diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## [0.0.0.4] - 2026-02-25
+
+### Changed
+
+* `pureGoldenNixOptions` now prepends a generated file comment pointing to the test that generated each file
+
 ## [0.0.0.3] - 2025-11-20
 
 ### Added
diff --git a/opt-env-conf-test.cabal b/opt-env-conf-test.cabal
--- a/opt-env-conf-test.cabal
+++ b/opt-env-conf-test.cabal
@@ -1,11 +1,11 @@
 cabal-version: 1.12
 
--- This file has been generated from package.yaml by hpack version 0.36.1.
+-- This file has been generated from package.yaml by hpack version 0.38.3.
 --
 -- see: https://github.com/sol/hpack
 
 name:           opt-env-conf-test
-version:        0.0.0.3
+version:        0.0.0.4
 synopsis:       A testing companion package for opt-env-conf
 homepage:       https://github.com/NorfairKing/opt-env-conf#readme
 bug-reports:    https://github.com/NorfairKing/opt-env-conf/issues
diff --git a/src/OptEnvConf/Test.hs b/src/OptEnvConf/Test.hs
--- a/src/OptEnvConf/Test.hs
+++ b/src/OptEnvConf/Test.hs
@@ -38,10 +38,12 @@
 where
 
 import Data.Aeson as JSON
+import Data.Char (isDigit)
 import Data.Maybe
 import Data.Text (Text)
 import qualified Data.Text as T
-import GHC.Stack (HasCallStack, withFrozenCallStack)
+import GHC.Stack (CallStack, HasCallStack, getCallStack, withFrozenCallStack)
+import qualified GHC.Stack as Stack
 import OptEnvConf
 import OptEnvConf.Args
 import OptEnvConf.Completion
@@ -106,7 +108,8 @@
   let arg = fromMaybe "" $ listToMaybe $ drop ix ws
   let completions = pureCompletionQuery p ix ws
   evaluatedCompletions <- evalCompletions arg completions
-  evaluatedCompletions `shouldBe` expected
+  let toStringCompletion c = c {completionSuggestion = completionResultValue (completionSuggestion c)}
+  map toStringCompletion evaluatedCompletions `shouldBe` expected
 
 parserCompletionDescriptionTest :: Parser a -> Int -> [String] -> [String] -> IO ()
 parserCompletionDescriptionTest p ix ws descriptions = do
@@ -136,7 +139,42 @@
   specify "produces the nix options as before" $
     pureGoldenNixOptions path parser
 
-pureGoldenNixOptions :: FilePath -> Parser a -> GoldenTest Text
+pureGoldenNixOptions :: (HasCallStack) => FilePath -> Parser a -> GoldenTest Text
 pureGoldenNixOptions path parser =
   pureGoldenTextFile path $
-    renderParserNixOptions parser
+    generatedFileComment Stack.callStack <> renderParserNixOptions parser
+
+generatedFileComment :: CallStack -> T.Text
+generatedFileComment cs =
+  let loc = case getCallStack cs of
+        (_, srcLoc) : _ ->
+          packageName (Stack.srcLocPackage srcLoc)
+            <> ":"
+            <> Stack.srcLocFile srcLoc
+            <> ":"
+            <> show (Stack.srcLocStartLine srcLoc)
+        [] -> "unknown"
+   in T.pack $
+        unlines $
+          map
+            ("# " <>)
+            [ "DO NOT EDIT THIS FILE DIRECTLY",
+              "This file was generated by",
+              loc,
+              "To update this it, run the test with --golden-reset"
+            ]
+
+-- | Extract just the package name from a GHC package identifier.
+--
+-- GHC package identifiers look like: @name-version-hash-unitid@
+-- This function returns just @name@.
+packageName :: String -> String
+packageName = go
+  where
+    go [] = []
+    go ('-' : rest)
+      | isVersion version = []
+      where
+        version = takeWhile (\c -> isDigit c || c == '.') rest
+    go (c : rest) = c : go rest
+    isVersion v = not (null v) && elem '.' v && all (\c -> isDigit c || c == '.') v
diff --git a/test/OptEnvConf/APISpec.hs b/test/OptEnvConf/APISpec.hs
--- a/test/OptEnvConf/APISpec.hs
+++ b/test/OptEnvConf/APISpec.hs
@@ -112,8 +112,7 @@
         parserDocs p
 
   it "renders the Nix options the same way" $
-    pureGoldenTextFile ("test_resources/docs/" <> dir <> "/nix-options.nix") $
-      renderParserNixOptions p
+    pureGoldenNixOptions ("test_resources/docs/" <> dir <> "/nix-options.nix") p
 
 sameHelpParser :: Parser (Either Int String, Bool)
 sameHelpParser =
diff --git a/test/OptEnvConf/CompleterSpec.hs b/test/OptEnvConf/CompleterSpec.hs
--- a/test/OptEnvConf/CompleterSpec.hs
+++ b/test/OptEnvConf/CompleterSpec.hs
@@ -27,6 +27,9 @@
         -- File in dir in dir
         exampleFile3 <- resolveFile deeperDir "gold.txt"
         writeFile (fromAbsFile exampleFile3) ""
+        -- YAML file
+        yamlFile <- resolveFile tdir "config.yaml"
+        writeFile (fromAbsFile yamlFile) ""
         -- Hidden file
         hiddenFile <- resolveFile tdir ".hidden.txt"
         writeFile (fromAbsFile hiddenFile) ""
@@ -43,37 +46,192 @@
       )
     $ do
       describe "filePath" $ do
-        let c :: (HasCallStack) => String -> [String] -> TestDef '[Path Abs Dir] ()
+        let c :: (HasCallStack) => String -> [CompletionResult] -> TestDef '[Path Abs Dir] ()
             c s l =
               withFrozenCallStack $
-                itWithOuter (unwords ["can complete", show s, "to", show l]) $ \tdir ->
+                itWithOuter (unwords ["can complete", show s, "to", show (map completionResultValue l)]) $ \tdir ->
                   withCurrentDir tdir $
                     unCompleter filePath s `shouldReturn` l
 
-        c "" ["foo.txt", "bar/"]
-        c "f" ["foo.txt"]
-        c "b" ["bar/"]
-        c "bar" ["bar/quux.txt", "bar/", "bar/deep/"]
+        c "" [fileR "foo.txt", fileR "config.yaml", dirR "bar/"]
+        c "f" [fileR "foo.txt"]
+        c "b" [dirR "bar/"]
+        c "bar" [fileR "bar/quux.txt", dirR "bar/", dirR "bar/deep/"]
+        c "c" [fileR "config.yaml"]
         c "q" []
-        c "." [".hidden.txt", ".hidden/"]
-        c "./" ["./foo.txt", "./bar/"]
-        c "././" ["././foo.txt", "././bar/"]
-        c "./." ["./.hidden.txt", "./.hidden/"]
-        c "./bar" ["./bar/quux.txt", "./bar/", "./bar/deep/"]
+        c "." [fileR ".hidden.txt", dirR ".hidden/"]
+        c "./" [fileR "./foo.txt", fileR "./config.yaml", dirR "./bar/"]
+        c "././" [fileR "././foo.txt", fileR "././config.yaml", dirR "././bar/"]
+        c "./." [fileR "./.hidden.txt", dirR "./.hidden/"]
+        c "./bar" [fileR "./bar/quux.txt", dirR "./bar/", dirR "./bar/deep/"]
 
+        -- Deeper nesting.
+        -- Directories end in /, files do not.  This convention is how
+        -- shells decide whether to append a trailing space after a
+        -- completion.
+        c "bar/" [fileR "bar/quux.txt", dirR "bar/deep/"]
+        c "bar/d" [dirR "bar/deep/"]
+        c "bar/deep" [fileR "bar/deep/gold.txt", dirR "bar/deep/"]
+        c "bar/deep/" [fileR "bar/deep/gold.txt"]
+        c "bar/q" [fileR "bar/quux.txt"]
+
+        -- Parent directory paths (..)
+        -- These tests run from inside bar/ so that .. refers to the
+        -- test root directory.
+        itWithOuter "can complete \"..\" to parent directory contents" $ \tdir -> do
+          subdir <- resolveDir tdir "bar"
+          withCurrentDir subdir $ do
+            results <- unCompleter filePath ".."
+            results
+              `shouldBe` [ fileR "../foo.txt",
+                           fileR "../config.yaml",
+                           dirR "../bar/"
+                         ]
+        itWithOuter "can complete \"../\" to parent directory contents" $ \tdir -> do
+          subdir <- resolveDir tdir "bar"
+          withCurrentDir subdir $ do
+            results <- unCompleter filePath "../"
+            results
+              `shouldBe` [ fileR "../foo.txt",
+                           fileR "../config.yaml",
+                           dirR "../bar/"
+                         ]
+        itWithOuter "can complete \"../f\" to matching parent files" $ \tdir -> do
+          subdir <- resolveDir tdir "bar"
+          withCurrentDir subdir $ do
+            results <- unCompleter filePath "../f"
+            results
+              `shouldBe` [fileR "../foo.txt"]
+        itWithOuter "can complete \"../bar/\" to sibling dir contents" $ \tdir -> do
+          subdir <- resolveDir tdir "bar"
+          withCurrentDir subdir $ do
+            results <- unCompleter filePath "../bar/"
+            results
+              `shouldBe` [ fileR "../bar/quux.txt",
+                           dirR "../bar/deep/"
+                         ]
+
+        -- Parent directory in the middle of a path
+        itWithOuter "can complete \"bar/../\" to current dir contents" $ \tdir ->
+          withCurrentDir tdir $ do
+            results <- unCompleter filePath "bar/../"
+            results
+              `shouldBe` [ fileR "bar/../foo.txt",
+                           fileR "bar/../config.yaml",
+                           dirR "bar/../bar/"
+                         ]
+        itWithOuter "can complete \"bar/../f\" to matching files" $ \tdir ->
+          withCurrentDir tdir $ do
+            results <- unCompleter filePath "bar/../f"
+            results
+              `shouldBe` [fileR "bar/../foo.txt"]
+        itWithOuter "can complete \"../bar/deep/../\" to bar/ contents" $ \tdir -> do
+          subdir <- resolveDir tdir "bar"
+          withCurrentDir subdir $ do
+            results <- unCompleter filePath "../bar/deep/../"
+            results
+              `shouldBe` [ fileR "../bar/deep/../quux.txt",
+                           dirR "../bar/deep/../deep/"
+                         ]
+
+        -- Absolute paths
+        itWithOuter "can complete absolute paths" $ \tdir ->
+          withCurrentDir tdir $ do
+            let absPrefix = fromAbsDir tdir
+            results <- unCompleter filePath absPrefix
+            results
+              `shouldBe` [ fileR (absPrefix <> "foo.txt"),
+                           fileR (absPrefix <> "config.yaml"),
+                           dirR (absPrefix <> "bar/")
+                         ]
+
       describe "directoryPath" $ do
-        let c :: (HasCallStack) => String -> [String] -> TestDef '[Path Abs Dir] ()
+        let c :: (HasCallStack) => String -> [CompletionResult] -> TestDef '[Path Abs Dir] ()
             c s l = withFrozenCallStack $
-              itWithOuter (unwords ["can complete", show s, "to", show l]) $ \tdir ->
+              itWithOuter (unwords ["can complete", show s, "to", show (map completionResultValue l)]) $ \tdir ->
                 withCurrentDir tdir $
                   unCompleter directoryPath s `shouldReturn` l
 
-        c "" ["bar/"]
-        c "b" ["bar/"]
+        c "" [dirR "bar/"]
+        c "b" [dirR "bar/"]
         c "f" []
-        c "." [".hidden/"]
-        c "./" ["./bar/"]
-        c "./." ["./.hidden/"]
-        c "././" ["././bar/"]
-        c "./." ["./.hidden/"]
-        c "./bar" ["./bar/", "./bar/deep/"]
+        c "." [dirR ".hidden/"]
+        c "./" [dirR "./bar/"]
+        c "./." [dirR "./.hidden/"]
+        c "././" [dirR "././bar/"]
+        c "./." [dirR "./.hidden/"]
+        c "./bar" [dirR "./bar/", dirR "./bar/deep/"]
+
+        -- Deeper nesting.
+        -- Only directories are returned, never files.
+        c "bar/" [dirR "bar/", dirR "bar/deep/"]
+        c "bar/d" [dirR "bar/deep/"]
+        c "bar/deep" [dirR "bar/deep/"]
+
+        -- Parent directory paths (..)
+        itWithOuter "can complete \"..\" to parent directories" $ \tdir -> do
+          subdir <- resolveDir tdir "bar"
+          withCurrentDir subdir $ do
+            results <- unCompleter directoryPath ".."
+            results
+              `shouldBe` [dirR "../bar/"]
+        itWithOuter "can complete \"../\" to parent directories" $ \tdir -> do
+          subdir <- resolveDir tdir "bar"
+          withCurrentDir subdir $ do
+            results <- unCompleter directoryPath "../"
+            results
+              `shouldBe` [dirR "../bar/"]
+        itWithOuter "can complete \"../b\" to matching parent directories" $ \tdir -> do
+          subdir <- resolveDir tdir "bar"
+          withCurrentDir subdir $ do
+            results <- unCompleter directoryPath "../b"
+            results
+              `shouldBe` [dirR "../bar/"]
+
+        -- Parent directory in the middle of a path
+        itWithOuter "can complete \"bar/../\" to current dir directories" $ \tdir ->
+          withCurrentDir tdir $ do
+            results <- unCompleter directoryPath "bar/../"
+            results
+              `shouldBe` [dirR "bar/../bar/"]
+        itWithOuter "can complete \"bar/../b\" to matching directories" $ \tdir ->
+          withCurrentDir tdir $ do
+            results <- unCompleter directoryPath "bar/../b"
+            results
+              `shouldBe` [dirR "bar/../bar/"]
+
+      describe "filePathWithExtension" $ do
+        let c :: (HasCallStack) => String -> [CompletionResult] -> TestDef '[Path Abs Dir] ()
+            c s l = withFrozenCallStack $
+              itWithOuter (unwords ["can complete", show s, "to", show (map completionResultValue l)]) $ \tdir ->
+                withCurrentDir tdir $
+                  unCompleter (filePathWithExtension ".yaml") s `shouldReturn` l
+
+        c "" [fileR "config.yaml", dirR "bar/"]
+        c "c" [fileR "config.yaml"]
+        c "b" [dirR "bar/"]
+        c "bar" [dirR "bar/", dirR "bar/deep/"]
+
+      describe "filePathWithExtensions" $ do
+        let c :: (HasCallStack) => String -> [CompletionResult] -> TestDef '[Path Abs Dir] ()
+            c s l = withFrozenCallStack $
+              itWithOuter (unwords ["can complete", show s, "to", show (map completionResultValue l)]) $ \tdir ->
+                withCurrentDir tdir $
+                  unCompleter (filePathWithExtensions [".txt", ".yaml"]) s `shouldReturn` l
+
+        c "" [fileR "foo.txt", fileR "config.yaml", dirR "bar/"]
+        c "bar/" [fileR "bar/quux.txt", dirR "bar/deep/"]
+
+fileR :: String -> CompletionResult
+fileR s =
+  CompletionResult
+    { completionResultValue = s,
+      completionResultFinality = CompletionFinal
+    }
+
+dirR :: String -> CompletionResult
+dirR s =
+  CompletionResult
+    { completionResultValue = s,
+      completionResultFinality = CompletionNotFinal
+    }
diff --git a/test/OptEnvConf/CompletionSpec.hs b/test/OptEnvConf/CompletionSpec.hs
--- a/test/OptEnvConf/CompletionSpec.hs
+++ b/test/OptEnvConf/CompletionSpec.hs
@@ -4,236 +4,1543 @@
 module OptEnvConf.CompletionSpec (spec) where
 
 import Control.Applicative
-import OptEnvConf.Completer
-import OptEnvConf.Completion
-import OptEnvConf.Parser
-import OptEnvConf.Setting
-import OptEnvConf.Test
-import Path
-import Test.Syd
-
-spec :: Spec
-spec = do
-  describe "bash" $ do
-    it "produces the same bash completion script" $
-      pureGoldenStringFile "test_resources/completion/bash-completion-script.bash" $
-        bashCompletionScript [absfile|/usr/bin/example-executable|] "example-executable"
-  describe "zsh" $ do
-    it "produces the same zsh completion script" $
-      pureGoldenStringFile "test_resources/completion/zsh-completion-script.zsh" $
-        zshCompletionScript [absfile|/usr/bin/example-executable|] "example-executable"
-  describe "fish" $ do
-    it "produces the same fish completion script" $
-      pureGoldenStringFile "test_resources/completion/fish-completion-script.fish" $
-        fishCompletionScript [absfile|/usr/bin/example-executable|] "example-executable"
-
-  describe "pureCompletionQuery" $ do
-    it "can complete a switch from nothing" $
-      parserCompletionTest
-        (setting [switch (), short 'e', long "example"])
-        0
-        []
-        ["--example"] -- Only the long version
-    it "can complete a short switch from a single dash" $
-      parserCompletionTest
-        (setting [switch (), short 'e'])
-        0
-        ["-"]
-        ["-e"]
-
-    it "can complete a long switch from a single dash" $
-      parserCompletionTest
-        (setting [switch (), long "example"])
-        0
-        ["-"]
-        ["--example"]
-
-    it "can complete a long switch from a double dash" $
-      parserCompletionTest
-        (setting [switch (), long "example"])
-        0
-        ["--"]
-        ["--example"]
-
-    it "can complete a short option's dashed" $
-      parserCompletionTest
-        (setting [option, short 'e', completer $ listCompleter ["hi"]])
-        0
-        []
-        ["-e"]
-
-    it "can complete a long option's dashed" $
-      parserCompletionTest
-        (setting [option, long "example", completer $ listCompleter ["hi"]])
-        0
-        []
-        ["--example"]
-
-    it "can complete a short option with a separate arg" $
-      parserCompletionTest
-        (setting [option, short 'e', completer $ listCompleter ["hi"]])
-        1
-        ["-e"]
-        ["hi"]
-
-    -- Don't think we want to support this.
-    -- pending "can complete a short option in short-hand mode.
-
-    it "can complete a long option" $
-      parserCompletionTest
-        (setting [option, long "example", completer $ listCompleter ["hi"]])
-        1
-        ["--example"]
-        ["hi"]
-
-    -- Don't think we want to support this
-    -- pending "can complete a long option with equals sign"
-
-    it "can complete both switches of a tuple" $
-      parserCompletionTest
-        ((,) <$> setting [switch (), long "foo"] <*> setting [switch (), long "bar"])
-        0
-        []
-        ["--foo", "--bar"]
-
-    it "can complete both switches of a tuple, with a prefix" $
-      parserCompletionTest
-        ((,) <$> setting [switch (), long "bar"] <*> setting [switch (), long "baz"])
-        0
-        ["--b"]
-        ["--bar", "--baz"]
-
-    it "can complete both switches of an either" $
-      parserCompletionTest
-        (setting [switch (), long "foo"] <|> setting [switch (), long "bar"])
-        0
-        []
-        ["--foo", "--bar"]
-
-    it "can complete both switches of an either wrapped in optionals" $
-      parserCompletionTest
-        (optional (setting [switch (), long "foo"]) <|> optional (setting [switch (), long "bar"]))
-        0
-        []
-        ["--foo", "--bar"]
-
-    describe "commands" $ do
-      let p =
-            commands
-              [ command "foo" "1" $ pure (),
-                command "bar" "2" $ pure (),
-                command "baz" "3" $ pure ()
-              ]
-
-      it "can complete a command argument" $
-        parserCompletionTest
-          p
-          0
-          []
-          [Completion "foo" (Just "1"), Completion "bar" (Just "2"), Completion "baz" (Just "3")]
-
-      it "can complete a command argument when it's been partially provided" $
-        parserCompletionTest
-          p
-          0
-          ["b"]
-          [Completion "bar" (Just "2"), Completion "baz" (Just "3")]
-
-    describe "completion after a command" $ do
-      it "can complete a command with a switch" $
-        parserCompletionTest
-          (commands [command "foo" "1" $ setting [help "ex", switch (), short 'e', long "example"]])
-          1
-          ["foo"]
-          [Completion "--example" (Just "ex")] -- Only the long version
-      it "can complete a command's short switch" $
-        parserCompletionTest
-          (commands [command "foo" "1" $ setting [switch (), short 'e']])
-          1
-          ["foo", "-"]
-          ["-e"]
-
-      it "can complete a command's long switch from a single dash" $
-        parserCompletionTest
-          (commands [command "foo" "1" $ setting [switch (), long "example"]])
-          1
-          ["foo", "-"]
-          ["--example"]
-
-      it "can complete a command's long switch from a double dash" $
-        parserCompletionTest
-          (commands [command "foo" "1" $ setting [switch (), long "example"]])
-          1
-          ["foo", "--"]
-          ["--example"]
-
-      it "can complete a command's short option" $
-        parserCompletionTest
-          (commands [command "foo" "1" $ setting [option, short 'e', completer $ listCompleter ["hi"]]])
-          2
-          ["foo", "-e"]
-          ["hi"]
-
-      it "can complete a command's long option" $
-        parserCompletionTest
-          (commands [command "foo" "1" $ setting [option, long "example", completer $ listCompleter ["hi"]]])
-          2
-          ["foo", "--example"]
-          ["hi"]
-
-    it "can complete a file argument" $
-      parserCompletionDescriptionTest
-        (filePathSetting [help "file arg", argument])
-        0
-        []
-        ["file arg"]
-
-    it "can complete a file option" $
-      parserCompletionDescriptionTest
-        (filePathSetting [help "file arg", option, long "file"])
-        1
-        ["--file"]
-        ["file arg"]
-
-    it "can complete a directory argument" $
-      parserCompletionDescriptionTest
-        (directoryPathSetting [help "dir arg", argument])
-        0
-        []
-        ["dir arg"]
-
-    it "can complete a directory option" $
-      parserCompletionDescriptionTest
-        (directoryPathSetting [help "dir arg", option, long "file"])
-        1
-        ["--file"]
-        ["dir arg"]
-
-    it "no longer suggests a switch that has already been parsed" $
-      parserCompletionTest
-        ((,) <$> setting [switch (), long "foo"] <*> setting [switch (), long "bar"])
-        1
-        ["--foo"]
-        ["--bar"]
-
-    it "no longer suggests an option that has already been parsed" $
-      parserCompletionTest
-        ( (,,)
-            <$> setting [option, reader (str :: Reader String), long "foo"]
-            <*> setting [option, reader (str :: Reader String), long "bar"]
-            <*> setting [switch (), long "quux"]
-        )
-        2
-        ["--foo", "foo"]
-        ["--bar", "--quux"]
-
-    it "no longer suggests an argument that has already been parsed" $
-      parserCompletionDescriptionTest
-        ( (,,)
-            <$> setting [argument, reader (str :: Reader String), help "hi", completer $ listCompleter ["hi"]]
-            <*> setting [argument, reader (str :: Reader String), help "ho", completer $ listCompleter ["ho"]]
-            <*> setting [switch (), long "bar", help "hu"]
-        )
-        1
-        ["foo"]
-        ["ho", "hu"]
+import qualified Data.List.NonEmpty as NE
+import Data.Maybe
+import OptEnvConf.Completer
+import OptEnvConf.Completion
+import OptEnvConf.Parser
+import OptEnvConf.Setting
+import OptEnvConf.Test
+import Path
+import Path.IO
+import Test.Syd
+
+spec :: Spec
+spec = do
+  describe "bash" $ do
+    it "produces the same bash completion script" $
+      pureGoldenStringFile "test_resources/completion/bash-completion-script.bash" $
+        bashCompletionScript [absfile|/usr/bin/example-executable|] "example-executable"
+  describe "zsh" $ do
+    it "produces the same zsh completion script" $
+      pureGoldenStringFile "test_resources/completion/zsh-completion-script.zsh" $
+        zshCompletionScript [absfile|/usr/bin/example-executable|] "example-executable"
+  describe "fish" $ do
+    it "produces the same fish completion script" $
+      pureGoldenStringFile "test_resources/completion/fish-completion-script.fish" $
+        fishCompletionScript [absfile|/usr/bin/example-executable|] "example-executable"
+
+  describe "pureCompletionQuery" $ do
+    it "can complete a switch from nothing" $
+      parserCompletionTest
+        (setting [switch (), short 'e', long "example"])
+        0
+        []
+        ["--example"] -- Only the long version
+    it "can complete a short switch from a single dash" $
+      parserCompletionTest
+        (setting [switch (), short 'e'])
+        0
+        ["-"]
+        ["-e"]
+
+    it "can complete a long switch from a single dash" $
+      parserCompletionTest
+        (setting [switch (), long "example"])
+        0
+        ["-"]
+        ["--example"]
+
+    it "can complete a long switch from a double dash" $
+      parserCompletionTest
+        (setting [switch (), long "example"])
+        0
+        ["--"]
+        ["--example"]
+
+    it "can complete a short option's dashed" $
+      parserCompletionTest
+        (setting [option, short 'e', completer $ listCompleter ["hi"]])
+        0
+        []
+        ["-e"]
+
+    it "can complete a long option's dashed" $
+      parserCompletionTest
+        (setting [option, long "example", completer $ listCompleter ["hi"]])
+        0
+        []
+        ["--example"]
+
+    it "can complete a short option with a separate arg" $
+      parserCompletionTest
+        (setting [option, short 'e', completer $ listCompleter ["hi"]])
+        1
+        ["-e"]
+        ["hi"]
+
+    -- Don't think we want to support this.
+    -- pending "can complete a short option in short-hand mode.
+
+    it "can complete a long option" $
+      parserCompletionTest
+        (setting [option, long "example", completer $ listCompleter ["hi"]])
+        1
+        ["--example"]
+        ["hi"]
+
+    -- Don't think we want to support this
+    -- pending "can complete a long option with equals sign"
+
+    it "can complete both switches of a tuple" $
+      parserCompletionTest
+        ((,) <$> setting [switch (), long "foo"] <*> setting [switch (), long "bar"])
+        0
+        []
+        [ "--foo",
+          "--bar"
+        ]
+
+    it "can complete both switches of a tuple, with a prefix" $
+      parserCompletionTest
+        ((,) <$> setting [switch (), long "bar"] <*> setting [switch (), long "baz"])
+        0
+        ["--b"]
+        [ "--bar",
+          "--baz"
+        ]
+
+    it "can complete both switches of an either" $
+      parserCompletionTest
+        (setting [switch (), long "foo"] <|> setting [switch (), long "bar"])
+        0
+        []
+        [ "--foo",
+          "--bar"
+        ]
+
+    it "can complete both switches of an either wrapped in optionals" $
+      parserCompletionTest
+        (optional (setting [switch (), long "foo"]) <|> optional (setting [switch (), long "bar"]))
+        0
+        []
+        [ "--foo",
+          "--bar"
+        ]
+
+    describe "commands" $ do
+      let p =
+            commands
+              [ command "foo" "1" $ pure (),
+                command "bar" "2" $ pure (),
+                command "baz" "3" $ pure ()
+              ]
+
+      it "can complete a command argument" $
+        parserCompletionTest
+          p
+          0
+          []
+          [ Completion "foo" (Just "1"),
+            Completion "bar" (Just "2"),
+            Completion "baz" (Just "3")
+          ]
+
+      it "can complete a command argument when it's been partially provided" $
+        parserCompletionTest
+          p
+          0
+          ["b"]
+          [ Completion "bar" (Just "2"),
+            Completion "baz" (Just "3")
+          ]
+
+    describe "completion after a command" $ do
+      it "can complete a command with a switch" $
+        parserCompletionTest
+          (commands [command "foo" "1" $ setting [help "ex", switch (), short 'e', long "example"]])
+          1
+          ["foo"]
+          [Completion "--example" (Just "ex")] -- Only the long version
+      it "can complete a command's short switch" $
+        parserCompletionTest
+          (commands [command "foo" "1" $ setting [switch (), short 'e']])
+          1
+          ["foo", "-"]
+          ["-e"]
+
+      it "can complete a command's long switch from a single dash" $
+        parserCompletionTest
+          (commands [command "foo" "1" $ setting [switch (), long "example"]])
+          1
+          ["foo", "-"]
+          ["--example"]
+
+      it "can complete a command's long switch from a double dash" $
+        parserCompletionTest
+          (commands [command "foo" "1" $ setting [switch (), long "example"]])
+          1
+          ["foo", "--"]
+          ["--example"]
+
+      it "can complete a command's short option" $
+        parserCompletionTest
+          (commands [command "foo" "1" $ setting [option, short 'e', completer $ listCompleter ["hi"]]])
+          2
+          ["foo", "-e"]
+          ["hi"]
+
+      it "can complete a command's long option" $
+        parserCompletionTest
+          (commands [command "foo" "1" $ setting [option, long "example", completer $ listCompleter ["hi"]]])
+          2
+          ["foo", "--example"]
+          ["hi"]
+
+    it "can complete a file argument" $
+      parserCompletionDescriptionTest
+        (filePathSetting [help "file arg", argument])
+        0
+        []
+        ["file arg"]
+
+    it "can complete a file option" $
+      parserCompletionDescriptionTest
+        (filePathSetting [help "file arg", option, long "file"])
+        1
+        ["--file"]
+        ["file arg"]
+
+    it "can complete a directory argument" $
+      parserCompletionDescriptionTest
+        (directoryPathSetting [help "dir arg", argument])
+        0
+        []
+        ["dir arg"]
+
+    it "can complete a directory option" $
+      parserCompletionDescriptionTest
+        (directoryPathSetting [help "dir arg", option, long "file"])
+        1
+        ["--file"]
+        ["dir arg"]
+
+    it "no longer suggests a switch that has already been parsed" $
+      parserCompletionTest
+        ((,) <$> setting [switch (), long "foo"] <*> setting [switch (), long "bar"])
+        1
+        ["--foo"]
+        ["--bar"]
+
+    it "no longer suggests an option that has already been parsed" $
+      parserCompletionTest
+        ( (,,)
+            <$> setting [option, reader (str :: Reader String), long "foo"]
+            <*> setting [option, reader (str :: Reader String), long "bar"]
+            <*> setting [switch (), long "quux"]
+        )
+        2
+        ["--foo", "foo"]
+        [ "--bar",
+          "--quux"
+        ]
+
+    it "no longer suggests an argument that has already been parsed" $
+      parserCompletionDescriptionTest
+        ( (,,)
+            <$> setting [argument, reader (str :: Reader String), help "hi", completer $ listCompleter ["hi"]]
+            <*> setting [argument, reader (str :: Reader String), help "ho", completer $ listCompleter ["ho"]]
+            <*> setting [switch (), long "bar", help "hu"]
+        )
+        1
+        ["foo"]
+        [ "ho",
+          "hu"
+        ]
+
+    describe "commands with a default command" $ do
+      let p =
+            commands
+              [ command "foo" "1" $ pure (),
+                command "bar" "2" $ pure (),
+                command "baz" "3" $ pure (),
+                defaultCommand "bar"
+              ]
+
+      it "still lists all commands when there is a default" $
+        parserCompletionTest
+          p
+          0
+          []
+          [ Completion "foo" (Just "1"),
+            Completion "bar" (Just "2"),
+            Completion "baz" (Just "3")
+          ]
+
+      it "still filters commands by prefix when there is a default" $
+        parserCompletionTest
+          p
+          0
+          ["b"]
+          [ Completion "bar" (Just "2"),
+            Completion "baz" (Just "3")
+          ]
+
+      it "completes the default command's switch when no command is given" $
+        parserCompletionTest
+          ( commands
+              [ command "foo" "1" $ setting [switch (), long "example"],
+                command "bar" "2" $ pure (),
+                defaultCommand "foo"
+              ]
+          )
+          0
+          ["--"]
+          ["--example"]
+
+      it "completes both commands and the default command's switch" $
+        parserCompletionTest
+          ( commands
+              [ command "foo" "1" $ setting [switch (), long "example"],
+                command "bar" "2" $ pure (),
+                defaultCommand "foo"
+              ]
+          )
+          0
+          []
+          [ Completion "foo" (Just "1"),
+            Completion "bar" (Just "2"),
+            "--example"
+          ]
+
+      it "completes the default command's option when no command is given" $
+        parserCompletionTest
+          ( commands
+              [ command "foo" "1" $ setting [option, long "example", completer $ listCompleter ["hi"]],
+                command "bar" "2" $ pure (),
+                defaultCommand "foo"
+              ]
+          )
+          0
+          ["--"]
+          ["--example"]
+
+      it "completes the default command's option value when no command is given" $
+        parserCompletionTest
+          ( commands
+              [ command "foo" "1" $ setting [option, long "example", reader (str :: Reader String), completer $ listCompleter ["hi"]],
+                command "bar" "2" $ pure "bar",
+                defaultCommand "foo"
+              ]
+          )
+          1
+          ["--example"]
+          ["hi"]
+
+      it "completes the default command's argument when no command is given" $
+        parserCompletionDescriptionTest
+          ( commands
+              [ command "foo" "1" $ setting [argument, reader (str :: Reader String), help "arg help", completer $ listCompleter ["val"]],
+                command "bar" "2" $ pure "bar",
+                defaultCommand "foo"
+              ]
+          )
+          0
+          []
+          -- Should include the default command's argument completer along with command names
+          [ "1",
+            "2",
+            "arg help"
+          ]
+
+      it "completes inside the default command after consuming its switch" $
+        parserCompletionTest
+          ( commands
+              [ command "foo" "1" $
+                  (,)
+                    <$> setting [switch (), long "first"]
+                    <*> setting [switch (), long "second"],
+                command "bar" "2" $ pure ((), ()),
+                defaultCommand "foo"
+              ]
+          )
+          1
+          ["--first"]
+          ["--second"]
+
+      it "completes inside the default command after consuming its option" $
+        parserCompletionTest
+          ( commands
+              [ command "foo" "1" $
+                  (,)
+                    <$> setting [option, reader (str :: Reader String), long "name"]
+                    <*> setting [switch (), long "verbose"],
+                command "bar" "2" $ pure ("bar", ()),
+                defaultCommand "foo"
+              ]
+          )
+          2
+          ["--name", "hello"]
+          ["--verbose"]
+
+    describe "global options with commands and a default" $ do
+      it "completes global options and commands together" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [switch (), long "verbose"]
+              <*> commands
+                [ command "foo" "1" $ pure (),
+                  command "bar" "2" $ pure (),
+                  defaultCommand "foo"
+                ]
+          )
+          0
+          []
+          [ "--verbose",
+            Completion "foo" (Just "1"),
+            Completion "bar" (Just "2")
+          ]
+
+      it "completes commands after a global option" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [switch (), long "verbose"]
+              <*> commands
+                [ command "foo" "1" $ pure (),
+                  command "bar" "2" $ pure (),
+                  defaultCommand "foo"
+                ]
+          )
+          1
+          ["--verbose"]
+          [ Completion "foo" (Just "1"),
+            Completion "bar" (Just "2")
+          ]
+
+      it "completes the default command's options after a global option" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [switch (), long "verbose"]
+              <*> commands
+                [ command "foo" "1" $ setting [switch (), long "example"],
+                  command "bar" "2" $ pure (),
+                  defaultCommand "foo"
+                ]
+          )
+          1
+          ["--verbose"]
+          [ Completion "foo" (Just "1"),
+            Completion "bar" (Just "2"),
+            "--example"
+          ]
+
+    describe "many" $ do
+      it "can complete repeated switches" $
+        parserCompletionTest
+          (length <$> many (setting [switch (), long "verbose", short 'v']))
+          0
+          []
+          ["--verbose"]
+
+      it "can still complete after consuming one" $
+        parserCompletionTest
+          (length <$> many (setting [switch (), long "verbose", short 'v']))
+          1
+          ["--verbose"]
+          ["--verbose"]
+
+      it "can still complete after consuming two" $
+        parserCompletionTest
+          (length <$> many (setting [switch (), long "verbose", short 'v']))
+          2
+          ["-v", "-v"]
+          ["--verbose"]
+
+      it "can complete repeated options" $
+        parserCompletionTest
+          ( many
+              ( setting
+                  [ option,
+                    reader (str :: Reader String),
+                    long "include",
+                    completer $ listCompleter ["foo", "bar"]
+                  ]
+              )
+          )
+          1
+          ["--include"]
+          [ "foo",
+            "bar"
+          ]
+
+      it "can complete repeated options after one has already been parsed" $
+        parserCompletionTest
+          ( many
+              ( setting
+                  [ option,
+                    reader (str :: Reader String),
+                    long "include",
+                    completer $ listCompleter ["foo", "bar"]
+                  ]
+              )
+          )
+          3
+          [ "--include",
+            "foo",
+            "--include"
+          ]
+          [ "foo",
+            "bar"
+          ]
+
+    describe "some" $ do
+      it "can complete at least one switch" $
+        parserCompletionTest
+          (NE.length <$> someNonEmpty (setting [switch (), long "verbose", short 'v']))
+          0
+          []
+          ["--verbose"]
+
+      it "can still complete after consuming one" $
+        parserCompletionTest
+          (NE.length <$> someNonEmpty (setting [switch (), long "verbose", short 'v']))
+          1
+          ["--verbose"]
+          ["--verbose"]
+
+    describe "allOrNothing" $ do
+      it "completes normally inside allOrNothing" $
+        parserCompletionTest
+          ( allOrNothing $
+              (,)
+                <$> setting [option, reader (str :: Reader String), long "host"]
+                <*> setting [option, reader (str :: Reader String), long "port"]
+          )
+          0
+          []
+          [ "--host",
+            "--port"
+          ]
+
+      it "still suggests the remaining option after one is consumed" $
+        parserCompletionTest
+          ( allOrNothing $
+              (,)
+                <$> setting [option, reader (str :: Reader String), long "host"]
+                <*> setting [option, reader (str :: Reader String), long "port"]
+          )
+          2
+          ["--host", "localhost"]
+          ["--port"]
+
+    describe "check" $ do
+      it "completes through a checkMapEither" $
+        parserCompletionTest
+          ( checkMapEither
+              (\s -> if null s then Left "empty" else Right s)
+              (setting [argument, reader (str :: Reader String), completer $ listCompleter ["hello"]])
+          )
+          0
+          []
+          ["hello"]
+
+      it "completes through a mapIO" $
+        parserCompletionTest
+          ( mapIO pure $
+              setting [switch (), long "example"]
+          )
+          0
+          []
+          ["--example"]
+
+    describe "hidden settings" $ do
+      it "does not suggest hidden switches" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [switch (), long "visible"]
+              <*> setting [switch (), long "secret", hidden]
+          )
+          0
+          []
+          ["--visible"]
+
+      it "does not suggest hidden options" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [option, reader (str :: Reader String), long "visible"]
+              <*> setting [option, reader (str :: Reader String), long "secret", hidden]
+          )
+          0
+          []
+          ["--visible"]
+
+    describe "settings with only env or conf" $ do
+      it "does not error on env-only settings combined with arg settings" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [switch (), long "verbose"]
+              <*> setting [reader (str :: Reader String), env "MY_VAR"]
+          )
+          0
+          []
+          ["--verbose"]
+
+    describe "enableDisableSwitch" $ do
+      -- enableDisableSwitch uses a visible "dummy" with the
+      -- (enable|disable)- prefix for documentation, while the actual
+      -- --enable-feature and --disable-feature switches are hidden.
+      it "completes the documented dummy flag" $
+        parserCompletionTest
+          ( enableDisableSwitch
+              [ help "enable feature",
+                name "feature",
+                value False
+              ]
+          )
+          0
+          []
+          [Completion "--(enable|disable)-feature" (Just "enable feature")]
+
+      it "filters the documented flag by prefix" $
+        parserCompletionTest
+          ( enableDisableSwitch
+              [ help "enable feature",
+                name "feature",
+                value False
+              ]
+          )
+          0
+          ["--(e"]
+          [Completion "--(enable|disable)-feature" (Just "enable feature")]
+
+    describe "choice" $ do
+      it "completes across all choices" $
+        parserCompletionTest
+          ( choice
+              [ setting [switch (), long "alpha"],
+                setting [switch (), long "beta"],
+                setting [switch (), long "gamma"]
+              ]
+          )
+          0
+          []
+          [ "--alpha",
+            "--beta",
+            "--gamma"
+          ]
+
+    describe "withDefault" $ do
+      it "completes the underlying parser" $
+        parserCompletionTest
+          (withDefault "default" $ setting [option, reader (str :: Reader String), long "name", completer $ listCompleter ["alice", "bob"]])
+          1
+          ["--name"]
+          [ "alice",
+            "bob"
+          ]
+
+      it "still suggests the option when it has a default" $
+        parserCompletionTest
+          (withDefault "default" $ setting [option, reader (str :: Reader String), long "name"])
+          0
+          []
+          ["--name"]
+
+    describe "nested commands" $ do
+      let p =
+            commands
+              [ command "top" "top-level" $
+                  commands
+                    [ command "sub-a" "sub a" $ pure (),
+                      command "sub-b" "sub b" $ pure ()
+                    ],
+                command "other" "other" $ pure ()
+              ]
+
+      it "completes top-level commands" $
+        parserCompletionTest
+          p
+          0
+          []
+          [ Completion "top" (Just "top-level"),
+            Completion "other" (Just "other")
+          ]
+
+      it "completes sub-commands after selecting a top-level command" $
+        parserCompletionTest
+          p
+          1
+          ["top"]
+          [ Completion "sub-a" (Just "sub a"),
+            Completion "sub-b" (Just "sub b")
+          ]
+
+      it "filters sub-commands by prefix" $
+        parserCompletionTest
+          p
+          1
+          ["top", "sub-a"]
+          [Completion "sub-a" (Just "sub a")]
+
+      it "completes nested default commands" $
+        parserCompletionTest
+          ( commands
+              [ command "top" "top-level" $
+                  commands
+                    [ command "sub-a" "sub a" $ setting [switch (), long "flag"],
+                      command "sub-b" "sub b" $ pure (),
+                      defaultCommand "sub-a"
+                    ],
+                command "other" "other" $ pure ()
+              ]
+          )
+          1
+          ["top"]
+          [ Completion "sub-a" (Just "sub a"),
+            Completion "sub-b" (Just "sub b"),
+            "--flag"
+          ]
+
+    describe "commands merged via alternative" $ do
+      it "completes commands from both sides of an alternative" $
+        parserCompletionTest
+          ( commands [command "foo" "1" $ pure ()]
+              <|> commands [command "bar" "2" $ pure ()]
+          )
+          0
+          []
+          [ Completion "foo" (Just "1"),
+            Completion "bar" (Just "2")
+          ]
+
+    describe "arguments after double dash" $ do
+      -- A bare -- is consumed as the argument value "--" when it's
+      -- the only argument remaining, so completion sees nothing left.
+      it "consumes -- as the argument value" $
+        parserCompletionTest
+          (setting [argument, reader (str :: Reader String), completer $ listCompleter ["file1", "file2"]])
+          1
+          ["--"]
+          []
+
+      -- After --, the completion should suggest positional arguments
+      -- rather than switches. Currently it does not: the switch is
+      -- still suggested because the completion engine does not
+      -- account for -- separating options from arguments.
+      it "suggests the switch even after -- (known bug)" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [switch (), long "verbose"]
+              <*> setting [argument, reader (str :: Reader String), completer $ listCompleter ["file1", "file2"]]
+          )
+          2
+          ["--", "fi"]
+          ["--verbose"]
+
+    describe "mixed arguments and options" $ do
+      it "can complete an option after a positional argument" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [argument, reader (str :: Reader String), completer $ listCompleter ["input"]]
+              <*> setting [switch (), long "verbose"]
+          )
+          1
+          ["input"]
+          ["--verbose"]
+
+      it "can complete a positional after an option" $
+        parserCompletionDescriptionTest
+          ( (,)
+              <$> setting [switch (), long "verbose"]
+              <*> setting [argument, reader (str :: Reader String), help "file", completer $ listCompleter ["output"]]
+          )
+          1
+          ["--verbose"]
+          ["file"]
+
+    describe "multiple arguments" $ do
+      -- When no args have been typed, both argument completers fire
+      -- because the completion engine doesn't know which one will be
+      -- consumed first. This is the documented TODO in Completion.hs.
+      it "completes both arguments when none have been typed" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [argument, reader (str :: Reader String), completer $ listCompleter ["src"]]
+              <*> setting [argument, reader (str :: Reader String), completer $ listCompleter ["dst"]]
+          )
+          0
+          []
+          [ "src",
+            "dst"
+          ]
+
+      it "completes the second argument after the first" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [argument, reader (str :: Reader String), completer $ listCompleter ["src"]]
+              <*> setting [argument, reader (str :: Reader String), completer $ listCompleter ["dst"]]
+          )
+          1
+          ["something"]
+          ["dst"]
+
+    describe "empty parser" $ do
+      it "produces no completions for empty" $
+        parserCompletionTest
+          (empty :: Parser ())
+          0
+          []
+          []
+
+    describe "pure parser" $ do
+      it "produces no completions for pure" $
+        parserCompletionTest
+          (pure () :: Parser ())
+          0
+          []
+          []
+
+    describe "select" $ do
+      -- Select uses andCompletions: both branches contribute because
+      -- the completion engine cannot know at completion time whether
+      -- the first parser will return Left or Right.
+      it "completes through a select" $
+        parserCompletionTest
+          ( select
+              (Left <$> setting [argument, reader (str :: Reader String), completer $ listCompleter ["hello"]])
+              (const <$> setting [argument, reader (str :: Reader String), completer $ listCompleter ["world"]])
+          )
+          0
+          []
+          [ "hello",
+            "world"
+          ]
+
+    describe "withConfig" $ do
+      it "completes the main parser through withConfig" $
+        parserCompletionTest
+          ( withConfig (pure Nothing) $
+              setting [switch (), long "example"]
+          )
+          0
+          []
+          ["--example"]
+
+      it "completes the config file option together with the main parser" $
+        parserCompletionTest
+          ( withConfig
+              (Nothing <$ setting [option, reader (str :: Reader String), long "config-file", completer $ listCompleter ["config.yaml"]])
+              (setting [switch (), long "verbose"])
+          )
+          0
+          []
+          -- Main parser completions come first (p2), then config parser completions (p1)
+          [ "--verbose",
+            "--config-file"
+          ]
+
+      it "completes the config file value along with main parser suggestions" $
+        parserCompletionTest
+          ( withConfig
+              (Nothing <$ setting [option, reader (str :: Reader String), long "config-file", completer $ listCompleter ["config.yaml"]])
+              (setting [switch (), long "verbose"])
+          )
+          1
+          ["--config-file"]
+          -- The main parser (p2) still suggests --verbose since it hasn't
+          -- consumed anything, and the config parser (p1) offers the completer.
+          [ "--verbose",
+            "config.yaml"
+          ]
+
+      it "completes the main parser after the config option is consumed" $
+        parserCompletionTest
+          ( withConfig
+              (Nothing <$ setting [option, reader (str :: Reader String), long "config-file", completer $ listCompleter ["config.yaml"]])
+              (setting [switch (), long "verbose"])
+          )
+          2
+          ["--config-file", "config.yaml"]
+          ["--verbose"]
+
+    describe "optional" $ do
+      it "completes through an optional parser" $
+        parserCompletionTest
+          (optional $ setting [switch (), long "verbose"])
+          0
+          []
+          ["--verbose"]
+
+      it "completes an optional with an applicative" $
+        parserCompletionTest
+          ( (,)
+              <$> optional (setting [option, reader (str :: Reader String), long "name", completer $ listCompleter ["alice"]])
+              <*> setting [switch (), long "verbose"]
+          )
+          0
+          []
+          [ "--name",
+            "--verbose"
+          ]
+
+      it "completes the second part when the optional is skipped" $
+        parserCompletionTest
+          ( (,)
+              <$> optional (setting [option, reader (str :: Reader String), long "name"])
+              <*> setting [switch (), long "verbose"]
+          )
+          0
+          []
+          [ "--name",
+            "--verbose"
+          ]
+
+    describe "many with other parsers" $ do
+      it "completes both many and a following switch" $
+        parserCompletionTest
+          ( (,)
+              <$> many (setting [option, reader (str :: Reader String), long "include", completer $ listCompleter ["foo"]])
+              <*> setting [switch (), long "verbose"]
+          )
+          0
+          []
+          [ "--include",
+            "--verbose"
+          ]
+
+      it "completes both after consuming one many-option" $
+        parserCompletionTest
+          ( (,)
+              <$> many (setting [option, reader (str :: Reader String), long "include", completer $ listCompleter ["foo"]])
+              <*> setting [switch (), long "verbose"]
+          )
+          2
+          ["--include", "foo"]
+          [ "--include",
+            "--verbose"
+          ]
+
+      it "completes many switches combined with a command" $
+        parserCompletionTest
+          ( (,)
+              <$> many (setting [switch (), long "verbose", short 'v'])
+              <*> commands
+                [ command "run" "run it" $ pure (),
+                  command "build" "build it" $ pure ()
+                ]
+          )
+          0
+          []
+          [ "--verbose",
+            Completion "run" (Just "run it"),
+            Completion "build" (Just "build it")
+          ]
+
+      it "completes commands after consuming many switches" $
+        parserCompletionTest
+          ( (,)
+              <$> many (setting [switch (), long "verbose", short 'v'])
+              <*> commands
+                [ command "run" "run it" $ pure (),
+                  command "build" "build it" $ pure ()
+                ]
+          )
+          2
+          ["-v", "-v"]
+          [ "--verbose",
+            Completion "run" (Just "run it"),
+            Completion "build" (Just "build it")
+          ]
+
+    describe "folded short switches" $ do
+      it "can complete after a folded short switch is consumed" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [switch (), short 'v']
+              <*> setting [switch (), short 'n']
+          )
+          1
+          ["-v"]
+          ["-n"]
+
+      it "no longer suggests a switch consumed via folding" $
+        parserCompletionTest
+          ( (,,)
+              <$> setting [switch (), short 'v']
+              <*> setting [switch (), short 'n']
+              <*> setting [switch (), short 'x']
+          )
+          1
+          ["-vn"]
+          ["-x"]
+
+    describe "short option shorthand" $ do
+      it "completes after a short option consumed in shorthand" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [option, reader (str :: Reader String), short 'f']
+              <*> setting [switch (), long "verbose"]
+          )
+          1
+          ["-ffoo.txt"]
+          ["--verbose"]
+
+    describe "deeply nested parsers" $ do
+      it "completes through optional + many + applicative" $
+        parserCompletionTest
+          ( (,,)
+              <$> optional (setting [option, reader (str :: Reader String), long "config"])
+              <*> many (setting [switch (), long "verbose", short 'v'])
+              <*> setting [argument, reader (str :: Reader String), completer $ listCompleter ["file.txt"]]
+          )
+          0
+          []
+          [ "--config",
+            "--verbose",
+            "file.txt"
+          ]
+
+      it "completes correctly after all optional+many consumed" $
+        parserCompletionTest
+          ( (,,)
+              <$> optional (setting [option, reader (str :: Reader String), long "config"])
+              <*> many (setting [switch (), long "verbose", short 'v'])
+              <*> setting [argument, reader (str :: Reader String), completer $ listCompleter ["file.txt"]]
+          )
+          3
+          [ "--config",
+            "foo",
+            "--verbose"
+          ]
+          [ "--verbose",
+            "file.txt"
+          ]
+
+    describe "commands with options inside" $ do
+      it "completes a command's many options" $
+        parserCompletionTest
+          ( commands
+              [ command "run" "run it" $
+                  many (setting [option, reader (str :: Reader String), long "arg", completer $ listCompleter ["val"]])
+              ]
+          )
+          2
+          ["run", "--arg"]
+          ["val"]
+
+      it "completes a command's many options after one is consumed" $
+        parserCompletionTest
+          ( commands
+              [ command "run" "run it" $
+                  many (setting [option, reader (str :: Reader String), long "arg", completer $ listCompleter ["val"]])
+              ]
+          )
+          3
+          [ "run",
+            "--arg",
+            "val"
+          ]
+          ["--arg"]
+
+    describe "multiple commands with shared options" $ do
+      it "completes options in the selected command only" $
+        parserCompletionTest
+          ( commands
+              [ command "foo" "1" $ setting [switch (), long "alpha"],
+                command "bar" "2" $ setting [switch (), long "beta"]
+              ]
+          )
+          1
+          ["foo"]
+          ["--alpha"]
+
+      it "does not leak options from other commands" $
+        parserCompletionTest
+          ( commands
+              [ command "foo" "1" $ setting [switch (), long "alpha"],
+                command "bar" "2" $ setting [switch (), long "beta"]
+              ]
+          )
+          1
+          ["bar"]
+          ["--beta"]
+
+    describe "alternative branch failures" $ do
+      -- A parser that is not detected as isEmpty but still fails during
+      -- completion (andCompletions fails because the inner empty fails).
+      -- This avoids the (<|>) optimization that removes empty alternatives.
+      let failingP = (empty :: Parser ()) *> pure ()
+      it "restores state when first branch fails in an alternative" $
+        parserCompletionTest
+          (failingP <|> setting [switch (), long "foo"])
+          0
+          []
+          ["--foo"]
+
+      it "returns first branch completions when second branch fails" $
+        parserCompletionTest
+          (setting [switch (), long "foo"] <|> failingP)
+          0
+          []
+          ["--foo"]
+
+      it "returns no completions when both alternatives fail" $
+        parserCompletionTest
+          (failingP <|> failingP)
+          0
+          []
+          []
+
+    describe "applicative branch failures" $ do
+      it "returns nothing when first applicative branch fails" $
+        parserCompletionTest
+          ((,) <$> ((empty :: Parser ()) *> pure ()) <*> setting [switch (), long "foo"])
+          0
+          []
+          []
+
+      it "returns nothing when second applicative branch fails" $
+        parserCompletionTest
+          ((,) <$> setting [switch (), long "foo"] <*> ((empty :: Parser String) *> pure ("" :: String)))
+          0
+          []
+          []
+
+    describe "many edge cases" $ do
+      it "handles many where the inner parser fails" $
+        parserCompletionTest
+          (many ((empty :: Parser ()) *> pure ()))
+          0
+          []
+          []
+
+      it "returns first iteration completions when recursive call fails" $
+        parserCompletionTest
+          (many (commands [command "foo" "1" $ pure ()]))
+          1
+          ["foo"]
+          [Completion "foo" (Just "1")]
+
+    describe "command not found" $ do
+      it "returns no completions for an unknown command" $
+        parserCompletionTest
+          (commands [command "foo" "1" $ pure (), command "bar" "2" $ pure ()])
+          1
+          ["unknown"]
+          []
+
+    describe "argument completer at end" $ do
+      it "offers the argument completer at the end after a switch is consumed" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [switch (), long "verbose"]
+              <*> setting [argument, reader (str :: Reader String), completer $ listCompleter ["file"]]
+          )
+          1
+          ["--verbose"]
+          ["file"]
+
+      it "does not offer option completer when not at end of args" $
+        parserCompletionTest
+          ( (,,)
+              <$> setting [switch (), long "other"]
+              <*> setting [option, reader (str :: Reader String), long "name", completer $ listCompleter ["val"]]
+              <*> setting [switch (), long "extra"]
+          )
+          3
+          [ "--name",
+            "--other",
+            "--extra"
+          ]
+          []
+
+    describe "option with different dashed in args" $ do
+      it "does not suggest an option when a different dashed is in the args" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [option, reader (str :: Reader String), long "output", completer $ listCompleter ["file.txt"]]
+              <*> setting [option, reader (str :: Reader String), long "input", completer $ listCompleter ["data.csv"]]
+          )
+          1
+          ["--input"]
+          ["data.csv"]
+
+    describe "default command parser failure" $ do
+      let emptyS = empty :: Parser String
+      it "falls back to explicit commands when default command parser fails" $
+        parserCompletionTest
+          ( commands
+              [ command "foo" "1" $ (,) <$> setting [argument, reader (str :: Reader String)] <*> emptyS,
+                command "bar" "2" $ pure ("", ""),
+                defaultCommand "foo"
+              ]
+          )
+          0
+          []
+          [ Completion "foo" (Just "1"),
+            Completion "bar" (Just "2")
+          ]
+
+    describe "prefix filtering" $ do
+      it "filters switches by typed prefix" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [switch (), long "verbose"]
+              <*> setting [switch (), long "version"]
+          )
+          0
+          ["--verb"]
+          ["--verbose"]
+
+      it "returns nothing when prefix matches nothing" $
+        parserCompletionTest
+          (setting [switch (), long "verbose"])
+          0
+          ["--xyz"]
+          []
+
+      it "filters commands by typed prefix" $
+        parserCompletionDescriptionTest
+          ( commands
+              [ command "generate" "gen" $ pure (),
+                command "get" "getter" $ pure (),
+                command "build" "builder" $ pure ()
+              ]
+          )
+          0
+          ["ge"]
+          [ "gen",
+            "getter"
+          ]
+
+    describe "argument completion with dashed values" $ do
+      -- When a dashed-looking value is provided as a positional argument,
+      -- the completion engine treats it as a potential switch (first
+      -- consumeArgument possibility) instead of consuming it.  This
+      -- causes the argument's completer to fire even though a value was
+      -- already provided.
+      it "should not offer the argument completer after a dashed value is consumed" $
+        parserCompletionTest
+          (setting [argument, reader (str :: Reader String), completer $ listCompleter ["file"]])
+          1
+          ["--foo"]
+          []
+
+      -- Same issue in a tuple: the first argument's completer fires
+      -- alongside the second's, even though the first argument already
+      -- has a value.
+      it "should only complete the second argument after a dashed first argument" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [argument, reader (str :: Reader String), completer $ listCompleter ["file"]]
+              <*> setting [argument, reader (str :: Reader String), completer $ listCompleter ["dest"]]
+          )
+          1
+          ["--foo"]
+          ["dest"]
+
+    describe "partial option value completion" $ do
+      it "filters option values by typed prefix" $
+        parserCompletionTest
+          ( setting
+              [ option,
+                reader (str :: Reader String),
+                long "name",
+                completer $ listCompleter ["alice", "bob"]
+              ]
+          )
+          1
+          ["--name", "al"]
+          ["alice"]
+
+      it "returns all option values when prefix is empty" $
+        parserCompletionTest
+          ( setting
+              [ option,
+                reader (str :: Reader String),
+                long "name",
+                completer $ listCompleter ["alice", "bob"]
+              ]
+          )
+          1
+          ["--name", ""]
+          [ "alice",
+            "bob"
+          ]
+
+    describe "partial argument completion" $ do
+      it "filters argument values by typed prefix" $
+        parserCompletionTest
+          ( setting
+              [ argument,
+                reader (str :: Reader String),
+                completer $ listCompleter ["file1", "file2", "data"]
+              ]
+          )
+          0
+          ["fi"]
+          [ "file1",
+            "file2"
+          ]
+
+      it "filters argument values by a different prefix" $
+        parserCompletionTest
+          ( setting
+              [ argument,
+                reader (str :: Reader String),
+                completer $ listCompleter ["file1", "file2", "data"]
+              ]
+          )
+          0
+          ["da"]
+          ["data"]
+
+    describe "partial command name with inner option completion" $ do
+      it "completes a command's options after selecting by prefix" $
+        parserCompletionTest
+          ( commands
+              [ command "deploy" "deploy it" $ setting [switch (), long "force"],
+                command "debug" "debug it" $ pure ()
+              ]
+          )
+          1
+          ["deploy"]
+          ["--force"]
+
+    describe "completion at a middle index" $ do
+      it "completes the value of an option at its value position with a matching prefix" $
+        parserCompletionTest
+          ( (,)
+              <$> setting
+                [ option,
+                  reader (str :: Reader String),
+                  long "foo",
+                  completer $ listCompleter ["val1", "val2"]
+                ]
+              <*> setting [switch (), long "bar"]
+          )
+          1
+          ["--foo", "v", "--bar"]
+          [ "val1",
+            "val2"
+          ]
+
+      it "filters completions when cursor word narrows the match" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [switch (), long "alpha"]
+              <*> setting [switch (), long "beta"]
+          )
+          0
+          ["--alpha", "--beta"]
+          ["--alpha"]
+
+    describe "partial long option prefix with multiple matches" $ do
+      it "filters options by a short prefix matching multiple" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [switch (), long "verbose"]
+              <*> setting [switch (), long "version"]
+          )
+          0
+          ["--ver"]
+          [ "--verbose",
+            "--version"
+          ]
+
+      it "filters options by a longer prefix matching one" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [switch (), long "verbose"]
+              <*> setting [switch (), long "version"]
+          )
+          0
+          ["--verb"]
+          ["--verbose"]
+
+    describe "partial argument completion after consuming earlier args" $ do
+      it "filters the second argument's completer by prefix after the first is consumed" $
+        parserCompletionTest
+          ( (,)
+              <$> setting [argument, reader (str :: Reader String), completer $ listCompleter ["src"]]
+              <*> setting [argument, reader (str :: Reader String), completer $ listCompleter ["dst", "data"]]
+          )
+          1
+          ["src", "ds"]
+          ["dst"]
+
+    describe "commands with partial option value inside" $ do
+      it "filters a command's option values by prefix" $
+        parserCompletionTest
+          ( commands
+              [ command "run" "run it" $
+                  setting
+                    [ option,
+                      reader (str :: Reader String),
+                      long "output",
+                      completer $ listCompleter ["file.txt", "final.out", "data.csv"]
+                    ]
+              ]
+          )
+          2
+          ["run", "--output", "fi"]
+          [ "file.txt",
+            "final.out"
+          ]
+
+    describe "many with partial values" $ do
+      it "filters many option values by prefix" $
+        parserCompletionTest
+          ( many
+              ( setting
+                  [ option,
+                    reader (str :: Reader String),
+                    long "include",
+                    completer $ listCompleter ["foo", "bar"]
+                  ]
+              )
+          )
+          1
+          ["--include", "fo"]
+          ["foo"]
+
+      it "filters many option values by prefix after one is consumed" $
+        parserCompletionTest
+          ( many
+              ( setting
+                  [ option,
+                    reader (str :: Reader String),
+                    long "include",
+                    completer $ listCompleter ["foo", "bar"]
+                  ]
+              )
+          )
+          3
+          ["--include", "foo", "--include", "ba"]
+          ["bar"]
+
+  sequential . doNotRandomiseExecutionOrder
+    $ aroundAll
+      ( \func -> withSystemTempDir "completion-spec" $ \tdir -> do
+          exampleFile <- resolveFile tdir "example.txt"
+          writeFile (fromAbsFile exampleFile) ""
+          exampleDir <- resolveDir tdir "exampledir"
+          createDir exampleDir
+          nested <- resolveFile exampleDir "nested.txt"
+          writeFile (fromAbsFile nested) ""
+          func tdir
+      )
+    $ do
+      let evalQuery p ix ws tdir = withCurrentDir tdir $ do
+            let arg = fromMaybe "" $ listToMaybe $ drop ix ws
+            let completions = pureCompletionQuery p ix ws
+            evalCompletions arg completions
+          suggestionValues = map (completionResultValue . completionSuggestion)
+
+      describe "file and directory completion" $ do
+        describe "filePathSetting" $ do
+          itWithOuter "completes files and directories for a file argument" $ \tdir -> do
+            results <- evalQuery (filePathSetting [help "f", argument]) 0 [] tdir
+            suggestionValues results `shouldBe` ["example.txt", "exampledir/"]
+
+          itWithOuter "completes files and directories after a file option's dashed" $ \tdir -> do
+            results <- evalQuery (filePathSetting [help "f", option, long "file"]) 1 ["--file"] tdir
+            suggestionValues results `shouldBe` ["example.txt", "exampledir/"]
+
+          itWithOuter "filters by prefix" $ \tdir -> do
+            results <- evalQuery (filePathSetting [help "f", argument]) 0 ["exampledi"] tdir
+            suggestionValues results `shouldBe` ["exampledir/"]
+
+          -- Directories end in /, files do not.  This convention is how
+          -- shells decide whether to append a trailing space after a
+          -- completion.  The exact values are checked by
+          -- "completes files and directories for a file argument" above;
+          -- this test re-states the invariant explicitly.
+          itWithOuter "directories end in / and files do not" $ \tdir -> do
+            results <- evalQuery (filePathSetting [help "f", argument]) 0 [] tdir
+            suggestionValues results `shouldBe` ["example.txt", "exampledir/"]
+
+          itWithOuter "files are final and directories are not final" $ \tdir -> do
+            results <- evalQuery (filePathSetting [help "f", argument]) 0 [] tdir
+            map (completionResultFinality . completionSuggestion) results
+              `shouldBe` [CompletionFinal, CompletionNotFinal]
+
+          itWithOuter "carries the description through to file completions" $ \tdir -> do
+            results <- evalQuery (filePathSetting [help "my file", argument]) 0 [] tdir
+            map completionDescription results `shouldBe` [Just "my file", Just "my file"]
+
+        describe "directoryPathSetting" $ do
+          itWithOuter "completes only directories for a directory argument" $ \tdir -> do
+            results <- evalQuery (directoryPathSetting [help "d", argument]) 0 [] tdir
+            suggestionValues results `shouldBe` ["exampledir/"]
+
+          itWithOuter "completes only directories after a directory option's dashed" $ \tdir -> do
+            results <- evalQuery (directoryPathSetting [help "d", option, long "dir"]) 1 ["--dir"] tdir
+            suggestionValues results `shouldBe` ["exampledir/"]
+
+          itWithOuter "never includes files" $ \tdir -> do
+            results <- evalQuery (directoryPathSetting [help "d", argument]) 0 [] tdir
+            suggestionValues results `shouldBe` ["exampledir/"]
+
+          itWithOuter "directories are not final" $ \tdir -> do
+            results <- evalQuery (directoryPathSetting [help "d", argument]) 0 [] tdir
+            map (completionResultFinality . completionSuggestion) results
+              `shouldBe` [CompletionNotFinal]
+
+          itWithOuter "carries the description through to directory completions" $ \tdir -> do
+            results <- evalQuery (directoryPathSetting [help "my dir", argument]) 0 [] tdir
+            map completionDescription results `shouldBe` [Just "my dir"]
+
+        describe "combined with other settings" $ do
+          itWithOuter "includes file completions alongside other options" $ \tdir -> do
+            let parser =
+                  (,)
+                    <$> filePathSetting [help "f", option, long "file"]
+                    <*> setting [switch (), long "verbose"]
+            results <- evalQuery parser 1 ["--file"] tdir
+            suggestionValues results `shouldBe` ["example.txt", "exampledir/", "--verbose"]
+
+          itWithOuter "includes directory completions alongside other options" $ \tdir -> do
+            let parser =
+                  (,)
+                    <$> directoryPathSetting [help "d", option, long "dir"]
+                    <*> setting [switch (), long "verbose"]
+            results <- evalQuery parser 1 ["--dir"] tdir
+            suggestionValues results `shouldBe` ["exampledir/", "--verbose"]
+
+          -- After typing the dashed of an option that takes a value, the
+          -- cursor is in the value position.  The option's completer
+          -- should fire first, then other options should follow.
+          --
+          -- Shell sends index pointing at the empty cursor word:
+          --   exe --dir <tab> -> index=1, words=["--dir", ""]
+          itWithOuter "completes directory option value first, then other options" $ \tdir -> do
+            let parser =
+                  (,)
+                    <$> directoryPathSetting [help "d", option, long "dir"]
+                    <*> setting [switch (), long "verbose"]
+            results <- evalQuery parser 1 ["--dir", ""] tdir
+            suggestionValues results `shouldBe` ["exampledir/", "--verbose"]
+
+          itWithOuter "completes file option value first, then other options" $ \tdir -> do
+            let parser =
+                  (,)
+                    <$> filePathSetting [help "f", option, long "file"]
+                    <*> setting [switch (), long "verbose"]
+            results <- evalQuery parser 1 ["--file", ""] tdir
+            suggestionValues results `shouldBe` ["example.txt", "exampledir/", "--verbose"]
+
+          -- A default command with an argument combined with a
+          -- directory option causes the directory completer not to fire
+          -- when completing the option's value.
+          itWithOuter "completes directory option value alongside default command with argument" $ \tdir -> do
+            let parser =
+                  (,)
+                    <$> commands
+                      [ command "file" "f" $
+                          setting [help "f", argument, reader (str :: Reader String)],
+                        defaultCommand "file"
+                      ]
+                    <*> directoryPathSetting [help "a", option, long "archive-dir"]
+            results <- evalQuery parser 1 ["--archive-dir", ""] tdir
+            suggestionValues results `shouldSatisfy` elem "exampledir/"
diff --git a/test/OptEnvConf/RunSpec.hs b/test/OptEnvConf/RunSpec.hs
--- a/test/OptEnvConf/RunSpec.hs
+++ b/test/OptEnvConf/RunSpec.hs
@@ -8,6 +8,7 @@
 import Autodocodec
 import Control.Applicative
 import Control.Concurrent
+import Control.Monad (void)
 import Data.Aeson as JSON (Object, Value (Null), toJSON)
 import qualified Data.Aeson.Key as Key
 import qualified Data.Aeson.KeyMap as KeyMap
@@ -25,6 +26,7 @@
 import qualified OptEnvConf.EnvMap as EnvMap
 import OptEnvConf.EnvMap.Gen ()
 import OptEnvConf.Error
+import qualified System.Timeout as Timeout
 import Test.Syd
 import Test.Syd.Validity
 import Text.Colour
@@ -129,6 +131,45 @@
               let expected = NE.toList ls
               shouldParse p args e mConf expected
 
+      -- Regression test for an exponential-time bug.
+      --
+      -- A parser shaped like
+      --
+      --     choice [some argument, many --filter] <*> many --opt1 <*> many --opt2 <*> ...
+      --
+      -- combined with input that has both several @--opt1 VAL@ pairs and at
+      -- least one @--opt2 VAL@ pair scaled super-linearly: in the broken
+      -- version, every added @--opt2@ multiplied total parse time by ~3x.
+      --
+      -- The original report came from a sydtest mutation suite invocation
+      -- with 6 @--mutation@ + 6 @--mutation-suite-exe@ flags taking
+      -- > 30 seconds of CPU just to parse settings. With the parser shape
+      -- below and 6 @--opt1@ + 6 @--opt2@ pairs the broken version takes
+      -- many minutes; the fixed version completes in milliseconds.
+      it "parses many-many input in bounded time (regression: no exponential blowup)" $ do
+        let parser :: Parser ()
+            parser =
+              void $
+                (,,)
+                  <$> choice
+                    [ some (setting [reader str, argument, help "F", metavar "F"] :: Parser String),
+                      many (setting [reader str, option, long "filter", help "F", metavar "F"])
+                    ]
+                  <*> many (setting [reader str, option, long "opt1", help "x", metavar "X"] :: Parser String)
+                  <*> many (setting [reader str, option, long "opt2", help "x", metavar "X"] :: Parser String)
+        let args =
+              parseArgs $
+                concat (replicate 6 ["--opt1", "/v"])
+                  ++ concat (replicate 6 ["--opt2", "/v"])
+        mResult <-
+          Timeout.timeout
+            (500 * 1000)
+            (runParserOn allCapabilities Nothing parser args EnvMap.empty Nothing)
+        case mResult of
+          Nothing -> expectationFailure "parser took longer than 0.5 seconds; likely exponential blowup"
+          Just (Left errs) -> expectationFailure $ T.unpack $ renderChunksText With24BitColours $ renderErrors errs
+          Just (Right ()) -> pure ()
+
     describe "MapIO" $ do
       it "can run an IO action on the result of a parser" $
         forAllValid $ \e ->
@@ -526,16 +567,15 @@
 
       -- Unfolding short options as well
       argParseSpecs
-        ( (,)
-            <$> ( length
-                    <$> many
-                      ( setting
-                          [ help "verbosity",
-                            switch (),
-                            short 'v'
-                          ]
-                      )
+        ( ( (,) . length
+              <$> many
+                ( setting
+                    [ help "verbosity",
+                      switch (),
+                      short 'v'
+                    ]
                 )
+          )
             <*> setting
               [ reader str,
                 option,
@@ -650,8 +690,9 @@
         verbosityArgsExamples
       argParseSpecs
         ( swap
-            <$> ( (,)
-                    <$> (length <$> many (setting [switch (), short 'v', long "verbose"]))
+            <$> ( ( (,) . length
+                      <$> many (setting [switch (), short 'v', long "verbose"])
+                  )
                     <*> many (setting [reader str, argument])
                 ) ::
             Parser ([String], Int)
diff --git a/test_resources/completion/fish-completion-script.fish b/test_resources/completion/fish-completion-script.fish
--- a/test_resources/completion/fish-completion-script.fish
+++ b/test_resources/completion/fish-completion-script.fish
@@ -8,10 +8,11 @@
       set tmpline $tmpline --completion-word $arg
     end
     for opt in (/usr/bin/example-executable $tmpline)
-      if test -d $opt
-        echo -E "$opt/"
+      set -l val (string split \t -- $opt)[1]
+      if test -d $val
+        echo -E "$val/"
       else
-        echo -E "$opt"
+        echo -E "$val"
       end
     end
 end
diff --git a/test_resources/completion/zsh-completion-script.zsh b/test_resources/completion/zsh-completion-script.zsh
--- a/test_resources/completion/zsh-completion-script.zsh
+++ b/test_resources/completion/zsh-completion-script.zsh
@@ -22,11 +22,18 @@
      if [[ $word[1] == "-" ]]; then
        local desc=("$parts[1] ($parts[2])")
        compadd -d desc -- $parts[1]
+     elif [[ $parts[3] == 'N' ]]; then
+       local desc=($(print -f  "%-019s -- %s" $parts[1] $parts[2]))
+       compadd -f -l -S '' -d desc -- $parts[1]
      else
        local desc=($(print -f  "%-019s -- %s" $parts[1] $parts[2]))
-       compadd -l -d desc -- $parts[1]
+       compadd -f -l -d desc -- $parts[1]
      fi
   else
-    compadd -f -- $word
+    if [[ $parts[3] == 'N' ]]; then
+      compadd -f -S '' -- $parts[1]
+    else
+      compadd -f -- $parts[1]
+    fi
   fi
 done
diff --git a/test_resources/docs/big-config/nix-options.nix b/test_resources/docs/big-config/nix-options.nix
--- a/test_resources/docs/big-config/nix-options.nix
+++ b/test_resources/docs/big-config/nix-options.nix
@@ -1,3 +1,7 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:25
+# To update this it, run the test with --golden-reset
 { lib }:
 {
   big = lib.mkOption {
diff --git a/test_resources/docs/empty/nix-options.nix b/test_resources/docs/empty/nix-options.nix
--- a/test_resources/docs/empty/nix-options.nix
+++ b/test_resources/docs/empty/nix-options.nix
@@ -1,2 +1,6 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:21
+# To update this it, run the test with --golden-reset
 { lib }:
 { }
diff --git a/test_resources/docs/enable-disable-optional/nix-options.nix b/test_resources/docs/enable-disable-optional/nix-options.nix
--- a/test_resources/docs/enable-disable-optional/nix-options.nix
+++ b/test_resources/docs/enable-disable-optional/nix-options.nix
@@ -1,3 +1,7 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:30
+# To update this it, run the test with --golden-reset
 { lib }:
 {
   example = lib.mkOption {
diff --git a/test_resources/docs/enable-disable/nix-options.nix b/test_resources/docs/enable-disable/nix-options.nix
--- a/test_resources/docs/enable-disable/nix-options.nix
+++ b/test_resources/docs/enable-disable/nix-options.nix
@@ -1,3 +1,7 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:28
+# To update this it, run the test with --golden-reset
 { lib }:
 {
   example = lib.mkOption {
diff --git a/test_resources/docs/greet/nix-options.nix b/test_resources/docs/greet/nix-options.nix
--- a/test_resources/docs/greet/nix-options.nix
+++ b/test_resources/docs/greet/nix-options.nix
@@ -1,3 +1,7 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:37
+# To update this it, run the test with --golden-reset
 { lib }:
 {
   greeting = lib.mkOption {
diff --git a/test_resources/docs/hidden/nix-options.nix b/test_resources/docs/hidden/nix-options.nix
--- a/test_resources/docs/hidden/nix-options.nix
+++ b/test_resources/docs/hidden/nix-options.nix
@@ -1,2 +1,6 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:27
+# To update this it, run the test with --golden-reset
 { lib }:
 { }
diff --git a/test_resources/docs/many-args/nix-options.nix b/test_resources/docs/many-args/nix-options.nix
--- a/test_resources/docs/many-args/nix-options.nix
+++ b/test_resources/docs/many-args/nix-options.nix
@@ -1,2 +1,6 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:22
+# To update this it, run the test with --golden-reset
 { lib }:
 { }
diff --git a/test_resources/docs/optional/nix-options.nix b/test_resources/docs/optional/nix-options.nix
--- a/test_resources/docs/optional/nix-options.nix
+++ b/test_resources/docs/optional/nix-options.nix
@@ -1,2 +1,6 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:24
+# To update this it, run the test with --golden-reset
 { lib }:
 { }
diff --git a/test_resources/docs/same-help/nix-options.nix b/test_resources/docs/same-help/nix-options.nix
--- a/test_resources/docs/same-help/nix-options.nix
+++ b/test_resources/docs/same-help/nix-options.nix
@@ -1,3 +1,7 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:33
+# To update this it, run the test with --golden-reset
 { lib }:
 {
   int = lib.mkOption {
diff --git a/test_resources/docs/secret/nix-options.nix b/test_resources/docs/secret/nix-options.nix
--- a/test_resources/docs/secret/nix-options.nix
+++ b/test_resources/docs/secret/nix-options.nix
@@ -1,3 +1,7 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:35
+# To update this it, run the test with --golden-reset
 { lib }:
 {
   first-secret-file = lib.mkOption {
diff --git a/test_resources/docs/some-args/nix-options.nix b/test_resources/docs/some-args/nix-options.nix
--- a/test_resources/docs/some-args/nix-options.nix
+++ b/test_resources/docs/some-args/nix-options.nix
@@ -1,2 +1,6 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:23
+# To update this it, run the test with --golden-reset
 { lib }:
 { }
diff --git a/test_resources/docs/sub-commands/nix-options.nix b/test_resources/docs/sub-commands/nix-options.nix
--- a/test_resources/docs/sub-commands/nix-options.nix
+++ b/test_resources/docs/sub-commands/nix-options.nix
@@ -1,3 +1,7 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:39
+# To update this it, run the test with --golden-reset
 { lib }:
 {
   name = lib.mkOption {
diff --git a/test_resources/docs/sub-settings/nix-options.nix b/test_resources/docs/sub-settings/nix-options.nix
--- a/test_resources/docs/sub-settings/nix-options.nix
+++ b/test_resources/docs/sub-settings/nix-options.nix
@@ -1,3 +1,7 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:26
+# To update this it, run the test with --golden-reset
 { lib }:
 {
   foo = lib.mkOption {
diff --git a/test_resources/docs/sum-type/nix-options.nix b/test_resources/docs/sum-type/nix-options.nix
--- a/test_resources/docs/sum-type/nix-options.nix
+++ b/test_resources/docs/sum-type/nix-options.nix
@@ -1,3 +1,7 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:34
+# To update this it, run the test with --golden-reset
 { lib }:
 {
   sum-type = lib.mkOption {
diff --git a/test_resources/docs/three-commands/nix-options.nix b/test_resources/docs/three-commands/nix-options.nix
--- a/test_resources/docs/three-commands/nix-options.nix
+++ b/test_resources/docs/three-commands/nix-options.nix
@@ -1,3 +1,7 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:38
+# To update this it, run the test with --golden-reset
 { lib }:
 {
   enable = lib.mkOption {
diff --git a/test_resources/docs/verbose/nix-options.nix b/test_resources/docs/verbose/nix-options.nix
--- a/test_resources/docs/verbose/nix-options.nix
+++ b/test_resources/docs/verbose/nix-options.nix
@@ -1,2 +1,6 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:32
+# To update this it, run the test with --golden-reset
 { lib }:
 { }
diff --git a/test_resources/docs/with-default/nix-options.nix b/test_resources/docs/with-default/nix-options.nix
--- a/test_resources/docs/with-default/nix-options.nix
+++ b/test_resources/docs/with-default/nix-options.nix
@@ -1,2 +1,6 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:36
+# To update this it, run the test with --golden-reset
 { lib }:
 { }
diff --git a/test_resources/docs/yes-no-optional/nix-options.nix b/test_resources/docs/yes-no-optional/nix-options.nix
--- a/test_resources/docs/yes-no-optional/nix-options.nix
+++ b/test_resources/docs/yes-no-optional/nix-options.nix
@@ -1,3 +1,7 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:31
+# To update this it, run the test with --golden-reset
 { lib }:
 {
   example = lib.mkOption {
diff --git a/test_resources/docs/yes-no/nix-options.nix b/test_resources/docs/yes-no/nix-options.nix
--- a/test_resources/docs/yes-no/nix-options.nix
+++ b/test_resources/docs/yes-no/nix-options.nix
@@ -1,3 +1,7 @@
+# DO NOT EDIT THIS FILE DIRECTLY
+# This file was generated by
+# opt-env-conf-test:test/OptEnvConf/APISpec.hs:29
+# To update this it, run the test with --golden-reset
 { lib }:
 {
   example = lib.mkOption {
diff --git a/test_resources/error/all-or-nothing-relevant.txt b/test_resources/error/all-or-nothing-relevant.txt
--- a/test_resources/error/all-or-nothing-relevant.txt
+++ b/test_resources/error/all-or-nothing-relevant.txt
@@ -1,5 +1,5 @@
 Missing option: --bar This one will not exist
 You are seeing this error because at least one, but not all, of the settings in an allOrNothing (or subSettings) parser have been defined.
 The following settings have been parsed:
-test/OptEnvConf/ErrorSpec.hs:153:21 in main:OptEnvConf.ErrorSpec
+test/OptEnvConf/ErrorSpec.hs:153:21 in opt-env-conf-test:OptEnvConf.ErrorSpec
 Hit the 'empty' case of the Parser type, this should not happen.
diff --git a/test_resources/error/all-or-nothing.txt b/test_resources/error/all-or-nothing.txt
--- a/test_resources/error/all-or-nothing.txt
+++ b/test_resources/error/all-or-nothing.txt
@@ -1,4 +1,4 @@
 Missing option: --bar This one will not exist
 You are seeing this error because at least one, but not all, of the settings in an allOrNothing (or subSettings) parser have been defined.
 The following settings have been parsed:
-test/OptEnvConf/ErrorSpec.hs:141:19 in main:OptEnvConf.ErrorSpec
+test/OptEnvConf/ErrorSpec.hs:141:19 in opt-env-conf-test:OptEnvConf.ErrorSpec
diff --git a/test_resources/help/toplevel-pure-with-invalid-port.txt b/test_resources/help/toplevel-pure-with-invalid-port.txt
--- a/test_resources/help/toplevel-pure-with-invalid-port.txt
+++ b/test_resources/help/toplevel-pure-with-invalid-port.txt
@@ -1,4 +1,4 @@
-Usage: example [--config-file FILE_PATH] [--port PORT] [--log-level LOG_LEVEL] [--payment-public-key PUBLIC_KEY --payment-secret-key FILE_PATH [--payment-currency CURRENCY]] COMMAND
+Usage: example [--config-file FILE_PATH] [--port PORT] [--log-level LOG_LEVEL] [--payment-public-key PUBLIC_KEY --payment-secret-key SECRET_KEY_FILE [--payment-currency CURRENCY]] COMMAND
 
 example program description
 
@@ -37,8 +37,8 @@
       <string>
 
   Secret key
-  option: --payment-secret-key FILE_PATH
-  env: PAYMENT_SECRET_KEY FILE_PATH
+  option: --payment-secret-key SECRET_KEY_FILE
+  env: PAYMENT_SECRET_KEY SECRET_KEY_FILE
   config:
     payment.secret-key: # or null
       <string>
diff --git a/test_resources/help/toplevel-pure.txt b/test_resources/help/toplevel-pure.txt
--- a/test_resources/help/toplevel-pure.txt
+++ b/test_resources/help/toplevel-pure.txt
@@ -1,4 +1,4 @@
-Usage: example [--config-file FILE_PATH] [--port PORT] [--log-level LOG_LEVEL] [--payment-public-key PUBLIC_KEY --payment-secret-key FILE_PATH [--payment-currency CURRENCY]] COMMAND
+Usage: example [--config-file FILE_PATH] [--port PORT] [--log-level LOG_LEVEL] [--payment-public-key PUBLIC_KEY --payment-secret-key SECRET_KEY_FILE [--payment-currency CURRENCY]] COMMAND
 
 example program description
 
@@ -37,8 +37,8 @@
       <string>
 
   Secret key
-  option: --payment-secret-key FILE_PATH
-  env: PAYMENT_SECRET_KEY FILE_PATH
+  option: --payment-secret-key SECRET_KEY_FILE
+  env: PAYMENT_SECRET_KEY SECRET_KEY_FILE
   config:
     payment.secret-key: # or null
       <string>
diff --git a/test_resources/help/wrong-command.txt b/test_resources/help/wrong-command.txt
--- a/test_resources/help/wrong-command.txt
+++ b/test_resources/help/wrong-command.txt
@@ -1,4 +1,4 @@
-Usage: example [--config-file FILE_PATH] [--port PORT] [--log-level LOG_LEVEL] [--payment-public-key PUBLIC_KEY --payment-secret-key FILE_PATH [--payment-currency CURRENCY]] COMMAND
+Usage: example [--config-file FILE_PATH] [--port PORT] [--log-level LOG_LEVEL] [--payment-public-key PUBLIC_KEY --payment-secret-key SECRET_KEY_FILE [--payment-currency CURRENCY]] COMMAND
 
 example program description
 
@@ -37,8 +37,8 @@
       <string>
 
   Secret key
-  option: --payment-secret-key FILE_PATH
-  env: PAYMENT_SECRET_KEY FILE_PATH
+  option: --payment-secret-key SECRET_KEY_FILE
+  env: PAYMENT_SECRET_KEY SECRET_KEY_FILE
   config:
     payment.secret-key: # or null
       <string>
diff --git a/test_resources/lint/config-without-load.txt b/test_resources/lint/config-without-load.txt
--- a/test_resources/lint/config-without-load.txt
+++ b/test_resources/lint/config-without-load.txt
@@ -3,4 +3,4 @@
   Invalid Setting:
   conf or name was called with no way to load configuration.
   You can load configuration with withConfig, or explicitly not load any configuration with withoutConfig.
-  Defined at: test/OptEnvConf/LintSpec.hs:124:7 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:124:7 in opt-env-conf-test:OptEnvConf.LintSpec
diff --git a/test_resources/lint/dash-in-long.txt b/test_resources/lint/dash-in-long.txt
--- a/test_resources/lint/dash-in-long.txt
+++ b/test_resources/lint/dash-in-long.txt
@@ -4,4 +4,4 @@
   long may not start with a '-'.
   Found long "--switch".
   Try long "switch" instead.
-  Defined at: test/OptEnvConf/LintSpec.hs:33:7 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:33:7 in opt-env-conf-test:OptEnvConf.LintSpec
diff --git a/test_resources/lint/dash-in-short.txt b/test_resources/lint/dash-in-short.txt
--- a/test_resources/lint/dash-in-short.txt
+++ b/test_resources/lint/dash-in-short.txt
@@ -3,4 +3,4 @@
   Invalid Setting:
   short may not contain a '-'.
   Found short '-'.
-  Defined at: test/OptEnvConf/LintSpec.hs:25:7 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:25:7 in opt-env-conf-test:OptEnvConf.LintSpec
diff --git a/test_resources/lint/empty-setting.txt b/test_resources/lint/empty-setting.txt
--- a/test_resources/lint/empty-setting.txt
+++ b/test_resources/lint/empty-setting.txt
@@ -3,4 +3,4 @@
   Invalid Setting:
   This setting parses nothing.
   Add an argument, switch, option, env, conf, or value.
-  Defined at: test/OptEnvConf/LintSpec.hs:19:7 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:19:7 in opt-env-conf-test:OptEnvConf.LintSpec
diff --git a/test_resources/lint/no-commands.txt b/test_resources/lint/no-commands.txt
--- a/test_resources/lint/no-commands.txt
+++ b/test_resources/lint/no-commands.txt
@@ -2,4 +2,4 @@
   
   Invalid Setting:
   commands was called with an empty list.
-  Defined at: test/OptEnvConf/LintSpec.hs:121:6 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:121:6 in opt-env-conf-test:OptEnvConf.LintSpec
diff --git a/test_resources/lint/no-dashed-for-option.txt b/test_resources/lint/no-dashed-for-option.txt
--- a/test_resources/lint/no-dashed-for-option.txt
+++ b/test_resources/lint/no-dashed-for-option.txt
@@ -2,4 +2,4 @@
   
   Invalid Setting:
   option has no long or short.
-  Defined at: test/OptEnvConf/LintSpec.hs:67:7 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:67:7 in opt-env-conf-test:OptEnvConf.LintSpec
diff --git a/test_resources/lint/no-dashed-for-switch.txt b/test_resources/lint/no-dashed-for-switch.txt
--- a/test_resources/lint/no-dashed-for-switch.txt
+++ b/test_resources/lint/no-dashed-for-switch.txt
@@ -2,4 +2,4 @@
   
   Invalid Setting:
   switch has no long or short.
-  Defined at: test/OptEnvConf/LintSpec.hs:98:7 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:98:7 in opt-env-conf-test:OptEnvConf.LintSpec
diff --git a/test_resources/lint/no-metavar-for-argument.txt b/test_resources/lint/no-metavar-for-argument.txt
--- a/test_resources/lint/no-metavar-for-argument.txt
+++ b/test_resources/lint/no-metavar-for-argument.txt
@@ -2,4 +2,4 @@
   
   Invalid Setting:
   argument has no metavar.
-  Defined at: test/OptEnvConf/LintSpec.hs:49:7 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:49:7 in opt-env-conf-test:OptEnvConf.LintSpec
diff --git a/test_resources/lint/no-metavar-for-env.txt b/test_resources/lint/no-metavar-for-env.txt
--- a/test_resources/lint/no-metavar-for-env.txt
+++ b/test_resources/lint/no-metavar-for-env.txt
@@ -2,4 +2,4 @@
   
   Invalid Setting:
   env or name has no metavar.
-  Defined at: test/OptEnvConf/LintSpec.hs:112:7 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:112:7 in opt-env-conf-test:OptEnvConf.LintSpec
diff --git a/test_resources/lint/no-metavar-for-option.txt b/test_resources/lint/no-metavar-for-option.txt
--- a/test_resources/lint/no-metavar-for-option.txt
+++ b/test_resources/lint/no-metavar-for-option.txt
@@ -2,4 +2,4 @@
   
   Invalid Setting:
   option or name has no metavar.
-  Defined at: test/OptEnvConf/LintSpec.hs:88:7 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:88:7 in opt-env-conf-test:OptEnvConf.LintSpec
diff --git a/test_resources/lint/no-option-or-switch-for-dashed.txt b/test_resources/lint/no-option-or-switch-for-dashed.txt
--- a/test_resources/lint/no-option-or-switch-for-dashed.txt
+++ b/test_resources/lint/no-option-or-switch-for-dashed.txt
@@ -2,4 +2,4 @@
   
   Invalid Setting:
   long or short has no option or switch.
-  Defined at: test/OptEnvConf/LintSpec.hs:77:7 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:77:7 in opt-env-conf-test:OptEnvConf.LintSpec
diff --git a/test_resources/lint/no-reader-for-argument.txt b/test_resources/lint/no-reader-for-argument.txt
--- a/test_resources/lint/no-reader-for-argument.txt
+++ b/test_resources/lint/no-reader-for-argument.txt
@@ -2,4 +2,4 @@
   
   Invalid Setting:
   argument has no reader.
-  Defined at: test/OptEnvConf/LintSpec.hs:41:7 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:41:7 in opt-env-conf-test:OptEnvConf.LintSpec
diff --git a/test_resources/lint/no-reader-for-env.txt b/test_resources/lint/no-reader-for-env.txt
--- a/test_resources/lint/no-reader-for-env.txt
+++ b/test_resources/lint/no-reader-for-env.txt
@@ -2,8 +2,8 @@
   
   Invalid Setting:
   env or name has no reader.
-  Defined at: test/OptEnvConf/LintSpec.hs:105:7 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:105:7 in opt-env-conf-test:OptEnvConf.LintSpec
   
   Invalid Setting:
   env or name has no metavar.
-  Defined at: test/OptEnvConf/LintSpec.hs:105:7 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:105:7 in opt-env-conf-test:OptEnvConf.LintSpec
diff --git a/test_resources/lint/no-reader-for-option.txt b/test_resources/lint/no-reader-for-option.txt
--- a/test_resources/lint/no-reader-for-option.txt
+++ b/test_resources/lint/no-reader-for-option.txt
@@ -2,4 +2,4 @@
   
   Invalid Setting:
   option or name has no reader.
-  Defined at: test/OptEnvConf/LintSpec.hs:58:7 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:58:7 in opt-env-conf-test:OptEnvConf.LintSpec
diff --git a/test_resources/lint/null-setting.txt b/test_resources/lint/null-setting.txt
--- a/test_resources/lint/null-setting.txt
+++ b/test_resources/lint/null-setting.txt
@@ -2,9 +2,9 @@
   
   Invalid Setting:
   missing help.
-  Defined at: test/OptEnvConf/LintSpec.hs:16:6 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:16:6 in opt-env-conf-test:OptEnvConf.LintSpec
   
   Invalid Setting:
   This setting parses nothing.
   Add an argument, switch, option, env, conf, or value.
-  Defined at: test/OptEnvConf/LintSpec.hs:16:6 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:16:6 in opt-env-conf-test:OptEnvConf.LintSpec
diff --git a/test_resources/lint/unknown-default-command.txt b/test_resources/lint/unknown-default-command.txt
--- a/test_resources/lint/unknown-default-command.txt
+++ b/test_resources/lint/unknown-default-command.txt
@@ -2,4 +2,4 @@
   
   Invalid Setting:
   defaultCommand was called with an unknown command: b
-  Defined at: test/OptEnvConf/LintSpec.hs:185:7 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:185:7 in opt-env-conf-test:OptEnvConf.LintSpec
diff --git a/test_resources/lint/unreadable-example.txt b/test_resources/lint/unreadable-example.txt
--- a/test_resources/lint/unreadable-example.txt
+++ b/test_resources/lint/unreadable-example.txt
@@ -3,4 +3,4 @@
   Invalid Setting:
   example was called with an example that none of the readers succeed in reading.
   Example: NaN
-  Defined at: test/OptEnvConf/LintSpec.hs:132:7 in main:OptEnvConf.LintSpec
+  Defined at: test/OptEnvConf/LintSpec.hs:132:7 in opt-env-conf-test:OptEnvConf.LintSpec