private void VisitBinaryArithmetic(BinaryExpression n)
{
var lhs = CheckSubTree(n.Left);
var rhs = CheckSubTree(n.Right);
if (lhs.IsNumeric && rhs.IsNumeric)
{
_lastSeenType = n.InternalType = Supertype(lhs, rhs);
}
else if(lhs.CilType == typeof(DateTime) && rhs.CilType == typeof(DateTime))
{
_lastSeenType = n.InternalType = new TypeSpan();
}
else
{
ReportError(n.Location, "Invalid operands for operation {0}. Got types '{1}' and '{2}'.", n.GetType().ToString(), TypeToFriendlyName(lhs), TypeToFriendlyName(rhs));
}
}
