Assertion failure sometimes shows file+line number of macro, instead of use site

[RalfJung]

Sometimes, when an assertion fails, the file+line point to the macro in libstd, instead of the place where the macro is used. See for example #73007 (comment), and @Mark-Simulacrum said they also saw this happen locally.

Currently, it is unclear how to reproduce this problem.

[Aaron1011]

I believe this is a duplicate of #70963, and will be fixed by #72121

[RalfJung]

Sounds plausible, yeah. Closing then, thanks!