Recycle prevProps in simple memo based on the shallowEqual check

Author: Andarist

packages/react-reconciler/src/ReactFiberBeginWork.new.js

@@ -592,7 +592,9 @@ function updateSimpleMemoComponent(
   }
   if (current !== null) {
     const prevProps = current.memoizedProps;
-    nextProps = shallowEqual(prevProps, nextProps) ? prevProps : nextProps;
+    workInProgress.pendingProps = nextProps = shallowEqual(prevProps, nextProps)
+      ? prevProps
+      : nextProps;
     if (
       prevProps === nextProps &&
       current.ref === workInProgress.ref &&

packages/react-reconciler/src/ReactFiberBeginWork.old.js

@@ -592,7 +592,9 @@ function updateSimpleMemoComponent(
   }
   if (current !== null) {
     const prevProps = current.memoizedProps;
-    nextProps = shallowEqual(prevProps, nextProps) ? prevProps : nextProps;
+    workInProgress.pendingProps = nextProps = shallowEqual(prevProps, nextProps)
+      ? prevProps
+      : nextProps;
     if (
       prevProps === nextProps &&
       current.ref === workInProgress.ref &&

packages/react-reconciler/src/__tests__/ReactMemo-test.js

@@ -222,6 +222,12 @@ describe('memo', () => {
         expect(ReactNoop.getChildren()).toEqual([
           span('Inner render count: 1'),
         ]);
+
+        ReactNoop.render(<Parent value={ctxValue++} />);
+        expect(Scheduler).toFlushAndYield([]);
+        expect(ReactNoop.getChildren()).toEqual([
+          span('Inner render count: 1'),
+        ]);
       });
 
       it('accepts custom comparison function', async () => {