[PATCH] [libc++] Make std::deque instantiable with incomplete element type

[Howard Hinnant]

On Sep 19, 2013, at 1:16 AM, Peter Collingbourne <peter at pcc.me.uk> wrote:

> This is a QOI improvement to allow std::deque to be instantiated with
> an incomplete element type.  The only thing preventing it from being
> so instantiated was the __block_size constant, which this patch moves
> into a constexpr function and calls where necessary.
> 
> http://llvm-reviews.chandlerc.com/D1724
> 
> Files:
>  include/deque
>  test/containers/sequences/deque/types.pass.cpp
> <D1724.1.patch>_______________________________________________
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I really like this patch.  It is a nice piece of work.  Unfortunately I think I'm going to have to decline it for ABI reasons.  If the client writes code like this:

#include <deque>

void
test(std::deque<int>::iterator);

int
main()
{
    test(std::deque<int>::iterator());
}

This patch changes the mangling of the customer's function from:

__Z4testNSt3__116__deque_iteratorIiPiRiPS1_lLl1024EEE

to:

__Z4testNSt3__116__deque_iteratorIiPiRiPS1_lEE

Howard