http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57170
Bug #: 57170
Summary: No diagnostic for a negative case when switching over
unsigned
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: vvnic.ho...@gmail.com
A signed->unsigned conversion is narrowing, so -1 is not a converted constant
expression. However, the following emits no warning with -Wall, with or without
-std=c++11:
int main() {
unsigned a = 10;
switch (a) {
case -1:
break;
}
return 0;
}
But replacing "unsigned" with any smaller unsigned type (unsigned char or
unsigned short) yields the following warning:
test.cpp:4:9: warning: case label value is less than minimum value for type
[enabled by default]
case -1:
