Most programming languages use ~ to represent a unary bitwise-not operation. Go, by contrast, uses ^:
fmt.Println(^1) // Prints -2
Why did the Go designers decide to break with convention here?
Because ^x is equivalent to m ^ x with m = "all bits set to 1" for unsigned x and m = -1 for signed x. Says so in the spec.
It's similar to how -x is 0 - x