avr-gcc-15.2 C++23 compilation errors

[jputcu]

Using ZakKemble 15.2 avr-gcc compiler I get following errors:

include/bits/stl_iterator.h:2155:47: error: 'const class std::counted_iterator<_It>' has no member named '_M_current' [-Wtemplate-body]
 2155 |       noexcept(noexcept(ranges::iter_move(__i._M_current)))
      |                                               ^~~~~~~~~~
include/bits/stl_iterator.h:2163:49: error: 'const class std::counted_iterator<_It>' has no member named '_M_current' [-Wtemplate-body]
 2163 |         noexcept(noexcept(ranges::iter_swap(__x._M_current, __y._M_current)))
      |                                                 ^~~~~~~~~~
~~~~

I know you are using gcc-14.2 but I like to already report is so other know about it.

[jwakely]

In general libstdc++ headers can only be used with the right version of GCC that they shipped with. When using bleeding edge standards modes like -std=c++23 that's going to apply even more, because that code is less likely to work with older versions of the compiler (because the code in the headers uses new language features that might be unsupported or buggy in the older compiler).

Trying to use C++23 seems unlikely to work well.

This is one of the main reasons why I still think the work should be upstream (#23). If the upstream libstdc++ works for AVR then you don't need a separate fork which is tied to a specific release of GCC. You can already just build avr-gcc with --enable-libstdcxx to include a working libstdc++.

That said ... this error makes no sense. Are there any earlier errors or is that the whole output? That error would have to be a g++ bug but I don't recall any such bug. Those lines of code have been present since GCC 10 and work fine in all versions of GCC, including 15.2

[jwakely]

Aha, maybe you're using an old version of avr-libstdcpp? That error should have been fixed by 5354296#diff-cd81b614d4fa13893bb943062e901fdee823de09143cb56a0dbf362d7d88339b

[jwakely]

Yes, this is the same error shown at #41 (comment) and was fixed by #41 so you probably just need to use the latest avr-libstdcpp code (and this can be closed).

[jputcu]

@jwakely Thanks for the quick feedback, will try asap. I also agree with you working with upstream, that is why I left a idea in the modm discussion lists to maybe dream of using the libstdc++ delivered with the latest gcc's

[jputcu]

Indeed fixed in the latest commit.