Why is mostNegative!T not of type T?

[Andrei Alexandrescu]

> Looking at the definition of clamp:
> 
> auto clamp(T1, T2, T3)(T1 val, T2 lower, T3 upper)
> if (is(typeof(max(min(val, upper), lower))))
> in
> {
>      import std.functional : greaterThan;
>      assert(!lower.greaterThan(upper), "Lower can't be greater than 
> upper.");
> }
> do
> {
>      return max(min(val, upper), lower);
> }
> 
> In turn, min and max use mostNegative and makes surprising deductions 
> based on its type. The surprise has been deemed desirable and has become 
> part of an unnecessarily complex mesh.
> 
> The failing unittest is:
> 
>      int a = -5;
>      uint f = 5;
>      short b = 6;
>      static assert(is(typeof(clamp(f, a, b)) == int));
> 
> This is bizarre and very arguably a bug, as one would expect clamping a 
> value of type `whatever` would yield a value of type `whatever`.

Update:

https://issues.dlang.org/show_bug.cgi?id=22414
https://github.com/dlang/phobos/pull/8293