FYI, [Boost].UT (since v1.1.2) has relaxed the standard requirement to C++17 (although some limitations apply depending on the standard/compiler combination).
In general, source_location is available since C++20, however, the builtin functionality powering it (__builtin_FILE(), __builtin_LINE()) is available since GCC-9/Clang-9.
Therefore, now:
* [Boost].UT with Clang/GCC >= 9 and with either C++17 or C++20 works as expected (although with C++17 it uses compiler builtin designed for C++20 source_location)
* [Boost].UT with Clang/GCC < 9 and with either C++17 or C++20 still compiles/`works`, however, the file/line in assertion won't be propagated
Also, MSVC-2019 doesn't support source_location yet neither with /std:C++20 nor with /std:C++latest, hence, the file/line is also not propagated yet.
-Kris