[libcxx-commits] [PATCH] D119029: [libc++] [D2358R0] ADL-proof `projected`

[Arthur O'Dwyer via Phabricator via libcxx-commits]

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This implements D2538R0 "ADL-proof std::projected", just to prove
that it works.

Notice that because `Holder<Incomplete>` is _possible_ to complete,
but _unsafe_ to complete, that means that `Holder<Incomplete>*`
is basically not an iterator and it's not even safe to ask if
`input_iterator<Holder<Incomplete>*>` because that _will_ necessarily
complete the type. So it's totally expected that we still cannot
safely ask e.g.

  static_assert(std::indirect_unary_predicate<bool(&)(Holder<Incomplete>&), Holder<Incomplete>*>);

or even

  static_assert(!std::indirect_unary_predicate<int, Holder<Incomplete>*>);


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D119029

Files:
  libcxx/include/__iterator/projected.h
  libcxx/test/std/iterators/iterator.requirements/indirectcallable/indirectinvocable/indirect_binary_predicate.compile.pass.cpp
  libcxx/test/std/iterators/iterator.requirements/indirectcallable/indirectinvocable/indirect_equivalence_relation.compile.pass.cpp
  libcxx/test/std/iterators/iterator.requirements/indirectcallable/indirectinvocable/indirect_result_t.compile.pass.cpp
  libcxx/test/std/iterators/iterator.requirements/indirectcallable/indirectinvocable/indirect_strict_weak_order.compile.pass.cpp
  libcxx/test/std/iterators/iterator.requirements/indirectcallable/indirectinvocable/indirect_unary_predicate.compile.pass.cpp
  libcxx/test/std/iterators/iterator.requirements/indirectcallable/indirectinvocable/indirectly_comparable.compile.pass.cpp
  libcxx/test/std/iterators/iterator.requirements/indirectcallable/indirectinvocable/indirectly_regular_unary_invocable.compile.pass.cpp
  libcxx/test/std/iterators/iterator.requirements/indirectcallable/indirectinvocable/indirectly_unary_invocable.compile.pass.cpp

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