Why does this template constraint not work?

[Ross Hays]

import std.stdio;

void test(T)()
        if (is (T : float))
{
        writeln(typeid(T));
}
void main()
{
        test!int;
}

When I run this I am getting the output "int"
My understanding of template constraints is that the call to 
test!int will not find a match since the function test only 
accepts float as a template parameter. I just ran into this 
problem while trying to understand something unrelated.