anchor.diff:  %% @see transform/2
   
   -ifndef(NO_UNUSED).
  +-spec core_transform(cerl:c_module(), [_]) -> cerl:c_module().
  +
   core_transform(M, Opts) ->
       cerl:to_records(transform(cerl:from_records(M), Opts)).
   -endif.	% NO_UNUSED
  
positive.code: %% @see core_transform/2
  
  -ifndef(NO_UNUSED).
  transform(M, _Opts) ->
    expr(M, env__empty()).
  -endif.	% NO_UNUSED
  
negative.code: %% @see expr/2
  %% @see transform/2
  
  -spec clauses([cerl:cerl(),...], rec_env:environment()) ->
            {cerl:cerl(), [cerl:cerl()]}.
  
  clauses(Cs, Env) ->
  