ASSERT$.html -- ACL2 Version 6.3

### ASSERT$

cause a hard error if the given test is false

    Major Section:  ACL2-BUILT-INS

    General Form:
    (assert$ test form)

where `test` returns a single value and `form` is arbitrary. Semantically, this call of `assert$` is equivalent to `form`. However, it causes a hard error if the value of `test` is `nil`. That hard error invokes the function `illegal`, which has a guard that is equal to `nil`; so if you use `assert$` in code for which you verify guards, then a proof obligation will be that the occurrence of `test` is never `nil`.