Bug 103402

Summary: Compile-time less/more comparison of a pointer vs nullptr
Product: gcc Reporter: Fedor Chelnokov <fchelnokov>
Component: c++Assignee: Not yet assigned to anyone <unassigned>
Status: NEW ---    
Severity: normal CC: gabravier, webrown.cpp
Priority: P3 Keywords: accepts-invalid
Version: 12.0   
Target Milestone: ---   
See Also: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70196
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111379
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103552
Host: Target:
Build: Known to work:
Known to fail: Last reconfirmed: 2025-03-17 00:00:00
Bug Depends on:    
Bug Blocks: 55004    

Description Fedor Chelnokov 2021-11-24 08:52:35 UTC
The following code is invalid and must be rejected:
```
int main() {
    static constexpr int x = 1;
    constexpr const int * p = nullptr;
    static_assert( p < &x );
}
```
because less/more comparison with nullptr has unspecified value and cannot appear in a constant expression.

Clang correctly rejects the code, demo: https://gcc.godbolt.org/z/E4ME4zh3M
Comment 1 Drea Pinski 2021-11-24 09:02:54 UTC
Confirmed.