Description
Affected rules
M5-0-3M5-0-7M5-0-8M5-0-9
Description
Return value of static_cast seems to be treated as a cvalue interferring with several MISRA rules:
M-0-8
When upcasting variable using static_cast and rightaway using the result in another expression, it triggers a M5-0-9 warning (illustrated in example function false_positive).
It forces the user to create a intermediate variable containing the result of the static_cast, then using this intermediate variable in the expression (illustrated in example function true_negative).
M-0-9
When changing variable's signedness using static_cast and rightaway using the result in another expression, it triggers a M5-0-9 warning (illustrated in example function false_positive).
It forces the user to create a intermediate variable containing the result of the static_cast, then using this intermediate variable in the expression (illustrated in example function true_negative).
Example
M-0-8
void false_positive() {
std::vector<std::uint8_t> v{0};
std::uint32_t u32{0};
v.at(static_cast<std::size_t>(u32)); // Triggers a M5-0-8 warning
}
void true_negative() {
std::vector<std::uint8_t> v{0};
std::size_t st = static_cast<std::size_t>(u32);
v.at(st); // Does not trigger a M5-0-8 warning
}M-0-9
void false_positive() {
std::vector<std::uint8_t> v{0};
std::int32_t s32{0};
v.at(static_cast<std::size_t>(s32)); // Triggers a M5-0-9 warning
}
void true_negative() {
std::vector<std::uint8_t> v{0};
std::size_t st = static_cast<std::size_t>(s32);
v.at(st); // Does not trigger a M5-0-9 warning
}