Description

Problem

Resolves #6519

Summary

This is a breaking change because this code used to compile:

trait Foo {
  fn foo(self) -> Field {
    self.x
  }
}

That is, you could access a member of self in a trait method. Because the trait default method was checked against the actual concrete type, if it had a member x it compiled fine. Now that code is rejected (like in Rust). And... we have code like that in Aztec-Packages.

Additional Context

Documentation

Check one:

• No documentation needed.
• Documentation included in this PR.
• [For Experimental Features] Documentation to be submitted in a separate PR.

PR Checklist

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