union elements in interfaces

gistfile1.txt

jordan@wonkavator[1] ~: cat what.go
package main

import (
	"fmt"
)

type Smallboi interface {
	int8 | int16
}

func blep[T Smallboi](b T) {
	fmt.Println(b)
}

func main() {
	x := int8(12)
	y := int16(15)

	blep(x)
	blep(y)
}
jordan@wonkavator[1] ~: go version
go version go1.17.3 linux/amd64
jordan@wonkavator[1] ~: go run what.go
# command-line-arguments
./what.go:8:7: syntax error: unexpected |, expecting semicolon or newline or }
./what.go:11:6: missing function body
./what.go:11:10: syntax error: unexpected [, expecting (
jordan@wonkavator[1] ~: go1.18 version
go version devel go1.18-91abe4be0e Sat Nov 20 08:47:36 2021 +0000 linux/amd64
jordan@wonkavator[1] ~: go1.18 run what.go
12
15