diff --git a/.travis.yml b/.travis.yml
index 48edc458..217680f3 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -13,8 +13,7 @@ before_script:
 
 script:
   - vendor/bin/phpunit --coverage-clover build/logs/clover.xml
-  # Allow phpstan failures until we've fixed the majority of them
-  - composer analyze || true
+  - composer analyze
 
 after_success:
  - wget https://github.com/php-coveralls/php-coveralls/releases/download/v1.0.1/coveralls.phar -O coveralls.phar
diff --git a/composer.json b/composer.json
index d7fe0ab2..272fb546 100644
--- a/composer.json
+++ b/composer.json
@@ -42,7 +42,7 @@
             "phpunit"
         ],
         "analyze": [
-            "phpstan analyse -l 7 src/ tests/"   
+            "phpstan analyse -l 1 src/ tests/"   
         ]
     },
     "autoload-dev": {
diff --git a/src/Execution/ExecutionArguments.php b/src/Execution/ExecutionArguments.php
index 048eee7e..e4ec93f1 100644
--- a/src/Execution/ExecutionArguments.php
+++ b/src/Execution/ExecutionArguments.php
@@ -29,7 +29,7 @@ class ExecutionArguments
     protected $contextValue;
 
     /**
-     * @var []
+     * @var array
      */
     protected $variableValues;
 
@@ -49,18 +49,18 @@ class ExecutionArguments
      * @param DocumentNode            $document
      * @param mixed                   $rootValue
      * @param mixed                   $contextValue
-     * @param                         $variableValues
+     * @param array                   $variableValues
      * @param OperationDefinitionNode $operation
      * @param mixed                   $fieldResolver
      */
     public function __construct(
         Schema $schema,
         DocumentNode $document,
-        mixed $rootValue,
-        mixed $contextValue,
-        $variableValues,
+        $rootValue,
+        $contextValue,
+        array $variableValues,
         OperationDefinitionNode $operation,
-        mixed $fieldResolver
+        $fieldResolver
     ) {
         $this->schema         = $schema;
         $this->document       = $document;
diff --git a/src/Language/AST/Schema/DefinitionBuilder.php b/src/Language/AST/Schema/DefinitionBuilder.php
index de62a251..39092967 100644
--- a/src/Language/AST/Schema/DefinitionBuilder.php
+++ b/src/Language/AST/Schema/DefinitionBuilder.php
@@ -28,6 +28,7 @@
 use Digia\GraphQL\Type\Definition\ScalarType;
 use Digia\GraphQL\Type\Definition\TypeInterface;
 use Digia\GraphQL\Type\Definition\UnionType;
+use function Digia\GraphQL\Type\introspectionTypes;
 use Psr\SimpleCache\CacheInterface;
 use function Digia\GraphQL\Execution\getDirectiveValues;
 use function Digia\GraphQL\Language\valueFromAST;
@@ -76,7 +77,7 @@ public function __construct(callable $resolveTypeFunction, CacheInterface $cache
         $this->resolveTypeFunction = $resolveTypeFunction;
 
         $builtInTypes = keyMap(
-            array_merge(specifiedScalarTypes()/*, introspectionTypes()*/),
+            array_merge(specifiedScalarTypes(), introspectionTypes()),
             function (NamedTypeInterface $type) {
                 return $type->getName();
             }
diff --git a/src/Language/Parser.php b/src/Language/Parser.php
index 53fd6394..2d99875c 100644
--- a/src/Language/Parser.php
+++ b/src/Language/Parser.php
@@ -173,7 +173,7 @@ protected function expectKeyword(LexerInterface $lexer, string $value): Token
             return $token;
         }
 
-        throw new SyntaxError(sprintf('Expected %s, found ${getTokenDesc(token)}', $value, $token));
+        throw new SyntaxError(sprintf('Expected %s, found %s', $value, $token));
     }
 
     /**