- now uses the right type for a boolean function

- these tests do not use anymore datacons, another error is thus triggered

- now, its a single constructor
- also adds a boolean logic constant

Also documents that the behavior of a%b depends on the behavior of a/b.

Only emits overflow alarms on [a/b] when [a] may be equal to [min_int] AND
[b] may be equal to [-1]. Also reduces the values of [a] and [b] when possible.

According to the C standard, section 6.5.5 §6:
"If the quotient a/b is representable, the expression (a/b)*b + a%b shall equal a;
otherwise, the behavior of both a/b and a%b is undefined."

When an invalid status is emitted for the instance of a precondition at a
callsite, registers as "high priority" the instance as well as the precondition
itself.

- object_pointer end of structure
- dangling -> not object_pointer