Question

I have been trying the following

interface IUIntegral : IEquatable<Byte>, IEquatable<UInt16>, IEquatable<UInt32>, IEquatable<UInt64> { }
class Counter<T> where T : IUIntegral {
    T _value;
}

With this calling code

Counter<UInt32> foo = null;

But I get this compiler error

Error   1   The type 'uint' cannot be used as type parameter 'T' in the generic type or method 'Test.Counter<T>'. There is no boxing conversion from 'uint' to 'Test.IUIntegral'.

Answer 1

tldr; This approach will not work.

C# uses a nominative type system (types are determined by names) and not a structural type system (types determined by data/operations).

unit32 and IUIntegral are not related: even if they share the same structure.

(They don’t anyway, uint32 does not conform to IEquatable<byte>.)

If a type needs to be Equatable with itself this can be done by referring to the type in a type restriction:

class Counter<T> where T : IEquatable<T> {
    T _value;
}