From 7427f881fd6c6fcd230f83feea35e4a7ad0113f7 Mon Sep 17 00:00:00 2001
From: Tagir Valeev <Tagir.Valeev@jetbrains.com>
Date: Fri, 25 Jun 2021 15:46:14 +0700
Subject: [PATCH] [java-analysis] NullableNotNullManager: prefer type
 annotation over inherited annotation

Fixes IDEA-272250 False-positive warning when overridden method has a nullability type annotation

GitOrigin-RevId: a05ae5bdad95e475ac8a2af7736bcafc0e008364
---
 .../codeInsight/NullableNotNullManager.java   | 23 +++++++++++--------
 .../nullableProblems/InheritAmbiguous.java    | 10 ++++++++
 .../NullableStuffInspectionTest.java          |  6 +++++
 3 files changed, 29 insertions(+), 10 deletions(-)
 create mode 100644 java/java-tests/testData/inspection/nullableProblems/InheritAmbiguous.java

diff --git a/java/java-psi-api/src/com/intellij/codeInsight/NullableNotNullManager.java b/java/java-psi-api/src/com/intellij/codeInsight/NullableNotNullManager.java
index 7648b7e93461..25a16e692a21 100644
--- a/java/java-psi-api/src/com/intellij/codeInsight/NullableNotNullManager.java
+++ b/java/java-psi-api/src/com/intellij/codeInsight/NullableNotNullManager.java
@@ -258,18 +258,21 @@ public abstract class NullableNotNullManager {
       memberAnno = null;
     }
     if (memberAnno != null) {
-      if (type != null) {
-        for (PsiAnnotation typeAnno : type.getApplicableAnnotations()) {
-          if (areDifferentNullityAnnotations(memberAnno.annotation, typeAnno)) {
-            if (typeAnno != memberAnno.annotation) return null;
-            Nullability nullability = annotations.getNullability(typeAnno.getQualifiedName());
-            if (nullability == null) return null;
-            return new NullabilityAnnotationInfo(typeAnno, nullability, false);
-          }
-        }
-      }
       Nullability nullability = annotations.getNullability(memberAnno.annotation.getQualifiedName());
       if (nullability == null) return null;
+      if (type != null) {
+        for (PsiAnnotation typeAnno : type.getApplicableAnnotations()) {
+          if (typeAnno == memberAnno.annotation) continue;
+          Nullability typeNullability = annotations.getNullability(typeAnno.getQualifiedName());
+          if (typeNullability == null) continue;
+          if (typeNullability != nullability) {
+            return null;
+          }
+          // Prefer type annotation over inherited annotation; necessary for Nullable/NotNull inspection
+          memberAnno = new AnnotationAndOwner(owner, typeAnno);
+          break;
+        }
+      }
       return new NullabilityAnnotationInfo(memberAnno.annotation, nullability, memberAnno.owner == owner ? null : memberAnno.owner, false);
     }
     if (type instanceof PsiPrimitiveType) return null;
diff --git a/java/java-tests/testData/inspection/nullableProblems/InheritAmbiguous.java b/java/java-tests/testData/inspection/nullableProblems/InheritAmbiguous.java
new file mode 100644
index 000000000000..68bfb6679501
--- /dev/null
+++ b/java/java-tests/testData/inspection/nullableProblems/InheritAmbiguous.java
@@ -0,0 +1,10 @@
+import typeUse.*;
+
+abstract class A {
+  class B {}
+
+  @NotNull abstract A.B get();
+}
+abstract class C extends A {
+  abstract A.@NotNull B get();
+}
diff --git a/java/java-tests/testSrc/com/intellij/java/codeInspection/NullableStuffInspectionTest.java b/java/java-tests/testSrc/com/intellij/java/codeInspection/NullableStuffInspectionTest.java
index fe90ecad42a7..031632597d54 100644
--- a/java/java-tests/testSrc/com/intellij/java/codeInspection/NullableStuffInspectionTest.java
+++ b/java/java-tests/testSrc/com/intellij/java/codeInspection/NullableStuffInspectionTest.java
@@ -334,6 +334,12 @@ public class NullableStuffInspectionTest extends LightJavaCodeInsightFixtureTest
     doTest();
   }
 
+  public void testInheritAmbiguous() {
+    myInspection.REPORT_ANNOTATION_NOT_PROPAGATED_TO_OVERRIDERS = true;
+    DataFlowInspection8Test.setupAmbiguousAnnotations("typeUse", myFixture);
+    doTest();
+  }
+
   public void testIncorrectPlacementAmbiguous() {
     DataFlowInspection8Test.setupAmbiguousAnnotations("typeUse", myFixture);
     doTest();