{"ast_node_type":"other","tokens":[{"end":41,"kind":"keyword","start":0,"text":"AssignOp(AssignOp,"}]}
    AssignOp(AssignOp, P<Expr>, P<Expr>),
    /// E.g., `a += 1`.
    /// Access of a named (e.g., `obj.foo`) or unnamed (e.g., `obj.0`) struct field.