[valadoc] doclets/gtkdoclet: FormalParameter: Fix null ptr warning triggered by generic types

[Florian Brosch <flobrosch src gnome org>]

commit 8e8a9a8f923251aa53f6ffdfe3a11fcec1e243e7
Author: Florian Brosch <flo brosch gmail com>
Date:   Sat Jul 30 14:24:54 2011 +0200

    doclets/gtkdoclet: FormalParameter: Fix null ptr warning triggered by generic types

 src/doclets/gtkdoc/generator.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/doclets/gtkdoc/generator.vala b/src/doclets/gtkdoc/generator.vala
index ed90599..b1a1028 100755
--- a/src/doclets/gtkdoc/generator.vala
+++ b/src/doclets/gtkdoc/generator.vala
@@ -682,7 +682,7 @@ It is important that your <link linkend=\"GValue\"><type>GValue</type></link> ho
 				null, get_parameter_pos (current_method_or_delegate, param_name)+0.1);
 		}
 
-		if (!param.ellipsis && get_cname (param.parameter_type.data_type) == "GError") {
+		if (!param.ellipsis && param.parameter_type.data_type != null && get_cname (param.parameter_type.data_type) == "GError") {
 			annotations += "not-error";
 		}