---
name: compiler-verify
description: Use when you need to run all compiler checks (tests, lint, format) before committing. Detects whether TS or Rust code changed and runs the appropriate checks.
title: compiler-verify
canonical_url: https://skilld.dev/gh/facebook/react/compiler-verify
last_updated: 2026-09-26T15:14:42.000Z
---

> **Skill from skilld.dev.** Follow the instructions below for this session. You do not need to install anything.
>
> If the user asked to install this Skill, run `npx skilld install facebook/react/compiler-verify`. Install writes the Skill files into the project, so every session loads them.

# Compiler Verify

Run all verification steps for compiler changes.

Arguments:
- $ARGUMENTS: Optional test pattern for `yarn snap -p <pattern>`

## Instructions

1. **Detect what changed** by running `git diff --name-only HEAD` (or vs the base branch).
   Categorize changes:
   - **TS changes**: files in `compiler/packages/`
   - **Rust changes**: files in `compiler/crates/`
   - **Both**: run all checks

2. **If TS changed**, run these sequentially (stop on failure):
   - `yarn snap` (or `yarn snap -p <pattern>` if a pattern was provided) — compiler tests
   - `yarn test` — test full compiler
   - `yarn workspace babel-plugin-react-compiler lint` — lint compiler source

3. **If Rust changed**, run these sequentially (stop on failure):
   - `bash compiler/scripts/test-babel-ast.sh` — Babel AST round-trip tests
   - `bash compiler/scripts/test-rust-port.sh` — full Rust port test suite (compares Rust vs TS compiler output across all passes; must have 0 failures — do not regress)
   - `yarn snap --rust` — end-to-end snap tests using the Rust compiler (compares compiled output and logger events against `.expect.md` fixtures; use `yarn snap --rust -p <pattern>` for focused checks)

4. **Always run** (from the repo root):
   - `yarn prettier-all` — format all changed files

5. **If implementing a plan doc**, check:
   - Plan doc has no unaddressed "Remaining Work" items
   - Plan doc status is updated to reflect current state

6. Report results: list each step as passed/failed. On failure, stop and show the error with suggested fixes.

## Common Mistakes

- **Running `yarn snap` without `-p`** is fine for full verification, but slow. Use `-p` for focused checks.
- **Running prettier from compiler/** — must run from the repo root.
- **Forgetting Rust tests** — if you touched `.rs` files, always run the round-trip test and `yarn snap --rust`.