Using built-in source maps breaks webpack build

I have a library with src / and lib / and compiling with babel —source-maps inline

. src -> lib. I am using this library in another project (webpack + babel-loader).

If not embedded, access to the original maps is available. It points to files - lib/a.js

instead of src/a.js

. So you will have to use the built-in source maps

When the source maps are inline, babel generates lib/a.js

correctly, but the webpack build finishes with the message -Module build failed: Error: No element indexed by 1