diff --git a/src/Type/Definition/Type.php b/src/Type/Definition/Type.php
index c4d07fc..69a3789 100644
--- a/src/Type/Definition/Type.php
+++ b/src/Type/Definition/Type.php
@@ -138,8 +138,7 @@ abstract class Type implements \JsonSerializable
      */
     public static function isLeafType($type)
     {
-        $nakedType = self::getNamedType($type);
-        return $nakedType instanceof LeafType;
+        return $type instanceof LeafType;
     }
 
     /**
diff --git a/src/Validator/Rules/ScalarLeafs.php b/src/Validator/Rules/ScalarLeafs.php
index 6da1723..de1f7d6 100644
--- a/src/Validator/Rules/ScalarLeafs.php
+++ b/src/Validator/Rules/ScalarLeafs.php
@@ -25,7 +25,7 @@ class ScalarLeafs
             NodeKind::FIELD => function(FieldNode $node) use ($context) {
                 $type = $context->getType();
                 if ($type) {
-                    if (Type::isLeafType($type)) {
+                    if (Type::isLeafType(Type::getNamedType($type))) {
                         if ($node->selectionSet) {
                             $context->reportError(new Error(
                                 self::noSubselectionAllowedMessage($node->name->value, $type),