fix(frontend): Call trait method with mut self from generic definition

[vezenovm]

Description

Problem*

Resolves

Not sure if there is another issue for this I will have to look again, but I found this bug when trying to implement #4514

Summary*

When type checking a MethodCall from the HIR now we also add a mutable reference to the object type when we have a HirMethodReference::TraitMethodId. We were previously only doing this for a HirMethodReference::FuncId.

For example that meant this program would fail with the following errors laid out in the comments:

fn hash_simple_array<H>(input: [Field; 2]) -> Field where H: Hasher + Default {
    // Check that we can a trait method to instead a trait implementation
    let mut hasher: H = H::default();
    // Regression that the object is converted to a mutable reference type `&mut _`.
    // Otherwise will see `Expected type &mut _, found type H`.
    // Then we need to make sure to also auto dereference later in the type checking process
    // when searching for a matching impl or else we will get `No matching impl found for `&mut H: Hasher`
    hasher.write(input[0]);
    hasher.write(input[1]);
    hasher.finish()
}

I also had to add auto dereferencing when verifying the trait constraints later inside of type_check_func. So first we add a mutable reference to the method call's object type to avoid a mismatched type error, and then we later dereference it to find the appropriate trait implementation.

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.

Comments were resolved but was not approved again