x/tools/cmd/goimports: panic on reading from stdin on Windows

[nasitra]

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

1.8.3

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

windows/amd64

What did you do?

Make the code(hello.go) without importing 'fmt' package

package main

func main() {
  fmt.Println("hello")
}

Then run goimports reading the code from stdin

type hello.go | goimports

What did you expect to see?

Output code text with importing 'fmt' package

package main

import "fmt"

func main() {
        fmt.Println("hello")
}

What did you see instead?

Runtime error occurred.

panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xc0000005 code=0x0 addr=0x8 pc=0x5a2dc1]

goroutine 18 [running]:
golang.org/x/tools/imports.fixImports.func2(0xc04205a0c8, 0xc04202ec00, 0x616eb5, 0x10, 0xc0420311e4, 0x3, 0xc042058e70)
        C:/XXX/go/src/golang.org/x/tools/imports/fix.go:257 +0x41
created by golang.org/x/tools/imports.fixImports
        C:/XXX/go/src/golang.org/x/tools/imports/fix.go:268 +0x676

Because of the error, I can't use goimports in GoSublime for Sublime Text 3 on Windows.

I tried the local change (it works), but it seems that this problem is caused by a different result of dirPackageInfoFile() for stdin between Windows and other platforms.

[gopherbot]

CL https://golang.org/cl/47810 mentions this issue.