This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 118f. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2025-11-07

3108. Reflection on type aliases

(From submission #789.)

It is not clear in 7.6.2.10 [expr.reflect] paragraph 6 whether the phrasing "names a type alias" also applies for type aliases appearing somewhere in a type-id, e.g. ^^const my_typedef_name.

Proposed resolution (approved by CWG 2025-11-04):

Change in 7.6.2.10 [expr.reflect] bullet 6.2 as follows:

A reflect-expression R of the form ^^type-id represents an entity determined as follows:

• If the type-id designates a placeholder type (9.2.9.7.1 [dcl.spec.auto.general]), R is ill-formed.
• Otherwise, if the type-id names a type alias that is a specialization of is of the form nested-name-specifier_opt template_opt simple-template-id and whose terminal name is a template-name that names an alias template (13.7.8 [temp.alias]), R represents that the type alias so named.
• Otherwise, R represents the type denoted by the type-id.