Fix completions in JSX tag with unstructured spreads

[DanielRosenwasser]

Fixes #2332.

[Copilot]

Pull request overview

This PR fixes a bug where completions in JSX tags with unstructured spread elements would cause a crash. The fix adds a type check before attempting to access properties on spread types, preventing nil pointer dereferences when the spread type is primitive (e.g., any, unknown, never, number).

Key Changes

• Added a TypeFlagsStructuredType check before calling AsStructuredType().Properties() to prevent crashes on primitive types
• Added comprehensive test coverage for various spread element types in JSX tags, including both structured types (objects, unions) and primitive types (any, unknown, never, undefined, number, boolean)

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
internal/ls/completions.go	Adds type flag validation to ensure only structured types (Object, Union, Intersection) attempt property access, preventing nil pointer dereferences
internal/fourslash/tests/completionsInJsxTagDifferentSpreadElementTypes_test.go	New test file verifying completions work correctly for JSX spread elements with various type categories

[gabritto]

You can't put ` in the test content, unless you concatenate the pieces (it's very annoying) 🙁

[DanielRosenwasser]

Oof!