diff --git a/wp-includes/post.php b/wp-includes/post.php
index 6a4d62c15d..334a0b8c0c 100644
--- a/wp-includes/post.php
+++ b/wp-includes/post.php
@@ -5106,9 +5106,10 @@ function wp_attachment_is( $type, $post_id = 0 ) {
 
 	case 'video':
 		return in_array( $ext, wp_get_video_extensions() );
-	}
 
-	return false;
+	default:
+		return $type === $ext;
+	}
 }
 
 /**
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 4f029931b5..29c9ba0589 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.2-alpha-31645';
+$wp_version = '4.2-alpha-31646';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.