https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90390
Bug ID: 90390
Summary: incorrect list initialization behavior for references
Product: gcc
Version: 9.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: boehm-gc
Assignee: unassigned at gcc dot gnu.org
Reporter: mikedlui+gccbugzilla at gmail dot com
Target Milestone: ---
https://stackoverflow.com/a/54120116/1371191
Example from the link:
int g_i = 10;
struct S {
operator int&(){ return g_i; }
};
int main() {
S s;
int& iref1 = s; // implicit conversion
int& iref2 = {s}; // clang++ error, g++ compiles fine:
// `s` is converted
// to a temporary int and binds with
// lvalue reference
int&& iref3 = {s}; // clang++ compiles, g++ error:
// cannot bind rvalue reference
// to lvalue
}
Because `s` of type `S` is not reference-related to `int`, a temporary of type
`int` should be created during list initialization. Instead, it seems that the
user-defined conversion occurs first.
