https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97034
--- Comment #7 from Marek Polacek <mpolacek at gcc dot gnu.org> --- Candidate patch: --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -27279,7 +27279,10 @@ type_dependent_expression_p (tree expression) && DECL_UNIQUE_FRIEND_P (expression) && (!DECL_FRIEND_CONTEXT (expression) || dependent_type_p (DECL_FRIEND_CONTEXT (expression)))) - && !DECL_LOCAL_DECL_P (expression)) + && !DECL_LOCAL_DECL_P (expression) + /* We build deduction guides without any DECL_CONTEXT, but they can + be type-dependent. */ + && !deduction_guide_p (expression)) { gcc_assert (!dependent_type_p (TREE_TYPE (expression)) || undeduced_auto_decl (expression));