[Select] Unable to override styles with variants

• The issue is present in the latest release.
• I have searched the issues of this repository and believe that this is not a duplicate.

Current Behavior 😯

I’m unable to provide style overrides for the MuiSelect component.

Expected Behavior 🤔

I’m able to provide style overrides for the MuiSelect component.

Steps to Reproduce 🕹

The following codebox shows an example. I can change the styles for the Button, but not for the select. I’ve tried several combos of styles, but nothing seems to be injected:

https://codesandbox.io/s/material-ui-themes-forked-msl7f?file=/src/index.js

Context 🔦

Configuring the theme

Your Environment 🌎

System: OS: Linux 5.11 Ubuntu 21.04 (Hirsute Hippo) Binaries: Node: 12.14.0 - /usr/local/bin/node Yarn: 1.22.4 - /usr/local/bin/yarn npm: 6.14.4 - /usr/local/bin/npm Browsers: Chrome: Not Found Firefox: 92.0 npmPackages: @emotion/react: ^11.4.1 => 11.4.1 @emotion/styled: ^11.3.0 => 11.3.0 @mui/core: 5.0.0-alpha.49 @mui/icons-material: ^5.0.0 => 5.0.1 @mui/material: ^5.0.2 => 5.0.2 @mui/private-theming: 5.0.1 @mui/styled-engine: 5.0.1 @mui/system: 5.0.2 @mui/types: 7.0.0 @mui/utils: 5.0.1 @types/react: ^17.0.0 => 17.0.24 react: ^17.0.2 => 17.0.2 react-dom: ^17.0.2 => 17.0.2 typescript: ^4.1.2 => 4.4.3

[michaldudak]

@phudekar sure, go ahead!

[michaldudak]

Thanks for the report. It’s either a bug or insufficient info in the docs. I’ll take care of it.