On Friday, 25 May 2018 at 23:05:51 UTC, Jonathan M Davis wrote:
Sure, it can be argued that this should be unnecessary and that the programmer should just get it right, but it's not an altogether uncommon bug to screw up case statements and invadvertently fall through to the next one when you meant to put a break or some other control statement there. Originally, implicit fallthrough was perfectly legal in D just like it is in C or C++. However, when it was made illegal, it caught quite a few bugs in existing programs - including at companies using D. This change to the language fixed bugs and almost certainly saved people time and money.
and that the issue is real in C is also illustrated by the fact that gcc now warns about implicit fallthrough since version 7. One has to add at least a comment to suppress the warning (btw the implementation of the heuristic to analyse the comments is more or less broken, I had to file my first bug report to gcc about it).
