Autocomplete self's attributes and methods

[echebbi]

Current behavior

The Xtext editor's autocomplete does not suggest anything (accurate) after typing self.:

Desired behavior

The editor autocompletes with the name of available attributes and methods.

Example

Given (| represents the cursor):

open class HelloWorld {

    @main
    def void main () {
        self.say|
    }

    def void sayHello() {
        'hello'.log();
    }
}

Hitting CTRL+Space would show available attributes/methods, and completes the code when the user selects one:

open class HelloWorld {

    @main
    def void main () {
        self.sayHello();|
    }

    def void sayHello() {
        'hello'.log();
    }
}