### Fixed

* Disallow using base to invoke an abstract base method ([Issue #13926](https://github.com/dotnet/fsharp/issues/13926), [PR #16773](https://github.com/dotnet/fsharp/pull/16773))

### Added

* `while!` ([Language suggestion #1038](https://github.com/fsharp/fslang-suggestions/issues/1038), [PR #14238](https://github.com/dotnet/fsharp/pull/14238))
