2 files changed, 14 insertions, 6 deletions
diff --git a/compiler/GHC/Core/FamInstEnv.hs b/compiler/GHC/Core/FamInstEnv.hs
index 78ed3a104c..bfbd2000cb 100644
--- a/compiler/GHC/Core/FamInstEnv.hs
+++ b/compiler/GHC/Core/FamInstEnv.hs
@@ -16,7 +16,7 @@ module GHC.Core.FamInstEnv (
 
         FamInstEnvs, FamInstEnv, emptyFamInstEnv, emptyFamInstEnvs,
         unionFamInstEnv, extendFamInstEnv, extendFamInstEnvList,
-        famInstEnvElts, famInstEnvSize, familyInstances,
+        famInstEnvElts, famInstEnvSize, familyInstances, familyNameInstances,
 
         -- * CoAxioms
         mkCoAxBranch, mkBranchedCoAxiom, mkUnbranchedCoAxiom, mkSingleCoAxiom,
@@ -397,11 +397,15 @@ famInstEnvElts (FamIE _ rm) = elemsRM rm
   -- size.
 
 familyInstances :: (FamInstEnv, FamInstEnv) -> TyCon -> [FamInst]
-familyInstances (pkg_fie, home_fie) fam
+familyInstances envs tc
+  = familyNameInstances envs (tyConName tc)
+
+familyNameInstances :: (FamInstEnv, FamInstEnv) -> Name -> [FamInst]
+familyNameInstances (pkg_fie, home_fie) fam
   = get home_fie ++ get pkg_fie
   where
     get :: FamInstEnv -> [FamInst]
-    get (FamIE _ env) = lookupRM [RML_KnownTc (tyConName fam)] env
+    get (FamIE _ env) = lookupRM [RML_KnownTc fam] env
 
 
 -- | Makes no particular effort to detect conflicts.
diff --git a/compiler/GHC/Core/InstEnv.hs b/compiler/GHC/Core/InstEnv.hs
index e223a7cd87..63dde6f6b5 100644
--- a/compiler/GHC/Core/InstEnv.hs
+++ b/compiler/GHC/Core/InstEnv.hs
@@ -27,6 +27,7 @@ module GHC.Core.InstEnv (
         memberInstEnv,
         instIsVisible,
         classInstances, instanceBindFun,
+        classNameInstances,
         instanceCantMatch, roughMatchTcs,
         isOverlappable, isOverlapping, isIncoherent
     ) where
@@ -435,8 +436,8 @@ instEnvElts :: InstEnv -> [ClsInst]
 instEnvElts (InstEnv rm) = elemsRM rm
   -- See Note [InstEnv determinism]
 
-instEnvEltsForClass :: InstEnv -> Class -> [ClsInst]
-instEnvEltsForClass (InstEnv rm) cls = lookupRM [RML_KnownTc (className cls)] rm
+instEnvEltsForClass :: InstEnv -> Name -> [ClsInst]
+instEnvEltsForClass (InstEnv rm) cls_nm = lookupRM [RML_KnownTc cls_nm] rm
 
 -- N.B. this is not particularly efficient but used only by GHCi.
 instEnvClasses :: InstEnv -> UniqDSet Class
@@ -457,7 +458,10 @@ instIsVisible vis_mods ispec
                | otherwise                   -> True
 
 classInstances :: InstEnvs -> Class -> [ClsInst]
-classInstances (InstEnvs { ie_global = pkg_ie, ie_local = home_ie, ie_visible = vis_mods }) cls
+classInstances envs cls = classNameInstances envs (className cls)
+
+classNameInstances :: InstEnvs -> Name -> [ClsInst]
+classNameInstances (InstEnvs { ie_global = pkg_ie, ie_local = home_ie, ie_visible = vis_mods }) cls
   = get home_ie ++ get pkg_ie
   where
     get :: InstEnv -> [ClsInst]