Compile of method call on interface fails with "too many arguments to call Method (1:1)"

[enijns]

Using expr.Eval seems to work fine though.
I will also submit the following example as a pull request:

`type AnInterface interface {
Method(x string) []AnInterface
}

type A struct{ I int }

func (self A) Method(x string) []AnInterface {
return []AnInterface{self}
}

func ExampleCompileInterfaceMethodCall() {

type B_Env struct{ Ai AnInterface }

env := B_Env{A{6}}

prog, err := expr.Compile(`Ai.Method("x")`, expr.Env(env))

if err != nil {
	fmt.Printf("%v", err)
	return
}

output, err := expr.Run(prog, env)

if err != nil {
	fmt.Printf("%v", err)
	return
}

fmt.Printf("%v", output)

// Output: 6

}`

[antonmedv]

Fixed in 9c096db