From 0897cc8a0f51afb2576326bb2a91af15182e7c40 Mon Sep 17 00:00:00 2001
From: Sathya Gunasekaran <gsathya.ceg@gmail.com>
Date: Tue, 20 Jun 2023 14:58:36 +0100
Subject: [PATCH] Add failing test for DropMemoCalls failing to DCE dep array

Found this while running Forget on the React tests.

This isn't a high priority because the ESLint plugin would've caught this. But
it'd be nice if either our validation rules caught this or if our compiler did
correctly eliminate the dep array.
---
 ...g.useMemo-deps-array-not-cleared.expect.md | 41 +++++++++++++++++++
 .../bug.useMemo-deps-array-not-cleared.js     |  9 ++++
 2 files changed, 50 insertions(+)
 create mode 100644 compiler/forget/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/bug.useMemo-deps-array-not-cleared.expect.md
 create mode 100644 compiler/forget/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/bug.useMemo-deps-array-not-cleared.js

diff --git a/compiler/forget/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/bug.useMemo-deps-array-not-cleared.expect.md b/compiler/forget/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/bug.useMemo-deps-array-not-cleared.expect.md
new file mode 100644
index 0000000000..10a05f4e40
--- /dev/null
+++ b/compiler/forget/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/bug.useMemo-deps-array-not-cleared.expect.md
@@ -0,0 +1,41 @@
+
+## Input
+
+```javascript
+function App({text, hasDeps}) {
+  const resolvedText = useMemo(
+    () => {
+      return text.toUpperCase();
+    },
+    hasDeps ? null : [text], // should be DCE'd
+  );
+  return resolvedText;
+}
+
+```
+
+## Code
+
+```javascript
+import { unstable_useMemoCache as useMemoCache } from "react";
+function App(t26) {
+  const $ = useMemoCache(2);
+  const { text, hasDeps } = t26;
+
+  hasDeps ? null : [text];
+  const c_0 = $[0] !== text;
+  let t0;
+  if (c_0) {
+    t0 = text.toUpperCase();
+    $[0] = text;
+    $[1] = t0;
+  } else {
+    t0 = $[1];
+  }
+  const t19 = t0;
+  const resolvedText = t19;
+  return resolvedText;
+}
+
+```
+      
\ No newline at end of file
diff --git a/compiler/forget/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/bug.useMemo-deps-array-not-cleared.js b/compiler/forget/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/bug.useMemo-deps-array-not-cleared.js
new file mode 100644
index 0000000000..711783d4f9
--- /dev/null
+++ b/compiler/forget/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/bug.useMemo-deps-array-not-cleared.js
@@ -0,0 +1,9 @@
+function App({ text, hasDeps }) {
+  const resolvedText = useMemo(
+    () => {
+      return text.toUpperCase();
+    },
+    hasDeps ? null : [text] // should be DCE'd
+  );
+  return resolvedText;
+}