One small comment, LGTM otherwise.
|464 ↗||(On Diff #151405)|
What about suggesting an alternative like:
Use ``rm -rf %t && mkdir %t`` instead if a temporary directory is necessary.
Perhaps that could even replace the Shouldn't be used, because [reason] sentence if brevity is desired.
%T should also be deprecated (or removed) below, where it's documented incorrectly:
Good catch. https://reviews.llvm.org/D48842.