Multiple declare module '@mui/material/Button' don't work

Duplicates

• I have searched the existing issues

Latest version

• I have tested the latest version

Current behavior 😯

The current advise is to use the following code

declare module '@mui/material/Button' {
  interface ButtonPropsVariantOverrides {
    pill2: true
  }
}

This works if they are in the same file, you can see that pill2 is recognized:

If I move the second declaration to another file it isn't picked up anymore:

If I replace the import paths with '@mui/material/Button/Button' it works as expected:

Expected behavior 🤔

The documentation should probably advise the following code:

declare module '@mui/material/Button/Button' {
  interface ButtonPropsVariantOverrides {
    pill2: true
  }
}

Steps to reproduce 🕹

See screenshots in Current behavior.

Context 🔦

We have some base declarations we want to make and allow 'implementors' add new declarations.

Your environment 🌎

 System:
    OS: macOS 12.2.1
  Binaries:
    Node: 14.19.0 - ~/.nvm/versions/node/v14.19.0/bin/node
    Yarn: 1.19.1 - ~/.nvm/versions/node/v14.19.0/bin/yarn
    npm: 6.14.16 - ~/.nvm/versions/node/v14.19.0/bin/npm
  Browsers:
    Chrome: 99.0.4844.51
    Edge: 99.0.1150.36
    Firefox: Not Found
    Safari: 15.3

Reproduce the issue using two separate TypeScript declaration files for '@mui/material/Button', then compare that result with the '@mui/material/Button/Button' path shown in the report. Start by examining the module-augmentation guidance referenced in the issue; done means the documented declaration path works when declarations are split across files.