Remove `runs` function which already exists in base

Reviewers: austin, bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie

Differential Revision: https://phabricator.haskell.org/D3320

4 files changed, 9 insertions, 27 deletions

diff --git a/compiler/deSugar/Match.hs b/compiler/deSugar/Match.hs
index 92f78bed33..692db8b036 100644
--- a/compiler/deSugar/Match.hs
+++ b/compiler/deSugar/Match.hs
@@ -39,7 +39,6 @@ import Coercion ( eqCoercion )
 import TcType ( toTcTypeBag )
 import TyCon( isNewTyCon )
 import TysWiredIn
-import ListSetOps
 import SrcLoc
 import Maybes
 import Util
@@ -52,6 +51,7 @@ import UniqDFM
 
 import Control.Monad( when, unless )
 import qualified Data.Map as Map
+import Data.List (groupBy)
 
 {-
 ************************************************************************
@@ -887,7 +887,7 @@ groupEquations :: DynFlags -> [EquationInfo] -> [[(PatGroup, EquationInfo)]]
 -- (b) none of the gi are empty
 -- The ordering of equations is unchanged
 groupEquations dflags eqns
-  = runs same_gp [(patGroup dflags (firstPat eqn), eqn) | eqn <- eqns]
+  = groupBy same_gp [(patGroup dflags (firstPat eqn), eqn) | eqn <- eqns]
   where
     same_gp :: (PatGroup,EquationInfo) -> (PatGroup,EquationInfo) -> Bool
     (pg1,_) `same_gp` (pg2,_) = pg1 `sameGroup` pg2
diff --git a/compiler/deSugar/MatchCon.hs b/compiler/deSugar/MatchCon.hs
index 4a7d1cd2b7..0e1aa802e9 100644
--- a/compiler/deSugar/MatchCon.hs
+++ b/compiler/deSugar/MatchCon.hs
@@ -22,7 +22,6 @@ import DsMonad
 import DsUtils
 import MkCore   ( mkCoreLets )
 import Util
-import ListSetOps ( runs )
 import Id
 import NameEnv
 import FieldLabel ( flSelector )
@@ -30,6 +29,7 @@ import SrcLoc
 import DynFlags
 import Outputable
 import Control.Monad(liftM)
+import Data.List (groupBy)
 
 {-
 We are confronted with the first column of patterns in a set of
@@ -153,8 +153,8 @@ matchOneConLike vars ty (eqn1 : eqns)   -- All eqns for a single constructor
 
         -- Divide into sub-groups; see Note [Record patterns]
         ; let groups :: [[(ConArgPats, EquationInfo)]]
-              groups = runs compatible_pats [ (pat_args (firstPat eqn), eqn)
-                                            | eqn <- eqn1:eqns ]
+              groups = groupBy compatible_pats [ (pat_args (firstPat eqn), eqn)
+                                               | eqn <- eqn1:eqns ]
 
         ; match_results <- mapM (match_group arg_vars) groups
 
@@ -245,7 +245,7 @@ Now consider:
 In the first we must test y first; in the second we must test x
 first.  So we must divide even the equations for a single constructor
 T into sub-goups, based on whether they match the same field in the
-same order.  That's what the (runs compatible_pats) grouping.
+same order.  That's what the (groupBy compatible_pats) grouping.
 
 All non-record patterns are "compatible" in this sense, because the
 positional patterns (T a b) and (a `T` b) all match the arguments
diff --git a/compiler/simplCore/CoreMonad.hs b/compiler/simplCore/CoreMonad.hs
index ac3e2c4fb9..209d0f8370 100644
--- a/compiler/simplCore/CoreMonad.hs
+++ b/compiler/simplCore/CoreMonad.hs
@@ -76,7 +76,6 @@ import UniqFM       ( UniqFM, mapUFM, filterUFM )
 import MonadUtils
 import NameCache
 import SrcLoc
-import ListSetOps       ( runs )
 import Data.List
 import Data.Ord
 import Data.Dynamic
@@ -348,7 +347,7 @@ pprTickCounts counts
   where
     groups :: [[(Tick,Int)]]    -- Each group shares a comon tag
                                 -- toList returns common tags adjacent
-    groups = runs same_tag (Map.toList counts)
+    groups = groupBy same_tag (Map.toList counts)
     same_tag (tick1,_) (tick2,_) = tickToTag tick1 == tickToTag tick2
 
 pprTickGroup :: [(Tick, Int)] -> SDoc
diff --git a/compiler/utils/ListSetOps.hs b/compiler/utils/ListSetOps.hs
index eaa79bd7fb..e5315ddfd4 100644
--- a/compiler/utils/ListSetOps.hs
+++ b/compiler/utils/ListSetOps.hs
@@ -14,7 +14,7 @@ module ListSetOps (
         Assoc, assoc, assocMaybe, assocUsing, assocDefault, assocDefaultUsing,
 
         -- Duplicate handling
-        hasNoDups, runs, removeDups, findDupsEq,
+        hasNoDups, removeDups, findDupsEq,
         equivClasses,
 
         -- Indexing
@@ -111,27 +111,10 @@ equivClasses :: (a -> a -> Ordering) -- Comparison
 
 equivClasses _         []  = []
 equivClasses _   stuff@[_] = [stuff]
-equivClasses cmp items     = runs eq (sortBy cmp items)
+equivClasses cmp items     = groupBy eq (sortBy cmp items)
   where
     eq a b = case cmp a b of { EQ -> True; _ -> False }
 
-{-
-The first cases in @equivClasses@ above are just to cut to the point
-more quickly...
-
-@runs@ groups a list into a list of lists, each sublist being a run of
-identical elements of the input list. It is passed a predicate @p@ which
-tells when two elements are equal.
--}
-
-runs :: (a -> a -> Bool) -- Equality
-     -> [a]
-     -> [[a]]
-
-runs _ []     = []
-runs p (x:xs) = case (span (p x) xs) of
-                (first, rest) -> (x:first) : (runs p rest)
-
 removeDups :: (a -> a -> Ordering) -- Comparison function
            -> [a]
            -> ([a],     -- List with no duplicates