https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87724
Bug ID: 87724
Summary: gcc allows narrowing conversions in converted constant
expressions
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: blitzrakete at gmail dot com
Target Milestone: ---
Compiled with -std=c++17 (https://godbolt.org/z/fO32Pd)
int main() {
static_assert(2); // ill-formed, gcc accepts
if constexpr (2); // ill-formed, gcc accepts
}
2 doesn't fit in a bool, and as such it is a narrowing conversion and fails to
be a "contextually converted constant expression of type bool" as per
[expr.const]p5.
