[ruff] Resolve type alias for annotations (RUF012)

[vladNed]

Summary

Check on mutable class default was not resolving the annotation that was a type alias thus the default values might have been flagged as mutable.

Added a helper function similar to map_subscript in order to check bindings on annotation to resolve to the final type.

Resolves #16174

Test Plan

• Checked with type aliases with both mutable and immutable
• Checked the original behavior was intact.

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.

[vladNed]

figured that there should be a loop for type inference to resolve until final if a alias is mapped to another alias.

[vladNed]

added a small improvement, should be good for review now

[dhruvmanila]

I think we can avoid the clone here

Suggested change

	let Some(expr_name) = expr.clone().name_expr() else {
	let Some(expr_name) = expr.as_name_expr() else {

[dhruvmanila]

Should we use find_assigned_value instead? This will only look in the current scope and will work with forward references as well.

ruff/crates/ruff_python_semantic/src/analyze/typing.rs

Lines 1137 to 1151 in f58a54f

	/// Find the assigned [`Expr`] for a given symbol, if any.
	///
	/// For example given:
	/// ```python
	/// foo = 42
	/// (bar, bla) = 1, "str"
	/// ```
	///
	/// This function will return a `NumberLiteral` with value `Int(42)` when called with `foo` and a
	/// `StringLiteral` with value `"str"` when called with `bla`.
	pub fn find_assigned_value<'a>(symbol: &str, semantic: &'a SemanticModel<'a>) -> Option<&'a Expr> {
	let binding_id = semantic.lookup_symbol(symbol)?;
	let binding = semantic.binding(binding_id);
	find_binding_value(binding, semantic)
	}

[vladNed]

@dhruvmanila I tested with find_assigned_value but its not fixing the forwarded value. If you import the type it does not resolves it completely.

I tried using multiple method with ResolvedReferences and with resolve_qualified_name but I didn't had any success on this.

Is there any function that resolves a FromImport to an Exp somehow ?

[dhruvmanila]

Sorry for the late reply, I somehow missed this in the notification.

Can you provide an example of what you're trying to test here?

Is there any function that resolves a FromImport to an Exp somehow ?

Do you mean to follow the import and resolve it to the expression that defines it? That's not possible as it requires multi-file analysis.