[Tooltip] Improve docs and warning for custom children

docs/src/pages/guides/composition/composition.md

@@ -168,18 +168,18 @@ React in your console similar to:
 
 > Function components cannot be given refs. Attempts to access this ref will fail. Did you mean to use React.forwardRef()?
 
-Be aware that you will still get this warning for `lazy` and `memo` components if their
-wrapped component can't hold a ref.
-
+Note that you will still get this warning for `lazy` and `memo` components if their wrapped component can't hold a ref.
 In some instances an additional warning is issued to help with debugging, similar to:
 
 > Invalid prop `component` supplied to `ComponentName`. Expected an element type that can hold a ref.
 
 Only the two most common use cases are covered. For more information see [this section in the official React docs](https://reactjs.org/docs/forwarding-refs.html).
 
 ```diff
--const MyButton = props => <div role="button" {...props} />;
-+const MyButton = React.forwardRef((props, ref) => <div role="button" {...props} ref={ref} />);
+-const MyButton = () => <div role="button" />;
++const MyButton = React.forwardRef((props, ref) =>
++  <div role="button" {...props} ref={ref} />);
+
 <Button component={MyButton} />;
 ```
 

packages/material-ui/src/SpeedDialAction/SpeedDialAction.test.js

@@ -40,7 +40,7 @@ describe('<SpeedDialAction />', () => {
       inheritComponent: Tooltip,
       mount,
       refInstanceof: window.HTMLButtonElement,
-      skip: ['componentProp'],
+      skip: ['componentProp', 'reactTestRenderer'],
     }),
   );
 

packages/material-ui/src/Tooltip/Tooltip.js

@@ -459,6 +459,22 @@ const Tooltip = React.forwardRef(function Tooltip(props, ref) {
     ref: handleRef,
   };
 
+  if (process.env.NODE_ENV !== 'production') {
+    childrenProps['data-mui-internal-clone-element'] = true;
+
+    // eslint-disable-next-line react-hooks/rules-of-hooks
+    React.useEffect(() => {
+      if (childNode && !childNode.getAttribute('data-mui-internal-clone-element')) {
+        console.error(
+          [
+            'Material-UI: The `children` component of the Tooltip is not forwarding its props correctly.',
+            'Please make sure the props are spread on the same element that the ref is applied to.',
+          ].join('\n'),
+        );
+      }
+    }, [childNode]);
+  }
+
   const interactiveWrapperListeners = {};
 
   if (!disableTouchListener) {

packages/material-ui/src/Tooltip/Tooltip.test.js

@@ -878,9 +878,10 @@ describe('<Tooltip />', () => {
       // Tooltip should not assume that event handlers of children are attached to the
       // outermost host
       const TextField = React.forwardRef(function TextField(props, ref) {
+        const { onFocus, ...other } = props;
         return (
-          <div ref={ref}>
-            <input type="text" {...props} />
+          <div ref={ref} {...other}>
+            <input type="text" onFocus={onFocus} />
           </div>
         );
       });
@@ -917,6 +918,20 @@ describe('<Tooltip />', () => {
         'Material-UI: A component is changing the uncontrolled open state of Tooltip to be controlled.',
       );
     });
+
+    it('should warn when not forwarding props', () => {
+      const BrokenButton = React.forwardRef((props, ref) => <button ref={ref}>Hello World</button>);
+
+      expect(() => {
+        render(
+          <Tooltip title="Hello World">
+            <BrokenButton />
+          </Tooltip>,
+        );
+      }).toErrorDev(
+        'The `children` component of the Tooltip is not forwarding its props correctly.',
+      );
+    });
   });
 
   it('should use the same popper.js instance between two renders', () => {