[gxml] Parser: improve error on collection initialization

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit 36750ef6ca7bfb4502ecd3c64b60497fa79060c5
Author: Daniel Espinosa <esodan gmail com>
Date:   Tue Jul 9 14:19:49 2019 -0500

    Parser: improve error on collection initialization

 gxml/Parser.vala | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/gxml/Parser.vala b/gxml/Parser.vala
index 409675f..3012e63 100644
--- a/gxml/Parser.vala
+++ b/gxml/Parser.vala
@@ -250,19 +250,19 @@ public interface GXml.Parser : GLib.Object {
       if (col.items_type == GLib.Type.INVALID
           || !(col.items_type.is_a (typeof (GXml.Object)))) {
         throw new DomError.INVALID_NODE_TYPE_ERROR
-                    (_("Invalid object type set to Collection"));
+                    (_("Collection '%s' hasn't been constructed properly: items type propeerty was not set 
at construction time or set to invalid type"), col.get_type ().name ());
       }
       if (col.items_name == "" || col.items_name == null) {
         throw new DomError.INVALID_NODE_TYPE_ERROR
-                    (_("Invalid DomElement name for objects in Collection"));
+                    (_("Collection '%s' hasn't been constructed properly: items' name property was not set 
at construction time"), col.get_type ().name ());
       }
       if (col.element == null || !(col.element is GXml.Object)) {
         throw new DomError.INVALID_NODE_TYPE_ERROR
-                    (_("Collection hasn't been constructed properly: element property was not set at 
construction time"));
+                    (_("Collection '%s' hasn't been constructed properly: element property was not set at 
construction time"), col.get_type ().name ());
       }
       if (!(col.element is GXml.Object)) {
         throw new DomError.INVALID_NODE_TYPE_ERROR
-                    (_("Invalid object's type '%s' it doesn't implemement GXml.Object interface: can't be 
handled by the collection"), col.element.get_type ().name ());
+                    (_("Invalid object of type '%s' doesn't implemement GXml.Object interface: can't be 
handled by the collection"), col.element.get_type ().name ());
       }
       if (col.items_name.down () == current_node_name ().down ()) {
         if (parent.owner_document == null)