diff --git a/src/Error/Warning.php b/src/Error/Warning.php
index 0d2e299..1ebf329 100644
--- a/src/Error/Warning.php
+++ b/src/Error/Warning.php
@@ -3,21 +3,39 @@ namespace GraphQL\Error;
 
 final class Warning
 {
-    static $supressWarnings = false;
+    const NAME_WARNING = 1;
+    const ASSIGN_WARNING = 2;
+    const CONFIG_WARNING = 4;
+
+    const ALL = self::NAME_WARNING | self::ASSIGN_WARNING | self::CONFIG_WARNING;
+
+    static $enableWarnings = self::ALL;
 
     static $warned = [];
 
-    static function supress($set = true)
+    static function suppress($suppress = true)
     {
-        self::$supressWarnings = $set;
+        if (true === $suppress) {
+            self::$enableWarnings = 0;
+        } else if (false === $suppress) {
+            self::$enableWarnings = self::ALL;
+        } else {
+            $suppress = (int) $suppress;
+            self::$enableWarnings &= ~$suppress;
+        }
     }
 
-    static function warnOnce($errorMessage, $errorId = null)
+    static function warnOnce($errorMessage, $warningId)
     {
-        $errorId = $errorId ?: $errorMessage;
+        if ((self::$enableWarnings & $warningId) > 0 && !isset(self::$warned[$warningId])) {
+            self::$warned[$warningId] = true;
+            trigger_error($errorMessage, E_USER_WARNING);
+        }
+    }
 
-        if (!self::$supressWarnings && !isset(self::$warned[$errorId])) {
-            self::$warned[$errorId] = true;
+    static function warn($errorMessage, $warningId)
+    {
+        if ((self::$enableWarnings & $warningId) > 0) {
             trigger_error($errorMessage, E_USER_WARNING);
         }
     }
diff --git a/src/Type/Definition/Config.php b/src/Type/Definition/Config.php
index 9cc8fa5..1ddcda1 100644
--- a/src/Type/Definition/Config.php
+++ b/src/Type/Definition/Config.php
@@ -2,6 +2,7 @@
 namespace GraphQL\Type\Definition;
 
 use GraphQL\Error\InvariantViolation;
+use GraphQL\Error\Warning;
 use GraphQL\Utils;
 
 /**
@@ -127,7 +128,10 @@ class Config
 
         if (!empty($unexpectedKeys)) {
             if (!self::$allowCustomOptions) {
-                trigger_error(sprintf('Error in "%s" type definition: Non-standard keys "%s" ' . $suffix, $typeName, implode(', ', $unexpectedKeys)));
+                Warning::warnOnce(
+                    sprintf('Error in "%s" type definition: Non-standard keys "%s" ' . $suffix, $typeName, implode(', ', $unexpectedKeys)),
+                    Warning::CONFIG_WARNING
+                );
             }
             $map = array_intersect_key($map, $definitions);
         }
diff --git a/src/Utils.php b/src/Utils.php
index ce3ec61..252c9c0 100644
--- a/src/Utils.php
+++ b/src/Utils.php
@@ -34,7 +34,10 @@ class Utils
         foreach ($vars as $key => $value) {
             if (!property_exists($obj, $key)) {
                 $cls = get_class($obj);
-                trigger_error("Trying to set non-existing property '$key' on class '$cls'");
+                Warning::warn(
+                    "Trying to set non-existing property '$key' on class '$cls'",
+                    Warning::ASSIGN_WARNING
+                );
             }
             $obj->{$key} = $value;
         }
@@ -356,7 +359,7 @@ class Utils
                 'Name "'.$name.'" must not begin with "__", which is reserved by ' .
                 'GraphQL introspection. In a future release of graphql this will ' .
                 'become an exception',
-                'warnAboutDunder'
+                Warning::NAME_WARNING
             );
         }
 
diff --git a/tests/Type/ConfigTest.php b/tests/Type/ConfigTest.php
index 103c5fb..8ab3622 100644
--- a/tests/Type/ConfigTest.php
+++ b/tests/Type/ConfigTest.php
@@ -643,7 +643,7 @@ class ConfigTest extends \PHPUnit_Framework_TestCase
                 ['test' => Config::STRING]
             );
             $this->fail('Expected exception not thrown');
-        } catch (\PHPUnit_Framework_Error_Notice $e) {
+        } catch (\PHPUnit_Framework_Error_Warning $e) {
             $this->assertEquals(
                 $this->typeError('Non-standard keys "test2" '),
                 $e->getMessage()