syntax_data: {"ast_node_type":"other","tokens":[{"end":62,"kind":"keyword","start":0,"text":"///"}]}
source_snippet: /// 2. A `Seq` is never directly nested beneath another `Seq`.
context_before: /// 1. An `Alt` is never directly nested beneath another `Alt`.
context_after: /// 3. `Seq`s and `Alt`s with a single member do not exist.