Unexpected compile error using a typed constant

[joshring]

module test;
import std::math;

const float M_PI = 3.14159265358979323846;

fn void main()
{
    double error_here = math::copysign(M_PI / 2, 1.0000);
}

Error: @require "values::@assign_to(sgn, values::promote_int(mag))" violated.

but replacing 2 with 2.0 works

module test;
import std::math;

const float M_PI = 3.14159265358979323846;

fn void main()
{
    double error_here = math::copysign(M_PI / 2.0, 1.0000);
}

or replacing the const with it's value:

module test;
import std::math;

fn void main()
{
    double error_here = math::copysign(3.14159265358979323846 / 2, 1.0000);
}

[lerno]

This was a too strict contract, please try now.

[joshring]

Nice one