https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127722
Bug ID: 127722
Summary: gcc --implicit-fallthrough documentation should
mention consecutive case labels
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: Keith.S.Thompson at gmail dot com
Target Milestone: ---
The "-Wimplicit-fallthrough" option causes gcc to warn about a
missing "break" statement in a switch statement. It has a number
of options that are irrelevant to this report.
If you have two or more consecutive case labels, that is strictly
speaking a "fallthrough":
switch (foo) {
case 0:
case 1:
// blah blah
break;
case 2:
// blah blah
break;
}
gcc quite reasonably doesn't warn about it, and I'm not suggesting
that it should -- but the documentation doesn't mention this case.
I suggest adding some wording, probably one sentence with a brief
example, saying that "case 0: case 1:" is not considered a
"fallthrough" for warning purposes.
The change would be in gcc/doc/invoke.texi .
(This is not a serious problem. I have not been inconvenienced by
it, other than a few minutes looking into it.)
