Fix EntityHandle.GetDeclaringType extension and add TypeSpecification.GetGenericType

ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs

@@ -633,7 +633,7 @@ namespace ICSharpCode.Decompiler.CSharp
 		/// </summary>
 		public static CodeMappingInfo GetCodeMappingInfo(PEFile module, EntityHandle member)
 		{
-			var declaringType = member.GetDeclaringType(module.Metadata);
+			var declaringType = (TypeDefinitionHandle)member.GetDeclaringType(module.Metadata);
 
 			if (declaringType.IsNil && member.Kind == HandleKind.TypeDefinition)
 			{
@@ -835,20 +835,8 @@ namespace ICSharpCode.Decompiler.CSharp
 						return (TypeDefinitionHandle)memberRef.Parent;
 					case HandleKind.TypeSpecification:
 						var ts = module.Metadata.GetTypeSpecification((TypeSpecificationHandle)memberRef.Parent);
-						if (ts.Signature.IsNil)
-							return default;
-						// Do a quick scan using BlobReader
-						var signature = module.Metadata.GetBlobReader(ts.Signature);
-						// When dealing with FSM implementations, we can safely assume that if it's a type spec,
-						// it must be a generic type instance.
-						if (signature.ReadByte() != (byte)SignatureTypeCode.GenericTypeInstance)
-							return default;
-						// Skip over the rawTypeKind: value type or class
-						var rawTypeKind = signature.ReadCompressedInteger();
-						if (rawTypeKind < 17 || rawTypeKind > 18)
-							return default;
 						// Only read the generic type, ignore the type arguments
-						var genericType = signature.ReadTypeHandle();
+						var genericType = ts.GetGenericType(module.Metadata);
 						// Again, we assume this is a type def, because we are only looking at nested types
 						if (genericType.Kind != HandleKind.TypeDefinition)
 							return default;

ICSharpCode.Decompiler/SRMExtensions.cs

@@ -140,31 +140,61 @@ namespace ICSharpCode.Decompiler
 			return accessors.Raiser;
 		}
 
-		public static TypeDefinitionHandle GetDeclaringType(this EntityHandle entity, MetadataReader metadata)
+		public static EntityHandle GetGenericType(this in TypeSpecification ts, MetadataReader metadata)
+		{
+			if (ts.Signature.IsNil)
+				return default;
+			// Do a quick scan using BlobReader
+			var signature = metadata.GetBlobReader(ts.Signature);
+			// When dealing with FSM implementations, we can safely assume that if it's a type spec,
+			// it must be a generic type instance.
+			if (signature.ReadByte() != (byte)SignatureTypeCode.GenericTypeInstance)
+				return default;
+			// Skip over the rawTypeKind: value type or class
+			var rawTypeKind = signature.ReadCompressedInteger();
+			if (rawTypeKind < 17 || rawTypeKind > 18)
+				return default;
+			// Only read the generic type, ignore the type arguments
+			return signature.ReadTypeHandle();
+		}
+
+		public static EntityHandle GetDeclaringType(this EntityHandle entity, MetadataReader metadata)
 		{
 			switch (entity.Kind)
 			{
 				case HandleKind.TypeDefinition:
 					var td = metadata.GetTypeDefinition((TypeDefinitionHandle)entity);
 					return td.GetDeclaringType();
+				case HandleKind.TypeReference:
+					var tr = metadata.GetTypeReference((TypeReferenceHandle)entity);
+					return tr.GetDeclaringType();
+				case HandleKind.TypeSpecification:
+					var ts = metadata.GetTypeSpecification((TypeSpecificationHandle)entity);
+					return ts.GetGenericType(metadata).GetDeclaringType(metadata);
 				case HandleKind.FieldDefinition:
 					var fd = metadata.GetFieldDefinition((FieldDefinitionHandle)entity);
 					return fd.GetDeclaringType();
 				case HandleKind.MethodDefinition:
 					var md = metadata.GetMethodDefinition((MethodDefinitionHandle)entity);
 					return md.GetDeclaringType();
+				case HandleKind.MemberReference:
+					var mr = metadata.GetMemberReference((MemberReferenceHandle)entity);
+					return mr.Parent;
 				case HandleKind.EventDefinition:
 					var ed = metadata.GetEventDefinition((EventDefinitionHandle)entity);
 					return metadata.GetMethodDefinition(ed.GetAccessors().GetAny()).GetDeclaringType();
 				case HandleKind.PropertyDefinition:
 					var pd = metadata.GetPropertyDefinition((PropertyDefinitionHandle)entity);
 					return metadata.GetMethodDefinition(pd.GetAccessors().GetAny()).GetDeclaringType();
+				case HandleKind.MethodSpecification:
+					var ms = metadata.GetMethodSpecification((MethodSpecificationHandle)entity);
+					return ms.Method.GetDeclaringType(metadata);
 				default:
 					throw new ArgumentOutOfRangeException();
 			}
 		}
 
-		public static TypeReferenceHandle GetDeclaringType(this TypeReference tr)
+		public static TypeReferenceHandle GetDeclaringType(this in TypeReference tr)
 		{
 			switch (tr.ResolutionScope.Kind)
 			{

ILSpy/Languages/Language.cs

@@ -541,7 +541,7 @@ namespace ICSharpCode.ILSpy
 
 		public virtual CodeMappingInfo GetCodeMappingInfo(PEFile module, SRM.EntityHandle member)
 		{
-			var declaringType = member.GetDeclaringType(module.Metadata);
+			var declaringType = (SRM.TypeDefinitionHandle)member.GetDeclaringType(module.Metadata);
 
 			if (declaringType.IsNil && member.Kind == SRM.HandleKind.TypeDefinition)
 			{