| 16719cd0 | 12-May-2022 |
Hui Xie <[email protected]> |
[libc++] P2321R2 section [tuple.tuple]. Adding C++23 constructors, assignment operators and swaps to `tuple`
1. for constructors that takes cvref variation of tuple<UTypes...>, there
used to be two
[libc++] P2321R2 section [tuple.tuple]. Adding C++23 constructors, assignment operators and swaps to `tuple`
1. for constructors that takes cvref variation of tuple<UTypes...>, there
used to be two SFINAE helper _EnableCopyFromOtherTuple,
_EnableMoveFromOtherTuple. And the implementations of these two helpers
seem to slightly differ from the spec. But now, we need 4 variations.
Instead of adding another two, this change refactored it to a single one
_EnableCtrFromUTypesTuple, which directly maps to the spec without
changing the C++11 behaviour. However, we need the helper __copy_cvref_t
to get the type of std::get<i>(cvref tuple<Utypes...>) for different
cvref, so I made __copy_cvref_t to be available in C++11.
2. for constructors that takes variations of std::pair, there used to be
four helpers _EnableExplicitCopyFromPair, _EnableImplicitCopyFromPair,
_EnableImplicitMoveFromPair, _EnableExplicitMoveFromPair. Instead of
adding another four, this change refactored into two helper
_EnableCtrFromPair and _BothImplicitlyConvertible. This also removes the
need to use _nat
3. for const member assignment operator, since the requirement is very
simple, I haven't refactored the old code but instead directly adding
the new c++23 code.
4. for const swap, I pretty much copy pasted the non-const version to make
these overloads look consistent
5. while doing these change, I found two of the old constructors wasn't
marked constexpr for C++20 but they should. fixed them and added unit
tests
Reviewed By: #libc, ldionne
Differential Revision: https://reviews.llvm.org/D116621
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