Remove switch case fallthrough

[Steven Schveighoffer]

On 5/13/21 10:27 AM, rempas wrote:
> On Thursday, 13 May 2021 at 14:15:15 UTC, Steven Schveighoffer wrote:
>> On 5/13/21 9:28 AM, rempas wrote:
>>> [...]
>>
>> It's already deprecated, since 2.072. It's also been a warning since 
>> 2.054. I'm not sure if this is intended to be removed or not, but 
>> removing it today would put it at a 4.5 year deprecation period, and 
>> 10 years since it's been a warning.
>>
>>> [...]
>>
>> Nobody thinks case fallthrough is good, this is why it's a warning and 
>> deprecated.
>>
> 
> My mistake for not being clear, like I said to the other comments, I 
> mean that we should not need the "break" anymore.

First step is to make implicit fallthrough an error instead of a 
deprecation. Then after a time, we might be able to make break optional.

-Steve