[java] allows nulls to nullable parameters (IDEA-193726)

java/java-analysis-impl/src/com/intellij/codeInspection/nullable/NullableStuffInspectionBase.java

@@ -1,4 +1,4 @@
-// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package com.intellij.codeInspection.nullable;
 
 import com.intellij.codeInsight.*;
@@ -822,12 +822,14 @@ public class NullableStuffInspectionBase extends AbstractBaseJavaLocalInspection
                                                                 int parameterIdx,
                                                                 PsiParameter parameter) {
     if (!REPORT_NULLS_PASSED_TO_NOT_NULL_PARAMETER || !isOnFly) return;
+
     PsiElement elementToHighlight;
     if (DfaPsiUtil.getTypeNullability(getMemberType(parameter)) == Nullability.NOT_NULL) {
       elementToHighlight = parameter.getNameIdentifier();
-    } else {
+    }
+    else {
       NullabilityAnnotationInfo info = nullableManager.findOwnNullabilityAnnotationInfo(parameter);
-      if (info == null || info.isInferred()) return;
+      if (info == null || info.getNullability() != Nullability.NOT_NULL || info.isInferred()) return;
       PsiAnnotation notNullAnnotation = info.getAnnotation();
       boolean physical = PsiTreeUtil.isAncestor(parameter, notNullAnnotation, true);
       elementToHighlight = physical ? notNullAnnotation : parameter.getNameIdentifier();

java/java-tests/testData/inspection/nullableProblems/NullPassedToNullableParameter.java

@@ -0,0 +1,11 @@
+import org.jetbrains.annotations.Nullable;
+
+class AcceptsNull {
+  void recepient(@Nullable String s) {
+    System.out.println("s=" + s);
+  }
+
+  void donor() {
+    recepient(null);
+  }
+}

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

@@ -1,18 +1,4 @@
-/*
- * Copyright 2000-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 
 package com.intellij.java.codeInspection;
 
@@ -302,4 +288,7 @@ public class NullableStuffInspectionTest extends LightCodeInsightFixtureTestCase
     myFixture.checkResultByFile(getTestName(false) + "_after.java");
   }
 
+  public void testNullPassedToNullableParameter() {
+    doTest();
+  }
 }