Minecraft crashed and the launcher showed a dialog box asking me to report the crash. I accepted and then clicked the report button at the top right of the Crash Report pane of the launcher window. This caused the dialog box to reappear. This meant that I could not report the crash through the launcher, because clicking either of the two buttons would just present the other for me to click.

This was also the first time the launcher asked me to report a crash, and the first time a crash report file was generated. All previous crashes have resulted in the launcher exiting immediately after the game.