https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99018
Bug ID: 99018
Summary: Comparing address of array element not considered a
constant expression in certain contexts
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: david at doublewise dot net
Target Milestone: ---
The following valid translation unit
```
struct s {
constexpr s() = default;
constexpr s(s const & other) {
if (this == &other) {
}
}
};
constexpr auto f() {
s init[2];
for (auto & element : init) {
s foo = element;
}
return true;
}
static_assert(f());
```
is rejected by gcc with
```
<source>:18:16: error: non-constant condition for static assertion
18 | static_assert(f());
| ~^~
<source>:18:16: in 'constexpr' expansion of 'f()'
<source>:13:11: in 'constexpr' expansion of 's((*(const s*)(& element)))'
<source>:5:26: error: '(((const s*)(& foo)) == (((const s*)(& init)) + 1))' is
not a constant expression
5 | if (this == &other) {
| ~~~~~^~~~~~~~~
Compiler returned: 1
```
See it live: https://godbolt.org/z/xG5dv5
