syntax_data: {"ast_node_type":"other","tokens":[{"end":66,"kind":"keyword","start":0,"text":"self.tcx.mk_args(&[self.old_yield_ty.into()]),"}]}
source_snippet:                     self.tcx.mk_args(&[self.old_yield_ty.into()]),
context_before:                     VariantIdx::ZERO,
context_after:                     IndexVec::new(),