https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104392
Bug ID: 104392
Summary: Unexpected Narrowing Warning when spaceship comparison
of unsigned bit field
Product: gcc
Version: 11.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: bieri.hp at gmail dot com
Target Milestone: ---
struct A
{
unsigned int a:5;
};
constexpr std::strong_ordering operator<=>(const A & left, const A & right )
{
return left.a <=> right.a;
}
results in the unexpected warnings
<source>: In function 'constexpr std::strong_ordering operator<=>(const A&,
const A&)':
<source>:15:21: warning: narrowing conversion of 'left.A::a' from 'const
unsigned int' to 'int' [-Wnarrowing]
15 | return left.a <=> right.a;
| ~~~~~^
<source>:15:33: warning: narrowing conversion of 'right.A::a' from 'const
unsigned int' to 'int' [-Wnarrowing]
15 | return left.a <=> right.a;
| ~~~~~~^
it seems to choose the int comparison operator although the type is unsigned
