syntax_data: {"ast_node_type":"other","tokens":[{"end":40,"kind":"keyword","start":0,"text":"closure_tupled_upvars_ty:"}]}
source_snippet:         closure_tupled_upvars_ty: I::Ty,
context_before:         env_region: I::Region,
context_after:         coroutine_captures_by_ref_ty: I::Ty,