[PATCH] [libcxx] Delay evaluation of __make_tuple_types to prevent blowing the max template instantiation depth. Fixes Bug #18345

[Agustín Bergé]

Have you considered a non-recursive implementation of `__tuple_constructible_imp`? For instance, checking whether `foo(declval<Up>()...)` is well-formed given `void foo(Tp...)`.

http://reviews.llvm.org/D4467