public override char CheckType()
{
char tmpType = expression.CheckType();
if (tmpType == 'I')
{
tmpType = FindIndentType(((Leaf)expression.assign).value);
}
if (tmpType == 'e' || instruction.CheckType() == 'e')
{
return('e');
}
if (tmpType != 'b')
{
CallAnError(line_number, "Incorrect type of expression. Must be bool");
return('e');
}
return('o');
}