Warn about setting propTypes too

packages/react-reconciler/src/__tests__/ReactLazy-test.internal.js

@@ -510,6 +510,18 @@ describe('ReactLazy', () => {
     expect(root).toMatchRenderedOutput('Friends Bye');
   });
 
+  it('warns about defining propTypes on the outer wrapper', async () => {
+    const LazyText = lazy(() => fakeImport(Text));
+    expect(() => {
+      LazyText.propTypes = {hello: () => {}};
+    }).toWarnDev(
+      'React.lazy(...): It is not supported to assign `propTypes` to ' +
+        'a lazy component import. Either specify them where the component ' +
+        'is defined, or create a wrapping component around it.',
+      {withoutStack: true},
+    );
+  });
+
   it('includes lazy-loaded component in warning stack', async () => {
     const LazyFoo = lazy(() => {
       ReactTestRenderer.unstable_yield('Started loading');

packages/react/src/ReactLazy.js

@@ -22,6 +22,7 @@ export function lazy<T, R>(ctor: () => Thenable<T, R>): LazyComponent<T> {
   if (__DEV__) {
     // In production, this would just set it on the object.
     let defaultProps;
+    let propTypes;
     Object.defineProperties(lazyType, {
       defaultProps: {
         get() {
@@ -37,6 +38,20 @@ export function lazy<T, R>(ctor: () => Thenable<T, R>): LazyComponent<T> {
           defaultProps = newDefaultProps;
         },
       },
+      propTypes: {
+        get() {
+          return propTypes;
+        },
+        set(newPropTypes) {
+          warning(
+            false,
+            'React.lazy(...): It is not supported to assign `propTypes` to ' +
+              'a lazy component import. Either specify them where the component ' +
+              'is defined, or create a wrapping component around it.',
+          );
+          propTypes = newPropTypes;
+        },
+      },
     });
   }