default values depending on type of template variable

[berni]

I'd like to write a template, that takes a different default 
value depending on the type of a variable. I tried this, but it 
doesn't work:

>void main()
>{
>    double a = 1e-8;
>    double b = 1e-10;
>    float c = 1e-4;
>    float d = 1e-6;
>
>    assert(!test(a));
>    assert(test(b));
>    assert(!test(c));
>    assert(test(d));
>}
> 
>auto test(T, U)(T value, U limit=1e-9)
>{
>    return value<limit;
>}
>
>auto test(T:float)(T value)
>{
>    return test(value, 1e-5);
>}

Although being called with a double in the first two tests, the 
second overload is always used and therefore the first test 
fails. And without this overload, the last test obviously doesn't 
pass.

Is there a way, to provide default values for template parameters 
depending on the type of an other parameter?