False positive U1000?

[MaximMolchanov]

Let's say we have two files:

package main

func foo() int {
	return 0
}

func main() {
}

and

//go:build sometag

package main

import (
	"github.com/stretchr/testify/assert"
	"testing"
)

func TestFoo(t *testing.T) {
	assert.Equal(t, 0, foo())
}

Is foo() unused?

$ staticcheck -f binary > tmp1
$ staticcheck -tags=sometag -f binary > tmp2
$ staticcheck -merge tmp1 tmp2
main.go:3:6: func foo is unused (U1000)

But is it?

We can move foo() to the second file, but is it correct to mark it as unused in such case? If yes, then why do we need merge at all?

[MaximMolchanov]

Anyway if we say that if function is used only in tests is still unused, then without tag:

package main

import (
	"github.com/stretchr/testify/assert"
	"testing"
)

func TestFoo(t *testing.T) {
	assert.Equal(t, 0, foo())
}

It also should be unused, right? But it is not:

$ staticcheck 
$ 

[dominikh]

I'll have to investigate this. At first glance the observed behavior in your first comment seems incorrect.