https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87230
Bug ID: 87230
Summary: GCC should warn if [[fallthrough]] is used in the last
case in a switch
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: david.bolvansky at gmail dot com
Target Milestone: ---
void f(int n) {
void g(), h(), i();
switch (n) {
case 1:
case 2:
g();
[[fallthrough]];
case 3: // no warning on fallthrough
h();
case 4: // compiler may warn on fallthrough
if(n < 3) {
i();
[[fallthrough]]; // OK
}
else {
return;
}
case 5:
[[fallthrough]]; // ill-formed, no subsequent case or default label
}
}
gcc -O3 -std=c++17 -Wall -Werror -> no errors
clang -O3 -std=c++17 -Wall -Werror ->
<source>:24:7: error: fallthrough annotation does not directly precede switch
label
[[fallthrough]]; // ill-formed, no subsequent case or default label
^
