https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102629
Bug ID: 102629 Summary: internal compiler error: tree check: expected record_type or union_type or qual_union_type, have decltype_type in lookup_base, at cp/search.c:233 Product: gcc Version: 12.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: hewillk at gmail dot com Target Milestone: --- 12 Regression: #include <utility> struct S {}; template <typename... Args> void foo(Args&&... args) { [...args = std::forward<Args> /*(args)*/] { [](auto...) { } (std::forward<Args>(args)...); }; } void bar( ) { foo(S{}); } https://godbolt.org/z/WhnWTbvoj