[clang] [clang] [SemaCXX] Implement CWG2627 Bit-fields and narrowing conversions (PR #78112)

[Mital Ashok via cfe-commits]

MitalAshok wrote:

New version gives a pedantic warning if this is used before C++23 (and it is a substitution failure before C++23)

https://github.com/llvm/llvm-project/pull/78112