http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55924
Bug #: 55924
Summary: [C++11] Not all copy-assignment operator forms are
correctly detected
Classification: Unclassified
Product: gcc
Version: 4.7.2
Status: UNCONFIRMED
Severity: minor
Priority: P3
Component: c++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: daniel.krueg...@googlemail.com
The following code, compiled with
-Wall -std=c++11 -pedantic
is rejected by gcc 4.7.2 and gcc 4.8.0 20130106 (experimental):
//----------------
struct mine
{
mine& operator=(mine rhs) { return *this; }
mine& operator=(mine&& rhs) noexcept { return *this; }
};
int main()
{
mine a;
mine b;
a = b;
}
//----------------
"In function 'int main()':|
12|error: use of deleted function 'constexpr mine::mine(const mine&)'|
1|note: 'constexpr mine::mine(const mine&)' is implicitly declared as deleted
because 'mine' declares a move constructor or move assignment operator|
3|error: initializing argument 1 of 'mine& mine::operator=(mine)'|
"
According to 12.8 p17:
"A user-declared copy assignment operator X::operator= is a non-static
non-template member function of class X with exactly one parameter of type X,
X&, const X&, volatile X& or const volatile X&."
and p18:
"If the class definition does not explicitly declare a copy assignment
operator, one is declared implicitly. If the class definition declares a move
constructor or move assignment operator, the implicitly declared copy
assignment operator is defined as deleted;"
Therefore class mine provides a user-declared copy-assignment operator, but gcc
doesn't recognize that.
This code should be accepted.
I reduced the severity, because this kind of code is expected to be a rather
unusual edge-case. Every other form of the copy-assignment operator using
references is correctly detected.
