[Bug lto/83997] ICE with alias template and attribute

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83997

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
bu11.cc:10:1: internal compiler error: tree code 'template_parm_index' is not
supported in LTO streams

this usually means FE tree codes leak somehow into the middle-end there's a
free_lang_data langhook for the FE to prune these from types/decls when needed.