syntax_data: {"ast_node_type":"other","tokens":[{"end":64,"kind":"keyword","start":0,"text":"ty:"}]}
source_snippet:                         ty: Ty::new_tup_from_iter(tcx, arg_tys),
context_before:                     let tupled_args = Expr {
context_after:                         temp_lifetime: TempLifetime { temp_lifetime, backwards_incompatible },