private static void addFacet(
     final ISyntacticElement e,
     final String key,
     final IExpressionDescription expr,
     final Set<Diagnostic> errors) {
   if (e.hasFacet(key)) {
     // if ( key.equals(TYPE) ) {
     // GuiUtils.debug("GamlCompatibilityConverter.addFacet:");
     // }
     addWarning(
         "Double definition of facet " + key + ". Only the last one will be considered",
         e.getElement(),
         errors);
   }
   e.setFacet(key, expr);
 }