Ignore null suppression operator when matching Is.Not.Null

nunit · Mar 12, 2024 · 0aacb17 · 0aacb17
1 parent 4798485
commit 0aacb17
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diff --git a/....analyzers.tests/DiagnosticSuppressors/DereferencePossiblyNullReferenceSuppressorTests.cs b/....analyzers.tests/DiagnosticSuppressors/DereferencePossiblyNullReferenceSuppressorTests.cs
@@ -997,5 +997,32 @@ public Extra(string info, int value)
                 ExpectedDiagnostic.Create(DereferencePossiblyNullReferenceSuppressor.SuppressionDescriptors["CS8602"]),
                 testCode);
         }
+
+        [Test]
+        public void TestNullSuppressionOperator()
+        {
+            var testCode = TestUtility.WrapMethodInClassNamespaceAndAddUsings(@"
+                [TestCase(default(string))]
+                public void Test(string ?possibleNullString)
+                {
+                    HasString str = new(possibleNullString);
+
+                    string nonNullString = GetStringSuppress(str);
+                    Assert.That(nonNullString, Is.Not.Null);
+                }
+
+                private static string GetStringSuppress(HasString? str) // argument is nullable
+                {
+                    Assert.That(str!.Inner, Is.Not.Null);
+                    return str.Inner; // warning: possible null reference return
+                }
+
+                private record HasString(string? Inner);
+            ");
+
+            RoslynAssert.Suppressed(suppressor,
+                ExpectedDiagnostic.Create(DereferencePossiblyNullReferenceSuppressor.SuppressionDescriptors["CS8603"]),
+                testCode);
+        }
     }
 }
diff --git a/src/nunit.analyzers/DiagnosticSuppressors/DereferencePossiblyNullReferenceSuppressor.cs b/src/nunit.analyzers/DiagnosticSuppressors/DereferencePossiblyNullReferenceSuppressor.cs
@@ -407,6 +407,12 @@ private static bool InvalidatedBy(string assignment, string possibleNullReferenc
 
         private static bool CoveredBy(string assertedNotNull, string possibleNullReference)
         {
+            int exclamation = assertedNotNull.IndexOf('!');
+            if (exclamation >= 0)
+            {
+                assertedNotNull = assertedNotNull.Replace("!", string.Empty);
+            }
+
             if (possibleNullReference == assertedNotNull)
             {
                 return true;