diff --git a/compiler/cmm/CmmBuildInfoTables.hs b/compiler/cmm/CmmBuildInfoTables.hs
index 90d15aeea77766b824143f55a455382ac61697b4..9c05a8fe298bced4bbb06f8ce3942134c4b92ec8 100644
--- a/compiler/cmm/CmmBuildInfoTables.hs
+++ b/compiler/cmm/CmmBuildInfoTables.hs
@@ -19,7 +19,6 @@ import Module
 import GHC.Platform
 import Digraph
 import CLabel
-import PprCmmDecl ()
 import Cmm
 import CmmUtils
 import DynFlags
@@ -30,7 +29,6 @@ import UniqSupply
 import CostCentre
 import StgCmmHeap
 
-import PprCmm()
 import Control.Monad
 import Data.Map (Map)
 import qualified Data.Map as Map
diff --git a/compiler/cmm/CmmCallConv.hs b/compiler/cmm/CmmCallConv.hs
index 4e6a9d293a25edab8a3d790799e849c573ef773b..df1eaad0057d0dd6b01ada57e3e1e58a736eabd9 100644
--- a/compiler/cmm/CmmCallConv.hs
+++ b/compiler/cmm/CmmCallConv.hs
@@ -10,7 +10,7 @@ import GhcPrelude
 import CmmExpr
 import SMRep
 import Cmm (Convention(..))
-import PprCmm ()
+import PprCmm () -- For Outputable instances
 
 import DynFlags
 import GHC.Platform
diff --git a/compiler/cmm/CmmCommonBlockElim.hs b/compiler/cmm/CmmCommonBlockElim.hs
index b43d68970fc561eb8a9f777ced338054ea677eca..cbf7d83d36b950bb8aaa6b235f946fed1cdc7e47 100644
--- a/compiler/cmm/CmmCommonBlockElim.hs
+++ b/compiler/cmm/CmmCommonBlockElim.hs
@@ -13,7 +13,6 @@ import Cmm
 import CmmUtils
 import CmmSwitch (eqSwitchTargetWith)
 import CmmContFlowOpt
--- import PprCmm ()
 
 import Hoopl.Block
 import Hoopl.Graph
diff --git a/compiler/cmm/CmmLint.hs b/compiler/cmm/CmmLint.hs
index d5c3f844439877f547c8e1e499841197a65f59ef..3ad65bd53632fbb980b654fd1b89d8986a895efa 100644
--- a/compiler/cmm/CmmLint.hs
+++ b/compiler/cmm/CmmLint.hs
@@ -21,7 +21,7 @@ import Cmm
 import CmmUtils
 import CmmLive
 import CmmSwitch (switchTargetsToList)
-import PprCmm ()
+import PprCmm () -- For Outputable instances
 import Outputable
 import DynFlags
 
diff --git a/compiler/cmm/CmmLive.hs b/compiler/cmm/CmmLive.hs
index f340c32c8a52edbe2fdd037528a98397f76a0a5f..ca474ef61c182d5950087e5d4342b360a03231de 100644
--- a/compiler/cmm/CmmLive.hs
+++ b/compiler/cmm/CmmLive.hs
@@ -17,7 +17,7 @@ import GhcPrelude
 import DynFlags
 import BlockId
 import Cmm
-import PprCmmExpr ()
+import PprCmmExpr () -- For Outputable instances
 import Hoopl.Block
 import Hoopl.Collections
 import Hoopl.Dataflow
diff --git a/compiler/cmm/CmmProcPoint.hs b/compiler/cmm/CmmProcPoint.hs
index 528337c57e0a73eb635aa69edb3d2ac1dffa5f3e..746a175cfe3fa068098ede0c0612db836af2a353 100644
--- a/compiler/cmm/CmmProcPoint.hs
+++ b/compiler/cmm/CmmProcPoint.hs
@@ -14,7 +14,7 @@ import DynFlags
 import BlockId
 import CLabel
 import Cmm
-import PprCmm ()
+import PprCmm () -- For Outputable instances
 import CmmUtils
 import CmmInfo
 import CmmLive
diff --git a/compiler/cmm/CmmSink.hs b/compiler/cmm/CmmSink.hs
index 409cd0fbf225a1883307f93f4c23bd81bb4fabaf..8a6b1203774936ccf36275a2da1208163f6021a6 100644
--- a/compiler/cmm/CmmSink.hs
+++ b/compiler/cmm/CmmSink.hs
@@ -19,7 +19,6 @@ import GHC.Platform (isARM, platformArch)
 import DynFlags
 import Unique
 import UniqFM
-import PprCmm ()
 
 import qualified Data.IntSet as IntSet
 import Data.List (partition)
diff --git a/compiler/cmm/Debug.hs b/compiler/cmm/Debug.hs
index da374955308ca6c53c8eb9736ca0697116f83c59..4aec63fad6fa244d78ea6f5a0b50fce348e18061 100644
--- a/compiler/cmm/Debug.hs
+++ b/compiler/cmm/Debug.hs
@@ -32,7 +32,6 @@ import CoreSyn
 import FastString      ( nilFS, mkFastString )
 import Module
 import Outputable
-import PprCore         ()
 import PprCmmExpr      ( pprExpr )
 import SrcLoc
 import Util            ( seqList )
diff --git a/compiler/cmm/PprC.hs b/compiler/cmm/PprC.hs
index 7227edd57eb67b62bd0e88a516d755d2391adf6a..d412969ca7a5e392a05ead2df0dd8a5c3e0c7dee 100644
--- a/compiler/cmm/PprC.hs
+++ b/compiler/cmm/PprC.hs
@@ -32,7 +32,7 @@ import BlockId
 import CLabel
 import ForeignCall
 import Cmm hiding (pprBBlock)
-import PprCmm ()
+import PprCmm () -- For Outputable instances
 import Hoopl.Block
 import Hoopl.Collections
 import Hoopl.Graph
diff --git a/compiler/cmm/PprCmm.hs b/compiler/cmm/PprCmm.hs
index 90f26e4247473c90195fb39af7154d822c6cac28..397a6660229f5de22a0b6aed1a1a62d8b113dc8b 100644
--- a/compiler/cmm/PprCmm.hs
+++ b/compiler/cmm/PprCmm.hs
@@ -41,7 +41,6 @@ where
 
 import GhcPrelude hiding (succ)
 
-import BlockId ()
 import CLabel
 import Cmm
 import CmmUtils
@@ -52,7 +51,6 @@ import Outputable
 import PprCmmDecl
 import PprCmmExpr
 import Util
-import PprCore ()
 
 import BasicTypes
 import Hoopl.Block
diff --git a/compiler/codeGen/StgCmmClosure.hs b/compiler/codeGen/StgCmmClosure.hs
index 74de2d8756c477474cb17835ba56e53b8fb0a7ff..437219bf45508e91b4da70834c49258e25b149ec 100644
--- a/compiler/codeGen/StgCmmClosure.hs
+++ b/compiler/codeGen/StgCmmClosure.hs
@@ -71,7 +71,7 @@ import GhcPrelude
 import StgSyn
 import SMRep
 import Cmm
-import PprCmmExpr()
+import PprCmmExpr() -- For Outputable instances
 
 import CostCentre
 import BlockId
diff --git a/compiler/coreSyn/CoreSubst.hs b/compiler/coreSyn/CoreSubst.hs
index 695c7a2f9d48b55cfdbc82cbd6ed289f0e276461..2e3a0087f1f25b429f00bed27fef1c18bcdb9d99 100644
--- a/compiler/coreSyn/CoreSubst.hs
+++ b/compiler/coreSyn/CoreSubst.hs
@@ -61,7 +61,6 @@ import UniqSupply
 import Maybes
 import Util
 import Outputable
-import PprCore          ()              -- Instances
 import Data.List
 
 
diff --git a/compiler/coreSyn/CoreUnfold.hs b/compiler/coreSyn/CoreUnfold.hs
index 4570d7a8aaa8c66e9efb6871ba02118805e0b5f7..8a51e587ad579c9cceffaf3e562fb4782b1b1131 100644
--- a/compiler/coreSyn/CoreUnfold.hs
+++ b/compiler/coreSyn/CoreUnfold.hs
@@ -46,7 +46,6 @@ import GhcPrelude
 
 import DynFlags
 import CoreSyn
-import PprCore          ()      -- Instances
 import OccurAnal        ( occurAnalyseExpr_NoBinderSwap )
 import CoreOpt
 import CoreArity       ( manifestArity )
diff --git a/compiler/hsSyn/HsBinds.hs b/compiler/hsSyn/HsBinds.hs
index c5fadc0b4a1c81e717f3c6c188ecea8fe5bcb14f..4be761e3acaf29f1e81ae0a189240eb58b905e78 100644
--- a/compiler/hsSyn/HsBinds.hs
+++ b/compiler/hsSyn/HsBinds.hs
@@ -28,7 +28,6 @@ import {-# SOURCE #-} HsPat  ( LPat )
 
 import HsExtension
 import HsTypes
-import PprCore ()
 import CoreSyn
 import TcEvidence
 import Type
diff --git a/compiler/hsSyn/HsSyn.hs b/compiler/hsSyn/HsSyn.hs
index e04abbf70fa8c3368459b57f51d04caefeac03cf..622f1b9c77f73c90056ca679b48a66ff6a2be1a4 100644
--- a/compiler/hsSyn/HsSyn.hs
+++ b/compiler/hsSyn/HsSyn.hs
@@ -50,7 +50,7 @@ import HsTypes
 import BasicTypes       ( Fixity, WarningTxt )
 import HsUtils
 import HsDoc
-import HsInstances ()
+import HsInstances () -- For Data instances
 
 -- others:
 import Outputable
diff --git a/compiler/hsSyn/HsTypes.hs b/compiler/hsSyn/HsTypes.hs
index 08b8eade7d3b0895f0652f4e291bf270f4b90886..ad9c186c76df516f54896aaf2ed1751f7a34c8db 100644
--- a/compiler/hsSyn/HsTypes.hs
+++ b/compiler/hsSyn/HsTypes.hs
@@ -77,7 +77,6 @@ import GhcPrelude
 import {-# SOURCE #-} HsExpr ( HsSplice, pprSplice )
 
 import HsExtension
-import HsLit () -- for instances
 
 import Id ( Id )
 import Name( Name )
diff --git a/compiler/iface/FlagChecker.hs b/compiler/iface/FlagChecker.hs
index a9ab4c97d7be5ac2f291913411cbf9997ebe9ade..34b55e9fef0451b2c591f83f651c2a32ec51638a 100644
--- a/compiler/iface/FlagChecker.hs
+++ b/compiler/iface/FlagChecker.hs
@@ -11,7 +11,6 @@ module FlagChecker (
 import GhcPrelude
 
 import Binary
-import BinIface ()
 import DynFlags
 import HscTypes
 import Module
diff --git a/compiler/iface/IfaceSyn.hs b/compiler/iface/IfaceSyn.hs
index 3da0c63174d7eefe68aae04b2a4b04ed345798f9..688998f96d06df405d70014edb2305aa9ccf01a2 100644
--- a/compiler/iface/IfaceSyn.hs
+++ b/compiler/iface/IfaceSyn.hs
@@ -46,7 +46,6 @@ import GhcPrelude
 import IfaceType
 import BinFingerprint
 import CoreSyn( IsOrphan, isOrphan )
-import PprCore()            -- Printing DFunArgs
 import DynFlags( gopt, GeneralFlag (Opt_PrintAxiomIncomps) )
 import Demand
 import Class
diff --git a/compiler/main/HeaderInfo.hs b/compiler/main/HeaderInfo.hs
index c7557922bc21a7ae90a78dac816605a13668b3e2..0d7e6fd70273f238ba9b910cc01f393863ce6052 100644
--- a/compiler/main/HeaderInfo.hs
+++ b/compiler/main/HeaderInfo.hs
@@ -35,7 +35,6 @@ import DynFlags
 import ErrUtils
 import Util
 import Outputable
-import Pretty           ()
 import Maybes
 import Bag              ( emptyBag, listToBag, unitBag )
 import MonadUtils
diff --git a/compiler/nativeGen/BlockLayout.hs b/compiler/nativeGen/BlockLayout.hs
index 8904b4113b55cff34e9f712d50f830baa93be6c2..3755ed5db6973dc054374a7267a6113fa5fa0214 100644
--- a/compiler/nativeGen/BlockLayout.hs
+++ b/compiler/nativeGen/BlockLayout.hs
@@ -37,7 +37,6 @@ import Maybes
 --import Debug
 --import Debug.Trace
 import ListSetOps (removeDups)
-import PprCmm ()
 
 import OrdList
 import Data.List
diff --git a/compiler/nativeGen/CFG.hs b/compiler/nativeGen/CFG.hs
index af0c6da455360406bb96b7162f02181dc1c9ca30..44ddecd216e3cd5a56e581b4352cceec07d2f08b 100644
--- a/compiler/nativeGen/CFG.hs
+++ b/compiler/nativeGen/CFG.hs
@@ -56,7 +56,7 @@ import Outputable
 --import Debug
 --import OrdList
 --import Debug.Trace
-import PprCmm ()
+import PprCmm () -- For Outputable instances
 import qualified DynFlags as D
 
 import Data.List
diff --git a/compiler/nativeGen/PPC/Ppr.hs b/compiler/nativeGen/PPC/Ppr.hs
index 4254f23122649cbbaa11ee70832635177233e527..0c3aaccda2e50d3b4f30d30a215990b569670644 100644
--- a/compiler/nativeGen/PPC/Ppr.hs
+++ b/compiler/nativeGen/PPC/Ppr.hs
@@ -27,7 +27,7 @@ import Hoopl.Label
 
 import BlockId
 import CLabel
-import PprCmmExpr ()
+import PprCmmExpr () -- For Outputable instances
 
 import Unique                ( pprUniqueAlways, getUnique )
 import GHC.Platform
diff --git a/compiler/nativeGen/RegAlloc/Graph/Stats.hs b/compiler/nativeGen/RegAlloc/Graph/Stats.hs
index 487e3ee03a0dcbf5a62835db3462e29b8bf7f9e3..f7652240720421ef93d528494ac2dcd64a94b8da 100644
--- a/compiler/nativeGen/RegAlloc/Graph/Stats.hs
+++ b/compiler/nativeGen/RegAlloc/Graph/Stats.hs
@@ -28,7 +28,6 @@ import RegClass
 import Reg
 import TargetReg
 
-import PprCmm()
 import Outputable
 import UniqFM
 import UniqSet
diff --git a/compiler/nativeGen/RegAlloc/Liveness.hs b/compiler/nativeGen/RegAlloc/Liveness.hs
index bbb7976a753ffacc7ef832a3417509aaf263ccd6..3f160ea67817a42de3ccb319ea2478e5bec17c58 100644
--- a/compiler/nativeGen/RegAlloc/Liveness.hs
+++ b/compiler/nativeGen/RegAlloc/Liveness.hs
@@ -45,7 +45,6 @@ import CFG
 import Hoopl.Collections
 import Hoopl.Label
 import Cmm hiding (RegSet, emptyRegSet)
-import PprCmm()
 
 import Digraph
 import DynFlags
diff --git a/compiler/nativeGen/SPARC/CodeGen.hs b/compiler/nativeGen/SPARC/CodeGen.hs
index 056d0c6fbf0059a0226b3d57aa6d7797f9ebdf3f..bb8bbe16b6fe9be9c122c1b0e6683d149e9247ec 100644
--- a/compiler/nativeGen/SPARC/CodeGen.hs
+++ b/compiler/nativeGen/SPARC/CodeGen.hs
@@ -31,7 +31,6 @@ import SPARC.CodeGen.CondCode
 import SPARC.CodeGen.Gen64
 import SPARC.CodeGen.Gen32
 import SPARC.CodeGen.Base
-import SPARC.Ppr        ()
 import SPARC.Instr
 import SPARC.Imm
 import SPARC.AddrMode
diff --git a/compiler/nativeGen/SPARC/CodeGen/Base.hs b/compiler/nativeGen/SPARC/CodeGen/Base.hs
index e64af0c44e20b1a77bb25e852472eb9177ebcc5c..97c54a936475c130ea87657c2eae69917673ecb3 100644
--- a/compiler/nativeGen/SPARC/CodeGen/Base.hs
+++ b/compiler/nativeGen/SPARC/CodeGen/Base.hs
@@ -25,7 +25,7 @@ import Reg
 import CodeGen.Platform
 import DynFlags
 import Cmm
-import PprCmmExpr ()
+import PprCmmExpr () -- For Outputable instances
 import GHC.Platform
 
 import Outputable
diff --git a/compiler/nativeGen/SPARC/CodeGen/Expand.hs b/compiler/nativeGen/SPARC/CodeGen/Expand.hs
index 0b318740dbd9bd26a990534f385a2ca8762721db..a29c24dcd4eeb5dbe01052b8b9589d7f9d7b3d03 100644
--- a/compiler/nativeGen/SPARC/CodeGen/Expand.hs
+++ b/compiler/nativeGen/SPARC/CodeGen/Expand.hs
@@ -11,7 +11,6 @@ import SPARC.Instr
 import SPARC.Imm
 import SPARC.AddrMode
 import SPARC.Regs
-import SPARC.Ppr        ()
 import Instruction
 import Reg
 import Format
diff --git a/compiler/nativeGen/SPARC/CodeGen/Gen64.hs b/compiler/nativeGen/SPARC/CodeGen/Gen64.hs
index 6fa7482f9b874592b2634ae177e756906d4dab1e..18df9e19a3335c7f343e359365096daff73f6a0c 100644
--- a/compiler/nativeGen/SPARC/CodeGen/Gen64.hs
+++ b/compiler/nativeGen/SPARC/CodeGen/Gen64.hs
@@ -16,7 +16,7 @@ import SPARC.Regs
 import SPARC.AddrMode
 import SPARC.Imm
 import SPARC.Instr
-import SPARC.Ppr()
+-- import SPARC.Ppr()
 import NCGMonad
 import Instruction
 import Format
diff --git a/compiler/nativeGen/SPARC/CodeGen/Sanity.hs b/compiler/nativeGen/SPARC/CodeGen/Sanity.hs
index fcf5b65bdee763b81a6f58fb14e9d0c77b251077..7f9bfed229f3656c58fcc622b59566326ff29261 100644
--- a/compiler/nativeGen/SPARC/CodeGen/Sanity.hs
+++ b/compiler/nativeGen/SPARC/CodeGen/Sanity.hs
@@ -9,7 +9,7 @@ where
 import GhcPrelude
 
 import SPARC.Instr
-import SPARC.Ppr        ()
+import SPARC.Ppr        () -- For Outputable instances
 import Instruction
 
 import Cmm
diff --git a/compiler/nativeGen/SPARC/Ppr.hs b/compiler/nativeGen/SPARC/Ppr.hs
index fc67f7754197521a2f728ac98cbaef5b48b8a24d..2bec7ec01fdc3edcc8c7f6cb1df3f67c0147c2e0 100644
--- a/compiler/nativeGen/SPARC/Ppr.hs
+++ b/compiler/nativeGen/SPARC/Ppr.hs
@@ -39,7 +39,7 @@ import Format
 import PprBase
 
 import Cmm hiding (topInfoTable)
-import PprCmm()
+import PprCmm() -- For Outputable instances
 import BlockId
 import CLabel
 import Hoopl.Label
diff --git a/compiler/nativeGen/X86/CodeGen.hs b/compiler/nativeGen/X86/CodeGen.hs
index 13662f6807c59b73fb7ad7b916bf459f8d6b5d77..4aeb4eb635fc83be042876b648438a7372f8f6c4 100644
--- a/compiler/nativeGen/X86/CodeGen.hs
+++ b/compiler/nativeGen/X86/CodeGen.hs
@@ -38,9 +38,6 @@ import X86.Cond
 import X86.Regs
 import X86.RegInfo
 
---TODO: Remove - Just for development/debugging
-import X86.Ppr()
-
 import CodeGen.Platform
 import CPrim
 import Debug            ( DebugBlock(..), UnwindPoint(..), UnwindTable
@@ -60,7 +57,6 @@ import GHC.Platform
 import BasicTypes
 import BlockId
 import Module           ( primUnitId )
-import PprCmm           ()
 import CmmUtils
 import CmmSwitch
 import Cmm
diff --git a/compiler/typecheck/TcSimplify.hs b/compiler/typecheck/TcSimplify.hs
index d16be2877332ec0f1c1c96c9bea1172d3ea1a8f8..5a7924017dfdde67ff2d4fc5af136e993bd76e0e 100644
--- a/compiler/typecheck/TcSimplify.hs
+++ b/compiler/typecheck/TcSimplify.hs
@@ -48,7 +48,6 @@ import TcMType   as TcM
 import TcRnMonad as TcM
 import TcSMonad  as TcS
 import TcType
-import TrieMap       () -- DV: for now
 import Type
 import TysWiredIn    ( liftedRepTy )
 import Unify         ( tcMatchTyKi )
diff --git a/libraries/base/GHC/Err.hs b/libraries/base/GHC/Err.hs
index 26e3f2059d222945c1da03f9b24451275bd596c5..17b5b8ec4195b4f073603bd1910825a19ba817b1 100644
--- a/libraries/base/GHC/Err.hs
+++ b/libraries/base/GHC/Err.hs
@@ -23,7 +23,6 @@
 -----------------------------------------------------------------------------
 
 module GHC.Err( absentErr, error, errorWithoutStackTrace, undefined ) where
-import GHC.CString ()
 import GHC.Types (Char, RuntimeRep)
 import GHC.Stack.Types
 import GHC.Prim
diff --git a/libraries/ghc-prim/GHC/Magic.hs b/libraries/ghc-prim/GHC/Magic.hs
index 2cc3212d9522123fce96310acae68d7188c32ce2..403c3f0cca0816d0b77cf98aab6b79f4926dbce6 100644
--- a/libraries/ghc-prim/GHC/Magic.hs
+++ b/libraries/ghc-prim/GHC/Magic.hs
@@ -39,7 +39,6 @@ module GHC.Magic ( inline, noinline, lazy, oneShot, runRW# ) where
 import GHC.Prim (realWorld#)
 #endif
 import GHC.Prim (State#, RealWorld)
-import GHC.CString ()
 import GHC.Types (RuntimeRep, TYPE)
 
 -- | The call @inline f@ arranges that @f@ is inlined, regardless of
diff --git a/libraries/ghci/GHCi/Message.hs b/libraries/ghci/GHCi/Message.hs
index d8c27b0702236156187f0d294ced8fcb0e1363bf..70c532fc94a7aac6129ade5b86785a84167d3508 100644
--- a/libraries/ghci/GHCi/Message.hs
+++ b/libraries/ghci/GHCi/Message.hs
@@ -25,7 +25,7 @@ module GHCi.Message
 import Prelude -- See note [Why do we import Prelude here?]
 import GHCi.RemoteTypes
 import GHCi.FFI
-import GHCi.TH.Binary ()
+import GHCi.TH.Binary () -- For Binary instances
 import GHCi.BreakArray
 
 import GHC.LanguageExtensions