V: Cannot compile program contains interface that implemented by pointer type

[shouji-kazuo]

I found a bug while playing Vlang playground.

Steps to reproduce:

1. Enter program list:

interface Speaker {
  speak() string
}

struct Foobar{}

fn (f mut Foobar) speak() string {
  return 'I am foobar'
}

fn printSpeaker(s Speaker) {
  println(s.speak())
}

fn main() {
  // I think f's type is pointer to Foobar.
  // (and I assumed that f implement Speaker interface)
  f := &Foobar{}

  // I assumed like above, then I think f can be passed as printSpeaker()'s argument.
  printSpeaker(f)
}

1. Click Run Button
2. I got output as below:
   You just found a bug. V can't compile this program, but it should. Please create a GitHub issue.

(Maybe my English is something wrong. sorry.)

[medvednikov]

Thanks for reporting, this will take a bit more time to fix. Interfaces don't work with mutable receivers right now.

[AlexDyukov]

Looks like error raises not only with pointers. This code works well:

interface Speaker {
  speak() string
}

struct Foobar{}

fn (f Foobar) speak() string{
  return 'I am foobar'
}

fn main() {
  f := Foobar{}
  println(f.speak())
}

but this one dont:

interface Speaker {
  speak() string
}

struct Foobar{}

fn (f Foobar) speak() string{
  return 'I am foobar'
}

fn print_speaker(s Speaker) {
  println(s.speak())
}

fn main() {
  f := Foobar{}
  print_speaker(f)
}

[lutherwenxu]

Extension of #73.