Conformance and new members

[jskeet]

This is with reference to conformance.md.

Originally posted by @KalleOlaviNiemitalo in #1486 (comment)

using static A;

namespace B {
    using static System.Int32;
    class C {
        static int Main() => MaxValue;
    }
}

class A {
    public const int MaxValue = 42;
}

Now if the implementation extends System.Int32 with a public const int MaxValue member, then Main() will return that rather than A.MaxValue, thus changing the behaviour. So the rule seems to pretty much disallow providing additional static members. Or is this kind of program not strictly conforming?

[jskeet]

(Set to pre-C# 9.0 as I don't think this needs to block C# 8.0, but it would be good to discuss.)