DsExpr: Remove usage of concatFS in fingerprintName

This was the only user of concatFS and really just wants the `String`
anyways.

Stumbled upon while looking at #12357.

Test Plan: Validate

Reviewers: austin

Reviewed By: austin

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2386

1 files changed, 5 insertions, 7 deletions

diff --git a/compiler/deSugar/DsExpr.hs b/compiler/deSugar/DsExpr.hs
index 85177ee679..bf04f13ce9 100644
--- a/compiler/deSugar/DsExpr.hs
+++ b/compiler/deSugar/DsExpr.hs
@@ -54,9 +54,9 @@ import SrcLoc
 import Util
 import Bag
 import Outputable
-import FastString
 import PatSyn
 
+import Data.List        ( intercalate )
 import Data.IORef       ( atomicModifyIORef' )
 
 import Control.Monad
@@ -470,12 +470,10 @@ dsExpr (HsStatic _ expr@(L loc _)) = do
     mkStaticPtrFingerprint :: Module -> DsM Fingerprint
     mkStaticPtrFingerprint this_mod = do
       n <- mkGenPerModuleNum this_mod
-      return $ fingerprintString $ unpackFS $ concatFS
-        [ unitIdFS $ moduleUnitId this_mod
-        , fsLit ":"
-        , moduleNameFS $ moduleName this_mod
-        , fsLit ":"
-        , mkFastString $ show n
+      return $ fingerprintString $ intercalate ":"
+        [ unitIdString $ moduleUnitId this_mod
+        , moduleNameString $ moduleName this_mod
+        , show n
         ]
 
     mkGenPerModuleNum :: Module -> DsM Int