static if with constant value

[Bill Baxter]

I can't understand why the little program below outputs what it does.
It seems like static if (constant) works in some cases but not others. 
Is this just a bug?

----
import std.stdio : writef, writefln;

template is_complex(T)
{
     static if (is(typeof(T.init.re)) && is(typeof(T.init.im))) {
         const bool is_complex = true;
     } else {
         const bool is_complex = false;
     }
}
template float_for_type(T)
{
     static if ( is_complex!(T) ) {
         alias typeof(T.init.re) float_for_type;
     } else {
         alias T float_for_type;
     }
}

void print_complex(T)(T* arg)
{
     static const bool cplx = is_complex!(T);
     writefln("print_complex: Type: %s, is_complex? ", typeid(T), cplx);
     static if ( is_complex!(T) ) {
         writefln("print_complex: static if is_complex? true");
     } else {
         writefln("print_complex: static if is_complex? false");
     }
}


void main()
{
     float f;
     cfloat c;
     double d;
     cdouble z;
     writefln("main: %s made from %s", typeid(typeof(f)), 
typeid(float_for_type!(typeof(f)))); print_complex(&f);
     writefln("main: %s made from %s", typeid(typeof(c)), 
typeid(float_for_type!(typeof(c)))); print_complex(&c);
     writefln("main: %s made from %s", typeid(typeof(d)), 
typeid(float_for_type!(typeof(d)))); print_complex(&d);
     writefln("main: %s made from %s", typeid(typeof(z)), 
typeid(float_for_type!(typeof(z)))); print_complex(&z);
}
----


Here's what it outputs for me with DMD:

main: float made from float
print_complex: Type: float, is_complex? true
print_complex: static if is_complex? true
main: cfloat made from float
print_complex: Type: cfloat, is_complex? true
print_complex: static if is_complex? true
main: double made from double
print_complex: Type: double, is_complex? true
print_complex: static if is_complex? true
main: cdouble made from double
print_complex: Type: cdouble, is_complex? true
print_complex: static if is_complex? true


In float_for_type!(T), is_complex!(T) works, but in print_complex it 
does not for some reason (it always evaluates to true).   Can anyone 
explain this behavior?

--bb