https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67342
Bug ID: 67342
Summary: Ill-formed move constructor ignored in favor of copy
constructor
Product: gcc
Version: 5.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: barry.revzin at gmail dot com
Target Milestone: ---
In the following code, A is neither movable nor copyable, and B has an A:
#include <utility>
struct A {
A() { }
A(A const&) = delete;
A(A&& ) = delete;
};
struct B {
A a;
B() = default;
B(B const& ) : a() { }
B(B&& ) = default;
};
int main()
{
B b1;
B b2(std::move(b1));
}
I would expect the move constructor to be preferred and this code to fail to
compile (with some diagnostic relating to the deleted A&& constructor), but
instead gcc (and clang) prefers the copy constructor for b2 here and the code
compiles.
I suspect this is a compiler bug, as if I instead defaulted the copy
constructor, gcc issues a diagnostic about "error: use of deleted function
'B::B(B&&)'"
