Merge pull request serokell#263 from serokell/dk318/serokell#208-redu…

…ndant-constraint-test [serokell#208] `redundant constraint` test
treeowl · Apr 28, 2022 · 86b30df · 86b30df
2 parents 4396fa9 + e1c7903
commit 86b30df
Show file tree

Hide file tree

Showing 2 changed files with 26 additions and 1 deletion.
diff --git a/test/Test/Universum/Issue208.hs b/test/Test/Universum/Issue208.hs
@@ -0,0 +1,23 @@
+{-# LANGUAGE
+    GeneralizedNewtypeDeriving
+  , UndecidableInstances
+  , FlexibleContexts
+  , GADTs
+  , DerivingStrategies
+  , CPP
+#-}
+module Test.Universum.Issue208
+  () where
+
+#if __GLASGOW_HASKELL__ >= 900
+
+import Universum (Container)
+
+-- In ghc-8.6.3 this code will produce a @redundant constraint@ warning.
+-- In ghc-9.0.2 and newer no warnings would be produced.
+-- Issue #208: https://github.com/serokell/universum/issues/208
+
+newtype Test = Test [Int]
+    deriving newtype (Container)
+
+#endif
diff --git a/universum.cabal b/universum.cabal
@@ -121,7 +121,9 @@ test-suite universum-test
   hs-source-dirs:      test
   main-is:             Spec.hs
 
-  other-modules:       Test.Universum.Property
+  other-modules:
+                       Test.Universum.Issue208
+                       Test.Universum.Property
 
   build-depends:       universum
                      , bytestring