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oxc-project__oxc/crates/oxc_react_compiler/fixtures/error.invalid-nested-function-reassign-local-variable-in-effect.js
Boshen 6efce65746 test(react_compiler): snapshot the upstream fixture corpus (#24101)
## Summary

`oxc_react_compiler` had no committed test over the upstream React
Compiler fixture corpus — the fixtures lived only in the
`oxc-project/forked-react-compiler` checkout, exercised out-of-tree.
That gap let real regressions slip past the 15 in-crate integration
tests. This PR closes it.

- **`crates/oxc_react_compiler/fixtures/`** — 1734 fixture *input* files
(`.js`/`.ts`/`.tsx`/`.jsx`/`.mjs`), copied from the fork's
`babel-plugin-react-compiler/src/__tests__/fixtures/compiler` tree with
subdirectories preserved. Flow fixtures (the `@flow`-pragma ones) are
excluded — oxc has no Flow parser. The upstream `.expect.md` goldens are
also not copied; insta is the golden here.
- **`crates/oxc_react_compiler/tests/snapshot.rs`** — an `insta::glob!`
test that, per fixture, derives `PluginOptions`/`EnvironmentConfig` from
the first-line `// @directive` pragmas (base `compilationMode=all` /
`panicThreshold=all_errors`, matching the upstream `snap` runner),
parses → builds semantic → runs `transform`, and snapshots the compiled
output plus diagnostics. Unrecognised directives are ignored, as
upstream does; camelCase flag directives map to `EnvironmentConfig`
fields via `convert_case`.
- **`crates/oxc_react_compiler/tests/snapshots/`** — 1734 committed
`.snap` goldens (oxc's own output).
- **`.typos.toml`** — excludes the fixtures dir (the upstream fixtures
contain intentional typos; `**/*.snap` was already excluded).

These snapshots are oxc's own golden output, so `cargo test` (and CI)
now catches any change in compiler behaviour across the corpus.
Regenerate after an intended change with `cargo insta accept`.

## Verification

- `cargo test -p oxc_react_compiler` passes — the 1734-fixture snapshot
test plus the existing 15 integration tests; also green under
`--all-features` (matches the cross-target CI job).
- clippy `-D warnings`, `cargo fmt`, and `typos` clean.
- No fixture panics; 1336 compiled / 398 unchanged / 335 with
diagnostics.
- The `error.*` fixtures capture the exact diagnostics — including the
"Cannot reassign variable after render" error that a recent scoping
change had silently suppressed, confirming the suite catches real
regressions.

---

AI usage disclosure: authored with Claude Code and reviewed before
submission.

🤖 Generated with [Claude Code](https://claude.com/claude-code)
2026-07-03 16:49:53 +08:00

38 lines
1.3 KiB
JavaScript

import {useEffect} from 'react';
function Component() {
let local;
const mk_reassignlocal = () => {
// Create the reassignment function inside another function, then return it
const reassignLocal = newValue => {
local = newValue;
};
return reassignLocal;
};
const reassignLocal = mk_reassignlocal();
const onMount = newValue => {
reassignLocal('hello');
if (local === newValue) {
// Without React Compiler, `reassignLocal` is freshly created
// on each render, capturing a binding to the latest `local`,
// such that invoking reassignLocal will reassign the same
// binding that we are observing in the if condition, and
// we reach this branch
console.log('`local` was updated!');
} else {
// With React Compiler enabled, `reassignLocal` is only created
// once, capturing a binding to `local` in that render pass.
// Therefore, calling `reassignLocal` will reassign the wrong
// version of `local`, and not update the binding we are checking
// in the if condition.
//
// To protect against this, we disallow reassigning locals from
// functions that escape
throw new Error('`local` not updated!');
}
};
useEffect(() => {
onMount();
}, [onMount]);
return 'ok';
}