diff --git a/graphql.cabal b/graphql.cabal
index 152af00..91a8ff9 100644
--- a/graphql.cabal
+++ b/graphql.cabal
@@ -60,6 +60,7 @@ library
       Language.GraphQL.Validate.Rules
   hs-source-dirs:
       src
+  ghc-options: -Wall
   build-depends:
       aeson
     , base >=4.7 && <5
@@ -98,7 +99,7 @@ test-suite graphql-test
       Paths_graphql
   hs-source-dirs:
       tests
-  ghc-options: -threaded -rtsopts -with-rtsopts=-N
+  ghc-options: -threaded -rtsopts -with-rtsopts=-N -Wall
   build-depends:
       QuickCheck
     , aeson