syntax_data: {"ast_node_type":"import","tokens":[{"end":27,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     ///         use foo::*;
context_before:     ///     macro n($j:ident) {
context_after:     ///         f(); // `f`'s `SyntaxContext` has a mark from `m` and a mark from `n`