{"ast_node_type":"variable","tokens":[{"end":87,"kind":"keyword","start":0,"text":"let"}]}
        let range = TyVid::from_usize(value_count)..TyVid::from_usize(self.num_vars());
    ) -> (Range<TyVid>, Vec<TypeVariableOrigin>) {
        (range.clone(), range.map(|index| self.var_origin(index)).collect())