Private trait methods should be available to types that implement them

[yorickpeterse]

When a class implements a trait that provides private methods, these methods should be available to the class, regardless of what module/namespace the trait is defined in. This removes the need for making such methods public in order to use them, which in turn prevents leaking of implementation details.

[bartlomieju]

I'm having trouble reproducing it:

mkdir -p /tmp/test
cd /tmp/test
mkdir -p src/greet
mkdir -p src/person
echo 'trait pub Greet {
  fn greet -> String
}' > src/greet/a.inko
echo 'import greet.a.Greet

class Person {
  let @greeting: String
}

impl Greet for Person {
  fn greet -> String {
    @greeting
  }
}' > src/person/b.inko
inko check

There's no error raised here. I'm probably missing some context here...

[yorickpeterse]

@bartlomieju I don't remember what the original way to reproduce this was. I wouldn't be surprised if making private symbols namespace private (instead of module private) fixed part of this.

However, the following still fails:

# src/foo.inko
trait pub Foo {
  fn foo {
    42
  }
}

# src/bar.inko
import foo.Foo

class Bar {
  fn baz {}
}

impl Foo for Bar {}

fn example(value: Bar) {
  value.foo
}

This fails with:

src/bar.inko:10:3 error(invalid-call): the method 'foo' exists but is private

If the method foo is defined directly on Bar (as private) it works fine. The problem here is that trait methods added to a class use the same ModuleId as the module they're defined in. The fix is probably to just get the ModuleId of the class the method is defined on, and then use that, though I'm not entirely sure that's all that's needed.