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Hello,

I am use Visual Studio 16.8.3 on netcoreapp3.1 project (besides, it's reproduce on more old versions of .net) and I get incorrect result (result with compilation error) from invocation of override snippet under type parameter in the example below:

#nullable enable
using System;

namespace ConsoleApp1
{
    abstract class Test<TResult>
    {
        public abstract TResult? Get();
    }

class G : Test<int>
    {
        public override int? Get()
        {
            throw new NotImplementedException();
        }
    }

class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
        }
    }
}
#nullable enable

The code is incorrect because Get in G must return System.Int32, not Nullable<System.Int32> (Suppose that the compiler behavior under type parameter constraint in this case with nullable ref types – is another question that doesn't affect Visual Studio). Marking G as returning int makes result compiling.

P.S.
Just to be clear I was make this simple example based on CsharpSyntaxVisitor<T> from Roslyn source codes.:

In attachments you will find screenshots the result of override snippet and the metadata of CsharpSyntaxVisitor<T>

Original Comments

Feedback Bot on 2/4/2021, 10:01 PM:

We have directed your feedback to the appropriate engineering team for further evaluation. The team will review the feedback and notify you about the next steps.

Feedback Bot on 2/5/2021, 00:19 PM:

Thank you for sharing your feedback! Our teams prioritize action on product issues with broad customer impact. See details at: https://docs.microsoft.com/en-us/visualstudio/ide/report-a-problem?view=vs-2019#faq. In case you need answers to common questions or need assisted support, be sure to use https://visualstudio.microsoft.com/vs/support/. We’ll keep you posted on any updates to this feedback.

Original Solutions

(no solutions)