False positive when wrapping errors

A minimal example:

The wrap function returns nil if the error passed to it is nil. The test function will only call wrap and pass err if err is not nil.

func wrap(msg string, err error) error {
    if err == nil {
        return nil
    }
    return errors.New(msg)
}

func test() (*string, error) {
    var err error
    if err != nil {
        return nil, wrap("failed to read file", err)
    }
    s := "qwe"
    return &s, nil
}

func main() {
    b, err := test()
    if err != nil {
        log.Fatal(err)
    }
    _ = *b
}

nilaway reports a potential nil panic:

error: Potential nil panic detected. Observed nil flow from source to dereference point: 
        - nilaway/main.go:18:10: literal `nil` returned from `test()` in position 0 when the error return in position 1 is not guaranteed to be non-nil through all paths
        - nilaway/main.go:29:7: result 0 of `test()` dereferenced via the assignment(s):
                - `test()` to `b` at nilaway/main.go:25:2

uber-go / nilaway

False positive when wrapping errors #276