This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 115f. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.
2024-12-06
[Accepted as a DR at the February, 2023 meeting.]
According to 3.51 [defns.signature.templ], the signature of a function template includes:
name, parameter-type-list, enclosing namespace, return type, template-head, and trailing requires-clause (if any)
The mention of the template-head is a change from previous versions of the Standard, which referred to the “template parameter list”, in order to include the requires-clause in the signature. However, template-head is a syntactic nonterminal and thus includes everything in that production, including default template arguments. It seems undesirable to make the default arguments part of the template signature.
CWG 2022-11-11
CWG agrees with the suggested direction.
Proposed resolution (approved by CWG 2023-02-09):
Change in 3.50 [defns.signature.friend] as follows:
signature
<function template>
name, parameter-type-list, enclosing namespace, return type, signature of the template-head, and trailing requires-clause (if any)
Change in 3.51 [defns.signature.templ] as follows:
signature
<friend function template with constraint involving enclosing template parameters>
name, parameter-type-list, return type, enclosing class, signature of the template-head, and trailing requires-clause (if any)
Change in 3.54 [defns.signature.member] as follows:
signature
<class member function template>
name, parameter-type-list, class of which the function is a member, cv-qualifiers (if any), ref-qualifier (if any), return type (if any), signature of the template-head, and trailing requires-clause (if any)
Add a new section in Clause 3 [intro.defs] as follows:
signature
<template-head>
template parameter list, excluding template parameter names and default arguments, and requires-clause (if any)