From c8375e7a6a9a8ae30dfe85c668ca7b403745ed7b Mon Sep 17 00:00:00 2001
From: Michael Sloan <mgsloan@gmail.com>
Date: Sun, 17 Dec 2017 16:10:08 -0800
Subject: [PATCH] Put file arguments first when stack is run as script
 interpreter #3658

---
 ChangeLog.md     | 2 ++
 src/main/Main.hs | 8 ++++++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/ChangeLog.md b/ChangeLog.md
index 2a3cc99a29..45b3cb503c 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -18,6 +18,8 @@ Bug fixes:
 * Run the Cabal file checking in the `sdist` command more reliably by
   allowing the Cabal library to flatten the
   `GenericPackageDescription` itself.
+* Script interpreter implicit file argumenst are now passed before other
+  arguments. See [#3658](https://github.com/commercialhaskell/stack/issues/3658).
 
 ## v1.6.1
 
diff --git a/src/main/Main.hs b/src/main/Main.hs
index fd845982fb..e8192e806b 100644
--- a/src/main/Main.hs
+++ b/src/main/Main.hs
@@ -563,8 +563,12 @@ interpreterHandler currentDir args f = do
       progName <- getProgName
       iargs <- getInterpreterArgs path
       let parseCmdLine = commandLineHandler currentDir progName True
-          separator = if "--" `elem` iargs then [] else ["--"]
-          cmdArgs = stackArgs ++ iargs ++ separator ++ path : fileArgs
+          -- Implicit file arguments are put before other arguments that
+          -- occur after "--". See #3658
+          cmdArgs = stackArgs ++ case break (== "--") iargs of
+            (beforeSep, []) -> beforeSep ++ ["--"] ++ [path] ++ fileArgs
+            (beforeSep, optSep : afterSep) ->
+              beforeSep ++ [optSep] ++ [path] ++ fileArgs ++ afterSep
        -- TODO show the command in verbose mode
        -- hPutStrLn stderr $ unwords $
        --   ["Running", "[" ++ progName, unwords cmdArgs ++ "]"]