https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118833
Bug ID: 118833
Summary: [15 Regression] ICE with structured binding as
condition of while/for loop since r15-7426
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: jakub at gcc dot gnu.org
Target Milestone: ---
My PR86769 fix regressed the following testcase, it now ICEs:
// P0963R3 - Structured binding declaration as a condition
// { dg-do compile { target c++11 } }
// { dg-options "" }
namespace std {
template<typename T> struct tuple_size;
template<int, typename> struct tuple_element;
}
struct S {
S () : s (0) {}
S (int x) : s (x) {}
S (const S &x) : s (x.s) {}
~S () {}
int s;
};
struct T {
S a, b, c;
~T () {}
explicit operator bool () const noexcept { return a.s == b.s; }
template <int I> S get () { return I ? a : b; }
};
template<> struct std::tuple_size<T> { static const int value = 2; };
template<int I> struct std::tuple_element<I,T> { using type = S; };
void
foo (T t, bool x)
{
while (auto [ i, j ] = T { 1, 1, 3 }) // { dg-warning "structured bindings in
conditions only available with" "" { target c++23_down } }
{
if (x)
break;
}
}
void
bar (T t, bool x)
{
for (int cnt = 0; auto [ i, j ] = T { 2, 2, 4 }; ++cnt) // { dg-warning
"structured bindings in conditions only available with" "" { target c++23_down
} }
{
if (x)
break;
}
}
The assumption that there is no or just a single cleanup isn't true for
structured bindings used as a condition, each name in the structured binding
can have its own cleanup.
