[PATCH] D36049: [Resubmitted] Remove uses of deprecated std::unary_function, binary_function, and pointer_to_unary_function.

[Justin Bogner via llvm-commits]

David Blaikie via Phabricator <reviews at reviews.llvm.org> writes:
> dblaikie added inline comments.
>
> ================
> Comment at: include/llvm/ADT/STLExtras.h:61-62
> +struct identity {
> +  using argument_type = Ty;
> +  using result_type = Ty;
> +
> ----------------
> Should these changes be adding all these typedefs? I assume the reason
> std::unary_function et. al. are deprecated is that callers should
> likely be using decltype & similar things to work here instead?

IIUC the intent of deprecating these wasn't to get rid of the typedefs,
but instead to discourage things from saying they operate specifically
on a unary_function. Ie, it's better if some algorithm depends (in a
SFINAE way) on the type defining an argument_type and result_type rather
than on the type being isa-unary_function.