> Making the constructor of `param::hstring` constexpr seems pretty trivial, and it would enable constexpr fast-pass strings.

I was referring to return values, which has a lot more optimizing value.

Originally posted by @kennykerr in #1338 (comment)

FWIW, I was noodling with something like this for constexpr/consteval "mini source location" per #1337 and got pretty far. Not super pleasant to look at, though.