usesOfOpenAcc :: Idx aenv s -> OpenAcc aenv t -> Int
usesOfOpenAcc idx (OpenAcc acc) = usesOfA usesOfOpenAcc idx acc
usesOfOpenAcc :: Idx aenv s -> OpenAcc aenv t -> Int
usesOfOpenAcc idx (OpenAcc acc) = usesOfA usesOfOpenAcc idx acc
usesOfOpenAcc idx (OpenAcc acc) = usesOfA usesOfOpenAcc idx acc