@Check
 public void checkExpression(TimeEventSpec expression) {
   typeInferrer.inferType(expression, this);
 }
 @Check
 public void checkExpression(Guard expression) {
   typeInferrer.inferType(expression, this);
 }
 @Check
 public void checkExpression(VariableDefinition expression) {
   if (expression.getType() == null || expression.getType().eIsProxy()) return;
   typeInferrer.inferType(expression, this);
 }