https://bugzilla.mozilla.org/show_bug.cgi?id=1443590 https://bugzilla.mozilla.org/show_bug.cgi?id=1443590 has info on why : > We've discussed this on several o

https://bugzilla.mozilla.org/show_bug.cgi?id=1443590 https://bugzilla.mozilla.org/show_bug.cgi?id=1443590 has info on why : > We've discussed this on several occasions but apparently nobody ever filed a bug. > There are a number of reasons using clang-cl for our official builds would be good: > * The ability to patch the toolchain as we do on other platforms > * The ability to diagnose and upstream fixes for compiler bugs we encounter > * It would provide motivation to switch to clang on all platforms, which would make it so we only have to worry about a single compiler for things like performance optimization (I don't assume we would drop support for MSVC or gcc, we just wouldn't have to worry as much about compiler quirks)