https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89700
Bug ID: 89700
Summary: Warn if move constructor is not generated and not
deleted
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Keywords: diagnostic
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: antoshkka at gmail dot com
Target Milestone: ---
It would be great to have a warning that helps to identify classes with
sub-optimal move semantics. Foe example it would be nice to have such a warning
for cases like following:
struct member {
member();
member(const member&);
member(member&&);
private:
int* data_;
};
// warninig: `my_class(const my_class&)` disables the
// implicit move constructor generation. Use
// `my_class(my_class&) = default;` to generate it or
// `my_class(my_class&) = delete;` to disable this warning.
struct my_class {
my_class() = default;
my_class(const my_class&);
private:
member member1;
member member2;
};
void foo(my_class c);
void test() {
my_class c;
foo(static_cast<my_class&&>(c)); // copies
}
The rules for the warning could be following:
Issue a warning if at least one of the class members has a move constructor,
class has a copy constructor and the move constructor is not implicitly
deleted.
