Add inferred throws inlay hints

[codeshaunted]

Changes

• Show declaration-site inlay hints for inferred non-never throws clauses.
• Reuse callable_throws and source-aware type rendering, with no compiler changes.
• Suppress hints for explicit throws clauses and synthetic functions.

Testing

• Unit tests added/updated
• cargo test -p baml_ide -p baml_lsp
• cargo clippy -p baml_ide -p baml_lsp --all-targets -- -D warnings
• RUSTDOCFLAGS='-D warnings' cargo doc -p baml_ide -p baml_lsp --no-deps

Screenshots

Not applicable.

PR Checklist

• Code follows the project style.
• Self-review completed.
• Documentation updated.
• No new warnings.

Summary by CodeRabbit

• New Features

  • Added inlay hints showing inferred throws clauses for functions that may raise user-defined errors.
  • Hints appear after return types and are omitted when a function already declares throws or cannot throw.

• Tests

  • Added coverage for direct and propagated throws hints.
  • Added end-to-end validation of hint content, type, and position.

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[github-actions]

⏭️ Performance benchmarks were skipped

Perf benchmarks (CodSpeed) are opt-in on pull requests — they no longer run on every push. They always run automatically after merge to canary/main.

To run them on this PR, do any of the following, then push a commit (or re-run CI):

• Add RUN_CODSPEED=1 to the PR description, or
• Include run-perf or /perf in the PR title or any commit message.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 540a6db4-f30b-4303-a28b-93a7105305a4

📥 Commits

Reviewing files that changed from the base of the PR and between 3e669ec and d8a2cce.

📒 Files selected for processing (3)

• baml_language/crates/baml_ide/src/annotations.rs
• baml_language/crates/baml_lsp/src/dispatch/requests.rs
• baml_language/crates/baml_lsp/tests/protocol.rs

Included review availability: Your plan provides up to 8 included reviews per hour; 7 remain after this review.

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📝 Walkthrough

Walkthrough

The IDE now emits inferred throws annotations for eligible user-defined functions. The LSP classifies these annotations as type inlay hints. IDE and protocol tests verify direct, propagated, explicit, non-throwing, suppressed, and positional cases.

Changes

Inferred throws hints

Layer / File(s)	Summary
IDE throws annotation generation baml_language/crates/baml_ide/src/annotations.rs	Adds AnnotationKind::Throws, documents its placement, emits inferred throws annotations for eligible user-defined functions, and tests direct and propagated throws behavior.
LSP hint mapping and protocol coverage baml_language/crates/baml_lsp/src/dispatch/requests.rs, baml_language/crates/baml_lsp/tests/protocol.rs	Classifies throws annotations as type inlay hints and verifies the label, hint kind, and source position.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: ⚪ Minimal · up to d8a2c

This change adds declaration-site hints for inferred non-never throws clauses while suppressing explicit and synthetic cases; no actionable merge-blocking risk remains after normal checks and review.

Sequence Diagram(s)

sequenceDiagram
  participant UserDefinedFunction
  participant AnnotationBuilder
  participant LSPDispatcher
  participant LSPClient
  UserDefinedFunction->>AnnotationBuilder: provide inferred throws contract
  AnnotationBuilder->>LSPDispatcher: emit Throws annotation
  LSPDispatcher->>LSPClient: return TYPE inlay hint

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Suggested reviewers: 2kai2kai2

Poem

A rabbit spots a throws sign bright
The IDE places it just right
The LSP carries the hint
Tests check each offset and print
Burrows now parse errors in sight

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: adding inferred throws inlay hints.
Docstring Coverage	✅ Passed	Docstring coverage is 85.71% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 7 functions across 3 files.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch codex/throws-inlay-hints

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[github-actions]

Binary size checks failed

❌ 2 violations · ✅ 5 passed

⚠️ Please fix the size gate issues or acknowledge them by updating baselines.

	Artifact	Platform	File	Gzip	Gated on	Baseline	Delta	Status
✅	baml-cli	Linux	🔒 72.7 MB	27.4 MB	file	82.3 MB	-9.6 MB (-11.7%)	OK
✅	packed-program	Linux	🔒 28.5 MB	10.8 MB	file	32.5 MB	-4.0 MB (-12.3%)	OK
✅	baml-cli	macOS	🔒 63.1 MB	25.0 MB	file	63.1 MB	-4.9 KB (-0.0%)	OK
✅	packed-program	macOS	🔒 25.7 MB	10.1 MB	file	25.8 MB	-142.9 KB (-0.6%)	OK
❌	baml-cli	Windows	🔒 82.8 MB	27.8 MB	file	80.2 MB	+2.6 MB (+3.3%)	FAIL
❌	packed-program	Windows	🔒 30.7 MB	10.7 MB	file	28.4 MB	+2.3 MB (+8.1%)	FAIL
✅	bridge_wasm	WASM	22.1 MB	🔒 5.6 MB	gzip	5.7 MB	-48.1 KB (-0.8%)	OK

🔒 = the size this artifact is GATED on (ceiling + delta). Binaries gate on file size (installed binary); WASM gates on gzip (download size). The other size is shown for information only.

Details & how to fix

Violations:

• baml-cli (Windows) file_bytes: 82.8 MB exceeds limit of 82.6 MB (exceeded by +204.6 KB, policy: max_file_bytes)
• baml-cli (Windows) file_delta_pct: +3.3% exceeds limit of 3.0% (exceeded by +0.3pp, policy: max_delta_pct)
• packed-program (Windows) file_bytes: 30.7 MB exceeds limit of 29.3 MB (exceeded by +1.5 MB, policy: max_file_bytes)
• packed-program (Windows) file_delta_pct: +8.1% exceeds limit of 3.0% (exceeded by +5.1pp, policy: max_delta_pct)

Add/update baselines:

.ci/size-gate/x86_64-pc-windows-msvc.toml:

[artifacts.baml-cli]
file_bytes = 82832384
stripped_bytes = 82832384
gzip_bytes = 27814411
[artifacts.packed-program]
file_bytes = 30711093
gzip_bytes = 10670634

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Generated by cargo size-gate · workflow run