From 8e96de7eceab39ded51067789f42d7bd66479b6a Mon Sep 17 00:00:00 2001
From: Andrzej Rybczak <andrzej@rybczak.net>
Date: Thu, 22 Aug 2024 20:14:03 +0200
Subject: [PATCH] doctest

---
 doctest.sh                              |  1 +
 effectful-core/src/Effectful/Labeled.hs | 18 ++++++++++++++++++
 effectful/tests/LabeledTests.hs         |  2 +-
 3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/doctest.sh b/doctest.sh
index 7b9167c..38f2780 100755
--- a/doctest.sh
+++ b/doctest.sh
@@ -27,6 +27,7 @@ run_doctest() {
     -XLambdaCase \
     -XMultiParamTypeClasses \
     -XNoStarIsType \
+    -XPolyKinds \
     -XRankNTypes \
     -XRecordWildCards \
     -XRoleAnnotations \
diff --git a/effectful-core/src/Effectful/Labeled.hs b/effectful-core/src/Effectful/Labeled.hs
index 277a094..641b847 100644
--- a/effectful-core/src/Effectful/Labeled.hs
+++ b/effectful-core/src/Effectful/Labeled.hs
@@ -22,6 +22,24 @@ import Effectful
 import Effectful.Dispatch.Static
 
 -- | Assign a label to an effect.
+--
+-- The constructor is for sending labeled operations of a dynamically dispatched
+-- effect to the handler:
+--
+-- >>> import Effectful.Dispatch.Dynamic
+--
+-- >>> :{
+--   data X :: Effect where
+--     X :: X m Int
+--   type instance DispatchOf X = Dynamic
+-- :}
+--
+-- >>> :{
+--   runPureEff . runLabeled @"x" (interpret_ $ \X -> pure 333) $ do
+--     send $ Labeled @"x" X
+-- :}
+-- 333
+--
 newtype Labeled (label :: k) (e :: Effect) :: Effect where
   -- | @since 2.4.0.0
   Labeled :: forall label e m a. e m a -> Labeled label e m a
diff --git a/effectful/tests/LabeledTests.hs b/effectful/tests/LabeledTests.hs
index d1a24b6..8b084b3 100644
--- a/effectful/tests/LabeledTests.hs
+++ b/effectful/tests/LabeledTests.hs
@@ -51,7 +51,7 @@ test_labeledSend = runEff $ do
 
 data X :: Effect where
   X1 :: X m Int
-  X2 :: X m Int
+  X2 :: (X :> es, Labeled "x" X :> es) => X (Eff es) Int
 
 type instance DispatchOf X = Dynamic