syntax_data: {"ast_node_type":"other","tokens":[{"end":68,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                     // : 'a`, but be wary of something like `for<'a>
context_before:                     // Search for a bound of the form `erased_self_ty
context_after:                     // erased_self_ty : 'a` (we interpret a