Disable tidy checks with too many hits

[ilya-biryukov]

Summary

Some tidy checks have too many hits in the codebase, making it hard to spot
other results from clang-tidy, therefore rendering the tool less useful.

Two checks were disabled:

• misc-non-private-member-variable-in-classes in the whole LLVM monorepo, it is very common to have those in LLVM and the style guide does not forbid them.
• readability-identifier-naming in the clang subtree. There are thousands of violations in 'Sema.h' alone.

Before the change, 'Sema.h' had >1000 tidy warnings, after the change the number
dropped to 3 warnings (unterminated namespace comments).

[ilya-biryukov]

• Also disable 'misc-non-private-member-variables-in-classes' in llvm/.clang-tidy

[hokein]

I'm +1 on disabling these checks as they add too much noise in editors (even though the naming check is correct, we can't do a global cleanup on the codebase). Let's commit it, we could revert it if someone has other concerns.

clang/.clang-tidy

2 ↗

(On Diff #184704)

"naming checks" => readability-identifier-naming check. Maybe also mention these violations add too much noise in editors?

[ilya-biryukov]

• Address comments

[alexfh]

I wonder whether a list of specific checks (without wildcards) would make more sense for llvm?

.clang-tidy

-Checks: '-*,clang-diagnostic-*,llvm-*,misc-*,-misc-unused-parameters,readability-identifier-naming'
+Checks: '-*,clang-diagnostic-*,llvm-*,misc-*,-misc-unused-parameters,-misc-non-private-member-variables-in-classes,-readability-identifier-naming'
+# Note that the readability-identifier-naming check is disabled, there are too
+# many violations in the codebase and they create too much noise in clang-tidy
+# results.
+# Naming settings are kept for documentation purposes and allowing to run the
+# check if the users would override this file, e.g. via a command-line arg.
 CheckOptions:
   - key:             readability-identifier-naming.ClassCase
     value:           CamelCase
   - key:             readability-identifier-naming.EnumCase
     value:           CamelCase
   - key:             readability-identifier-naming.FunctionCase
     value:           camelBack
   - key:             readability-identifier-naming.MemberCase
     value:           CamelCase
   - key:             readability-identifier-naming.ParameterCase
     value:           CamelCase
   - key:             readability-identifier-naming.UnionCase
     value:           CamelCase
   - key:             readability-identifier-naming.VariableCase
     value:           CamelCase