Fix DeriveGeneric for types with same OccName (#10487)

Summary:
DeriveGeneric generates some data types (for data type constructors and for
selectors of those constructors) and instances for those types. This patch
changes name generation for these new types to make it working with data types
with same names imported from different modules and with data types with same
names imported from same modules(using module imports).

Bonus content:

- Some refactoring in `TcGenGenerics.metaTyConsToDerivStuff` to remove some
  redundant partial function applications and to remove a duplicated function.
- Remove some unused names from `OccName`. (those were used for an old
  implementation of `DeriveGeneric`)

Reviewers: kosmikus, simonpj, dreixel, ezyang, bgamari, austin

Reviewed By: bgamari, austin

Subscribers: ezyang, thomie

Differential Revision: https://phabricator.haskell.org/D1081

GHC Trac Issues: #10487

10 files changed, 270 insertions, 191 deletions

diff --git a/compiler/basicTypes/OccName.hs b/compiler/basicTypes/OccName.hs
index c3f0c9ffcb..fa9d6ed7e6 100644
--- a/compiler/basicTypes/OccName.hs
+++ b/compiler/basicTypes/OccName.hs
@@ -60,7 +60,7 @@ module OccName (
         mkDerivedTyConOcc, mkNewTyCoOcc, mkClassOpAuxOcc,
         mkCon2TagOcc, mkTag2ConOcc, mkMaxTagOcc,
         mkClassDataConOcc, mkDictOcc, mkIPOcc,
-        mkSpecOcc, mkForeignExportOcc, mkRepEqOcc, mkGenOcc1, mkGenOcc2,
+        mkSpecOcc, mkForeignExportOcc, mkRepEqOcc,
         mkGenD, mkGenR, mkGen1R, mkGenRCo, mkGenC, mkGenS,
         mkDataTOcc, mkDataCOcc, mkDataConWorkerOcc,
         mkSuperDictSelOcc, mkSuperDictAuxOcc,
@@ -109,6 +109,7 @@ import FastString
 import Outputable
 import Lexeme
 import Binary
+import Module
 import Data.Char
 import Data.Data
 
@@ -602,8 +603,8 @@ mkDataConWrapperOcc, mkWorkerOcc,
         mkMatcherOcc, mkBuilderOcc,
         mkDefaultMethodOcc,
         mkGenDefMethodOcc, mkDerivedTyConOcc, mkClassDataConOcc, mkDictOcc,
-        mkIPOcc, mkSpecOcc, mkForeignExportOcc, mkRepEqOcc, mkGenOcc1, mkGenOcc2,
-        mkGenD, mkGenR, mkGen1R, mkGenRCo,
+        mkIPOcc, mkSpecOcc, mkForeignExportOcc, mkRepEqOcc,
+        mkGenR, mkGen1R, mkGenRCo,
         mkDataTOcc, mkDataCOcc, mkDataConWorkerOcc, mkNewTyCoOcc,
         mkInstTyCoOcc, mkEqPredCoOcc, mkClassOpAuxOcc,
         mkCon2TagOcc, mkTag2ConOcc, mkMaxTagOcc
@@ -634,19 +635,29 @@ mkCon2TagOcc        = mk_simple_deriv varName  "$con2tag_"
 mkTag2ConOcc        = mk_simple_deriv varName  "$tag2con_"
 mkMaxTagOcc         = mk_simple_deriv varName  "$maxtag_"
 
--- Generic derivable classes (old)
-mkGenOcc1           = mk_simple_deriv varName  "$gfrom"
-mkGenOcc2           = mk_simple_deriv varName  "$gto"
+-- Generic deriving mechanism
 
--- Generic deriving mechanism (new)
-mkGenD         = mk_simple_deriv tcName "D1"
+-- | Generate a module-unique name, to be used e.g. while generating new names
+-- for Generics types. We use module package key to avoid name clashes when
+-- package imports is used.
+mkModPrefix :: Module -> String
+mkModPrefix mod = pk ++ "_" ++ mn
+  where
+    pk = packageKeyString (modulePackageKey mod)
+    mn = moduleNameString (moduleName mod)
+
+mkGenD :: Module -> OccName -> OccName
+mkGenD mod = mk_simple_deriv tcName ("D1_" ++ mkModPrefix mod ++ "_")
 
-mkGenC :: OccName -> Int -> OccName
-mkGenC occ m   = mk_deriv tcName ("C1_" ++ show m) (occNameString occ)
+mkGenC :: Module -> OccName -> Int -> OccName
+mkGenC mod occ m   =
+  mk_deriv tcName ("C1_" ++ show m) $
+    mkModPrefix mod ++ "_" ++ occNameString occ
 
-mkGenS :: OccName -> Int -> Int -> OccName
-mkGenS occ m n = mk_deriv tcName ("S1_" ++ show m ++ "_" ++ show n)
-                   (occNameString occ)
+mkGenS :: Module -> OccName -> Int -> Int -> OccName
+mkGenS mod occ m n =
+  mk_deriv tcName ("S1_" ++ show m ++ "_" ++ show n) $
+    mkModPrefix mod ++ "_" ++ occNameString occ
 
 mkGenR   = mk_simple_deriv tcName "Rep_"
 mkGen1R  = mk_simple_deriv tcName "Rep1_"
diff --git a/compiler/typecheck/TcDeriv.hs b/compiler/typecheck/TcDeriv.hs
index 58aeb2edc9..2b1b77491e 100644
--- a/compiler/typecheck/TcDeriv.hs
+++ b/compiler/typecheck/TcDeriv.hs
@@ -447,11 +447,15 @@ type CommonAuxiliaries = NameEnv CommonAuxiliary
 
 commonAuxiliaries :: [DerivSpec ()] -> TcM (CommonAuxiliaries, BagDerivStuff)
 commonAuxiliaries = foldM snoc (emptyNameEnv, emptyBag) where
-  snoc acc@(cas, stuff) (DS {ds_name = nm, ds_cls = cls, ds_tc = rep_tycon})
+  snoc :: (CommonAuxiliaries, BagDerivStuff)
+       -> DerivSpec () -> TcM (CommonAuxiliaries, BagDerivStuff)
+  snoc acc@(cas, stuff) (DS {ds_cls = cls, ds_tc = rep_tycon})
     | getUnique cls `elem` [genClassKey, gen1ClassKey] =
-      extendComAux $ genGenericMetaTyCons rep_tycon (nameModule nm)
+      extendComAux $ genGenericMetaTyCons rep_tycon
     | otherwise = return acc
-   where extendComAux m -- don't run m if its already in the accumulator
+   where extendComAux :: TcM (MetaTyCons, BagDerivStuff)
+                      -> TcM (CommonAuxiliaries, BagDerivStuff)
+         extendComAux m -- don't run m if its already in the accumulator
            | elemNameEnv (tyConName rep_tycon) cas = return acc
            | otherwise = do (ca, new_stuff) <- m
                             return ( extendNameEnv cas (tyConName rep_tycon) ca
@@ -922,7 +926,7 @@ mk_data_eqn :: Maybe OverlapMode -> [TyVar] -> Class
             -> TcM EarlyDerivSpec
 mk_data_eqn overlap_mode tvs cls tycon tc_args rep_tc rep_tc_args mtheta
   = do loc                  <- getSrcSpanM
-       dfun_name            <- new_dfun_name cls tycon
+       dfun_name            <- newDFunName' cls tycon
        case mtheta of
         Nothing -> do --Infer context
             inferred_constraints <- inferConstraints cls inst_tys rep_tc rep_tc_args
@@ -1375,13 +1379,6 @@ non_coercible_class cls
                          , genClassKey, gen1ClassKey, typeableClassKey
                          , traversableClassKey, liftClassKey ])
 
-new_dfun_name :: Class -> TyCon -> TcM Name
-new_dfun_name clas tycon        -- Just a simple wrapper
-  = do { loc <- getSrcSpanM     -- The location of the instance decl, not of the tycon
-        ; newDFunName clas [mkTyConApp tycon []] loc }
-        -- The type passed to newDFunName is only used to generate
-        -- a suitable string; hence the empty type arg list
-
 badCon :: DataCon -> SDoc -> SDoc
 badCon con msg = ptext (sLit "Constructor") <+> quotes (ppr con) <+> msg
 
@@ -1465,7 +1462,7 @@ mkNewTypeEqn dflags overlap_mode tvs
     might_derive_via_coercible && ((newtype_deriving && not deriveAnyClass)
                                   || std_class_via_coercible cls)
   = do traceTc "newtype deriving:" (ppr tycon <+> ppr rep_tys <+> ppr all_preds)
-       dfun_name <- new_dfun_name cls tycon
+       dfun_name <- newDFunName' cls tycon
        loc <- getSrcSpanM
        case mtheta of
         Just theta -> return $ GivenTheta $ DS
@@ -2009,9 +2006,9 @@ genDerivStuff :: SrcSpan -> Class -> Name -> TyCon
               -> TcM (LHsBinds RdrName, BagDerivStuff)
 genDerivStuff loc clas dfun_name tycon comaux_maybe
   | let ck = classKey clas
-  , ck `elem` [genClassKey, gen1ClassKey]   -- Special case because monadic
-  = let gk = if ck == genClassKey then Gen0 else Gen1
-        -- TODO NSF: correctly identify when we're building Both instead of One
+  , -- Special case because monadic
+    Just gk <- lookup ck [(genClassKey, Gen0), (gen1ClassKey, Gen1)]
+  = let -- TODO NSF: correctly identify when we're building Both instead of One
         Just metaTyCons = comaux_maybe -- well-guarded by commonAuxiliaries and genInst
     in do
       (binds, faminst) <- gen_Generic_binds gk tycon metaTyCons (nameModule dfun_name)
diff --git a/compiler/typecheck/TcEnv.hs b/compiler/typecheck/TcEnv.hs
index fa67d491b2..9605ed57f8 100644
--- a/compiler/typecheck/TcEnv.hs
+++ b/compiler/typecheck/TcEnv.hs
@@ -54,7 +54,8 @@ module TcEnv(
         topIdLvl, isBrackStage,
 
         -- New Ids
-        newLocalName, newDFunName, newFamInstTyConName, newFamInstAxiomName,
+        newLocalName, newDFunName, newDFunName', newFamInstTyConName,
+        newFamInstAxiomName,
         mkStableIdFromString, mkStableIdFromName,
         mkWrapperName
   ) where
@@ -740,11 +741,9 @@ simpleInstInfoTyCon :: InstInfo a -> TyCon
   -- i.e. one of the form       instance (...) => C (T a b c) where ...
 simpleInstInfoTyCon inst = tcTyConAppTyCon (simpleInstInfoTy inst)
 
-{-
-Make a name for the dict fun for an instance decl.  It's an *external*
-name, like otber top-level names, and hence must be made with newGlobalBinder.
--}
-
+-- | Make a name for the dict fun for an instance decl.  It's an *external*
+-- name, like other top-level names, and hence must be made with
+-- newGlobalBinder.
 newDFunName :: Class -> [Type] -> SrcSpan -> TcM Name
 newDFunName clas tys loc
   = do  { is_boot <- tcIsHsBootOrSig
@@ -754,6 +753,15 @@ newDFunName clas tys loc
         ; dfun_occ <- chooseUniqueOccTc (mkDFunOcc info_string is_boot)
         ; newGlobalBinder mod dfun_occ loc }
 
+-- | Special case of 'newDFunName' to generate dict fun name for a single TyCon.
+newDFunName' :: Class -> TyCon -> TcM Name
+newDFunName' clas tycon        -- Just a simple wrapper
+  = do { loc <- getSrcSpanM     -- The location of the instance decl,
+                                -- not of the tycon
+       ; newDFunName clas [mkTyConApp tycon []] loc }
+       -- The type passed to newDFunName is only used to generate
+       -- a suitable string; hence the empty type arg list
+
 {-
 Make a name for the representation tycon of a family instance.  It's an
 *external* name, like other top-level names, and hence must be made with
diff --git a/compiler/typecheck/TcGenGenerics.hs b/compiler/typecheck/TcGenGenerics.hs
index 63fee7fc28..6ea541c384 100644
--- a/compiler/typecheck/TcGenGenerics.hs
+++ b/compiler/typecheck/TcGenGenerics.hs
@@ -6,7 +6,7 @@ The deriving code for the Generic class
 (equivalent to the code in TcGenDeriv, for other classes)
 -}
 
-{-# LANGUAGE CPP, ScopedTypeVariables #-}
+{-# LANGUAGE CPP, ScopedTypeVariables, TupleSections #-}
 {-# LANGUAGE FlexibleContexts #-}
 
 module TcGenGenerics (canDoGenerics, canDoGenerics1,
@@ -25,7 +25,7 @@ import TyCon
 import FamInstEnv       ( FamInst, FamFlavor(..), mkSingleCoAxiom )
 import FamInst
 import Module           ( Module, moduleName, moduleNameString
-                        , modulePackageKey, packageKeyString )
+                        , modulePackageKey, packageKeyString, getModule )
 import IfaceEnv         ( newGlobalBinder )
 import Name      hiding ( varName )
 import RdrName
@@ -71,18 +71,18 @@ gen_Generic_binds gk tc metaTyCons mod = do
   repTyInsts <- tc_mkRepFamInsts gk tc metaTyCons mod
   return (mkBindsRep gk tc, repTyInsts)
 
-genGenericMetaTyCons :: TyCon -> Module -> TcM (MetaTyCons, BagDerivStuff)
-genGenericMetaTyCons tc mod =
-  do  loc <- getSrcSpanM
-      let
+genGenericMetaTyCons :: TyCon -> TcM (MetaTyCons, BagDerivStuff)
+genGenericMetaTyCons tc =
+  do  let
         tc_name   = tyConName tc
+        mod       = nameModule tc_name
         tc_cons   = tyConDataCons tc
         tc_arits  = map dataConSourceArity tc_cons
 
         tc_occ    = nameOccName tc_name
-        d_occ     = mkGenD tc_occ
-        c_occ m   = mkGenC tc_occ m
-        s_occ m n = mkGenS tc_occ m n
+        d_occ     = mkGenD mod tc_occ
+        c_occ m   = mkGenC mod tc_occ m
+        s_occ m n = mkGenS mod tc_occ m n
 
         mkTyCon name = ASSERT( isExternalName name )
                        buildAlgTyCon name [] [] Nothing [] distinctAbstractTyConRhs
@@ -91,11 +91,14 @@ genGenericMetaTyCons tc mod =
                                           False          -- Not GADT syntax
                                           NoParentTyCon
 
-      d_name  <- newGlobalBinder mod d_occ loc
+      loc <- getSrcSpanM
+      -- we generate new names in current module
+      currentMod <- getModule
+      d_name  <- newGlobalBinder currentMod d_occ loc
       c_names <- forM (zip [0..] tc_cons) $ \(m,_) ->
-                    newGlobalBinder mod (c_occ m) loc
+                    newGlobalBinder currentMod (c_occ m) loc
       s_names <- forM (zip [0..] tc_arits) $ \(m,a) -> forM [0..a-1] $ \n ->
-                    newGlobalBinder mod (s_occ m n) loc
+                    newGlobalBinder currentMod (s_occ m n) loc
 
       let metaDTyCon  = mkTyCon d_name
           metaCTyCons = map mkTyCon c_names
@@ -103,23 +106,22 @@ genGenericMetaTyCons tc mod =
 
           metaDts = MetaTyCons metaDTyCon metaCTyCons metaSTyCons
 
-      -- pprTrace "rep0" (ppr rep0_tycon) $
       (,) metaDts `fmap` metaTyConsToDerivStuff tc metaDts
 
 -- both the tycon declarations and related instances
 metaTyConsToDerivStuff :: TyCon -> MetaTyCons -> TcM BagDerivStuff
 metaTyConsToDerivStuff tc metaDts =
-  do  loc <- getSrcSpanM
-      dflags <- getDynFlags
+  do  dflags <- getDynFlags
       dClas <- tcLookupClass datatypeClassName
-      let new_dfun_name clas tycon = newDFunName clas [mkTyConApp tycon []] loc
-      d_dfun_name <- new_dfun_name dClas tc
+      d_dfun_name <- newDFunName' dClas tc
       cClas <- tcLookupClass constructorClassName
-      c_dfun_names <- sequence [ new_dfun_name cClas tc | _ <- metaC metaDts ]
+      c_dfun_names <- sequence [ (conTy,) <$> newDFunName' cClas tc
+                               | conTy <- metaC metaDts ]
       sClas <- tcLookupClass selectorClassName
-      s_dfun_names <- sequence (map sequence [ [ new_dfun_name sClas tc
-                                               | _ <- x ]
-                                             | x <- metaS metaDts ])
+      s_dfun_names <-
+        sequence (map sequence [ [ (selector,) <$> newDFunName' sClas tc
+                                 | selector <- selectors ]
+                               | selectors <- metaS metaDts ])
       fix_env <- getFixityEnv
 
       let
@@ -143,9 +145,7 @@ metaTyConsToDerivStuff tc metaDts =
         d_mkInst = DerivInst (InstInfo { iSpec = d_inst, iBinds = d_binds })
 
         -- Constructor
-        c_metaTycons = metaC metaDts
-        c_insts = [ mk_inst cClas c ds
-                  | (c, ds) <- myZip1 c_metaTycons c_dfun_names ]
+        c_insts = [ mk_inst cClas c ds | (c, ds) <- c_dfun_names ]
         c_binds = [ InstBindings { ib_binds = c
                                  , ib_tyvars = []
                                  , ib_pragmas = []
@@ -156,9 +156,7 @@ metaTyConsToDerivStuff tc metaDts =
                    | (is,bs) <- myZip1 c_insts c_binds ]
 
         -- Selector
-        s_metaTycons = metaS metaDts
-        s_insts = map (map (\(s,ds) -> mk_inst sClas s ds))
-                      (myZip2 s_metaTycons s_dfun_names)
+        s_insts = map (map (\(s,ds) -> mk_inst sClas s ds)) s_dfun_names
         s_binds = [ [ InstBindings { ib_binds = s
                                    , ib_tyvars = []
                                    , ib_pragmas = []
diff --git a/testsuite/tests/deriving/should_compile/T10487.hs b/testsuite/tests/deriving/should_compile/T10487.hs
new file mode 100644
index 0000000000..473a1b37ef
--- /dev/null
+++ b/testsuite/tests/deriving/should_compile/T10487.hs
@@ -0,0 +1,12 @@
+{-# LANGUAGE StandaloneDeriving, DeriveGeneric #-}
+
+module T10487 where
+
+import GHC.Generics
+
+import qualified T10487_M as M
+
+data Name = Name
+
+deriving instance Generic Name
+deriving instance Generic M.Name
diff --git a/testsuite/tests/deriving/should_compile/T10487_M.hs b/testsuite/tests/deriving/should_compile/T10487_M.hs
new file mode 100644
index 0000000000..dc75fb2930
--- /dev/null
+++ b/testsuite/tests/deriving/should_compile/T10487_M.hs
@@ -0,0 +1,3 @@
+module T10487_M where
+
+data Name = Name
diff --git a/testsuite/tests/deriving/should_compile/all.T b/testsuite/tests/deriving/should_compile/all.T
index b1cf3bc475..9ffa07df3d 100644
--- a/testsuite/tests/deriving/should_compile/all.T
+++ b/testsuite/tests/deriving/should_compile/all.T
@@ -55,4 +55,4 @@ test('T9359', normal, compile, [''])
 test('T4896', normal, compile, [''])
 test('T7947', extra_clean(['T7947a.o', 'T7947a.hi', 'T7947b.o', 'T7947b.hi']), multimod_compile, ['T7947', '-v0'])
 test('T10561', normal, compile_fail, [''])
-
+test('T10487', extra_clean(['T10487_M.o', 'T10487_M.hi']), multimod_compile, ['T10487', '-v0'])
diff --git a/testsuite/tests/generics/GenDerivOutput.stderr b/testsuite/tests/generics/GenDerivOutput.stderr
index 68283ef63f..5698393496 100644
--- a/testsuite/tests/generics/GenDerivOutput.stderr
+++ b/testsuite/tests/generics/GenDerivOutput.stderr
@@ -88,84 +88,95 @@ Derived instances:
           ((GHC.Base..)
              (GHC.Base.fmap GHC.Generics.unRec1) GHC.Generics.unComp1 g2)
   
-  instance GHC.Generics.Datatype GenDerivOutput.D1List where
+  instance GHC.Generics.Datatype
+             GenDerivOutput.D1_main_GenDerivOutput_List where
     GHC.Generics.datatypeName _ = "List"
     GHC.Generics.moduleName _ = "GenDerivOutput"
     GHC.Generics.packageName _ = "main"
   
-  instance GHC.Generics.Constructor GenDerivOutput.C1_0List where
+  instance GHC.Generics.Constructor
+             GenDerivOutput.C1_0main_GenDerivOutput_List where
     GHC.Generics.conName _ = "Nil"
   
-  instance GHC.Generics.Constructor GenDerivOutput.C1_1List where
+  instance GHC.Generics.Constructor
+             GenDerivOutput.C1_1main_GenDerivOutput_List where
     GHC.Generics.conName _ = "Cons"
     GHC.Generics.conIsRecord _ = GHC.Types.True
   
-  instance GHC.Generics.Selector GenDerivOutput.S1_1_0List where
+  instance GHC.Generics.Selector
+             GenDerivOutput.S1_1_0main_GenDerivOutput_List where
     GHC.Generics.selName _ = "element"
   
-  instance GHC.Generics.Selector GenDerivOutput.S1_1_1List where
+  instance GHC.Generics.Selector
+             GenDerivOutput.S1_1_1main_GenDerivOutput_List where
     GHC.Generics.selName _ = "rest"
   
-  instance GHC.Generics.Datatype GenDerivOutput.D1Rose where
+  instance GHC.Generics.Datatype
+             GenDerivOutput.D1_main_GenDerivOutput_Rose where
     GHC.Generics.datatypeName _ = "Rose"
     GHC.Generics.moduleName _ = "GenDerivOutput"
     GHC.Generics.packageName _ = "main"
   
-  instance GHC.Generics.Constructor GenDerivOutput.C1_0Rose where
+  instance GHC.Generics.Constructor
+             GenDerivOutput.C1_0main_GenDerivOutput_Rose where
     GHC.Generics.conName _ = "Empty"
   
-  instance GHC.Generics.Constructor GenDerivOutput.C1_1Rose where
+  instance GHC.Generics.Constructor
+             GenDerivOutput.C1_1main_GenDerivOutput_Rose where
     GHC.Generics.conName _ = "Rose"
   
 
 Generic representation:
   
   Generated datatypes for meta-information:
-    GenDerivOutput.D1List
-    GenDerivOutput.C1_0List
-    GenDerivOutput.C1_1List
-    GenDerivOutput.S1_1_0List
-    GenDerivOutput.S1_1_1List
-    GenDerivOutput.D1Rose
-    GenDerivOutput.C1_0Rose
-    GenDerivOutput.C1_1Rose
-    GenDerivOutput.S1_1_0Rose
-    GenDerivOutput.S1_1_1Rose
+    GenDerivOutput.D1_main_GenDerivOutput_List
+    GenDerivOutput.C1_0main_GenDerivOutput_List
+    GenDerivOutput.C1_1main_GenDerivOutput_List
+    GenDerivOutput.S1_1_0main_GenDerivOutput_List
+    GenDerivOutput.S1_1_1main_GenDerivOutput_List
+    GenDerivOutput.D1_main_GenDerivOutput_Rose
+    GenDerivOutput.C1_0main_GenDerivOutput_Rose
+    GenDerivOutput.C1_1main_GenDerivOutput_Rose
+    GenDerivOutput.S1_1_0main_GenDerivOutput_Rose
+    GenDerivOutput.S1_1_1main_GenDerivOutput_Rose
   
   Representation types:
     type GHC.Generics.Rep (GenDerivOutput.List a) = GHC.Generics.D1
-                                                      GenDerivOutput.D1List
+                                                      GenDerivOutput.D1_main_GenDerivOutput_List
                                                       (GHC.Generics.C1
-                                                         GenDerivOutput.C1_0List GHC.Generics.U1
+                                                         GenDerivOutput.C1_0main_GenDerivOutput_List
+                                                         GHC.Generics.U1
                                                        GHC.Generics.:+: GHC.Generics.C1
-                                                                          GenDerivOutput.C1_1List
+                                                                          GenDerivOutput.C1_1main_GenDerivOutput_List
                                                                           (GHC.Generics.S1
-                                                                             GenDerivOutput.S1_1_0List
+                                                                             GenDerivOutput.S1_1_0main_GenDerivOutput_List
                                                                              (GHC.Generics.Rec0 a)
                                                                            GHC.Generics.:*: GHC.Generics.S1
-                                                                                              GenDerivOutput.S1_1_1List
+                                                                                              GenDerivOutput.S1_1_1main_GenDerivOutput_List
                                                                                               (GHC.Generics.Rec0
                                                                                                  (GenDerivOutput.List
                                                                                                     a))))
     type GHC.Generics.Rep1 GenDerivOutput.List = GHC.Generics.D1
-                                                   GenDerivOutput.D1List
+                                                   GenDerivOutput.D1_main_GenDerivOutput_List
                                                    (GHC.Generics.C1
-                                                      GenDerivOutput.C1_0List GHC.Generics.U1
+                                                      GenDerivOutput.C1_0main_GenDerivOutput_List
+                                                      GHC.Generics.U1
                                                     GHC.Generics.:+: GHC.Generics.C1
-                                                                       GenDerivOutput.C1_1List
+                                                                       GenDerivOutput.C1_1main_GenDerivOutput_List
                                                                        (GHC.Generics.S1
-                                                                          GenDerivOutput.S1_1_0List
+                                                                          GenDerivOutput.S1_1_0main_GenDerivOutput_List
                                                                           GHC.Generics.Par1
                                                                         GHC.Generics.:*: GHC.Generics.S1
-                                                                                           GenDerivOutput.S1_1_1List
+                                                                                           GenDerivOutput.S1_1_1main_GenDerivOutput_List
                                                                                            (GHC.Generics.Rec1
                                                                                               GenDerivOutput.List)))
     type GHC.Generics.Rep (GenDerivOutput.Rose a) = GHC.Generics.D1
-                                                      GenDerivOutput.D1Rose
+                                                      GenDerivOutput.D1_main_GenDerivOutput_Rose
                                                       (GHC.Generics.C1
-                                                         GenDerivOutput.C1_0Rose GHC.Generics.U1
+                                                         GenDerivOutput.C1_0main_GenDerivOutput_Rose
+                                                         GHC.Generics.U1
                                                        GHC.Generics.:+: GHC.Generics.C1
-                                                                          GenDerivOutput.C1_1Rose
+                                                                          GenDerivOutput.C1_1main_GenDerivOutput_Rose
                                                                           (GHC.Generics.S1
                                                                              GHC.Generics.NoSelector
                                                                              (GHC.Generics.Rec0 a)
@@ -176,11 +187,12 @@ Generic representation:
                                                                                                     (GenDerivOutput.Rose
                                                                                                        a)))))
     type GHC.Generics.Rep1 GenDerivOutput.Rose = GHC.Generics.D1
-                                                   GenDerivOutput.D1Rose
+                                                   GenDerivOutput.D1_main_GenDerivOutput_Rose
                                                    (GHC.Generics.C1
-                                                      GenDerivOutput.C1_0Rose GHC.Generics.U1
+                                                      GenDerivOutput.C1_0main_GenDerivOutput_Rose
+                                                      GHC.Generics.U1
                                                     GHC.Generics.:+: GHC.Generics.C1
-                                                                       GenDerivOutput.C1_1Rose
+                                                                       GenDerivOutput.C1_1main_GenDerivOutput_Rose
                                                                        (GHC.Generics.S1
                                                                           GHC.Generics.NoSelector
                                                                           GHC.Generics.Par1
diff --git a/testsuite/tests/generics/GenDerivOutput1_0.stderr b/testsuite/tests/generics/GenDerivOutput1_0.stderr
index 0a89f4bb1a..9b187f53ce 100644
--- a/testsuite/tests/generics/GenDerivOutput1_0.stderr
+++ b/testsuite/tests/generics/GenDerivOutput1_0.stderr
@@ -21,46 +21,52 @@ Derived instances:
       = GenDerivOutput1_0.Cons
           (GHC.Generics.unPar1 g1) (GHC.Generics.unRec1 g2)
   
-  instance GHC.Generics.Datatype GenDerivOutput1_0.D1List where
+  instance GHC.Generics.Datatype
+             GenDerivOutput1_0.D1_main_GenDerivOutput1_0_List where
     GHC.Generics.datatypeName _ = "List"
     GHC.Generics.moduleName _ = "GenDerivOutput1_0"
     GHC.Generics.packageName _ = "main"
   
-  instance GHC.Generics.Constructor GenDerivOutput1_0.C1_0List where
+  instance GHC.Generics.Constructor
+             GenDerivOutput1_0.C1_0main_GenDerivOutput1_0_List where
     GHC.Generics.conName _ = "Nil"
   
-  instance GHC.Generics.Constructor GenDerivOutput1_0.C1_1List where
+  instance GHC.Generics.Constructor
+             GenDerivOutput1_0.C1_1main_GenDerivOutput1_0_List where
     GHC.Generics.conName _ = "Cons"
     GHC.Generics.conIsRecord _ = GHC.Types.True
   
-  instance GHC.Generics.Selector GenDerivOutput1_0.S1_1_0List where
+  instance GHC.Generics.Selector
+             GenDerivOutput1_0.S1_1_0main_GenDerivOutput1_0_List where
     GHC.Generics.selName _ = "element"
   
-  instance GHC.Generics.Selector GenDerivOutput1_0.S1_1_1List where
+  instance GHC.Generics.Selector
+             GenDerivOutput1_0.S1_1_1main_GenDerivOutput1_0_List where
     GHC.Generics.selName _ = "rest"
   
 
 Generic representation:
   
   Generated datatypes for meta-information:
-    GenDerivOutput1_0.D1List
-    GenDerivOutput1_0.C1_0List
-    GenDerivOutput1_0.C1_1List
-    GenDerivOutput1_0.S1_1_0List
-    GenDerivOutput1_0.S1_1_1List
+    GenDerivOutput1_0.D1_main_GenDerivOutput1_0_List
+    GenDerivOutput1_0.C1_0main_GenDerivOutput1_0_List
+    GenDerivOutput1_0.C1_1main_GenDerivOutput1_0_List
+    GenDerivOutput1_0.S1_1_0main_GenDerivOutput1_0_List
+    GenDerivOutput1_0.S1_1_1main_GenDerivOutput1_0_List
   
   Representation types:
     type GHC.Generics.Rep1 GenDerivOutput1_0.List = GHC.Generics.D1
-                                                      GenDerivOutput1_0.D1List
+                                                      GenDerivOutput1_0.D1_main_GenDerivOutput1_0_List
                                                       (GHC.Generics.C1
-                                                         GenDerivOutput1_0.C1_0List GHC.Generics.U1
+                                                         GenDerivOutput1_0.C1_0main_GenDerivOutput1_0_List
+                                                         GHC.Generics.U1
                                                        GHC.Generics.:+: GHC.Generics.C1
-                                                                          GenDerivOutput1_0.C1_1List
+                                                                          GenDerivOutput1_0.C1_1main_GenDerivOutput1_0_List
                                                                           (GHC.Generics.S1
-                                                                             GenDerivOutput1_0.S1_1_0List
+                                                                             GenDerivOutput1_0.S1_1_0main_GenDerivOutput1_0_List
                                                                              GHC.Generics.Par1
                                                                            GHC.Generics.:*: GHC.Generics.S1
-                                                                                              GenDerivOutput1_0.S1_1_1List
+                                                                                              GenDerivOutput1_0.S1_1_1main_GenDerivOutput1_0_List
                                                                                               (GHC.Generics.Rec1
                                                                                                  GenDerivOutput1_0.List)))
 
diff --git a/testsuite/tests/generics/GenDerivOutput1_1.stderr b/testsuite/tests/generics/GenDerivOutput1_1.stderr
index 3fac6d2803..dc05cc4568 100644
--- a/testsuite/tests/generics/GenDerivOutput1_1.stderr
+++ b/testsuite/tests/generics/GenDerivOutput1_1.stderr
@@ -153,202 +153,234 @@ Derived instances:
                                                                              (GHC.Generics.M1 g2)))))
       = CanDoRep1_1.D1c (GHC.Generics.unPar1 g1) (GHC.Generics.unRec1 g2)
   
-  instance GHC.Generics.Datatype CanDoRep1_1.D1Da where
+  instance GHC.Generics.Datatype
+             CanDoRep1_1.D1_main_CanDoRep1_1_Da where
     GHC.Generics.datatypeName _ = "Da"
     GHC.Generics.moduleName _ = "CanDoRep1_1"
     GHC.Generics.packageName _ = "main"
   
-  instance GHC.Generics.Constructor CanDoRep1_1.C1_0Da where
+  instance GHC.Generics.Constructor
+             CanDoRep1_1.C1_0main_CanDoRep1_1_Da where
     GHC.Generics.conName _ = "D0"
   
-  instance GHC.Generics.Constructor CanDoRep1_1.C1_1Da where
+  instance GHC.Generics.Constructor
+             CanDoRep1_1.C1_1main_CanDoRep1_1_Da where
     GHC.Generics.conName _ = "D1"
     GHC.Generics.conIsRecord _ = GHC.Types.True
   
-  instance GHC.Generics.Selector CanDoRep1_1.S1_1_0Da where
+  instance GHC.Generics.Selector
+             CanDoRep1_1.S1_1_0main_CanDoRep1_1_Da where
     GHC.Generics.selName _ = "d11a"
   
-  instance GHC.Generics.Selector CanDoRep1_1.S1_1_1Da where
+  instance GHC.Generics.Selector
+             CanDoRep1_1.S1_1_1main_CanDoRep1_1_Da where
     GHC.Generics.selName _ = "d12a"
   
-  instance GHC.Generics.Datatype CanDoRep1_1.D1Db where
+  instance GHC.Generics.Datatype
+             CanDoRep1_1.D1_main_CanDoRep1_1_Db where
     GHC.Generics.datatypeName _ = "Db"
     GHC.Generics.moduleName _ = "CanDoRep1_1"
     GHC.Generics.packageName _ = "main"
   
-  instance GHC.Generics.Constructor CanDoRep1_1.C1_0Db where
+  instance GHC.Generics.Constructor
+             CanDoRep1_1.C1_0main_CanDoRep1_1_Db where
     GHC.Generics.conName _ = "D0b"
   
-  instance GHC.Generics.Constructor CanDoRep1_1.C1_1Db where
+  instance GHC.Generics.Constructor
+             CanDoRep1_1.C1_1main_CanDoRep1_1_Db where
     GHC.Generics.conName _ = "D1b"
     GHC.Generics.conIsRecord _ = GHC.Types.True
   
-  instance GHC.Generics.Selector CanDoRep1_1.S1_1_0Db where
+  instance GHC.Generics.Selector
+             CanDoRep1_1.S1_1_0main_CanDoRep1_1_Db where
     GHC.Generics.selName _ = "d11b"
   
-  instance GHC.Generics.Selector CanDoRep1_1.S1_1_1Db where
+  instance GHC.Generics.Selector
+             CanDoRep1_1.S1_1_1main_CanDoRep1_1_Db where
     GHC.Generics.selName _ = "d12b"
   
-  instance GHC.Generics.Datatype CanDoRep1_1.D1Dc where
+  instance GHC.Generics.Datatype
+             CanDoRep1_1.D1_main_CanDoRep1_1_Dc where
     GHC.Generics.datatypeName _ = "Dc"
     GHC.Generics.moduleName _ = "CanDoRep1_1"
     GHC.Generics.packageName _ = "main"
   
-  instance GHC.Generics.Constructor CanDoRep1_1.C1_0Dc where
+  instance GHC.Generics.Constructor
+             CanDoRep1_1.C1_0main_CanDoRep1_1_Dc where
     GHC.Generics.conName _ = "D0c"
   
-  instance GHC.Generics.Constructor CanDoRep1_1.C1_1Dc where
+  instance GHC.Generics.Constructor
+             CanDoRep1_1.C1_1main_CanDoRep1_1_Dc where
     GHC.Generics.conName _ = "D1c"
     GHC.Generics.conIsRecord _ = GHC.Types.True
   
-  instance GHC.Generics.Selector CanDoRep1_1.S1_1_0Dc where
+  instance GHC.Generics.Selector
+             CanDoRep1_1.S1_1_0main_CanDoRep1_1_Dc where
     GHC.Generics.selName _ = "d11c"
   
-  instance GHC.Generics.Selector CanDoRep1_1.S1_1_1Dc where
+  instance GHC.Generics.Selector
+             CanDoRep1_1.S1_1_1main_CanDoRep1_1_Dc where
     GHC.Generics.selName _ = "d12c"
   
-  instance GHC.Generics.Datatype CanDoRep1_1.D1Dd where
+  instance GHC.Generics.Datatype
+             CanDoRep1_1.D1_main_CanDoRep1_1_Dd where
     GHC.Generics.datatypeName _ = "Dd"
     GHC.Generics.moduleName _ = "CanDoRep1_1"
     GHC.Generics.packageName _ = "main"
   
-  instance GHC.Generics.Constructor CanDoRep1_1.C1_0Dd where
+  instance GHC.Generics.Constructor
+             CanDoRep1_1.C1_0main_CanDoRep1_1_Dd where
     GHC.Generics.conName _ = "D0d"
   
-  instance GHC.Generics.Constructor CanDoRep1_1.C1_1Dd where
+  instance GHC.Generics.Constructor
+             CanDoRep1_1.C1_1main_CanDoRep1_1_Dd where
     GHC.Generics.conName _ = "D1d"
     GHC.Generics.conIsRecord _ = GHC.Types.True
   
-  instance GHC.Generics.Selector CanDoRep1_1.S1_1_0Dd where
+  instance GHC.Generics.Selector
+             CanDoRep1_1.S1_1_0main_CanDoRep1_1_Dd where
     GHC.Generics.selName _ = "d11d"
   
-  instance GHC.Generics.Selector CanDoRep1_1.S1_1_1Dd where
+  instance GHC.Generics.Selector
+             CanDoRep1_1.S1_1_1main_CanDoRep1_1_Dd where
     GHC.Generics.selName _ = "d12d"
   
 
 Generic representation:
   
   Generated datatypes for meta-information:
-    CanDoRep1_1.D1Da
-    CanDoRep1_1.C1_0Da
-    CanDoRep1_1.C1_1Da
-    CanDoRep1_1.S1_1_0Da
-    CanDoRep1_1.S1_1_1Da
-    CanDoRep1_1.D1Db
-    CanDoRep1_1.C1_0Db
-    CanDoRep1_1.C1_1Db
-    CanDoRep1_1.S1_1_0Db
-    CanDoRep1_1.S1_1_1Db
-    CanDoRep1_1.D1Dc
-    CanDoRep1_1.C1_0Dc
-    CanDoRep1_1.C1_1Dc
-    CanDoRep1_1.S1_1_0Dc
-    CanDoRep1_1.S1_1_1Dc
-    CanDoRep1_1.D1Dd
-    CanDoRep1_1.C1_0Dd
-    CanDoRep1_1.C1_1Dd
-    CanDoRep1_1.S1_1_0Dd
-    CanDoRep1_1.S1_1_1Dd
+    CanDoRep1_1.D1_main_CanDoRep1_1_Da
+    CanDoRep1_1.C1_0main_CanDoRep1_1_Da
+    CanDoRep1_1.C1_1main_CanDoRep1_1_Da
+    CanDoRep1_1.S1_1_0main_CanDoRep1_1_Da
+    CanDoRep1_1.S1_1_1main_CanDoRep1_1_Da
+    CanDoRep1_1.D1_main_CanDoRep1_1_Db
+    CanDoRep1_1.C1_0main_CanDoRep1_1_Db
+    CanDoRep1_1.C1_1main_CanDoRep1_1_Db
+    CanDoRep1_1.S1_1_0main_CanDoRep1_1_Db
+    CanDoRep1_1.S1_1_1main_CanDoRep1_1_Db
+    CanDoRep1_1.D1_main_CanDoRep1_1_Dc
+    CanDoRep1_1.C1_0main_CanDoRep1_1_Dc
+    CanDoRep1_1.C1_1main_CanDoRep1_1_Dc
+    CanDoRep1_1.S1_1_0main_CanDoRep1_1_Dc
+    CanDoRep1_1.S1_1_1main_CanDoRep1_1_Dc
+    CanDoRep1_1.D1_main_CanDoRep1_1_Dd
+    CanDoRep1_1.C1_0main_CanDoRep1_1_Dd
+    CanDoRep1_1.C1_1main_CanDoRep1_1_Dd
+    CanDoRep1_1.S1_1_0main_CanDoRep1_1_Dd
+    CanDoRep1_1.S1_1_1main_CanDoRep1_1_Dd
   
   Representation types:
     type GHC.Generics.Rep1 CanDoRep1_1.Dd = GHC.Generics.D1
-                                              CanDoRep1_1.D1Dd
-                                              (GHC.Generics.C1 CanDoRep1_1.C1_0Dd GHC.Generics.U1
+                                              CanDoRep1_1.D1_main_CanDoRep1_1_Dd
+                                              (GHC.Generics.C1
+                                                 CanDoRep1_1.C1_0main_CanDoRep1_1_Dd GHC.Generics.U1
                                                GHC.Generics.:+: GHC.Generics.C1
-                                                                  CanDoRep1_1.C1_1Dd
+                                                                  CanDoRep1_1.C1_1main_CanDoRep1_1_Dd
                                                                   (GHC.Generics.S1
-                                                                     CanDoRep1_1.S1_1_0Dd
+                                                                     CanDoRep1_1.S1_1_0main_CanDoRep1_1_Dd
                                                                      GHC.Generics.Par1
                                                                    GHC.Generics.:*: GHC.Generics.S1
-                                                                                      CanDoRep1_1.S1_1_1Dd
+                                                                                      CanDoRep1_1.S1_1_1main_CanDoRep1_1_Dd
                                                                                       (GHC.Generics.Rec1
                                                                                          CanDoRep1_1.Dd)))
     type GHC.Generics.Rep (CanDoRep1_1.Dd a) = GHC.Generics.D1
-                                                 CanDoRep1_1.D1Dd
-                                                 (GHC.Generics.C1 CanDoRep1_1.C1_0Dd GHC.Generics.U1
+                                                 CanDoRep1_1.D1_main_CanDoRep1_1_Dd
+                                                 (GHC.Generics.C1
+                                                    CanDoRep1_1.C1_0main_CanDoRep1_1_Dd
+                                                    GHC.Generics.U1
                                                   GHC.Generics.:+: GHC.Generics.C1
-                                                                     CanDoRep1_1.C1_1Dd
+                                                                     CanDoRep1_1.C1_1main_CanDoRep1_1_Dd
                                                                      (GHC.Generics.S1
-                                                                        CanDoRep1_1.S1_1_0Dd
+                                                                        CanDoRep1_1.S1_1_0main_CanDoRep1_1_Dd
                                                                         (GHC.Generics.Rec0 a)
                                                                       GHC.Generics.:*: GHC.Generics.S1
-                                                                                         CanDoRep1_1.S1_1_1Dd
+                                                                                         CanDoRep1_1.S1_1_1main_CanDoRep1_1_Dd
                                                                                          (GHC.Generics.Rec0
                                                                                             (CanDoRep1_1.Dd
                                                                                                a))))
     type GHC.Generics.Rep (CanDoRep1_1.Dc a) = GHC.Generics.D1
-                                                 CanDoRep1_1.D1Dc
-                                                 (GHC.Generics.C1 CanDoRep1_1.C1_0Dc GHC.Generics.U1
+                                                 CanDoRep1_1.D1_main_CanDoRep1_1_Dc
+                                                 (GHC.Generics.C1
+                                                    CanDoRep1_1.C1_0main_CanDoRep1_1_Dc
+                                                    GHC.Generics.U1
                                                   GHC.Generics.:+: GHC.Generics.C1
-                                                                     CanDoRep1_1.C1_1Dc
+                                                                     CanDoRep1_1.C1_1main_CanDoRep1_1_Dc
                                                                      (GHC.Generics.S1
-                                                                        CanDoRep1_1.S1_1_0Dc
+                                                                        CanDoRep1_1.S1_1_0main_CanDoRep1_1_Dc
                                                                         (GHC.Generics.Rec0 a)
                                                                       GHC.Generics.:*: GHC.Generics.S1
-                                                                                         CanDoRep1_1.S1_1_1Dc
+                                                                                         CanDoRep1_1.S1_1_1main_CanDoRep1_1_Dc
                                                                                          (GHC.Generics.Rec0
                                                                                             (CanDoRep1_1.Dc
                                                                                                a))))
     type GHC.Generics.Rep1 CanDoRep1_1.Db = GHC.Generics.D1
-                                              CanDoRep1_1.D1Db
-                                              (GHC.Generics.C1 CanDoRep1_1.C1_0Db GHC.Generics.U1
+                                              CanDoRep1_1.D1_main_CanDoRep1_1_Db
+                                              (GHC.Generics.C1
+                                                 CanDoRep1_1.C1_0main_CanDoRep1_1_Db GHC.Generics.U1
                                                GHC.Generics.:+: GHC.Generics.C1
-                                                                  CanDoRep1_1.C1_1Db
+                                                                  CanDoRep1_1.C1_1main_CanDoRep1_1_Db
                                                                   (GHC.Generics.S1
-                                                                     CanDoRep1_1.S1_1_0Db
+                                                                     CanDoRep1_1.S1_1_0main_CanDoRep1_1_Db
                                                                      GHC.Generics.Par1
                                                                    GHC.Generics.:*: GHC.Generics.S1
-                                                                                      CanDoRep1_1.S1_1_1Db
+                                                                                      CanDoRep1_1.S1_1_1main_CanDoRep1_1_Db
                                                                                       (GHC.Generics.Rec1
                                                                                          CanDoRep1_1.Db)))
     type GHC.Generics.Rep (CanDoRep1_1.Da a) = GHC.Generics.D1
-                                                 CanDoRep1_1.D1Da
-                                                 (GHC.Generics.C1 CanDoRep1_1.C1_0Da GHC.Generics.U1
+                                                 CanDoRep1_1.D1_main_CanDoRep1_1_Da
+                                                 (GHC.Generics.C1
+                                                    CanDoRep1_1.C1_0main_CanDoRep1_1_Da
+                                                    GHC.Generics.U1
                                                   GHC.Generics.:+: GHC.Generics.C1
-                                                                     CanDoRep1_1.C1_1Da
+                                                                     CanDoRep1_1.C1_1main_CanDoRep1_1_Da
                                                                      (GHC.Generics.S1
-                                                                        CanDoRep1_1.S1_1_0Da
+                                                                        CanDoRep1_1.S1_1_0main_CanDoRep1_1_Da
                                                                         (GHC.Generics.Rec0 a)
                                                                       GHC.Generics.:*: GHC.Generics.S1
-                                                                                         CanDoRep1_1.S1_1_1Da
+                                                                                         CanDoRep1_1.S1_1_1main_CanDoRep1_1_Da
                                                                                          (GHC.Generics.Rec0
                                                                                             (CanDoRep1_1.Da
                                                                                                a))))
     type GHC.Generics.Rep1 CanDoRep1_1.Da = GHC.Generics.D1
-                                              CanDoRep1_1.D1Da
-                                              (GHC.Generics.C1 CanDoRep1_1.C1_0Da GHC.Generics.U1
+                                              CanDoRep1_1.D1_main_CanDoRep1_1_Da
+                                              (GHC.Generics.C1
+                                                 CanDoRep1_1.C1_0main_CanDoRep1_1_Da GHC.Generics.U1
                                                GHC.Generics.:+: GHC.Generics.C1
-                                                                  CanDoRep1_1.C1_1Da
+                                                                  CanDoRep1_1.C1_1main_CanDoRep1_1_Da
                                                                   (GHC.Generics.S1
-                                                                     CanDoRep1_1.S1_1_0Da
+                                                                     CanDoRep1_1.S1_1_0main_CanDoRep1_1_Da
                                                                      GHC.Generics.Par1
                                                                    GHC.Generics.:*: GHC.Generics.S1
-                                                                                      CanDoRep1_1.S1_1_1Da
+                                                                                      CanDoRep1_1.S1_1_1main_CanDoRep1_1_Da
                                                                                       (GHC.Generics.Rec1
                                                                                          CanDoRep1_1.Da)))
     type GHC.Generics.Rep (CanDoRep1_1.Db a) = GHC.Generics.D1
-                                                 CanDoRep1_1.D1Db
-                                                 (GHC.Generics.C1 CanDoRep1_1.C1_0Db GHC.Generics.U1
+                                                 CanDoRep1_1.D1_main_CanDoRep1_1_Db
+                                                 (GHC.Generics.C1
+                                                    CanDoRep1_1.C1_0main_CanDoRep1_1_Db
+                                                    GHC.Generics.U1
                                                   GHC.Generics.:+: GHC.Generics.C1
-                                                                     CanDoRep1_1.C1_1Db
+                                                                     CanDoRep1_1.C1_1main_CanDoRep1_1_Db
                                                                      (GHC.Generics.S1
-                                                                        CanDoRep1_1.S1_1_0Db
+                                                                        CanDoRep1_1.S1_1_0main_CanDoRep1_1_Db
                                                                         (GHC.Generics.Rec0 a)
                                                                       GHC.Generics.:*: GHC.Generics.S1
-                                                                                         CanDoRep1_1.S1_1_1Db
+                                                                                         CanDoRep1_1.S1_1_1main_CanDoRep1_1_Db
                                                                                          (GHC.Generics.Rec0
                                                                                             (CanDoRep1_1.Db
                                                                                                a))))
     type GHC.Generics.Rep1 CanDoRep1_1.Dc = GHC.Generics.D1
-                                              CanDoRep1_1.D1Dc
-                                              (GHC.Generics.C1 CanDoRep1_1.C1_0Dc GHC.Generics.U1
+                                              CanDoRep1_1.D1_main_CanDoRep1_1_Dc
+                                              (GHC.Generics.C1
+                                                 CanDoRep1_1.C1_0main_CanDoRep1_1_Dc GHC.Generics.U1
                                                GHC.Generics.:+: GHC.Generics.C1
-                                                                  CanDoRep1_1.C1_1Dc
+                                                                  CanDoRep1_1.C1_1main_CanDoRep1_1_Dc
                                                                   (GHC.Generics.S1
-                                                                     CanDoRep1_1.S1_1_0Dc
+                                                                     CanDoRep1_1.S1_1_0main_CanDoRep1_1_Dc
                                                                      GHC.Generics.Par1
                                                                    GHC.Generics.:*: GHC.Generics.S1
-                                                                                      CanDoRep1_1.S1_1_1Dc
+                                                                                      CanDoRep1_1.S1_1_1main_CanDoRep1_1_Dc
                                                                                       (GHC.Generics.Rec1
                                                                                          CanDoRep1_1.Dc)))