https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116476
Bug ID: 116476
Summary: error: binding reference of type 'int&&' to 'const
int' discards qualifiers for std::vector<field<int>>
f{2}; (OK under Clang and GCC<=13)
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: nabijaczleweli at nabijaczleweli dot xyz
Target Milestone: ---
minified reproducer, reduced from the original
(https://git.sr.ht/~nabijaczleweli/voreutils/tree/5781698e96ad3a085a2f3d712dc61b020ae287ad/item/cmd/df.cpp#L80):
#include <vector>
template <class T>
struct field {
field(T &&) {}
};
std::vector<field<int>> fields_normal{2}; // Error
std::vector<field<int>> fields_workaround{{2}}; // OK
All Clangs I cared to try and GCCs <=13 accept this and do the expected thing.
GCC 14 (and trunk according to godbolt) explode with
<source>:6:40: error: binding reference of type 'int&&' to 'const int' discards
qualifiers
6 | std::vector<field<int>> fields_normal{2}; // Error
| ^
<source>:4:11: note: initializing argument 1 of 'field<T>::field(T&&) [with T
= int]'
4 | field(T &&) {}
| ^~~~
<source>: In function 'void __static_initialization_and_destruction_0()':
<source>:6:40: error: cannot bind rvalue reference of type 'int&&' to lvalue of
type 'const int'
6 | std::vector<field<int>> fields_normal{2}; // Error
| ^
<source>:4:11: note: initializing argument 1 of 'field<T>::field(T&&) [with T
= int]'
4 | field(T &&) {}
| ^~~~
Compiler returned: 1
which feels nonsensical to me.
