Add Uniquable instances for InstalledPackageId/SourcePackageId/PackageName

Summary: Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: austin

Reviewed By: austin

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D633

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