> So that means there's a responsibility for Quality of Implementation on those features, they're not really "replaceable" because they're in the fundamental st

> So that means there's a responsibility for Quality of Implementation on those features, they're not really "replaceable" because they're in the fundamental standard library even on bare metal which means a "replacement" is just a parallel implementation. That's probably fine to some extent for std::unordered_map, but it's very silly for std::function, and I'd argue it's even silly for std::unique_ptr and std::string. I think we agree here - you can replace std::unordered_map with absl::map etc, so the impact is lower. I do wish we'd stop doing it, though - see fmt. I agree that it's incredibly stupid for std::function and std::unique_ptr to not be language level features - unique_ptr is the poster child for something that could faster and safer with less compile time overhead if implemented in the language rather than in the library. > There is a proposal (which I'd guess you'll hate) No, I think that's great actually, but I don't want that _and_ noinit/indeterminite (which is proposed in the link above) _and_ a new category of behaviour. I want one option, and I want failure of adherence to it to either be compiler enforced, implelentation defined, or Undefined Behaviour, _not_ "erroneus behaviour". > The C definition of assert, which C++ inherits, is problematic here, because it's a no-op in release builds. Sorry, yeah you're totally right. my day to day C++ work has a custom set of assertions that in release builds are basically the following (simplified for posting here) - #define our_assert(conditional) \ if (!conditional) { \ log_stuff_and_flush() \ std::abort() \ } > because it's a no-op in release builds. This falls into the same group of back compat as the unwillingness to break ABI IMO - you can have an optimised build without NDEBUG, or an unoptimised build with NDEBUG, and the side effects of disabling bounds checking is turning assert into a noop.