All the information

docs/pages/api-docs/popper.md

@@ -33,7 +33,7 @@ Poppers rely on the 3rd party library [Popper.js](https://popper.js.org/docs/v2/
 | <span class="prop-name">keepMounted</span> | <span class="prop-type">bool</span> | <span class="prop-default">false</span> | Always keep the children in the DOM. This prop can be useful in SEO situation or when you want to maximize the responsiveness of the Popper. |
 | <span class="prop-name">modifiers</span> | <span class="prop-type">Array&lt;{ data?: object, effect?: func, enabled?: bool, fn?: func, name: any, options?: object, phase?: 'afterMain'<br>&#124;&nbsp;'afterRead'<br>&#124;&nbsp;'afterWrite'<br>&#124;&nbsp;'beforeMain'<br>&#124;&nbsp;'beforeRead'<br>&#124;&nbsp;'beforeWrite'<br>&#124;&nbsp;'main'<br>&#124;&nbsp;'read'<br>&#124;&nbsp;'write', requires?: Array&lt;string&gt;, requiresIfExists?: Array&lt;string&gt; }&gt;</span> |  | Popper.js is based on a "plugin-like" architecture, most of its features are fully encapsulated "modifiers".<br>A modifier is a function that is called each time Popper.js needs to compute the position of the popper. For this reason, modifiers should be very performant to avoid bottlenecks. To learn how to create a modifier, [read the modifiers documentation](https://popper.js.org/docs/v2/modifiers/). |
 | <span class="prop-name required">open<abbr title="required">*</abbr></span> | <span class="prop-type">bool</span> |  | If `true`, the popper is visible. |
-| <span class="prop-name">placement</span> | <span class="prop-type">any</span> | <span class="prop-default">'bottom'</span> | Popper placement. |
+| <span class="prop-name">placement</span> | <span class="prop-type">'auto-end'<br>&#124;&nbsp;'auto-start'<br>&#124;&nbsp;'auto'<br>&#124;&nbsp;'bottom-end'<br>&#124;&nbsp;'bottom-start'<br>&#124;&nbsp;'bottom'<br>&#124;&nbsp;'left-end'<br>&#124;&nbsp;'left-start'<br>&#124;&nbsp;'left'<br>&#124;&nbsp;'right-end'<br>&#124;&nbsp;'right-start'<br>&#124;&nbsp;'right'<br>&#124;&nbsp;'top-end'<br>&#124;&nbsp;'top-start'<br>&#124;&nbsp;'top'</span> | <span class="prop-default">'bottom'</span> | Popper placement. |
 | <span class="prop-name">popperOptions</span> | <span class="prop-type">{ modifiers?: array, onFirstUpdate?: func, placement?: 'auto-end'<br>&#124;&nbsp;'auto-start'<br>&#124;&nbsp;'auto'<br>&#124;&nbsp;'bottom-end'<br>&#124;&nbsp;'bottom-start'<br>&#124;&nbsp;'bottom'<br>&#124;&nbsp;'left-end'<br>&#124;&nbsp;'left-start'<br>&#124;&nbsp;'left'<br>&#124;&nbsp;'right-end'<br>&#124;&nbsp;'right-start'<br>&#124;&nbsp;'right'<br>&#124;&nbsp;'top-end'<br>&#124;&nbsp;'top-start'<br>&#124;&nbsp;'top', strategy?: 'absolute'<br>&#124;&nbsp;'fixed' }</span> | <span class="prop-default">{}</span> | Options provided to the [`popper.js`](https://popper.js.org/docs/v2/constructors/#options) instance. |
 | <span class="prop-name">popperRef</span> | <span class="prop-type">ref</span> |  | A ref that points to the used popper instance. |
 | <span class="prop-name">transition</span> | <span class="prop-type">bool</span> | <span class="prop-default">false</span> | Help supporting a react-transition-group/Transition component. |

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

@@ -360,7 +360,23 @@ Popper.propTypes = {
   /**
    * Popper placement.
    */
-  placement: PropTypes.any,
+  placement: PropTypes.oneOf([
+    'auto-end',
+    'auto-start',
+    'auto',
+    'bottom-end',
+    'bottom-start',
+    'bottom',
+    'left-end',
+    'left-start',
+    'left',
+    'right-end',
+    'right-start',
+    'right',
+    'top-end',
+    'top-start',
+    'top',
+  ]),
   /**
    * Options provided to the [`popper.js`](https://popper.js.org/docs/v2/constructors/#options) instance.
    */