https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79094
Bug ID: 79094
Summary: Pack explansion in using-declaration rejects an
attempt to inherit a pack of constructors
Product: gcc
Version: 7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ville.voutilainen at gmail dot com
Target Milestone: ---
template <class... Args> struct X : Args...
{
using Args::Args...;
};
int main()
{
struct A {A() = default; A(int) {}};
struct B {B() = default; B(double) {}};
X<A, B> x1{42};
X<A, B> x2{666.0};
}
Clang accepts the code. GCC rejects it:
prog.cc:3:21: error: parameter packs not expanded with '...':
using Args::Args...;
^~~
prog.cc:3:21: note: 'Args'
prog.cc: In function 'int main()':
prog.cc:10:18: warning: missing initializer for member 'X<main()::A,
main()::B>::<anonymous>' [-Wmissing-field-initializers]
X<A, B> x1{42};
^
prog.cc:11:21: warning: missing initializer for member 'X<main()::A,
main()::B>::<anonymous>' [-Wmissing-field-initializers]
X<A, B> x2{666.0};
^
