[libcxx-commits] [libcxx] [libc++] Drop -Wno-user-defined-literals when running the test suite (PR #167073)

[Louis Dionne via libcxx-commits]

ldionne wrote:

Note that this came up while reducing a reproducer in one of our tests. I removed a bunch of warning flags from the command-line and noticed that our headers started emitting large numbers of these warnings. I think it's worth handling the low hanging fruit in the headers directly.

https://github.com/llvm/llvm-project/pull/167073