code-assertion.md

Code assertion

assert(bool_expression);

This statement introduces conditions to be checked at construction time only. If the condition fails, the compilation is aborted and the error is reported. It does not generate any constraint.

template Translate(n) {
assert(n<=254);
…..
}

The assert expression cannot depend on unknowns and will be checked at construction time. The next template will produce a compilation error.

template wrong(){
    signal input in;
    assert(0 < in);
}

Recall that, instead, when a constraint is introduced with ===, then an assert is automatically added in the witness generation code.