[Bug other/61321] demangler crash on casts in template parameters

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61321

--- Comment #12 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
_ZSt7forwardIRKZN5Write14DataMapGrammarISt20back_insert_iteratorISsEEC4EvEUlRT_E_EOS5_RNSt16remove_referenceIS5_E4typeE

still recurses endless, even with your patch applied.