Template specialization ignores attributes (at least 'immutable')

[Ali Çehreli]

I've tried a function that reads an answer from the standard input:
T get_answer(T)(string question)
{
    dout.writef(question, ": ");

    T answer;
    din.readf(&answer);

    return answer;
}

That doesn't work for strings, as they are immutable and din.readf fails.

So I wrote a specialization for string, which uses the instantiation of 
the same template for char[] and adds an .idup at the end:

T get_answer(T : string)(string question)
{
    return get_answer!(char[])(question).idup;
}

That did not work, because even the get_answer!(char[]) call selects the 
string specialization.

Then I realized that a compile time 'if' works:

T get_answer(T : string)(string question)
    if (is (T == string))                 // <--- NECESSARY
{
    return get_answer!(char[])(question).idup;
}

That's cool but is a little silly, as it means "this is the 
specialization for string AND consider it only when T is a string."

Should attributes be considered for specializations as well?

Ali