[libcxx-commits] [PATCH] D118963: [libc++] No longer support ranges::begin(x) when x is an array of incomplete type.

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

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var-const points out that `ranges::begin` is (non-normatively but explicitly) always supposed to return a `std::input_or_output_iterator`, and `Incomplete*` is not a `std::input_or_output_iterator` because it has no `operator++`. Therefore, we should never return `Incomplete*` from `ranges::begin(x)`, even when `x` is `Incomplete(&)[]`. Instead, just SFINAE away.

(The note in question: https://eel.is/c++draft/range.access.begin#4 "Whenever `ranges​::​begin(E)` is a valid expression, its type models `input_­or_­output_­iterator`.")


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D118963

Files:
  libcxx/include/__ranges/access.h
  libcxx/test/libcxx/ranges/range.access/begin.incomplete_type.sh.cpp
  libcxx/test/std/ranges/range.access/begin.pass.cpp

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