fix Autocomplete parameters of class pattern in match-case situation #2830

[asukaminato0721]

Summary

Fixes #2830

adds class-pattern keyword completions from the matched class’s instance attributes, so case A(...): now suggests a= / b= for dataclass fields.

Test Plan

add test

[Copilot]

Pull request overview

Fixes LSP completion behavior for Python match/case class patterns by suggesting keyword names derived from the matched class’s instance attributes (e.g. dataclass fields in case A(...)).

Changes:

• Add completion logic to suggest attr= items when completing inside case <Class>(...).
• Wire the new completion logic into the main completion flow (pattern-match keyword context + generic non-identifier context).
• Add a regression test ensuring dataclass fields (a=, b=) are suggested in case A( ).

Reviewed changes

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

File	Description
pyrefly/lib/lsp/wasm/completion.rs	Adds match-class keyword completion generation and hooks it into completion dispatch.
pyrefly/lib/test/lsp/completion.rs	Adds a regression test covering dataclass-field keyword completions in class patterns.

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[Copilot]

The completion detail here uses Type::to_string(), while other completion paths in this file format types with as_lsp_string(LspDisplayMode::Hover) for consistency and readability. Consider using the same formatting helper so match-class keyword completions display types consistently with attribute completions.

Suggested change

	detail: attr.ty.map(|ty| ty.to_string()),
	detail: attr
	.ty
	.map(|ty| ty.as_lsp_string(LspDisplayMode::Hover)),

[meta-codesync]

This pull request has been imported. If you are a Meta employee, you can view this in D115175141. (Because this pull request was imported automatically, there will not be any future comments.)

[github-actions]

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