https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125282
Fedor Chelnokov <fchelnokov at gmail dot com> changed:
What |Removed |Added
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CC| |fchelnokov at gmail dot com
--- Comment #2 from Fedor Chelnokov <fchelnokov at gmail dot com> ---
Another testcase for the same function (https://gcc.godbolt.org/z/x93rnnGxG):
```
struct x {};
template<int = 0>
void foo() { ([]{ auto [...xs] = x{}; xs; }, ...); }
template void foo<>();
// internal compiler error: Segmentation fault
// tsubst_pack_expansion(tree_node*, tree_node*, int, tree_node*)
// instantiate_decl(tree_node*, bool, bool)
```
Differences from comment 0: the pack is not named in the RHS of its own
binding, the initializer is not involved — tsubst_pack_expansion is reached
straight from instantiate_decl rather than through tsubst_init/tsubst_call_args
— and it is a segfault rather than the assert. 16.1 and trunk alike.
Replacing `xs;` with anything that does not name the pack unexpanded — `(xs,
...);`, `static_assert(sizeof...(xs) == 0);`, or nothing at all — gives the
correct "operand of fold expression has no unexpanded parameter packs"; same
for pack expansion in a call argument or in a braced initializer list.
Clang crashes on the same shape:
https://github.com/llvm/llvm-project/issues/214160
