syntax_data: {"ast_node_type":"other","tokens":[{"end":50,"kind":"keyword","start":0,"text":"ty::ClosureKind::FnOnce"}]}
source_snippet:             ty::ClosureKind::FnOnce => closure_ty,
context_before:             ty::ClosureKind::FnMut => Ty::new_mut_ref(self, env_region, closure_ty),
context_after:         }