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Subject: Re: git: 16079c7233be - main - hid: quiet -Wswitch
To: Ryan Libby <rlibby@freebsd.org>, Vladimir Kondratyev <wulf@freebsd.org>,
 John Baldwin <jhb@freebsd.org>
Cc: src-committers <src-committers@freebsd.org>,
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From: Hans Petter Selasky <hps@selasky.org>
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Date: Mon, 11 Jan 2021 21:56:14 +0100
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On 1/11/21 8:05 PM, Ryan Libby wrote:
>> If these cases are never reachable, then I think '__assert_unreachable()'
>> is preferred to a plain break.
>
Hi,

> I'll have to let wulf and hselasky speak to that...

__assert_unreachable() is a bit fresh in my opinion. Basically it comes 
down to a panic/assert when supposedly unreached cases are triggered.

commit c79cee71363ddaeb3c5ab7d3ccb87a11e1860d95
Author: Kyle Evans <kevans@FreeBSD.org>
Date:   Wed May 13 18:07:37 2020 +0000

     kernel: provide panicky version of __unreachable

I think:

default:
  break;

Or when you need:

/* FALLTHROUGH */

is perfectly fine, even though I see other OS'es even macrofy 
FALLTHROUGH as a built in compiler attribute.

Why do a) and not b) ?

Are there more things about switch cases we should do?

--HPS