bugprone-unchecked-optional-access does something even if no optional implementation is available

[firewave]

#57527 (comment) indicates that bugprone-unchecked-optional-access is in the upper third in terms of heaviness. This applies even if your are not using optional at all since you require either C++17 (std), the abseil library (absl::) or (apparently) the chromium project (base::).

It should be smarter about this and not do anything if these objects are not available.

The list of the objects to be checked should probably be configurable as well allowing additional optional implementations to be supported. It doesn't support Boost.Optional or llvm::Optional which is a bit strange as those are probably more wide-spread than the currently supported custom implementations.

This configuration could also offer another way to mitigate this issue by supporting an empty list essentially disabling the check.

[firewave]

Some comments on this from the original ticket: #57527 (comment).

[llvmbot]

@llvm/issue-subscribers-clang-tidy

[firewave]

The check is not that heavy but it isn't free either (the *-identifiers checks are still up there as I am still using LLVM 16 on this system):

   ---User Time---   --System Time--   --User+System--   ---Wall Time---  --- Name ---
   1.3305 ( 28.0%)   0.5332 ( 23.2%)   1.8638 ( 26.4%)   1.8645 ( 26.4%)  misc-confusable-identifiers
   0.5771 ( 12.1%)   0.1803 (  7.8%)   0.7574 ( 10.7%)   0.7491 ( 10.6%)  bugprone-reserved-identifier
   0.2187 (  4.6%)   0.0361 (  1.6%)   0.2548 (  3.6%)   0.2549 (  3.6%)  modernize-use-using
[...]
   0.0624 (  1.3%)   0.0343 (  1.5%)   0.0967 (  1.4%)   0.0971 (  1.4%)  bugprone-unchecked-optional-access