Tweak MonadUnliftIO TraceT instance

The new definition should be compatible both with unliftio <0.2 and
>=0.2.

Also add condition around `<>` import to avoid warnings in recent
versions of GHC.

LICENSE

@@ -1,4 +1,4 @@
-Copyright Matthieu Monsch (c) 2019
+Copyright Matthieu Monsch (c) 2019-2020
 
 All rights reserved.
 
@@ -27,4 +27,4 @@ LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

src/Control/Monad/Trace.hs

@@ -30,9 +30,9 @@ import Control.Monad.Trace.Internal
 
 import Control.Applicative ((<|>))
 import Control.Monad.IO.Class (MonadIO, liftIO)
-import Control.Monad.Reader (ReaderT(..), ask, asks, local, runReaderT)
+import Control.Monad.Reader (ReaderT(ReaderT), ask, asks, local, runReaderT)
 import Control.Monad.Reader.Class (MonadReader)
-import Control.Monad.Trans.Class (MonadTrans(..))
+import Control.Monad.Trans.Class (MonadTrans, lift)
 import qualified Data.Aeson as JSON
 import Data.Foldable (for_)
 import Data.List (sortOn)
@@ -41,7 +41,7 @@ import qualified Data.Map.Strict as Map
 import Data.Maybe (fromMaybe)
 import Data.Time.Clock (NominalDiffTime)
 import Data.Time.Clock.POSIX (POSIXTime, getPOSIXTime)
-import UnliftIO (MonadUnliftIO, UnliftIO(..), askUnliftIO, withUnliftIO)
+import UnliftIO (MonadUnliftIO, withRunInIO)
 import UnliftIO.Exception (finally)
 import UnliftIO.STM (TChan, TVar, atomically, modifyTVar', newTChanIO, newTVarIO, readTVar, writeTChan, writeTVar)
 
@@ -161,7 +161,7 @@ instance MonadUnliftIO m => MonadTrace (TraceT m) where
       atomically $ modifyTVar' tv ((time, key, val) :)
 
 instance MonadUnliftIO m => MonadUnliftIO (TraceT m) where
-  askUnliftIO = TraceT $ withUnliftIO $ \u -> pure (UnliftIO (unliftIO u . traceTReader ))
+  withRunInIO inner = TraceT $ withRunInIO $ \run -> inner (run . traceTReader)
 
 -- | Trace an action, sampling its generated spans. This method is thread-safe and can be used to
 -- trace multiple actions concurrently.

src/Monitor/Tracing/Zipkin.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE OverloadedStrings #-}
@@ -57,6 +58,9 @@ import Data.Map.Strict (Map)
 import qualified Data.Map.Strict as Map
 import Data.Maybe (catMaybes, fromMaybe, listToMaybe, maybeToList)
 import Data.Monoid (Endo(..))
+#if !MIN_VERSION_base(4, 11, 0)
+import Data.Semigroup ((<>))
+#endif
 import Data.Set (Set)
 import Data.String (IsString(..))
 import Data.Text (Text)

tracing.cabal

@@ -3,28 +3,26 @@ cabal-version: 1.12
 name: tracing
 version: 0.0.5.1
 synopsis: Distributed tracing
-category: Web
-homepage: https://github.com/mtth/tracing
 description:
   An OpenTracing-compliant, simple, and extensible distributed tracing library.
 
+category: Web
+homepage: https://github.com/mtth/tracing
 license: BSD3
 license-file: LICENSE
 author: Matthieu Monsch
 maintainer: [email protected]
 copyright: 2020 Matthieu Monsch
 
 build-type: Simple
-extra-source-files:
-    README.md
+extra-source-files: README.md
 
 source-repository head
   type: git
   location: https://github.com/mtth/yx
 
 library
-  hs-source-dirs:
-      src
+  hs-source-dirs: src
   exposed-modules:
       Control.Monad.Trace
     , Control.Monad.Trace.Class
@@ -50,15 +48,13 @@ library
     , time >= 1.8
     , transformers >= 0.5
     , unliftio >= 0.2
-    , unliftio-core < 0.2
   ghc-options: -Wall
   default-language: Haskell2010
 
 test-suite tracing-test
   type: exitcode-stdio-1.0
   main-is: Spec.hs
-  hs-source-dirs:
-      test
+  hs-source-dirs: test
   build-depends:
       base
     , containers