Assertions are to be used for situations that should never happen, so the expression on the assert statement has to mean an impossible condition. Should this condition happen, it means there is a defect in the software.
In contrast with the error handling approach, here there is (or should not be) a possibility of continuing the program. If such an error occurs, the program must stop. It makes sense to stop the program because, as commented before, we are in the presence of a defect, so there is no way to move forward by releasing a new version of the software that corrects this defect.
The idea of using assertions is to prevent the program from causing further damage if such an invalid scenario is presented. Sometimes, ...
