[libcxx-commits] [libcxx] [libcxxabi] [llvm] [libc++] Upgrade to GCC 16 (PR #206235)

[Volodymyr Sapsai via libcxx-commits]

https://github.com/vsapsai commented:

Parts of this change make libc++ uncompilable on the latest Ubuntu [26.04]. The default toolchain on Ubuntu 26.04 is GCC 15.2 but you can also install GCC 16.0.1 from a package repository. Both of these versions crash when 'concat_view.h' captures `this` directly. Only Ubuntu 26.10 that should be released in October (aka next month) has easy access to GCC 16.2.

I don't suggest any actions as I don't know if building libc++ should be supported with a toolchain retrieved from a package manager and not downloaded or built separately. Personally, I would find it nice if the 'concat_view.h' change is reverted until there is another Ubuntu LTS with a sufficiently recent toolchain. But waiting for 2 years isn't particularly realistic and most likely at that time something else would be broken. So another option is to revert 'concat_view.h' for ~2 months, so users can build the current libc++ with the latest toolchain on the latest Ubuntu version.

https://github.com/llvm/llvm-project/pull/206235