<pre class="notranslate">1. What is a short input program that triggers the error?
package foo
type Foo interface {
    X()
}
func Test(f Foo) {
    _ = f.(struct{Foo})
}

package main
import (
    "local/foo"
)

func main() {
    foo.Test(nil)
}


2. What is the full compiler output?
./tst.go:3: impossible type assertion:
    struct {} does not implement foo.Foo (missing X method)
./tst.go:7: internal compiler error: typename &lt;T&gt;


3. What version of the compiler are you using?  (Run it with the -V flag.)

6g version go1.1.2

This might be the same as <a href="https://golang.org/issue/5974" rel="nofollow">issue #5974</a>.</pre>
<pre class="notranslate">Running `go get` on Linux (Ubuntu 12.04) produces errors for go.net/ipv6 dependencies

  $ go get ./...
  
  # code.google.com/p/go.net/ipv6
  code.google.com/p/go.net/ipv6/control_rfc3542_linux.go:83: undefined: syscall.SizeofIPv6MTUInfo
  code.google.com/p/go.net/ipv6/control_rfc3542_linux.go:112: undefined: syscall.SizeofIPv6MTUInfo
  code.google.com/p/go.net/ipv6/control_rfc3542_linux.go:113: undefined: syscall.SizeofIPv6MTUInfo
  code.google.com/p/go.net/ipv6/control_rfc3542_linux.go:142: undefined: syscall.IPv6MTUInfo
  code.google.com/p/go.net/ipv6/icmp.go:30: defer requires function call, not conversion
  code.google.com/p/go.net/ipv6/icmp.go:37: defer requires function call, not conversion
  code.google.com/p/go.net/ipv6/icmp.go:44: defer requires function call, not conversion
  code.google.com/p/go.net/ipv6/icmp_linux.go:10: undefined: syscall.ICMPv6Filter
  code.google.com/p/go.net/ipv6/sockopt_rfc3542_linux.go:13: undefined: syscall.GetsockoptIPv6MTUInfo
  code.google.com/p/go.net/ipv6/sockopt_rfc3542_linux.go:33: undefined: syscall.GetsockoptICMPv6Filter
  code.google.com/p/go.net/ipv6/sockopt_rfc3542_linux.go:33: too many errors</pre>