syntax_data: {"ast_node_type":"other","tokens":[{"end":107,"kind":"keyword","start":0,"text":"///"}]}
source_snippet: ///     @call("mir_assign", args) => { args[0] }, // match invocations of the `mir_assign` special function
context_before: ///     "assignment", // the thing you're trying to parse
context_after: ///     ExprKind::Assign { lhs, .. } => { lhs }, // match thir assignment expressions