>>>>> "Michael" == Michael Matz <m...@suse.de> writes:
Michael> Not accepting
Michael> /* And here we intentionally fall through because ... */
Michael> and forcing users to replace this by:
Michael> /* fallthrough */
Michael> is not robust either. It's actually actively lowering robustness of
code,
Michael> it creates work for programmers that will be regarded as pointless
(and
Michael> rightly so) and will merely lead to everybody disabling the warning
(see
Michael> our generated files)
We can't control what programmers might do. My point is that accepting
too much is actively bad -- it hides errors. If this somehow makes some
programmer fall down a slippery slope, well, that's their error, not
gcc's.
TBH I think it would be better not to parse comments at all. Heuristics
are generally bad and this case and ensuing discussion is a great
demonstration of that.
The other day I built gdb with -Wimplicit-fallthrough. I was surprised
to find that gcc rejected this:
default:
{
complaint (&symfile_complaints,
_("Storage class %d not recognized during scan"),
sclass);
}
/* FALLTHROUGH */
/* C_FCN is .bf and .ef symbols. I think it is sufficient
to handle only the C_FUN and C_EXT. */
case C_FCN:
Presumably without the comment heuristic, this would be accepted.
Michael> The point of warnings is to make code robust under the condition of
not
Michael> being a pain by giving zillions of false positives.
My experience so far is that it's not so bad. gdb actually had comments
in most spots, they just required a quick pass to clean them up:
https://sourceware.org/ml/gdb-patches/2016-09/msg00375.html
And, code bases in more dire straights can just disable the warning after all.
Tom
