>> I was not aware of that. That's probably the right, but I remember >> having some troubles getting that to work the way I wanted in the >> previous implementation. It seemed like I actually had to evaluate the >> expression to determine if it was actually constexpr. > > > Right; an expression is a constant-expression iff it evaluates to a constant > value. Without evaluating the expression we can't catch things like > division by zero which prevent it from being a constant-expression.
I think that's may be a problem. It depends if substituting into the requires expression results in nodes that can be constexpr evaluated. That substitution certainly won't produce any real "values" that can be folded. We may end up with a kind of placeholder value. Andrew
