Overriden property in a custom attribute crashes runtime

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#119,490 7 comments 0 reactions 1 assignee View on GitHub

@AaronRobinsonMSFT is already working on this.

Since Jul 10, 2026.

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Description

area-System.Reflection

This crashes with internal CLR error.

using System;
using System.Reflection;

Console.WriteLine(typeof(Program).GetCustomAttribute<DerivedAttribute>().Prop);

[Derived(Prop = 123)]
partial class Program;

class BaseAttribute : Attribute
{
    public virtual object Prop { get; set; }
}

class DerivedAttribute : BaseAttribute
{
    public override Enum Prop { get => (Enum)base.Prop; }
}
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