staged functions with type arguments

[Simon Byrne]

I want to call a stagedfunction with a type argument: how do I access that type at the meta stage? I want to define something like:

stagedfunction prevfloat{T<:FloatingPoint,s}(t::Type{T},c::MathConst{s})

    bc = big(c())

    f = with_rounding(BigFloat,RoundDown) do

        convert(T,bc)

    end

    :(f)

end

However calling prevfloat(Float64,pi) gives me an ERROR: T not defined.

I can't use t instead, as at the meta stage, it has value Type{Float64}. I guess I could define an "untype" function to get access to the parameter, but that seems a bit too complicated. Is there a better way to do this?

-Simon

[Tim Holy]

See #8505. Besides fixing that bug, your untype is probably the best short-term
work-around.

--Tim