Shifting an integer value by more than the number of bits in its type always results in -1 for right-shifts of negative values and 0 for other shifts. Hence, such a shift expression is either redundant or indicates a logic mistake.

Examine the length check to see whether it is redundant and can be removed, or a mistake that should be fixed.

The following code snippet attempts to compute the value 2⁴⁰ (1099511627776). However, since the left operand base is of type int32 (32 bits), the shift operation overflows, yielding zero.

To prevent this, the type of base should be changed to int64:

The Go Programming Language Specification: Arithmetic operators.