Protected method not ignored when searching for extension method

[david04]

Compiler version

3.5.2

Minimized code

class C
object Implicits {
  implicit class RichC1(c: C) {
    // Please notice the protected:
    protected def m(): Unit = println("foo")
  }
  implicit class RichC2(c: C) {
    def m(): Unit = println("bar")
  }
}
object Sample {
  import Implicits._
  val c = new C
  c.m()
}

Output

Found:    (Playground.Sample.c : Playground.C)
Required: ?{ m: ? }
Note that implicit extension methods cannot be applied because they are ambiguous;
both method RichC1 in object Implicits and method RichC2 in object Implicits provide an extension method `m` on (Playground.Sample.c : Playground.C)

Expectation

should compile

[SethTisue]

Even if it's technically a bug, I'm curious what the intent behind this code is. Why would an implicit class even have a protected method?

One thing we do on bug tickets is discuss workarounds, but I'm not sure what to suggest without understanding the intent.

[david04]

In the end I refactored the code to work around it - it was because both implicit classes had similar behaviours and had the same method, needed for internal purposes of the implicit class, one of them was offering it to the outside as public. Again, with a little refactoring I managed to workaround it - I think the most tricky part is actually to come to the conclusion that the compilation issue is something in the compiler and not some logic bug around implicits in our code.