Template constraints error messages using cputs()

[bearophile]

Andrei Alexandrescu:
> pragma(msg, "Is this what you need?");

You are right, in some situations it works :-)

But you have to guard the pragma(msg) with a static if, so if your template constraint is a CTFE (that uses a normal 'if' instead of a 'static if') you can't use it, while ctputs() is OK, this shows the error message:

bool isGoodFoo(int x) {
    if (x > 10) {
        return true;
    } else {
        pragma(msg, "no good");
        // ctputs("no good");
        return false;
    }
}

void foo(int N)() if (isGoodFoo(N)) {}

void main() {
    foo!(20)();
}

Bye,
bearophile