Assert Function

Noir includes a special assert function which will explicitly constrain the predicate/comparison expression that follows to be true. If this expression is false at runtime, the program will fail to be proven.

Example

fn main(x : Field, y : Field) {
    assert(x == y);
}

The above snippet compiles because == is a predicate operation. Conversely, the following will not compile:

// INCORRECT

fn main(x : Field, y : Field) {
    assert(x + y);
}

The rationale behind this not compiling is due to ambiguity. It is not clear if the above should equate to x + y == 0 or if it should check the truthiness of the result.