Language: Python
Label: safe
CWE: CWE-682 \u2014 Incorrect Calculation
The product performs a calculation that generates incorrect or unintended results that are later used in security-critical decisions or resource management.

Code:
    def allocate_slot(self, n, var_name):
        ret = self._slot
        if self._slot + n >= 2**256:
            raise StorageLayoutException(
                f"Invalid storage slot for var {var_name}, tried to allocate"
                f" slots {self._slot} through {self._slot + n}"
            )
        self._slot += n
        return ret