Unused local variables

yourbasic.org/golang

As you may have noticed, programs with unused local variables do not compile.

func main() {
    var n int // “n declared and not used”
    n = 5     // this doesn’t help
}

../main.go:2:6: n declared and not used

This is a deliberate feature of the Go language.

The presence of an unused variable may indicate a bug […] Go refuses to compile programs with unused variables or imports, trading short-term convenience for long-term build speed and program clarity. Go FAQ: Can I stop these complaints about my unused variable/import?

Unused global variables and function arguments are however allowed.

Workaround

There’s no compiler option to allow unused local variables. If you don’t want to remove or comment out the declaration, you can add a dummy assignment.

func main() {
        var n int
        n = 5
        _ = n // n is now "used"
}

Further reading

Learn to love your compiler is a list of common Go compiler error messages: what they mean and how to fix the problem.