diff --git a/lib/PhpParser/Node/Expr/ShellExec.php b/lib/PhpParser/Node/Expr/ShellExec.php
index 23d0257..f0adf3e 100644
--- a/lib/PhpParser/Node/Expr/ShellExec.php
+++ b/lib/PhpParser/Node/Expr/ShellExec.php
@@ -15,7 +15,7 @@ class ShellExec extends Expr
      * @param array $parts      Encapsed string array
      * @param array $attributes Additional attributes
      */
-    public function __construct($parts, array $attributes = array()) {
+    public function __construct(array $parts, array $attributes = array()) {
         parent::__construct(null, $attributes);
         $this->parts = $parts;
     }
diff --git a/lib/PhpParser/Node/Param.php b/lib/PhpParser/Node/Param.php
index 147568f..e96eb03 100644
--- a/lib/PhpParser/Node/Param.php
+++ b/lib/PhpParser/Node/Param.php
@@ -28,7 +28,7 @@ class Param extends NodeAbstract
      * @param bool             $variadic   Whether this is a variadic argument
      * @param array            $attributes Additional attributes
      */
-    public function __construct($name, $default = null, $type = null, $byRef = false, $variadic = false, array $attributes = array()) {
+    public function __construct($name, Expr $default = null, $type = null, $byRef = false, $variadic = false, array $attributes = array()) {
         parent::__construct(null, $attributes);
         $this->type = $type;
         $this->byRef = $byRef;