diff --git a/hledger-lib/Hledger/Data/AccountName.hs b/hledger-lib/Hledger/Data/AccountName.hs
index 54c9759a0..e3cdc9cce 100644
--- a/hledger-lib/Hledger/Data/AccountName.hs
+++ b/hledger-lib/Hledger/Data/AccountName.hs
@@ -24,6 +24,8 @@ import Text.Printf
 import Hledger.Data.Types
 import Hledger.Utils
 
+-- $setup
+-- >>> :set -XOverloadedStrings
 
 acctsepchar :: Char
 acctsepchar = ':'