Replace a call to 'foldProgress'.

cabal-install/Distribution/Solver/Modular/Explore.hs

@@ -18,7 +18,6 @@ import Distribution.Solver.Modular.RetryLog
 import Distribution.Solver.Modular.Tree
 import Distribution.Solver.Types.PackagePath
 import Distribution.Solver.Types.Settings (EnableBackjumping(..), CountConflicts(..))
-import qualified Distribution.Solver.Types.Progress as P
 
 -- | This function takes the variable we're currently considering, an
 -- initial conflict set and a
@@ -165,8 +164,7 @@ backjumpAndExplore :: EnableBackjumping
                    -> CountConflicts
                    -> Tree QGoalReason -> Log Message (Assignment, RevDepMap)
 backjumpAndExplore enableBj countConflicts t =
-    toLog $ toProgress $
-    exploreLog enableBj countConflicts t (A M.empty M.empty M.empty) M.empty
+    toLog $ exploreLog enableBj countConflicts t (A M.empty M.empty M.empty) M.empty
   where
-    toLog :: P.Progress step fail done -> Log step done
-    toLog = P.foldProgress P.Step (const (P.Fail ())) P.Done
+    toLog :: RetryLog step fail done -> Log step done
+    toLog = toProgress . mapFailure (const ())

cabal-install/Distribution/Solver/Modular/RetryLog.hs

@@ -3,6 +3,7 @@ module Distribution.Solver.Modular.RetryLog
     ( RetryLog
     , toProgress
     , fromProgress
+    , mapFailure
     , retry
     , failWith
     , succeedWith
@@ -34,6 +35,12 @@ fromProgress l = RetryLog $ \f -> go f l
     go f (Fail failure) = f failure
     go f (Step m ms) = Step m (go f ms)
 
+-- | /O(1)/. Apply a function to the failure value in a log.
+mapFailure :: (fail1 -> fail2)
+           -> RetryLog step fail1 done
+           -> RetryLog step fail2 done
+mapFailure f l = retry l $ \failure -> RetryLog $ \g -> g (f failure)
+
 -- | /O(1)/. If the first log leads to failure, continue with the second.
 retry :: RetryLog step fail1 done
       -> (fail1 -> RetryLog step fail2 done)