Title
Incorrect grammar for deduction-guide
Status
c++20
Section
13.7.2.3 [temp.deduct.guide]
Submitter
Barry Revzin

Created on 2019-07-28.00:00:00 last changed 39 months ago

Messages

Date: 2019-09-15.00:00:00

Proposed resolution (September, 2019):

Change the grammar in 13.7.2.3 [temp.deduct.guide] paragraph 1 as follows:

    deduction-guide:
      explicit explicit-specifieropt template-name ( parameter-declaration-clause ) -> simple-template-id ;
Date: 2019-11-15.00:00:00

[Adopted as a DR at the November, 2019 meeting.]

According to 13.7.2.3 [temp.deduct.guide] paragraph 1, the syntax of a deduction-guide is:

    deduction-guide:
      explicitopt template-name ( parameter-declaration-clause ) -> simple-template-id ;

Instead of explicit, this production should use the explicit-specifier nonterminal. (The wording of 12.2.2.9 [over.match.class.deduct] has references to the explicit-specifier of a deduction guide, for example.)

History
Date User Action Args
2020-12-15 00:00:00adminsetmessages: + msg6474
2019-07-28 00:00:00admincreate