Silence clang-tidy "unused variable" warnings

[dunhor]

Clang-tidy (and I'm pretty sure just Clang in general since this is a Clang diagnostic) warns that these variables are unused. This happens because the single threaded collections types use the following lock guard type:

struct nop_lock_guard {};

I could also fix this issue by adding a destructor to the type, however that may have consequences on code-gen. This seemed to be the less risky change with the tradeoff of touching more lines.

[sylveon]

Would doing struct [[nodiscard]] nop_lock_guard {}; silence the warning as well?

[dunhor]

Would doing struct [[nodiscard]] nop_lock_guard {}; silence the warning as well?

Looks like no: https://godbolt.org/z/YY9vEqh4s