`TypographyVariants` type augmentation not always working

Duplicates

• I have searched the existing issues

Latest version

• I have tested the latest version

Steps to reproduce 🕹

No response

Current behavior 😯

Currently https://mui.com/material-ui/customization/typography/#adding-amp-disabling-variants instructs you to add the following type augmentations:

declare module '@mui/material/styles' {
  interface TypographyVariants {
    poster: React.CSSProperties;
  }

  // allow configuration using `createTheme`
  interface TypographyVariantsOptions {
    poster?: React.CSSProperties;
  }
}

// Update the Typography's variant prop options
declare module '@mui/material/Typography' {
  interface TypographyPropsVariantOverrides {
    poster: true;
    h3: false;
  }
}

But in some cases accessing theme.typography.poster will still result in a type error:

    packages/theme/src/componentsOverrides/MuiCssBaseline.ts:8:21 - error TS2339: Property 'poster' does not exist on type 'Typography'.
    8     pre: typography.poster,
                          ~~~~~~

Expected behavior 🤔

Accessing theme.typography.poster will never result in a type error.

In our project, I have only found one solution: augmenting Typography directly, instead of TypographyVariants (alias of Typography):

declare module "@mui/material/styles/createTypography" {
  interface Typography {
    poster: TypographyStyle;
  }
}

Context 🔦

No response

Your environment 🌎

No response

Start with the type augmentation example in the typography documentation and the failing access in packages/theme/src/componentsOverrides/MuiCssBaseline.ts. Compare TypographyVariants with the Typography declaration in @mui/material/styles/createTypography, then verify that theme.typography.poster is accepted without the direct augmentation workaround. Done means the documented augmentation works consistently and the reported TypeScript error no longer occurs.