https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122050
Bug ID: 122050
Summary: statement expressions with an empty expression at the
end have different behavior between C and C++
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Keywords: stmt-expr, wrong-code
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
Take:
```
int foo() {
return ({1; 2; 3;;});
}
```
The C and C++ front-end have different behaviors here.
>From my anlysis of the differences in the front-end behavior:
Looks like what is happening for the GCC's C front-end is an empty statement
that is ; by itself does NOT add to the statement lists so it is ignored. This
is the behavior since at least GCC 4.0. (I don't have any earlier to test). and
then when finished with the statement expression, the front-end only looks at
the statement list.
While the GCC's C++ front-end does the processing/parsing of a statement
expression differently. the end of the statement expression is handled while
parsing of the last expression.
Now the documentation of statement expressions
(https://gcc.gnu.org/onlinedocs/gcc-15.2.0/gcc/Statement-Exprs.html) seems to
imply the C++ behavior though:
```
The last thing in the compound statement should be an expression followed by a
semicolon; the value of this subexpression serves as the value of the entire
construct. (If you use some other kind of statement last within the braces, the
construct has type void, and thus effectively no value.)
```
Which one is right or is this just a documentation issue?
