Compiler Error CS0455

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Type parameter 'Type Parameter Name' inherits conflicting constraints 'Constraint Name 1' and 'Constraint Name 2'

Two common ways to get this error are to set up constraints so that the type parameter derives from two non-related classes, or so that it derives from a class type or reference type constraint and a struct type or value type constraint. To resolve this error, remove the conflict from your inheritance hierarchy.

Example

The following code generates error CS0455.

// CS0455.cs
using System;

public class GenericsErrors {
    public class B { }
    public class B2 { }
    public class G6<T> where T : B { public class N<U> where U : B2, T { } } // CS0455
}