bugprone-misplaced-widening-cast¶
This check will warn when there is a cast of a calculation result to a bigger type. If the intention of the cast is to avoid loss of precision then the cast is misplaced, and there can be loss of precision. Otherwise the cast is ineffective.
Example code:
long f(int x) {
return (long)(x * 1000);
}
The result x * 1000 is first calculated using int precision. If the
result exceeds int precision there is loss of precision. Then the result is
casted to long.
If there is no loss of precision then the cast can be removed or you can
explicitly cast to int instead.
If you want to avoid loss of precision then put the cast in a proper location, for instance:
long f(int x) {
return (long)x * 1000;
}
Implicit casts¶
Forgetting to place the cast at all is at least as dangerous and at least as
common as misplacing it. If CheckImplicitCasts is enabled the check
also detects these cases, for instance:
long f(int x) {
return x * 1000;
}
Floating point¶
Currently warnings are only written for integer conversion. No warning is written for this code:
double f(float x) {
return (double)(x * 10.0f);
}