[clang] [llvm] [clang] Clang multi-match behavior of WarningSuppressionMappings (PR #162237)

[Florian Mayer via cfe-commits]

https://github.com/fmayer commented:

I don't know how many use this, and if we need some gentler way to change this behavior to avoid breaking people.

https://github.com/llvm/llvm-project/pull/162237