The go-compiler reports variable declared but not used when using pointers-CodePudding

I have a snippet of code that i am unable to understand why the go compiler is reporting that a variable is declared but not used:

package main
import "fmt"
func main() {
    var StringSlice []*string
    
    MyStr0 := "Zero"
    StringSlice = append(StringSlice, &MyStr0)
    MyStr1 := "One"
    StringSlice = append(StringSlice, &MyStr1)
    MyStr2 := "Two"
    StringSlice = append(StringSlice, &MyStr2)

    var StrPtr *string
    for i, Value := range StringSlice {
        fmt.Println(Value)
        if i == 1 {
            StrPtr = Value
        }
    } // END for

With the Printf statement commented out, the go compiler claims »./prog.go:15:6: StrPtr declared but not used« - see the example in the go-playground at: https://go.dev/play/p/J3p4NDR6fBm When the Printf is commented out, everything is fine and there's even the correct string-pointer stored in StrPtr… Thank you very much in advance for your help!

CodePudding user response：

The problem is that you are not using StrPtr. You are reassigning it, but it is never read. If you add that to a Printf statement the error will go away.

package main
import "fmt"
func main() {
    var StringSlice []*string

    MyStr0 := "Zero"
    StringSlice = append(StringSlice, &MyStr0)
    MyStr1 := "One"
    StringSlice = append(StringSlice, &MyStr1)
    MyStr2 := "Two"
    StringSlice = append(StringSlice, &MyStr2)

    var StrPtr *string
    for i, Value := range StringSlice {
        fmt.Println(Value)
        if i == 1 {
            StrPtr = Value
            fmt.Println(StrPtr) // <--- add this
        }
    } // END for
}