refactor(formatter): add speculate_will_break and fix is_complex_type_arguments

[Dunqing]

Closes: #19436

Summary

• Add Formatter::speculate_will_break to encapsulate the snapshot/skip/intern/restore pattern for safely checking if formatted content would break across lines
• Replace the approximation heuristics in is_complex_type_arguments with Prettier's actual willBreak(print(typeArgs)) logic
• Add Comments::snapshot, restore, and skip_comments_before methods to support speculative formatting without losing comments

Details

The old is_complex_type_arguments couldn't call f.intern() because it would permanently advance the comment cursor, causing comments to be lost. It used heuristic checks (complex type references, mapped types, etc.) as an approximation instead.

With the new comment snapshot/restore infrastructure, we can now match Prettier's behavior exactly:

// Before: ~30 lines of heuristic checks
// After:
f.speculate_will_break(type_arguments)

Prettier ref: https://github.com/prettier/prettier/blob/a043ac0d733c4d53f980aa73807a63fc914f23bd/src/language-js/print/assignment.js#L432-L459

Test plan

• Existing formatter tests pass (193/193)
• Clippy clean
• Added snapshot tests for comment preservation with call expressions and type arguments

🤖 Generated with Claude Code

[Dunqing]

• refactor(formatter): add speculate_will_break and fix is_complex_type_arguments #19661 👈 (View in Graphite)
• fix(formatter): drop blank line between terminal call and first chain member #19659
• main

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[codspeed-hq]

Merging this PR will not alter performance

✅ 48 untouched benchmarks
⏩ 7 skipped benchmarks¹

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_{Comparing refactor/formatter-speculate-will-break (4c037e3) with main (b85f97b)}

Footnotes

1. 7 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[Dunqing]

https://github.com/oxc-project/monitor-oxc/actions/runs/22346484993/job/64662503654 No comments are being removed now

[leaysgur]

It's similar to the state_snapshot() APIs that were removed when porting Biome, right? 👀

Seems a lightweight version specializing in comments.

[Dunqing]

It's similar to the state_snapshot() APIs that were removed when porting Biome, right? 👀

Seems a lightweight version specializing in comments.

Yes, during the time I was porting, I didn't know what state_snapshot() does, since we don't have usages and can remove it without breaking tests. Now I know!

[Dunqing]

Merge activity

• Feb 25, 3:54 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
• Feb 25, 3:54 AM UTC: Dunqing added this pull request to the Graphite merge queue.
• Feb 25, 4:06 AM UTC: Merged by the Graphite merge queue.