zygoloid wrote: > > the special "the language rules say this is manifestly constant evaluated" > > cases that should be able to perform AST mutations, that we need to be > > extremely careful to invoke at exactly the right times and in exactly the > > right cases and to invoke only once > > Can you expand on the "to invoke only once" bit? As I understand the position > of authors of P2996, calls to `define_aggregate` with the same arguments are > supposed to be idempotent. Do you see reasons why we wouldn't be able to > achieve that, meaning that we need to prevent `define_aggregate` to be called > multiple times (with the same arguments) on the language level?
I think it's short-sighted to imagine that will work for the breadth of compile-time constructs we'll end up providing. People have already asked for things like a consteval function that produces a warning or an error -- is that also going to be idempotent? What about consteval facilities that generate random numbers, or produce a log file on the build machine? What about a consteval utility that generates a new anonymous global? What do you do if you *want* each call to your "make a new type" facility to guarantee to produce a new, distinct type? Maybe we can say no to some of those things, but I don't think we'll be able to say no to all of them forever. It seems more forward-looking to me to instead guarantee that we will evaluate exactly the things we're required to evaluate in this new mode, exactly once each. https://github.com/llvm/llvm-project/pull/115168 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
