fix no error on invalid call to __init_subclass__ #3447

[asukaminato0721]

Summary

Fixes #3447

Added __init_subclass__ lookup excluding object.__init_subclass__

Class metadata now checks class-header keywords against the first real base class’s __init_subclass__ via the existing callable checker

Preserved keyword identifiers through binding so diagnostics can point at class-header keyword names.

Test Plan

add test

[Copilot]

Pull request overview

This PR adds type-checking for class-header keyword arguments by routing them through __init_subclass__ (excluding the default object.__init_subclass__), and preserves keyword identifier ranges through binding so diagnostics can point at the keyword name in the class header.

Changes:

• Store class-header keywords as Identifier (not just Name) so keyword ranges survive into the solving phase.
• Add __init_subclass__ lookup (excluding object.__init_subclass__) and invoke the existing call checker to validate class-header keywords.
• Add a regression test covering an invalid keyword type in a __init_subclass__ call.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
pyrefly/lib/test/constructors.rs	Adds a regression test for validating class-header keywords against __init_subclass__.
pyrefly/lib/binding/class.rs	Preserves keyword identifiers/ranges in bindings; updates synthesized class keyword storage accordingly.
pyrefly/lib/binding/binding.rs	Updates BindingClassMetadata.keywords to store Identifier instead of Name.
pyrefly/lib/alt/class/class_metadata.rs	Implements __init_subclass__ keyword checking during class metadata computation.
pyrefly/lib/alt/class/class_field.rs	Adds get_dunder_init_subclass helper, excluding object.__init_subclass__.

Comments suppressed due to low confidence (1)

pyrefly/lib/alt/class/class_metadata.rs:550

• This only checks __init_subclass__ on bases_with_metadata.first(). If the leftmost base doesn't override __init_subclass__ but a later base does, class-header keywords won't be validated against the method that will actually be resolved via MRO. Consider scanning bases_with_metadata in order and picking the first base whose get_dunder_init_subclass(...) returns Some, instead of unconditionally using the first base.

        let Some((base, _)) = bases_with_metadata.first() else {
            return;
        };
        let base = self.promote_nontypeddict_silently_to_classtype(base);
        let Some(init_subclass) = self.get_dunder_init_subclass(&base) else {
            return;
        };

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[github-actions]

According to mypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅