go get GOROOT check is aggressive when GOPATH contains GOROOT files, specifically src/cmd/go/alldocs.go

The offending check is here

Moving the check to an else after the path equality check should solve the issue, altough I'm not sure if this file verification has a concrete reason behind it:

// Guard against people setting GOPATH=$GOROOT.
if filepath.Clean(list[0]) == filepath.Clean(cfg.GOROOT) {
	return fmt.Errorf("cannot download, $GOPATH must not be set to $GOROOT. For more details see: 'go help gopath'")
} else {
	if _, err := os.Stat(filepath.Join(list[0], "src/cmd/go/alldocs.go")); err == nil {
		return fmt.Errorf("cannot download, %s is a GOROOT, not a GOPATH. For more details see: 'go help gopath'", list[0])
	}
}

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

go version go1.8 windows/amd64

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

GOARCH=amd64
GOBIN=
GOEXE=.exe
GOHOSTARCH=amd64
GOHOSTOS=windows
GOOS=windows

What did you do?

While I was configuring my workspaces I made the seemengly innocuous mistake of copying GOROOT files into my GOPATH folder. After that I couldn't download packages anymore

What did you expect to see?

I expected go get to install the desired package into my workspace

What did you see instead?

I get the following error:
cannot download, C:\Users\user\go is a GOROOT, not a GOPATH. For more details see: 'go help gopath'