Validate directives are unique per location

tests/Language/GraphQL/AST/LexerSpec.hs

@@ -77,7 +77,7 @@ spec = describe "Lexer" $ do
             parse spread "" "..." `shouldParse` "..."
             parse colon "" `shouldSucceedOn` ":"
             parse equals "" "=" `shouldParse` "="
-            parse at "" "@" `shouldParse` "@"
+            parse at "" `shouldSucceedOn` "@"
             runBetween brackets `shouldSucceedOn` "[]"
             runBetween braces `shouldSucceedOn` "{}"
             parse pipe "" "|" `shouldParse` "|"

tests/Language/GraphQL/AST/ParserSpec.hs

@@ -128,7 +128,7 @@ spec = describe "Parser" $ do
         parse document "" `shouldSucceedOn` [r|extend schema { query: Query }|]
 
     it "parses schema extension with an operation type and directive" $
-        let newDirective = Directive "newDirective" []
+        let newDirective = Directive "newDirective" [] $ Location 1 15
             schemaExtension = SchemaExtension
                 $ SchemaOperationExtension [newDirective]
                 $ OperationTypeDefinition Query "Query" :| []