Preserve postfix member update values in nested functions

compiler/packages/babel-plugin-react-compiler/src/ReactiveScopes/CodegenReactiveFunction.ts

@@ -9,6 +9,7 @@ import * as t from '@babel/types';
 import {createHmac} from 'crypto';
 import {
   pruneHoistedContexts,
+  promoteUsedTemporaries,
   pruneUnusedLValues,
   pruneUnusedLabels,
   renameVariables,
@@ -311,6 +312,7 @@ export function codegenFunction(
     const reactiveFunction = buildReactiveFunction(outlinedFunction);
     pruneUnusedLabels(reactiveFunction);
     pruneUnusedLValues(reactiveFunction);
+    promoteUsedTemporaries(reactiveFunction);
     pruneHoistedContexts(reactiveFunction);
 
     const identifiers = renameVariables(reactiveFunction);
@@ -1665,11 +1667,16 @@ function codegenInstructionValue(
               const reactiveFunction = buildReactiveFunction(loweredFunc.func);
               pruneUnusedLabels(reactiveFunction);
               pruneUnusedLValues(reactiveFunction);
+              promoteUsedTemporaries(reactiveFunction);
+              const identifiers = new Set([
+                ...cx.uniqueIdentifiers,
+                ...renameVariables(reactiveFunction),
+              ]);
               const fn = codegenReactiveFunction(
                 new Context(
                   cx.env,
                   reactiveFunction.id ?? '[[ anonymous ]]',
-                  cx.uniqueIdentifiers,
+                  identifiers,
                   cx.fbtOperands,
                   cx.temp,
                 ),
@@ -1863,12 +1870,17 @@ function codegenInstructionValue(
       const reactiveFunction = buildReactiveFunction(loweredFunc);
       pruneUnusedLabels(reactiveFunction);
       pruneUnusedLValues(reactiveFunction);
+      promoteUsedTemporaries(reactiveFunction);
       pruneHoistedContexts(reactiveFunction);
+      const identifiers = new Set([
+        ...cx.uniqueIdentifiers,
+        ...renameVariables(reactiveFunction),
+      ]);
       const fn = codegenReactiveFunction(
         new Context(
           cx.env,
           reactiveFunction.id ?? '[[ anonymous ]]',
-          cx.uniqueIdentifiers,
+          identifiers,
           cx.fbtOperands,
           cx.temp,
         ),

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/bug-ref-prefix-postfix-operator.expect.md

@@ -77,8 +77,9 @@ function useFoo() {
   let t0;
   if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
     t0 = () => {
-      count.current = count.current + 1;
-      const id = count.current;
+      const t0 = count.current;
+      count.current = t0 + 1;
+      const id = t0;
       return id;
     };
     $[0] = t0;

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/postfix-member-assignment-in-callback.expect.md

@@ -0,0 +1,67 @@
+
+## Input
+
+```javascript
+function Component(props) {
+  const agg = {itemCounter: props.start};
+  const next = () => {
+    const count = agg.itemCounter++;
+    return count;
+  };
+  return [next(), agg.itemCounter];
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{start: 1}],
+  isComponent: false,
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+function Component(props) {
+  const $ = _c(6);
+  let agg;
+  let t0;
+  if ($[0] !== props.start) {
+    agg = { itemCounter: props.start };
+    const next = () => {
+      const t0 = agg.itemCounter;
+      agg.itemCounter = t0 + 1;
+      const count = t0;
+      return count;
+    };
+    t0 = next();
+    $[0] = props.start;
+    $[1] = agg;
+    $[2] = t0;
+  } else {
+    agg = $[1];
+    t0 = $[2];
+  }
+  let t1;
+  if ($[3] !== agg.itemCounter || $[4] !== t0) {
+    t1 = [t0, agg.itemCounter];
+    $[3] = agg.itemCounter;
+    $[4] = t0;
+    $[5] = t1;
+  } else {
+    t1 = $[5];
+  }
+  return t1;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ start: 1 }],
+  isComponent: false,
+};
+
+```
+
+### Eval output
+(kind: ok) [1,2]

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/postfix-member-assignment-in-callback.js

@@ -0,0 +1,14 @@
+function Component(props) {
+  const agg = {itemCounter: props.start};
+  const next = () => {
+    const count = agg.itemCounter++;
+    return count;
+  };
+  return [next(), agg.itemCounter];
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{start: 1}],
+  isComponent: false,
+};