https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61953
Bug ID: 61953
Summary: [C++11] The template parameter pack of a function
template should be the last template parameter
Product: gcc
Version: 4.10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: kariya_mitsuru at hotmail dot com
The both sample codes below should cause compilation error but they are
compiled successfully by gcc.
==============================================
template<class... T, class... U> void f() { }
==============================================
===========================================
template<class... T, class U> void g() { }
===========================================
According to C++11 standard 14.1 Template parameters [temp.param] paragraph 11,
"A template parameter pack of a function template shall not be followed by
another template parameter unless that template parameter can be deduced from
the parameter-type-list of the function template or has a default argument."
The latest draft is more clarified using the following example.
=======================================================================
// U can be neither deduced from the parameter-type-list nor specified
template<class... T, class... U> void f() { } // error
template<class... T, class U> void g() { } // error
=======================================================================
cf. http://melpon.org/wandbox/permlink/zO14UQDvxpXwRfYm
