codegen: Guard get_default_ref_sink_function() against null base-class

diff --git a/codegen/valaccodeattribute.vala b/codegen/valaccodeattribute.vala
index 3f12ff5f833e26ea52c64e8a91a37e1cd7ec3b53..1bc7f8ee79dd962623a5ba69d5a8f76678d68efc 100644 (file)
--- a/codegen/valaccodeattribute.vala
+++ b/codegen/valaccodeattribute.vala
@@ -853,7 +853,10 @@ public class Vala.CCodeAttribute : AttributeCache {
 
        private string get_default_ref_sink_function () {
                if (sym is Class) {
-                       return get_ccode_ref_sink_function (((Class) sym).base_class);
+                       unowned Class? base_class = ((Class) sym).base_class;
+                       if (base_class != null) {
+                               return get_ccode_ref_sink_function (base_class);
+                       }
                } else if (sym is Interface) {
                        foreach (var prereq in ((Interface) sym).get_prerequisites ()) {
                                string ref_sink_func = get_ccode_ref_sink_function ((ObjectTypeSymbol) prereq.data_type);