don't use AsFractional backwards and remove AsFractional → Fractional instance
The combine_sep_fractional_bwd
instance for CombineSepAs
uses AsFractional
in a backwards way: given a predicate Φ and a fraction q, compute the P that is equivalent to Φ q
. However this is not really how the AsFractional
typeclass is designed to be used, and beta reduction should take care of simplifying Φ q
if necessary.
Also the as_fractional_fractional
instance was only meant to be used internally in this file; let's see if we can get away without it.
Edited by Ralf Jung