syntax_data: {"ast_node_type":"other","tokens":[{"end":31,"kind":"keyword","start":0,"text":"self.add_ty(a);"}]}
source_snippet:                 self.add_ty(a);
context_before:             ty::PredicateKind::Coerce(ty::CoercePredicate { a, b }) => {
context_after:                 self.add_ty(b);