When Editor reload is on and user both hot reloads changes and tries to enter play-mode, editor crashes

More details from user: (needs confirmation)

it looks like if I recompile when it's not running (by using the shortcut of Fast Script Reload) and very quickly I use the shortcut to Play/Start by game, but the compilation has not finished, then it crashes Unity. (For info I use a Mac). I understand that it cannot run if the compilation is not finished, but sometimes I go too fast, and this happens. It would be good if it could just prevent to play instead of crashing Unity.

macOS の Unity editor で、Fast Script Reload をトリガーし、コンパイルが完了する前に直ちに Play mode に入ることで再現します。クラッシュの挙動を確認し、reload/play の遷移を追跡します。コンパイルがまだ実行中の場合に Play mode が安全に阻止され、Unity がクラッシュしない状態になれば完了です。

索引モデルが issue の本文から書いたものです。