https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93702
--- Comment #4 from Eric Botcazou <ebotcazou at gcc dot gnu.org> --- This comes from a long-standing issue with expression functions (that are not completions) in Ada 2012, which are fundamentally incompatible with GNAT's freezing model tailored to Ada 95. Various countermeasures to this have been implemented over the years in the compiler, but they are not bullet proof.
