What version of Go are you using (go version)?

go version go1.15 windows/amd64

When uint is decreased into negative value, it does not return constant .... overflows int error but instead it will return 18446744073709551615. So there is no overflow guard for unsigned integers.

This works as expected:

fmt.Println(1<<64)

returns error: constant 18446744073709551616 overflows int

this does not:

	var u uint
	fmt.Println(u)
	u--
	fmt.Println(u)

prints
0
18446744073709551615