https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103597
Bug ID: 103597
Summary: False -Wimplicit-fallthrough= involving macro
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: sbergman at redhat dot com
Target Milestone: ---
I think this is a recent regression on GCC 12 trunk (I'm at
basepoints/gcc-12-5818-g30a08286e67; it doesn't happen with e.g.
gcc-c++-11.2.1-1.fc35.x86_64):
> $ cat test.cc
> #define E(c, e) if (c) e
> int f(int n) {
> switch (n) {
> case 0:
> E(true, return 0);
> case 1:
> return 1;
> }
> return 2;
> }
> $ g++ -c -Wimplicit-fallthrough test.cc
> test.cc: In function ‘int f(int)’:
> test.cc:1:17: warning: this statement may fall through
> [-Wimplicit-fallthrough=]
> 1 | #define E(c, e) if (c) e
> | ^~
> test.cc:5:9: note: in expansion of macro ‘E’
> 5 | E(true, return 0);
> | ^
> test.cc:6:5: note: here
> 6 | case 1:
> | ^~~~
