net.Dial fails with an ip6 addres - connect: invalid argument

[krasi-georgiev]

go version
go version go1.15.5 linux/amd64

go env
GO111MODULE="on"
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/krasi/.cache/go-build"
GOENV="/home/krasi/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/krasi/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/krasi"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/krasi/src/github.com/arribada/i360/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build769533656=/tmp/go-build -gno-record-gcc-switches"

running the code below results in

2021/01/27 11:13:51 dial tcp [fe80::42:f1ff:feef:7dc8]:8080: connect: invalid argument
exit status 1

I tried all sort of combination but any ip6 address returns with an error invalid argument (except [::]:8080

package main

import (
	"bufio"
	"fmt"
	"log"
	"net"
	"time"
)

func main() {

	go func() {
		ln, err := net.Listen("tcp", ":8080")
		if err != nil {
			log.Print(err)
			// handle error
		}
		for {
			conn, err := ln.Accept()
			if err != nil {
				log.Print(err)
				// handle error
			}
			fmt.Println("conn", conn)
			// go handleConnection(conn)
		}
	}()

	time.Sleep(100 * time.Millisecond)

	conn, err := net.Dial("tcp", "[fe80::42:f1ff:feef:7dc8]:8080")
	if err != nil {
		log.Fatal(err)
		// handle error
	}
	fmt.Fprintf(conn, "GET / HTTP/1.0\r\n\r\n")
	status, err := bufio.NewReader(conn).ReadString('\n')
	log.Print(err.Error())
	fmt.Println("status", status)
}

 ifconfig

wlp4s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.0.105  netmask 255.255.255.0  broadcast 192.168.0.255
        inet6 fe80::7fef:8789:78f1:aeda  prefixlen 64  scopeid 0x20<link>
        ether d4:25:8b:b6:6a:e8  txqueuelen 1000  (Ethernet)
        RX packets 438123553  bytes 317785644433 (317.7 GB)
        RX errors 0  dropped 2  overruns 0  frame 0
        TX packets 474445465  bytes 191400554283 (191.4 GB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[seankhliao]

For questions please refer to https://github.com/golang/go/wiki/Questions

[krasi-georgiev]

Why did you think it is a question?
I am following the official docs and I would either consider the docs incorrect or there is a bug.

[seankhliao]

the address you used is link local and requires an interface name, which would've been apparent if you tried to search for the error

[krasi-georgiev]

yes I did search quite a bit, but apparently overlooked this detail.
Sorry for the noise and for anyone else coming to the same issue here is the answer
conn, err := net.Dial("tcp", "[fe80::42:f1ff:feef:7dc8%wlp4s0]:8080")