[Bug c++/84849] Ambiguous resolution of braze initializer list to a class with explicit constructors
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84849 Andrew Pinski changed: What|Removed |Added See Also||https://gcc.gnu.org/bugzill ||a/show_bug.cgi?id=97220 --- Comment #8 from Andrew Pinski --- PR 97220 looks similar and might be a dup of this bug.
[Bug c++/84849] Ambiguous resolution of braze initializer list to a class with explicit constructors
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84849 --- Comment #7 from ensadc at mailnesia dot com --- (In reply to Zhihao Yuan from comment #6) > Here is a possibly related case: > > [...] I think this is a different bug. GCC thinks the implicitly-deleted move assignment operator `pair& pair::operator=(pair&&)` is a candidate for the assignment, which causes ambiguity with `operator=(value_type&&)` (where value_type = pair). But as part of resolution of CWG 1402, [class.copy.assign] specifies that "A defaulted move assignment operator that is defined as deleted is ignored by overload resolution".
[Bug c++/84849] Ambiguous resolution of braze initializer list to a class with explicit constructors
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84849
Zhihao Yuan changed:
What|Removed |Added
CC||lichray at gmail dot com
--- Comment #6 from Zhihao Yuan ---
Here is a possibly related case:
#include
template
struct pair
{
using value_type = pair>;
T a, b;
constexpr pair& operator=(value_type const& other)
{
a = other.a;
b = other.b;
return *this;
}
constexpr pair& operator=(value_type&& other)
{
a = std::move(other.a);
b = std::move(other.b);
return *this;
}
};
template
constexpr pair tie(T& a, T& b) noexcept
{
return { a, b };
}
int main()
{
int a = 3;
int b = 5;
tie(a, b) = { b, a % b }; // works
tie(a, b) = { b, a }; // wat
}
Error messages are very similar https://godbolt.org/z/4FSeOO.
[Bug c++/84849] Ambiguous resolution of braze initializer list to a class with explicit constructors
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84849
ensadc at mailnesia dot com changed:
What|Removed |Added
CC||ensadc at mailnesia dot com
--- Comment #5 from ensadc at mailnesia dot com ---
This is also ambiguous and seems to have the same cause (i.e. overload
resolution accepts list-initialization that calls explicit constructor when
forming the implicit conversion sequence):
template
struct in_place_type_t { explicit in_place_type_t() = default; };
struct A { };
int f(A);
int f(in_place_type_t);
int x = f({});
[Bug c++/84849] Ambiguous resolution of braze initializer list to a class with explicit constructors
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84849 Marek Polacek changed: What|Removed |Added Status|NEW |ASSIGNED Assignee|unassigned at gcc dot gnu.org |mpolacek at gcc dot gnu.org --- Comment #4 from Marek Polacek --- Thanks, this sounds interesting.
[Bug c++/84849] Ambiguous resolution of braze initializer list to a class with explicit constructors
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84849 Raphael Kubo da Costa changed: What|Removed |Added CC||mpolacek at gcc dot gnu.org --- Comment #3 from Raphael Kubo da Costa --- +mpolacek in case he'd like to take a look. This is still reproducible with trunk.
[Bug c++/84849] Ambiguous resolution of braze initializer list to a class with explicit constructors
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84849
Jonathan Wakely changed:
What|Removed |Added
Summary|Ambiguous resolution of |Ambiguous resolution of
|braze initializer list to a |braze initializer list to a
|class with explicit |class with explicit
|copy/move constructors |constructors
--- Comment #2 from Jonathan Wakely ---
Further reduced:
struct X {
X(int) { }
};
struct Foo {
explicit Foo(const X&);
explicit Foo(X&&) { }
};
int main() {
Foo v({1});
}
vs.cc: In function 'int main()':
vs.cc:11:12: error: call of overloaded 'Foo()'
is ambiguous
Foo v({1});
^
vs.cc:7:12: note: candidate: 'Foo::Foo(X&&)'
explicit Foo(X&&) { }
^~~
vs.cc:6:12: note: candidate: 'Foo::Foo(const X&)'
explicit Foo(const X&);
^~~
vs.cc:5:8: note: candidate: 'constexpr Foo::Foo(const Foo&)'
struct Foo {
^~~
vs.cc:5:8: note: candidate: 'constexpr Foo::Foo(Foo&&)'
