https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66169
--- Comment #1 from Ying-Po Liao <yingpo.liao at gmail dot com> ---
The following example shows a Concept applied to the constructor of class A.
The compiler (r223061) will generate internal compiler error if A's subclass C
implements default behaviors of copy/move constructors in which base
constructor forwarding is placed. Note that this example only shows a copy
constructor version. However, it will work for any of these cases:
1) C's copy/move constructors do not forward to base class.
2) C's copy/move constructors are deleted.
3) Concept does not use "decltype()" to check things.
$ svn info
Path: .
Working Copy Root Path:
/Users/liao/Downloads/gcc-branch-c++-concepts/c++-concepts
URL: svn://gcc.gnu.org/svn/gcc/branches/c++-concepts
Relative URL: ^/branches/c++-concepts
Repository Root: svn://gcc.gnu.org/svn/gcc
Repository UUID: 138bc75d-0d04-0410-961f-82ee72b054a4
Revision: 223175
Node Kind: directory
Schedule: normal
Last Changed Author: asutton
Last Changed Rev: 223061
Last Changed Date: 2015-05-12 07:21:04 -0500 (Tue, 12 May 2015)
$ cat main.cpp
#include <iostream>
template <typename R>
concept bool Concept()
{
return requires( R r ) {
std::begin(r);
std::end(r);
requires __is_same_as(
decltype(std::begin(r)), decltype(std::end(r)) );
};
}
struct A
{
A() = default;
A( const A& ) = default;
template <Concept R>
explicit A( R&& r )
{}
};
struct C : A
{
C() = default;
C( const C& ) = default;
};
int main()
{
C c;
return 0;
}
$ g++ -std=c++1z main.cpp -o main
main.cpp: In substitution of ‘template<class R> requires
predicate((Concept<R>)()) A::A(R&&) [with R = const A&]’:
main.cpp:24:8: required from here
main.cpp:20:14: internal compiler error: in conjoin_constraints, at
cp/constraint.cc:89
explicit A( R&& r )
^
main.cpp:20:14: internal compiler error: Abort trap: 6
g++: internal compiler error: Abort trap: 6 (program cc1plus)
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
