diff --git a/UPGRADE.md b/UPGRADE.md
index 4ba9f44..976a195 100644
--- a/UPGRADE.md
+++ b/UPGRADE.md
@@ -2,7 +2,27 @@
 
 ## Upgrade v0.7.x > v1.0.x
 
-### 1. Protected property and method naming
+### 1. Custom directives handling
+When passing custom directives to schema, default directives (like `@skip` and `@include`) 
+are not added to schema automatically anymore. If you need them - add them explicitly with your other directives
+
+Before the change:
+```php
+$schema = new Schema([
+   // ...
+   'directives' => [$myDirective]
+]);
+```
+
+After the change:
+```php
+$schema = new Schema([
+    // ...
+    'directives' => array_merge(GraphQL::getInternalDirectives(), [$myDirective])
+]);
+```
+
+### 2. Protected property and method naming
 In order to unify coding style, leading underscores were removed from all private and protected properties 
 and methods. 
 
@@ -19,7 +39,7 @@ GraphQL\Schema::$queryType;
 So if you rely on any protected properties or methods of any GraphQL class, make sure to 
 delete leading underscores.
 
-### 2. Returning closure from field resolver
+### 3. Returning closure from field resolver
 Previously when you returned closure from any resolver, expected signature of this closure
 was `function($sourceValue)`, new signature is `function($args, $context)` 
 (now mirrors reference graphql-js implementation)
diff --git a/src/Executor/Values.php b/src/Executor/Values.php
index f4675a2..0300cee 100644
--- a/src/Executor/Values.php
+++ b/src/Executor/Values.php
@@ -234,11 +234,10 @@ class Values
 
         if ($type instanceof ListOfType) {
             $itemType = $type->getWrappedType();
-            // TODO: support iterable input
-            if (is_array($value)) {
-                return array_map(function ($item) use ($itemType) {
+            if (is_array($value) || $value instanceof \Traversable) {
+                return Utils::map($value, function($item) use ($itemType) {
                     return Values::coerceValue($itemType, $item);
-                }, $value);
+                });
             } else {
                 return [self::coerceValue($itemType, $value)];
             }
diff --git a/src/GraphQL.php b/src/GraphQL.php
index 4e25181..ea2e291 100644
--- a/src/GraphQL.php
+++ b/src/GraphQL.php
@@ -6,6 +6,7 @@ use GraphQL\Executor\Executor;
 use GraphQL\Language\AST\Document;
 use GraphQL\Language\Parser;
 use GraphQL\Language\Source;
+use GraphQL\Type\Definition\Directive;
 use GraphQL\Validator\DocumentValidator;
 use GraphQL\Validator\Rules\QueryComplexity;
 
@@ -57,4 +58,12 @@ class GraphQL
             return new ExecutionResult(null, [$e]);
         }
     }
+
+    /**
+     * @return array
+     */
+    public static function getInternalDirectives()
+    {
+        return array_values(Directive::getInternalDirectives());
+    }
 }
diff --git a/src/Language/AST/Document.php b/src/Language/AST/Document.php
index e071555..800f48b 100644
--- a/src/Language/AST/Document.php
+++ b/src/Language/AST/Document.php
@@ -6,7 +6,7 @@ class Document extends Node
     public $kind = Node::DOCUMENT;
 
     /**
-     * @var array<Definition>
+     * @var Definition[]
      */
     public $definitions;
 }
diff --git a/src/Language/SourceLocation.php b/src/Language/SourceLocation.php
index eec2bb3..d09363b 100644
--- a/src/Language/SourceLocation.php
+++ b/src/Language/SourceLocation.php
@@ -1,7 +1,7 @@
 <?php
 namespace GraphQL\Language;
 
-class SourceLocation
+class SourceLocation implements \JsonSerializable
 {
     public $line;
     public $column;
@@ -12,6 +12,9 @@ class SourceLocation
         $this->column = $col;
     }
 
+    /**
+     * @return array
+     */
     public function toArray()
     {
         return [
@@ -19,4 +22,24 @@ class SourceLocation
             'column' => $this->column
         ];
     }
+
+    /**
+     * @return array
+     */
+    public function toSerializableArray()
+    {
+        return $this->toArray();
+    }
+
+    /**
+     * Specify data which should be serialized to JSON
+     * @link http://php.net/manual/en/jsonserializable.jsonserialize.php
+     * @return mixed data which can be serialized by <b>json_encode</b>,
+     * which is a value of any type other than a resource.
+     * @since 5.4.0
+     */
+    function jsonSerialize()
+    {
+        return $this->toSerializableArray();
+    }
 }
diff --git a/src/Schema.php b/src/Schema.php
index 83b05bd..c9996ca 100644
--- a/src/Schema.php
+++ b/src/Schema.php
@@ -12,7 +12,30 @@ use GraphQL\Type\Definition\WrappingType;
 use GraphQL\Type\Introspection;
 
 /**
- * Class Schema
+ * Schema Definition
+ *
+ * A Schema is created by supplying the root types of each type of operation:
+ * query, mutation (optional) and subscription (optional). A schema definition is
+ * then supplied to the validator and executor.
+ *
+ * Example:
+ *
+ *     $schema = new GraphQL\Schema([
+ *       'query' => $MyAppQueryRootType,
+ *       'mutation' => $MyAppMutationRootType,
+ *     ]);
+ *
+ * Note: If an array of `directives` are provided to GraphQL\Schema, that will be
+ * the exact list of directives represented and allowed. If `directives` is not
+ * provided then a default set of the specified directives (e.g. @include and
+ * @skip) will be used. If you wish to provide *additional* directives to these
+ * specified directives, you must explicitly declare them. Example:
+ *
+ *     $mySchema = new GraphQL\Schema([
+ *       ...
+ *       'directives' => array_merge(GraphQL::getInternalDirectives(), [ $myCustomDirective ]),
+ *     ])
+ *
  * @package GraphQL
  */
 class Schema
@@ -119,10 +142,7 @@ class Schema
             "Schema directives must be Directive[] if provided but got " . Utils::getVariableType($config['directives'])
         );
 
-        $this->directives = array_merge($config['directives'], [
-            Directive::includeDirective(),
-            Directive::skipDirective()
-        ]);
+        $this->directives = $config['directives'] ?: GraphQL::getInternalDirectives();
 
         // Build type map now to detect any errors within this schema.
         $initialTypes = [
@@ -222,6 +242,15 @@ class Schema
             foreach ($this->getPossibleTypes($abstractType) as $type) {
                 $tmp[$type->name] = true;
             }
+
+            Utils::invariant(
+                !empty($tmp),
+                'Could not find possible implementing types for $%s ' .
+                'in schema. Check that schema.types is defined and is an array of ' .
+                'all possible types in the schema.',
+                $abstractType->name
+            );
+
             $this->possibleTypeMap[$abstractType->name] = $tmp;
         }
 
diff --git a/src/Type/Definition/Directive.php b/src/Type/Definition/Directive.php
index d815dfa..e5a6887 100644
--- a/src/Type/Definition/Directive.php
+++ b/src/Type/Definition/Directive.php
@@ -7,6 +7,8 @@ namespace GraphQL\Type\Definition;
  */
 class Directive
 {
+    const DEFAULT_DEPRECATION_REASON = 'No longer supported';
+
     /**
      * @var array
      */
@@ -16,6 +18,7 @@ class Directive
      * @var array
      */
     public static $directiveLocations = [
+        // Operations:
         'QUERY' => 'QUERY',
         'MUTATION' => 'MUTATION',
         'SUBSCRIPTION' => 'SUBSCRIPTION',
@@ -23,6 +26,19 @@ class Directive
         'FRAGMENT_DEFINITION' => 'FRAGMENT_DEFINITION',
         'FRAGMENT_SPREAD' => 'FRAGMENT_SPREAD',
         'INLINE_FRAGMENT' => 'INLINE_FRAGMENT',
+
+        // Schema Definitions
+        'SCHEMA' => 'SCHEMA',
+        'SCALAR' => 'SCALAR',
+        'OBJECT' => 'OBJECT',
+        'FIELD_DEFINITION' => 'FIELD_DEFINITION',
+        'ARGUMENT_DEFINITION' => 'ARGUMENT_DEFINITION',
+        'INTERFACE' => 'INTERFACE',
+        'UNION' => 'UNION',
+        'ENUM' => 'ENUM',
+        'ENUM_VALUE' => 'ENUM_VALUE',
+        'INPUT_OBJECT' => 'INPUT_OBJECT',
+        'INPUT_FIELD_DEFINITION' => 'INPUT_FIELD_DEFINITION'
     ];
 
     /**
@@ -43,6 +59,15 @@ class Directive
         return $internal['skip'];
     }
 
+    /**
+     * @return Directive
+     */
+    public static function deprecatedDirective()
+    {
+        $internal = self::getInternalDirectives();
+        return $internal['deprecated'];
+    }
+
     /**
      * @return array
      */
@@ -81,6 +106,25 @@ class Directive
                             'description' => 'Skipped when true'
                         ])
                     ]
+                ]),
+                'deprecated' => new self([
+                    'name' => 'deprecated',
+                    'description' => 'Marks an element of a GraphQL schema as no longer supported.',
+                    'locations' => [
+                        self::$directiveLocations['FIELD_DEFINITION'],
+                        self::$directiveLocations['ENUM_VALUE']
+                    ],
+                    'args' => [
+                        new FieldArgument([
+                            'name' => 'reason',
+                            'type' => Type::string(),
+                            'description' =>
+                                'Explains why this element was deprecated, usually also including a ' .
+                                'suggestion for how to access supported similar data. Formatted ' .
+                                'in [Markdown](https://daringfireball.net/projects/markdown/).',
+                            'defaultValue' => self::DEFAULT_DEPRECATION_REASON
+                        ])
+                    ]
                 ])
             ];
         }
diff --git a/src/Type/Definition/FieldDefinition.php b/src/Type/Definition/FieldDefinition.php
index 4d2bc50..44c380b 100644
--- a/src/Type/Definition/FieldDefinition.php
+++ b/src/Type/Definition/FieldDefinition.php
@@ -149,7 +149,6 @@ class FieldDefinition
     }
 
     /**
-     * @deprecated as of 17.10.2016 in favor of setting 'fields' as closure per ObjectType vs setting on field level
      * @return Type
      */
     public function getType()
diff --git a/src/Type/Definition/InputObjectField.php b/src/Type/Definition/InputObjectField.php
index 98aa8ed..aafe4bc 100644
--- a/src/Type/Definition/InputObjectField.php
+++ b/src/Type/Definition/InputObjectField.php
@@ -39,7 +39,6 @@ class InputObjectField
     }
 
     /**
-     * @deprecated in favor of defining all object 'fields' as closure vs defining closure per field
      * @return mixed
      */
     public function getType()
diff --git a/src/Type/Definition/ResolveInfo.php b/src/Type/Definition/ResolveInfo.php
index e0741c0..6c7c49e 100644
--- a/src/Type/Definition/ResolveInfo.php
+++ b/src/Type/Definition/ResolveInfo.php
@@ -36,6 +36,11 @@ class ResolveInfo
      */
     public $parentType;
 
+    /**
+     * @var array
+     */
+    public $path;
+
     /**
      * @var Schema
      */
diff --git a/src/Type/Definition/UnionType.php b/src/Type/Definition/UnionType.php
index 5fe0966..876e3bb 100644
--- a/src/Type/Definition/UnionType.php
+++ b/src/Type/Definition/UnionType.php
@@ -72,6 +72,11 @@ class UnionType extends Type implements AbstractType, OutputType, CompositeType
     {
         if ($this->types instanceof \Closure) {
             $this->types = call_user_func($this->types);
+            Utils::invariant(
+                is_array($this->types),
+                'Closure for option "types" of union "%s" is expected to return array of types',
+                $this->name
+            );
         }
         return $this->types;
     }
diff --git a/src/Utils.php b/src/Utils.php
index 968842c..a5089a2 100644
--- a/src/Utils.php
+++ b/src/Utils.php
@@ -221,6 +221,31 @@ class Utils
         return is_object($var) ? get_class($var) : gettype($var);
     }
 
+    /**
+     * @param $var
+     * @return string
+     */
+    public static function printSafe($var)
+    {
+        if ($var instanceof Type) {
+            // FIXME: Replace with schema printer call
+            if ($var instanceof WrappingType) {
+                $var = $var->getWrappedType(true);
+            }
+            return $var->name;
+        }
+        if (is_object($var)) {
+            return 'instance of ' . get_class($var);
+        }
+        if (is_scalar($var)) {
+            return (string) $var;
+        }
+        if (null === $var) {
+            return 'null';
+        }
+        return gettype($var);
+    }
+
     /**
      * UTF-8 compatible chr()
      *
diff --git a/tests/Type/DefinitionTest.php b/tests/Type/DefinitionTest.php
index 62f5b5f..5257e88 100644
--- a/tests/Type/DefinitionTest.php
+++ b/tests/Type/DefinitionTest.php
@@ -225,6 +225,54 @@ class DefinitionTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals($sub->name, 'articleSubscribe');
     }
 
+    /**
+     * @it defines an enum type with deprecated value
+     */
+    public function testDefinesEnumTypeWithDeprecatedValue()
+    {
+        $enumTypeWithDeprecatedValue = new EnumType([
+            'name' => 'EnumWithDeprecatedValue',
+            'values' => [
+                'foo' => ['deprecationReason' => 'Just because']
+            ]
+        ]);
+
+        $value = $enumTypeWithDeprecatedValue->getValues()[0];
+
+        $this->assertEquals([
+            'name' => 'foo',
+            'description' => null,
+            'deprecationReason' => 'Just because',
+            'value' => 'foo'
+        ], (array) $value);
+
+        $this->assertEquals(true, $value->isDeprecated());
+    }
+
+    /**
+     * @it defines an object type with deprecated field
+     */
+    public function testDefinesAnObjectTypeWithDeprecatedField()
+    {
+        $TypeWithDeprecatedField = new ObjectType([
+          'name' => 'foo',
+          'fields' => [
+            'bar' => [
+              'type' => Type::string(),
+              'deprecationReason' => 'A terrible reason'
+            ]
+          ]
+        ]);
+
+        $field = $TypeWithDeprecatedField->getField('bar');
+
+        $this->assertEquals(Type::string(), $field->getType());
+        $this->assertEquals(true, $field->isDeprecated());
+        $this->assertEquals('A terrible reason', $field->deprecationReason);
+        $this->assertEquals('bar', $field->name);
+        $this->assertEquals([], $field->args);
+    }
+
     /**
      * @it includes nested input objects in the map
      */
@@ -424,6 +472,21 @@ class DefinitionTest extends \PHPUnit_Framework_TestCase
         Config::disableValidation();
     }
 
+    /**
+     * @it allows a thunk for Union\'s types
+     */
+    public function testAllowsThunkForUnionTypes()
+    {
+        $union = new UnionType([
+            'name' => 'ThunkUnion',
+            'types' => function() {return [$this->objectType]; }
+        ]);
+
+        $types = $union->getTypes();
+        $this->assertEquals(1, count($types));
+        $this->assertSame($this->objectType, $types[0]);
+    }
+
     public function testAllowsRecursiveDefinitions()
     {
         // See https://github.com/webonyx/graphql-php/issues/16
diff --git a/tests/Validator/TestCase.php b/tests/Validator/TestCase.php
index 23f921b..b726d72 100644
--- a/tests/Validator/TestCase.php
+++ b/tests/Validator/TestCase.php
@@ -1,6 +1,7 @@
 <?php
 namespace GraphQL\Tests\Validator;
 
+use GraphQL\GraphQL;
 use GraphQL\Language\Parser;
 use GraphQL\Schema;
 use GraphQL\Type\Definition\Directive;
@@ -291,12 +292,12 @@ abstract class TestCase extends \PHPUnit_Framework_TestCase
 
         $defaultSchema = new Schema([
             'query' => $queryRoot,
-            'directives' => [
+            'directives' => array_merge(GraphQL::getInternalDirectives(), [
                 new Directive([
                     'name' => 'operationOnly',
                     'locations' => [ 'QUERY' ],
                 ])
-            ]
+            ])
         ]);
         return $defaultSchema;
     }