public override void CheckSemantics(Scope scope, List <SemanticError> errors)
{
Operand.CheckSemantics(scope, errors);
if (Operand.Type != Types.Int)
{
errors.Add(SemanticError.InvalidUseOfOperator(
"unary minus", Operand.Type.Equals(Types.Nil) ? "valued" : "integer", "operand", Operand));
}
}
