Repository: facebook/react
Pull request: [compiler] Visit nested scopes in pruned scopes in PromoteUsedTemporaries

Stack from [ghstack](https://github.com/ezyang/ghstack) (oldest at bottom):
* __->__ #30537

While debugging #30536 I happened to notice that the bug only reproduced
when there was interleaving scopes, and observed that an unpruned scope
nested inside of a pruned one was not being visited by
CollectPromotableTemporaries, which keeps track of which identifiers
should be promoted later. Therefore when actually promoting temporaries
we were skipping over the identifiers in children of pruned scopes

Changed files:
filename: compiler/packages/babel-plugin-react-compiler/src/ReactiveScopes/PromoteUsedTemporaries.ts
patch: @@ -138,6 +138,7 @@ class CollectPromotableTemporaries extends ReactiveFunctionVisitor<State> {
         usedOutsideScope: false,
       });
     }
+    this.visitBlock(scopeBlock.instructions, state);
   }
 
   override visitScope(scopeBlock: ReactiveScopeBlock, state: State): void {

filename: compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/bug-renaming-jsx-tag-lowercase.expect.md
patch: @@ -1,107 +0,0 @@
-
-## Input
-
-```javascript
-import {Stringify, identity, useIdentity} from 'shared-runtime';
-
-/**
- * Currently, we're passing a lower-case jsx tag `t0`.
- * We should either reorder Stringify or rename the local to `T0`.
- *
- * See evaluator error:
- * Found differences in evaluator results
- *   Non-forget (expected):
- *   (kind: ok) <div>{"value":{}}</div><div>{"value":{}}</div>
- *   Forget:
- *   (kind: ok) <t1 value="[object Object]"></t1><div>{"value":{}}</div>
- *   logs: ['Warning: The tag <%s> is unrecognized in this browser. If you meant to render a React component, start its name with an uppercase letter.%s','t1']
- */
-function Foo({}) {
-  const x = {};
-  const y = {};
-  useIdentity(0);
-  return (
-    <>
-      <Stringify value={identity(y)} />
-      <Stringify value={identity(x)} />
-    </>
-  );
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Foo,
-  params: [{}],
-};
-
-```
-
-## Code
-
-```javascript
-import { c as _c } from "react/compiler-runtime";
-import { Stringify, identity, useIdentity } from "shared-runtime";
-
-/**
- * Currently, we're passing a lower-case jsx tag `t0`.
- * We should either reorder Stringify or rename the local to `T0`.
- *
- * See evaluator error:
- * Found differences in evaluator results
- *   Non-forget (expected):
- *   (kind: ok) <div>{"value":{}}</div><div>{"value":{}}</div>
- *   Forget:
- *   (kind: ok) <t1 value="[object Object]"></t1><div>{"value":{}}</div>
- *   logs: ['Warning: The tag <%s> is unrecognized in this browser. If you meant to render a React component, start its name with an uppercase letter.%s','t1']
- */
-function Foo(t0) {
-  const $ = _c(9);
-  const x = {};
-  const y = {};
-  useIdentity(0);
-
-  const t1 = Stringify;
-  const t2 = identity(y);
-  let t3;
-  if ($[0] !== t1 || $[1] !== t2) {
-    t3 = <t1 value={t2} />;
-    $[0] = t1;
-    $[1] = t2;
-    $[2] = t3;
-  } else {
-    t3 = $[2];
-  }
-  const T0 = Stringify;
-  const t4 = identity(x);
-  let t5;
-  if ($[3] !== T0 || $[4] !== t4) {
-    t5 = <T0 value={t4} />;
-    $[3] = T0;
-    $[4] = t4;
-    $[5] = t5;
-  } else {
-    t5 = $[5];
-  }
-  let t6;
-  if ($[6] !== t3 || $[7] !== t5) {
-    t6 = (
-      <>
-        {t3}
-        {t5}
-      </>
-    );
-    $[6] = t3;
-    $[7] = t5;
-    $[8] = t6;
-  } else {
-    t6 = $[8];
-  }
-  return t6;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Foo,
-  params: [{}],
-};
-
-```
-      
\ No newline at end of file

filename: compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/bug-renaming-jsx-tag-lowercase.tsx
patch: @@ -1,30 +0,0 @@
-import {Stringify, identity, useIdentity} from 'shared-runtime';
-
-/**
- * Currently, we're passing a lower-case jsx tag `t0`.
- * We should either reorder Stringify or rename the local to `T0`.
- *
- * See evaluator error:
- * Found differences in evaluator results
- *   Non-forget (expected):
- *   (kind: ok) <div>{"value":{}}</div><div>{"value":{}}</div>
- *   Forget:
- *   (kind: ok) <t1 value="[object Object]"></t1><div>{"value":{}}</div>
- *   logs: ['Warning: The tag <%s> is unrecognized in this browser. If you meant to render a React component, start its name with an uppercase letter.%s','t1']
- */
-function Foo({}) {
-  const x = {};
-  const y = {};
-  useIdentity(0);
-  return (
-    <>
-      <Stringify value={identity(y)} />
-      <Stringify value={identity(x)} />
-    </>
-  );
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Foo,
-  params: [{}],
-};

filename: compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/renaming-jsx-tag-lowercase.expect.md
patch: @@ -0,0 +1,85 @@
+
+## Input
+
+```javascript
+import {Stringify, identity, useIdentity} from 'shared-runtime';
+
+function Foo({}) {
+  const x = {};
+  const y = {};
+  useIdentity(0);
+  return (
+    <>
+      <Stringify value={identity(y)} />
+      <Stringify value={identity(x)} />
+    </>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Foo,
+  params: [{}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import { Stringify, identity, useIdentity } from "shared-runtime";
+
+function Foo(t0) {
+  const $ = _c(9);
+  const x = {};
+  const y = {};
+  useIdentity(0);
+
+  const T0 = Stringify;
+  const t1 = identity(y);
+  let t2;
+  if ($[0] !== T0 || $[1] !== t1) {
+    t2 = <T0 value={t1} />;
+    $[0] = T0;
+    $[1] = t1;
+    $[2] = t2;
+  } else {
+    t2 = $[2];
+  }
+  const T1 = Stringify;
+  const t3 = identity(x);
+  let t4;
+  if ($[3] !== T1 || $[4] !== t3) {
+    t4 = <T1 value={t3} />;
+    $[3] = T1;
+    $[4] = t3;
+    $[5] = t4;
+  } else {
+    t4 = $[5];
+  }
+  let t5;
+  if ($[6] !== t2 || $[7] !== t4) {
+    t5 = (
+      <>
+        {t2}
+        {t4}
+      </>
+    );
+    $[6] = t2;
+    $[7] = t4;
+    $[8] = t5;
+  } else {
+    t5 = $[8];
+  }
+  return t5;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Foo,
+  params: [{}],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"value":{}}</div><div>{"value":{}}</div>
\ No newline at end of file

filename: compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/renaming-jsx-tag-lowercase.tsx
patch: @@ -0,0 +1,18 @@
+import {Stringify, identity, useIdentity} from 'shared-runtime';
+
+function Foo({}) {
+  const x = {};
+  const y = {};
+  useIdentity(0);
+  return (
+    <>
+      <Stringify value={identity(y)} />
+      <Stringify value={identity(x)} />
+    </>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Foo,
+  params: [{}],
+};