Title
Template aliases with default arguments and template parameter packs
Status
c++11
Section
13.2 [temp.param]
Submitter
Nikolay Ivchenkov

Created on 2010-03-27.00:00:00 last changed 96 months ago

Messages

Date: 2011-03-15.00:00:00

[Voted into the WP at the March, 2011 meeting.]

Date: 2011-01-15.00:00:00

Proposed resolution (January, 2011):

Change 13.2 [temp.param] paragraph 11 as follows:

If a template-parameter of a class template or alias template has a default template-argument, each subsequent template-parameter shall either have a default template-argument supplied or be a template parameter pack. If a template-parameter of a primary class template or alias template is a template parameter pack, it shall be the last template-parameter. [Note:...
Date: 2010-03-27.00:00:00

Since there appear to be no restrictions against it, it would appear that default arguments and template parameter packs can be used with template aliases just as with other templates. If that is the case, then, the current wording in 13.2 [temp.param] paragraph 11 requires adjustment:

If a template-parameter of a class template has a default template-argument, each subsequent template-parameter shall either have a default template-argument supplied or be a template parameter pack. If a template-parameter of a class template is a template parameter pack, it shall be the last template-parameter.

Presumably these restrictions should also apply to template aliases, but as written, they only apply to class templates.

History
Date User Action Args
2014-03-03 00:00:00adminsetstatus: fdis -> c++11
2011-04-10 00:00:00adminsetmessages: + msg3379
2011-04-10 00:00:00adminsetstatus: tentatively ready -> fdis
2011-02-28 00:00:00adminsetmessages: + msg3236
2011-02-28 00:00:00adminsetstatus: drafting -> tentatively ready
2010-08-23 00:00:00adminsetstatus: open -> drafting
2010-03-27 00:00:00admincreate