diff --git a/compiler/main/PackageConfig.hs b/compiler/main/PackageConfig.hs
index b94ea65a6571b48d82fd43b74a75b0c0fd8e99ed..3c41151c1195cfb05bfd9af608b5813ac765672d 100644
--- a/compiler/main/PackageConfig.hs
+++ b/compiler/main/PackageConfig.hs
@@ -34,6 +34,7 @@ import Data.Version
 import FastString
 import Outputable
 import Module
+import Unique
 
 -- -----------------------------------------------------------------------------
 -- Our PackageConfig type is the InstalledPackageInfo from bin-package-db,
@@ -66,6 +67,15 @@ instance BinaryStringRep PackageName where
   fromStringRep = PackageName . mkFastStringByteString
   toStringRep (PackageName s) = fastStringToByteString s
 
+instance Uniquable InstalledPackageId where
+  getUnique (InstalledPackageId n) = getUnique n
+
+instance Uniquable SourcePackageId where
+  getUnique (SourcePackageId n) = getUnique n
+
+instance Uniquable PackageName where
+  getUnique (PackageName n) = getUnique n
+
 instance Outputable InstalledPackageId where
   ppr (InstalledPackageId str) = ftext str