-- NB. we pass in the arity of the expression, which is expected
-- to be calculated by exprArity. This is because exprArity
-- knows how much eta expansion is going to be done by
-- CorePrep later on, and we don't want to duplicate that
-- NB. we pass in the arity of the expression, which is expected
-- to be calculated by exprArity. This is because exprArity
-- knows how much eta expansion is going to be done by
-- CorePrep later on, and we don't want to duplicate that