This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 110b. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2023-01-15


804. Deducing the type in new auto(x)

Section: 7.6.2.8  [expr.new]     Status: CD2     Submitter: UK     Date: 3 March, 2009

N2800 comment UK 71

[Voted into WP at October, 2009 meeting.]

The type of an allocated object wih the type specifier auto is determined by the rules of copy initialization, but the initialization applied will be direct initialization. This would affect classes which declare their copy constructor explicit, for instance. For consistency, use the same form of initiailization for the deduction as the new expression.

Proposed resolution (July, 2009):

Change 7.6.2.8 [expr.new] paragraph 2 as follows:

If the auto type-specifier appears in the type-specifier-seq of a new-type-id or type-id of a new-expression, the new-expression shall contain a new-initializer of the form

The allocated type is deduced from the new-initializer as follows: Let (e) be e be the assignment-expression in the new-initializer and T be the new-type-id or type-id of the new-expression, then the allocated type is the type deduced for the variable x in the invented declaration (9.2.9.6 [dcl.spec.auto]):

[Example:...