Fully normalize type families in normalizeType.

Normalize type did not recurse on the result of reducing a type
family, meaning if a type family reduced to another type family it
would not be normalized.

Author: Alex McKenna

changelog/2020-08-07T16_33_09+02_00_normalize_types.md

@@ -0,0 +1,4 @@
+Fixed: #1469
+The normalizeType function now fully normalizes types which require calls to
+reduceTypeFamily.
+

clash-lib/src/Clash/Core/Type.hs

@@ -646,7 +646,7 @@ normalizeType tcMap = go
              let args' = map go args
                  ty' = mkTyConApp tcNm args'
              in case reduceTypeFamily tcMap ty' of
-               Just ty'' -> ty''
+               Just ty'' -> go ty''
                Nothing  -> ty'
     FunTy ty1 ty2 -> mkFunTy (go ty1) (go ty2)
     OtherType (ForAllTy tyvar ty')