TypeScript "Move to a new file" code action not working for embedded documents

[johnsoncodehk]

For non-ts files, getEditsForRefactor will hit the following assertion.

Error: Debug Failure. File /.../xxx.yyy has unknown extension.

This is hardcoded by TS in the internal variable extensionsToRemove, and there is currently no way to modify it.

[louisgv]

Is it really not possible to fix this issue without patching TS? :-?... If so, I feel like we should tag the TS maintainer to ask or open an issue on TS to get their attention.