{"ast_node_type":"other","tokens":[{"end":58,"kind":"keyword","start":0,"text":"(ty::ClosureKind::Fn,"}]}
        (ty::ClosureKind::Fn, ty::ClosureKind::FnMut) => {
        }
            // The closure fn is a `fn(&self, ...)`, but we want a `fn(&mut self, ...)`.