[libcxx-commits] [clang] [libcxx] [llvm] Add unnecessary-virtual-specifier to -Wextra (PR #138741)

[Devon Loehr via libcxx-commits]

DKLoehr wrote:

Looks like all the libc++ checks passed, so we should be good.

> Alternatively, we could ‘fix’ our codebase instead by introducing an LLVM_VIRTUAL_ANCHOR macro or sth like that which disables the diagnostic for that one declaration.

This seems like a good way to do it, since it clearly documents what's going on. LLVM is the only project I've seen with such a policy; across all of chromium's dependencies, the extra `virtual` specifiers we flagged were indeed mistakes. The issue with libc++ was more to do with infrastructure than the warning itself, IIUC.

https://github.com/llvm/llvm-project/pull/138741