syntax_data: {"ast_node_type":"other","tokens":[{"end":34,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:         // Assert there is a Self.
context_before:     pub fn erase_self_ty(interner: I, trait_ref: TraitRef<I>) -> ExistentialTraitRef<I> {
context_after:         trait_ref.args.type_at(0);