niltype.go

package main

import (
    "fmt"
    "os"
    "reflect"
)

func main() {
    if len(os.Args) >= 2 && os.Args[1] == "-p" {
        // with -p
        t := reflect.TypeOf((*error)(nil)).Elem()
        fmt.Println(t.Kind())
        return
    }

    t := reflect.TypeOf((error)(nil))
    fmt.Println(t.Kind())
}

result.txt

$ go run niltype.go
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0xa0 pc=0x47b7d7]

goroutine 1 [running]:
main.main()
        ...(omitted).../niltype.go:18 +0x177
exit status 2
$ go run niltype.go -p
interface