[compiler] Fix false positive for useMemo reassigning context vars (#34904)

Within a function expression local variables may use StoreContext for
local context variables, so the reassignment check here was firing too
often. We should only report an error for variables that are declared
outside the function, ie part of its `context`.

---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/34904).
* #34903
* __->__ #34904

DiffTrain build for [2bcbf25](2bcbf25)

Author: josephsavona

compiled/eslint-plugin-react-hooks/index.js

@@ -50435,21 +50435,24 @@ function validateUseMemo(fn) {
     return errors.asResult();
 }
 function validateNoContextVariableAssignment(fn, errors) {
+    const context = new Set(fn.context.map(place => place.identifier.id));
     for (const block of fn.body.blocks.values()) {
         for (const instr of block.instructions) {
             const value = instr.value;
             switch (value.kind) {
                 case 'StoreContext': {
-                    errors.pushDiagnostic(CompilerDiagnostic.create({
-                        category: ErrorCategory.UseMemo,
-                        reason: 'useMemo() callbacks may not reassign variables declared outside of the callback',
-                        description: 'useMemo() callbacks must be pure functions and cannot reassign variables defined outside of the callback function',
-                        suggestions: null,
-                    }).withDetails({
-                        kind: 'error',
-                        loc: value.lvalue.place.loc,
-                        message: 'Cannot reassign variable',
-                    }));
+                    if (context.has(value.lvalue.place.identifier.id)) {
+                        errors.pushDiagnostic(CompilerDiagnostic.create({
+                            category: ErrorCategory.UseMemo,
+                            reason: 'useMemo() callbacks may not reassign variables declared outside of the callback',
+                            description: 'useMemo() callbacks must be pure functions and cannot reassign variables defined outside of the callback function',
+                            suggestions: null,
+                        }).withDetails({
+                            kind: 'error',
+                            loc: value.lvalue.place.loc,
+                            message: 'Cannot reassign variable',
+                        }));
+                    }
                     break;
                 }
             }

compiled/facebook-www/REVISION

@@ -1 +1 @@
-58bdc0bb967098f14562cd76af0668f2056459a0
+2bcbf254f168ddec567156f802d19315e64e4aa8

compiled/facebook-www/REVISION_TRANSFORMS

@@ -1 +1 @@
-58bdc0bb967098f14562cd76af0668f2056459a0
+2bcbf254f168ddec567156f802d19315e64e4aa8

compiled/facebook-www/React-dev.classic.js

@@ -1499,7 +1499,7 @@ __DEV__ &&
     exports.useTransition = function () {
       return resolveDispatcher().useTransition();
     };
-    exports.version = "19.3.0-www-classic-58bdc0bb-20251019";
+    exports.version = "19.3.0-www-classic-2bcbf254-20251020";
     "undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ &&
       "function" ===
         typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop &&

compiled/facebook-www/React-dev.modern.js

@@ -1499,7 +1499,7 @@ __DEV__ &&
     exports.useTransition = function () {
       return resolveDispatcher().useTransition();
     };
-    exports.version = "19.3.0-www-modern-58bdc0bb-20251019";
+    exports.version = "19.3.0-www-modern-2bcbf254-20251020";
     "undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ &&
       "function" ===
         typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop &&

compiled/facebook-www/React-prod.classic.js

@@ -606,4 +606,4 @@ exports.useSyncExternalStore = function (
 exports.useTransition = function () {
   return ReactSharedInternals.H.useTransition();
 };
-exports.version = "19.3.0-www-classic-58bdc0bb-20251019";
+exports.version = "19.3.0-www-classic-2bcbf254-20251020";

compiled/facebook-www/React-prod.modern.js

@@ -606,4 +606,4 @@ exports.useSyncExternalStore = function (
 exports.useTransition = function () {
   return ReactSharedInternals.H.useTransition();
 };
-exports.version = "19.3.0-www-modern-58bdc0bb-20251019";
+exports.version = "19.3.0-www-modern-2bcbf254-20251020";

compiled/facebook-www/React-profiling.classic.js

@@ -610,7 +610,7 @@ exports.useSyncExternalStore = function (
 exports.useTransition = function () {
   return ReactSharedInternals.H.useTransition();
 };
-exports.version = "19.3.0-www-classic-58bdc0bb-20251019";
+exports.version = "19.3.0-www-classic-2bcbf254-20251020";
 "undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ &&
   "function" ===
     typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop &&

compiled/facebook-www/React-profiling.modern.js

@@ -610,7 +610,7 @@ exports.useSyncExternalStore = function (
 exports.useTransition = function () {
   return ReactSharedInternals.H.useTransition();
 };
-exports.version = "19.3.0-www-modern-58bdc0bb-20251019";
+exports.version = "19.3.0-www-modern-2bcbf254-20251020";
 "undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ &&
   "function" ===
     typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop &&

compiled/facebook-www/ReactART-dev.classic.js

@@ -20371,10 +20371,10 @@ __DEV__ &&
     (function () {
       var internals = {
         bundleType: 1,
-        version: "19.3.0-www-classic-58bdc0bb-20251019",
+        version: "19.3.0-www-classic-2bcbf254-20251020",
         rendererPackageName: "react-art",
         currentDispatcherRef: ReactSharedInternals,
-        reconcilerVersion: "19.3.0-www-classic-58bdc0bb-20251019"
+        reconcilerVersion: "19.3.0-www-classic-2bcbf254-20251020"
       };
       internals.overrideHookState = overrideHookState;
       internals.overrideHookStateDeletePath = overrideHookStateDeletePath;
@@ -20409,7 +20409,7 @@ __DEV__ &&
     exports.Shape = Shape;
     exports.Surface = Surface;
     exports.Text = Text;
-    exports.version = "19.3.0-www-classic-58bdc0bb-20251019";
+    exports.version = "19.3.0-www-classic-2bcbf254-20251020";
     "undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ &&
       "function" ===
         typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop &&