cmd/vet: false positive about wrong argument for verb

[octomarat]

Please answer these questions before submitting your issue. Thanks!

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

go1.9.3 darwin/amd64

Does this issue reproduce with the latest release?

Yes

What did you do?

Run go vet on the following file:

package main

import "fmt"

type T int

func (t T) String() string { return "t" }

func main() {
	fmt.Printf("%s", [1]T{0})
	fmt.Printf("%s", []T{0})
}

What did you expect to see?

No errors.

What did you see instead?

For the first line go vet reports arg [1]T{0} for printf verb %s of wrong type: [1]main.T. This is false positive as file executes normally and prints [t][t].

[mvdan]

Thank you for taking the time to file these!

[gopherbot]

Change https://golang.org/cl/90455 mentions this issue: cmd/vet: %s is valid for an array of stringer