shopdi

Any call of the form `transferFrom(from, dest, amount)` with a value for amount that exceeds the balance of address from is expected to fail. However, in Token, some invocations of `transferFrom(from, dest, amount)` succeed even though the value in amount exceeds the available balance for address from. This is only marked minor however, as the balance is not increased. Here is an example: - TokenStrategy is set to a new EOA, but is not set to be tax exempt. - Assume that TokenStrategy has a balance of 1000 tokens. - Assume that the current tax rate is 1%. - Then if TokenStrategy calls `transfer(TokenStrategy,1010)` it will succeed when it should fail. - Similarly if msg.sender has sufficient approval and calls `transferFrom(TokenStrategy,TokenStrategy,1010)` it will succeed when it should fail. The issue is that first the tax is taken and then the amount. However, since the tax is given to the same address, the balance is not decreased so that as long as the amount after tax is less than the accounts balance the call will succeed.