Proposed resolution:

This wording is relative to the FDIS.

1. Change Table 28 — Allocator requirements in [allocator.requirements]:

   Table 28 — Allocator requirements

   Expression	Return type	Assertion/note pre-/post-condition	Default
   X a1(a); X a1 = a;		Shall not exit via an exception. post: a1 == a
   …
   X a1(move(a)); X a1 = move(a);		Shall not exit via an exception. post: a1 equals the prior value of a.

2. Change [allocator.requirements] paragraph 4:

   An allocator type X shall satisfy the requirements of CopyConstructible ([utility.arg.requirements]). The X::pointer, X::const_pointer, X::void_pointer, and X::const_void_pointer types shall satisfy the requirements of NullablePointer ([nullablepointer.requirements]). No constructor, comparison operator, copy operation, move operation, or swap operation on these types shall exit via an exception. X::pointer and X::const_pointer shall also satisfy the requirements for a random access iterator ([iterator.requirements]).

[ 2012, Portland: applied to WP ]

[ 2012, Kona ]

Move to Ready.

As discussed in c++std-lib-31054 and c++std-lib-31059, the Allocator requirements implicitly require CopyConstructible because a.select_on_container_copy_construction() and container.get_allocator() both return a copy by value, but the requirement is not stated explicitly anywhere.

In order to clarify that allocators cannot have 'explicit' copy constructors, the requirements should include CopyConstructible.