https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111602
Bug ID: 111602
Summary: "Error: symbol is already defined" for variable
template dependent on default argument lambda used in
sfinae and non-sfinae
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ed at catmur dot uk
Target Milestone: ---
Since gcc 8.1,
template<class> constexpr bool V = true;
struct F { template<class T, bool = V<T>> F(T) {} };
template<class T> struct C { C(F = []{}) {} };
template<class T> decltype(T()) g() { return T(); }
auto f() { struct T {} t; return t; };
int main() { g<C<decltype(f())>>(); }
compiled at -O0 (and -std=c++14 or above) causes assembler error:
/tmp/cccVZwwU.s: Assembler messages:
/tmp/cccVZwwU.s:106: Error: symbol `_Z1VIZN1CIZ1fvE1TEC4E1FEd_UlvE_E' is
already defined
The symbol demangles as 'V<C<f()::T>::C(F)::{default arg#1}::{lambda()#1}>'.
