syntax_data: {"ast_node_type":"other","tokens":[{"end":95,"kind":"keyword","start":0,"text":"ty::Binder::dummy(ty::PredicateKind::Subtype(ty::SubtypePredicate"}]}
source_snippet:                             ty::Binder::dummy(ty::PredicateKind::Subtype(ty::SubtypePredicate {
context_before:                             self.param_env,
context_after:                                 a_is_expected: true,