syntax_data: {"ast_node_type":"variable","tokens":[{"end":63,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// let b: Canonical<I, (T,)> = a.unchecked_map(|v| (v, ));
context_before:     /// let a: Canonical<I, T> = ...;
context_after:     /// ```