https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100215
Bug ID: 100215
Summary: Improve text of -Wmaybe-uninitialized references
Product: gcc
Version: 10.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: jengelh at inai dot de
Target Milestone: ---
Request for enhancements on a particular warning message emitted for shoddy
code.
Input:
```
#include <list>
#include <cstring>
struct C {
C() = default;
C(C &&o) { memcpy(bar, o.bar, sizeof(bar)); }
int foo = -1;
char bar[1024];
};
int main()
{
C z;
std::list<C>().push_back(std::move(z));
}
```
Command & observed output:
```
$ g++ -v
gcc version 10.3.0 (SUSE Linux)
$ g++ test.cpp -O2 -Wall
t2.cpp:5:19: warning: ‘*((void*)& z +4)’ may be used uninitialized in this
function [-Wmaybe-uninitialized]
5 | C(C &&o) { memcpy(bar, o.bar, sizeof(bar)); }
| ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
```
The warning references the original variable name, and the caret is placed in a
somewhat arbitrary position.
Expected output:
```
t2.cpp:5:19: warning: ‘o.bar’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
5 | C(C &&o) { memcpy(bar, o.bar, sizeof(bar)); }
| ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~
```
- granted, z+4 is a result of the optimizer; it would be nice if it could show
o+4 though
- more on that, z+4/o+4 could be shown as z.bar/o.bar
- caret be adjusted accordingly to point to the 2nd argument of memcpy
