syntax_data: {"ast_node_type":"other","tokens":[{"end":87,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                         // Use a type that can't appear in defaults of type parameters.
context_before:                     ty::ExistentialPredicate::Trait(trait_ref) => {
context_after:                         let dummy_self = Ty::new_fresh(p.tcx, 0);