[libcxx-commits] [PATCH] D145800: [libc++] Granularizes vector.

[Eric Fiselier via Phabricator via libcxx-commits]

EricWF requested changes to this revision.
EricWF added a comment.
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Herald added a subscriber: mikhail.ramalho.

I think this is a really bad idea. 
Splitting the specialization out so that only some files can depend on it, while others cannot, allowing some bits of the code to only see a partial implementation is going to be bug prone.

I'm also not sure I agree with the bug. The standard only requires the declaration of the type to be available without the format include. It says nothing about requiring the type to be complete IMHO.
Like that `hash<std::vector<bool>>` is declared in `<vector>` but technically you need to include `<utility>` to get its definition.

This dance is done specifically so that anytime a type T with a hash specialization is seen by the user, `hash<T>` has been properly declared, so the compiler knows to not instantiate the default implementation.

I would like to see other alternative solutions explored. I don't think this one should proceed.



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Comment at: libcxx/include/__vector/vector.h:339
 
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
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Comment at: libcxx/include/__vector/vector.h:3351
-_LIBCPP_BEGIN_NAMESPACE_STD
-namespace pmr {
-template <class _ValueT>
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Repository:
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  https://reviews.llvm.org/D145800/new/

https://reviews.llvm.org/D145800