[Bug libstdc++/127220] : clang rejects every dynamic width or precision ("{:{}}") in C++26 mode: __check_dynamic_spec is instantiated before its definition

[stevensudit at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127220

--- Comment #3 from Steve Sudit <stevensudit at gmail dot com> ---
The first 13 lines of the description are my own filing notes, pasted by
mistake; the report starts at "With clang on top of libstdc++".