Test TypeDefinition.GetDeclaringType().

Author: teo-tsirpanis

src/libraries/System.Reflection.Metadata/tests/Metadata/TypeSystem/TypeDefinitionTests.cs

@@ -35,7 +35,7 @@ public void ValidateTypeDefinitionIsNestedWindowsProjection()
         }
 
         [Fact]
-        public void ValidateDeclaringType()
+        public void ValidateMemberDeclaringType()
         {
             var reader = MetadataReaderTests.GetMetadataReader(Misc.Members);
 
@@ -45,12 +45,6 @@ public void ValidateDeclaringType()
             foreach (var typeDefHandle in reader.TypeDefinitions)
             {
                 var typeDef = reader.GetTypeDefinition(typeDefHandle);
-                // The assembly does not declare any nested types yet.
-                // foreach (var nestedTypeHandle in typeDef.GetNestedTypes())
-                // {
-                //     var nestedType = reader.GetTypeDefinition(nestedTypeHandle);
-                //     Assert.Equal(typeDefHandle, nestedType.GetDeclaringType());
-                // }
                 foreach (var fieldHandle in typeDef.GetFields())
                 {
                     var field = reader.GetFieldDefinition(fieldHandle);
@@ -73,5 +67,24 @@ public void ValidateDeclaringType()
                 }
             }
         }
+
+#if NET
+        [ActiveIssue("https://github.com/dotnet/runtime/pull/111642", TestRuntimes.Mono)]
+        [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotNativeAot))]
+        public unsafe void ValidateTypeDeclaringType()
+        {
+            var asm = typeof(TypeDefinitionTests).Assembly;
+            Assert.True(asm.TryGetRawMetadata(out byte* metadataBlob, out int length));
+            var reader = new MetadataReader(metadataBlob, length);
+
+            int nestedClassToken = typeof(TestNestedClass).MetadataToken;
+            int parentClassToken = typeof(TypeDefinitionTests).MetadataToken;
+
+            TypeDefinition nestedClassDef = reader.GetTypeDefinition((TypeDefinitionHandle)MetadataTokens.EntityHandle(nestedClassToken));
+            Assert.Equal(MetadataTokens.EntityHandle(parentClassToken), nestedClassDef.GetDeclaringType());
+        }
+
+        private class TestNestedClass;
+#endif
     }
 }