syntax_data: {"ast_node_type":"other","tokens":[{"end":52,"kind":"keyword","start":0,"text":"self_ty.instantiate(self.tcx,"}]}
source_snippet:                 self_ty.instantiate(self.tcx, args),
context_before:                 ty::TypingEnv::fully_monomorphized(),
context_after:                 impl_trait_ref.map(|impl_trait_ref| impl_trait_ref.instantiate(self.tcx, args)),