diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,7 @@
+## 0.1.1.1
+
+* Add explicit signature to work around [#12](https://github.com/fpco/optparse-simple/issues/12)
+
 ## 0.1.1
 
 * Switch dependency `gitrev` to `githash`
diff --git a/optparse-simple.cabal b/optparse-simple.cabal
--- a/optparse-simple.cabal
+++ b/optparse-simple.cabal
@@ -1,13 +1,13 @@
 cabal-version: 1.12
 
--- This file has been generated from package.yaml by hpack version 0.30.0.
+-- This file has been generated from package.yaml by hpack version 0.31.1.
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: fedb382b497ac88d5626d78481bca7e81964fa673d0aebf67c05ed96c7883775
+-- hash: 2b285a22930737d4130d35d7319b2a913433c6dc222a4fd799010d448a1b9c8c
 
 name:           optparse-simple
-version:        0.1.1
+version:        0.1.1.1
 synopsis:       Simple interface to optparse-applicative
 description:    Please see the README at <https://www.stackage.org/package/optparse-simple>
 category:       Options
diff --git a/src/Options/Applicative/Simple.hs b/src/Options/Applicative/Simple.hs
--- a/src/Options/Applicative/Simple.hs
+++ b/src/Options/Applicative/Simple.hs
@@ -1,3 +1,6 @@
+-- Try to ensure that https://github.com/fpco/optparse-simple/issues/12 doesn't recur.
+{-# LANGUAGE OverloadedStrings #-}
+
 {-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE CPP #-}
 
@@ -46,7 +49,7 @@
 import           Data.Semigroup
 #endif
 import           Data.Version
-import           GitHash (giDirty, giHash, tGitInfoCwdTry)
+import           GitHash (GitInfo, giDirty, giHash, tGitInfoCwdTry)
 import           Language.Haskell.TH (Q,Exp)
 import qualified Language.Haskell.TH.Syntax as TH
 import           Options.Applicative
@@ -86,7 +89,7 @@
   [|concat (["Version "
            ,$(TH.lift $ showVersion version)
            ] ++
-           case giResult of
+           case giResult :: Either String GitInfo of
              Left _ -> []
              Right gi -> [ ", Git revision "
                          , giHash gi