feat: Basic implementation of traits

[yordanmadzhunkov]

Description

Make the most basic test case for traits execute correctly. Although this review looks big, it's mostly test code.

Next step will be to refactor tests in resolver, so I can add more unit tests and move the errors from Def Collecter to Resolver.

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

After this PR this noir programs work:

Execution of specialized for the specific type:

trait Default {
    fn default(x: Field, y: Field) -> Self;
    fn method2(x: Field) -> Field {
	x
    }
}

struct Foo {
    bar: Field,
    array: [Field; 2],
}

impl Default for Foo {
    fn default(x: Field,y: Field) -> Self {
        Self { bar: x, array: [x,y] }
    }

    fn method2(x: Field) -> Field {
	x * 3
    }
}

fn main(x: Field) {
    let first = Foo::method2(x);
    assert(first == 3 * x);
}

Execution of trait provided default implementation

trait Default {
    fn default(x: Field, y: Field) -> Self;
    fn method2(x: Field) -> Field {
	x
    }
}

struct Foo {
    bar: Field,
    array: [Field; 2],
}

impl Default for Foo {
    fn default(x: Field,y: Field) -> Self {
        Self { bar: x, array: [x,y] }
    }
}

fn main(x: Field) {
    let first = Foo::method2(x);
    assert(first == x);
}

For more examples refer to tests added in this PR

[yordanmadzhunkov]

@jfecher Have a nice weekend :)

[jfecher]

Just a few more small suggestions

[jfecher]

Looks like you've got some import errors

[Savio-Sou]

Does this close #527?

[Savio-Sou]

@yordanmadzhunkov would you like to take a jab at documenting this PR? #3193

[yordanmadzhunkov]

Sure, we will document traits, but for now I prefer to focus on testing/bug fixing, before documentation.

[jfecher]

@Savio-Sou we're avoiding documenting traits until they're complete. We don't want users to be thinking they're in the language yet. There's also a compiler warning when using them to alert users they're still in development. This PR is just one in a series since traits are a large feature we need to break up into many PRs.

[Savio-Sou]

Thanks for the clarification @jfecher!

Do we have a list of the intermediate Issues that'd get us to completion? Would be great if you could help add a tasklist on #527 if not. Feel free to edit the Issue directly!

[jfecher]

@Savio-Sou I believe @yordanmadzhunkov and his team is currently working on such a list.

[signorecello]

@yordanmadzhunkov I'm documenting traits in the Noir docs. Will add you as a reviewer if you don't mind!

[yordanmadzhunkov]

@signorecello
Do it :)