Re-add the warning for useContext(Context.Consumer)

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

@@ -1341,6 +1341,18 @@ describe('ReactNewContext', () => {
       );
     });
 
+    it('warns when passed a consumer', async () => {
+      const Context = React.createContext(0);
+      function Foo() {
+        return useContext(Context.Consumer);
+      }
+      ReactNoop.render(<Foo />);
+      await expect(async () => await waitForAll([])).toErrorDev(
+        'Calling useContext(Context.Consumer) is not supported and will cause bugs. ' +
+          'Did you mean to call useContext(Context) instead?',
+      );
+    });
+
     // Context consumer bails out on propagating "deep" updates when `value` hasn't changed.
     // However, it doesn't bail out from rendering if the component above it re-rendered anyway.
     // If we bailed out on referential equality, it would be confusing that you

packages/react/src/ReactHooks.js

@@ -13,6 +13,7 @@ import type {
   StartTransitionOptions,
   Usable,
 } from 'shared/ReactTypes';
+import {REACT_CONSUMER_TYPE} from 'shared/ReactSymbols';
 
 import ReactCurrentDispatcher from './ReactCurrentDispatcher';
 import ReactCurrentCache from './ReactCurrentCache';
@@ -71,6 +72,14 @@ export function getCacheForType<T>(resourceType: () => T): T {
 
 export function useContext<T>(Context: ReactContext<T>): T {
   const dispatcher = resolveDispatcher();
+  if (__DEV__) {
+    if (Context.$$typeof === REACT_CONSUMER_TYPE) {
+      console.error(
+        'Calling useContext(Context.Consumer) is not supported and will cause bugs. ' +
+          'Did you mean to call useContext(Context) instead?',
+      );
+    }
+  }
   return dispatcher.useContext(Context);
 }