Warning on undocumented public symbol falsely detects stack variables in functions in `is(typeof(...))`

[thewilsonator]

enum isSeedable(Rng, SeedType) = isUniformRNG!(Rng) &&
	is(typeof(
    {
        Rng r = void;              // can define a Rng object
        SeedType s = void;
        r.seed(s); // can seed a Rng
    }));
}

Yields

std/random.d(311:13)[warn]: Public declaration 'r' is undocumented. 
std/random.d(312:18)[warn]: Public declaration 's' is undocumented.

But apparently not if written as

template  isSeedable(Rng, SeedType) 
{
     enum isSeedable = isUniformRNG!(Rng) &&
	is(typeof(
    {
        Rng r = void;              // can define a Rng object
        SeedType s = void;
        r.seed(s); // can seed a Rng
    }));
}

See dlang/phobos#10853