In Go, constants donโt have types. In constant expressions, -1 really is just the conceptual value, -1. The set of allowed values for a uint32 is [0, 2^32) and -1 is not in that set. It looks like you wanted a uint32 with all bits set to 1s. Two easy ways to do that in Go are:

const (
b0 = uint32(math.MaxUint32) // pre-defined constant
b1 = ^uint32(0) // invert the bits of a uint32 0
)