syntax_data: {"ast_node_type":"other","tokens":[{"end":79,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// i.e., each thing is mapped to a canonical variable with the same index.
context_before:     /// Returns `true` if this represents the generic parameters of the form `[?0, ?1, ?2]`,
context_after:     fn is_identity(&self) -> bool {