[anjuta] language-support-vala: remove remaining critical warnings

[Johannes Schmid <jhs src gnome org>]

commit 154e83e044f18c2c966dc0771830fa90ff23d047
Author: Abderrahim Kitouni <a kitouni gmail com>
Date:   Sat Aug 7 18:39:20 2010 +0100

    language-support-vala: remove remaining critical warnings

 plugins/language-support-vala/plugin.vala |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/plugins/language-support-vala/plugin.vala b/plugins/language-support-vala/plugin.vala
index 58e0355..59dc3bb 100644
--- a/plugins/language-support-vala/plugin.vala
+++ b/plugins/language-support-vala/plugin.vala
@@ -230,9 +230,13 @@ public class ValaPlugin : Plugin {
 		}
 		return matching_symbols;
 	}
-	List<Vala.Symbol> symbol_lookup_inherited (Vala.Symbol sym, string name, bool prefix_match, bool invocation = false) {
+	List<Vala.Symbol> symbol_lookup_inherited (Vala.Symbol? sym, string name, bool prefix_match, bool invocation = false) {
 		List<Vala.Symbol> result = null;
 
+		// This may happen if we cannot find all the needed packages
+		if (sym == null)
+			return result;
+
 		var symbol_table = sym.scope.get_symbol_table ();
 		if (symbol_table != null) {
 			foreach (string key in symbol_table.get_keys()) {