[material-ui][Alert] Can't set slots in theme's defaultProps in 5.15.11

[andrei-shoreline]

Steps to reproduce

Steps:

1. Create a custom theme using createTheme
2. Configure MuiAlert component:

const theme = createTheme({
  components: {
    MuiAlert: {
      defaultProps: {
        slots: {
          closeIcon: CloseRounded,
        },
      },
    },
  },
});

Current behavior

TypeScript gives the following error:

Object literal may only specify known properties, but 'slots' does not 
exist in type 'Partial<AlertProps>'. Did you mean to write 'slot'?

Expected behavior

It shouldn't throw an error and it should work the same as in the previous 5.15.10 version.

Context

In our application we customised the default theme using the createTheme utility.

Your environment

npx @mui/envinfo

  System:
    OS: macOS 14.3.1
  Binaries:
    Node: 20.11.1 - /opt/homebrew/opt/nvm/versions/node/v20.11.1/bin/node
    npm: 10.2.4 - /opt/homebrew/opt/nvm/versions/node/v20.11.1/bin/npm
    pnpm: Not Found
  npmPackages:
    @emotion/react: 11.11.4 => 11.11.4
    @emotion/styled: 11.11.0 => 11.11.0
    @mui/base:  5.0.0-beta.37
    @mui/core-downloads-tracker:  5.15.11
    @mui/icons-material: 5.15.11 => 5.15.11
    @mui/lab: 5.0.0-alpha.166 => 5.0.0-alpha.166
    @mui/material: 5.15.11 => 5.15.11
    @mui/private-theming:  5.15.11
    @mui/styled-engine:  5.15.11
    @mui/system:  5.15.11
    @mui/types:  7.2.13
    @mui/utils:  5.15.11
    @mui/x-data-grid: 6.19.5 => 6.19.5
    @mui/x-date-pickers: 6.19.5 => 6.19.5
    @types/react: 18.2.61 => 18.2.61
    react: 18.2.0 => 18.2.0
    react-dom: 18.2.0 => 18.2.0
    typescript: 5.3.3 => 5.3.3

Search keywords: Alert, slots, 5.15.11

[DiegoAndai]

Hey @andrei-shoreline, thanks for the report. We're working on it 👍🏼

[DiegoAndai]

The fix should be released on the next version, v5.15.13, next week. Sorry for the inconvenience.

[andrei-shoreline]

Thank you for the fix!