Had a bug in this code:
bool x;
for(const auto a : b)
{
x = x && a.b;
}
x should have initialized to true.
I'd like to raise a compiler error that the bool wasn't explicitly initialized, but I cannot find a warning which covers this. We have the obvious flags:
-Wall \
-pedantic \
-Werror=uninitialized \
Is there another Clang warning that would catch this and other uninitialized variables?
For this particular issue, compile with -Werror=conditional-uninitialized and you'll get a clear warning, turned into an error:
<source>:10:13: error: variable 'x' may be uninitialized when used here [-Werror,-Wconditional-uninitialized]
10 | x = x && a.b;
| ^
<source>:7:11: note: initialize the variable 'x' to silence this warning
7 | bool x;
| ^
| = false
-Weverything and then selectively turn off the warnings I don't want (like incompatibility with C++98 etc.). For example: -Weverything -Wno-c++98-compat -Wno-c++98-compat-pedantic -Wno-newline-eof -Wno-c++20-compat -Wno-missing-prototypes -Wno-ctad-maybe-unsupported
-Wall -Wextra -Wpedantic -Werror. There's probably a handful of stuff from -Weverything that might be useful but most of it is compatibility warnings that can often be mutually exclusive with these categories.-Weverything.-fsanitize=bool can catch it if you enable optimizations.
#include <vector>
struct foo { bool b = true; };
int main() {
bool x;
std::vector<foo> b(5);
for(const auto a : b)
{
x = x && a.b;
}
}
clang(trunk) and -fsanitize=bool -O3:
UndefinedBehaviorSanitizer:DEADLYSIGNAL
==1==ERROR: UndefinedBehaviorSanitizer: SEGV on unknown address 0x000000000001 (pc 0x000000000001 bp 0x000000000000 sp 0x7ffe5711f3a8 T1)
==1==Hint: pc points to the zero page.
==1==The signal is caused by a READ memory access.
==1==Hint: address points to the zero page.
UndefinedBehaviorSanitizer:DEADLYSIGNAL
UndefinedBehaviorSanitizer: nested bug in the same thread, aborting.
