(false)' might evaluate to null but is returned by the method declared as @NotNull">nullable2(false)</warning>;
+  }
+
+  @Nullable
+  @Contract("true -> !null")
+  Object nullable(boolean notNull) {
+    return notNull ? "" : anotherNullable();
+  }
+
+  @Nullable
+  @Contract("true -> !null; _->_")
+  Object nullable2(boolean notNull) {
+    return notNull ? "" : anotherNullable();
+  }
+
+  @Nullable
+  Object anotherNullable() {
+    return null;
+  }
+
 }