dialyzer types for return values of transformed results

[joedevivo]

-type sqerl_row() :: [{binary(), term()}].
-type sqerl_rows() :: [sqerl_row()].
-type sqerl_results() :: {ok, integer() | sqerl_rows()} |
                         {ok, integer(), sqerl_rows()} |
                         {error, atom() | tuple()}.

the return type sqerl_row is really only guaranteed if you're not using a sqerl_transformer.

At least you are restricted to the sqerl_transformer module. but each transform should be typed, and the composite type of those returns should be the real sqerl_row.