b37b307715
`[[nodiscard]]` should be applied to functions where discarding the return value is most likely a correctness issue. - https://libcxx.llvm.org/CodingGuidelines.html#apply-nodiscard-where-relevant The following functions/classes have been annotated in this patch: - [x] `bind_back`, `bind_front`, `bind` - [x] `function`, `mem_fn` - [x] `reference_wrapper`