• Rollup Plugin Name: plugin-babel
• Rollup Plugin Version: 5.3.0
• Rollup Version: 2.63
• Operating System (or Browser): Windows
• Node Version: v14.15.5
• Link to reproduction: https://regex101.com/r/y6BLj8/2

Expected Behavior

PreflightChecks are passed

Actual Behavior

Error: An unexpected situation arose. Please raise an issue at https://github.com/rollup/plugins/issues. Thanks!

Additional Information

https://github.com/facebook/create-react-app/blob/a422bf227cf5294a34d68696664e9568a152fd8f/packages/babel-preset-react-app/create.js#L194 is using

absoluteRuntimePath = path.dirname(
      require.resolve('@babel/runtime/package.json')
    );

which on Windows evaluates to <my-source-path>\\rollup-babel-bug\\node_modules\\@babel\\runtime. This breaks the preflightCheck at

const inheritsHelperRe = /[\\\/]+helpers[\\\/]+(esm[\\\/]+)?inherits/;

If possible to verify on Windows I can provide a reproduction repo.

No matter what, I'll create a PR for the change.