What version of Go are you using (go version)?

$ go version
1.12

Does this issue reproduce with the latest release?

Yes!

What operating system and processor architecture are you using (go env)?

play.golang.org

What did you do?

package main

import (
	"fmt"
)

type Foo int
func (f Foo) String() (string, error) {
	return "", fmt.Errorf("%v", f)
}

func main() {
	s, err := Foo(1).String()
	fmt.Println(s, err)
}

https://play.golang.org/p/-zpHBBPnetu

What did you expect to see?

No vet output

What did you see instead?

prog.go:9:13: Errorf format %v with arg f causes recursive String method call