Nunit1032 - consider dispose of a type having explicit interface implementation

src/nunit.analyzers.tests/DisposeFieldsAndPropertiesInTearDown/DisposeFieldsAndPropertiesInTearDownAnalyzerTests.cs

@@ -14,6 +14,15 @@ sealed class DummyDisposable : IDisposable
             public void Dispose() {}
         }";
 
+        private const string DummyExplicitDisposable = @"
+        sealed class DummyExplicitDisposable : IAnotherInterface, IDisposable
+        {
+            void IDisposable.Dispose() {}
+        }
+        public interface IAnotherInterface
+        {
+        }";
+
         // CA2000 allows transfer of ownership using ICollection<IDisposable>.Add
         private const string Disposer = @"
         private sealed class Disposer : IDisposable
@@ -114,6 +123,29 @@ public void TearDownMethod()
             RoslynAssert.Valid(analyzer, testCode);
         }
 
+        [Test]
+        public void AnalyzeWhenExplicitlyInterfaceImplementedDisposableFieldSetInConstructorIsDisposedInOneTimeTearDownMethod()
+        {
+            var testCode = TestUtility.WrapMethodInClassNamespaceAndAddUsings($@"
+        private IAnotherInterface field;
+
+        public TestClass()
+        {{
+            field = new DummyExplicitDisposable();
+        }}
+
+        [OneTimeTearDown]
+        public void TearDownMethod()
+        {{
+            ((IDisposable)field).Dispose();
+        }}
+
+        {DummyExplicitDisposable}
+        ");
+
+            RoslynAssert.Valid(analyzer, testCode);
+        }
+
         [TestCase("", "OneTime")]
         [TestCase("OneTime", "")]
         public void AnalyzeWhenFieldIsDisposedInWrongMethod(string attributePrefix1, string attributePrefix2)
@@ -1005,10 +1037,10 @@ public void TearDown()
         public partial class TestFixture
         {
             [Test]
-	        public void SomeTest()
-	        {
-		        SomeAsserts();
-	        }
+            public void SomeTest()
+            {
+                SomeAsserts();
+            }
         }");
 
             RoslynAssert.Valid(analyzer, testCodePart1, testCodePart2);

src/nunit.analyzers/DisposeFieldsAndPropertiesInTearDown/DisposeFieldsAndPropertiesInTearDownAnalyzer.cs

@@ -555,6 +555,16 @@ private static void DisposedIn(Parameters parameters, HashSet<string> disposals,
                 return memberAccessExpression.Name.Identifier.Text;
             }
 
+            // considering cast to IDisposable, e.g. in case of explicit interface implementation of IDisposable.Dispose()
+            else if (expression is ParenthesizedExpressionSyntax parenthesizedExpression &&
+                     parenthesizedExpression.Expression is CastExpressionSyntax castExpression &&
+                     castExpression.Expression is IdentifierNameSyntax castIdentifierName &&
+                     castExpression.Type is IdentifierNameSyntax typeIdentifierName &&
+                     typeIdentifierName.Identifier.Text.Equals("IDisposable", StringComparison.Ordinal))
+            {
+                return castIdentifierName.Identifier.Text;
+            }
+
             return null;
         }