[clang] [clang] Check constexpr int->enum conversions consistently. (PR #143034)

[Tom Stellard via cfe-commits]

tstellar wrote:

@efriedma-quic Thank you.  It looks like this bug was fixed in the chromium upstream already too: https://github.com/chromium/chromium/commit/b0ff8c3b258a8816c05bdebf472dbba719d3c491

https://github.com/llvm/llvm-project/pull/143034