Params being unused were being incorrectly reported.
This was because params need to be initialized
at a scope above both the validator functions. This
manifested when using a multi-validator where one of
the params was not used in both validators.
The easy fix was to add a field called
`is_validator_param` to `ArgName`. Then
when infering a function we don't initialize args
that are validator params. We now handle this
in a scope that is created before in the match branch for
validator in the `infer_definition` function. In there
we call `.in_new_scope` and initialize params for usage
detection.
This caused me some trouble. In my first approach, I ended up having
multiple traces because nested values would be evaluated twice; once
as condition, and once as part of the continuation.
To prevent this, we can simply evaluate the condition once, and return
plain True / False boolean as outcome. So this effectively transforms any
expression:
```
expr
```
as
```
if expr { True } else { trace("...", False) }
```
I decided to invert how I'm doing it. I'm passing
in a new argument to unify in environment called
allow_cast: bool and essentially at various
unification sites I can control whether or not I
want to allow casting to even occur. So we can
assume it's false by default always and then we
turn it on in a few places vs. just opening the
flood gates and locking it down at various sites
as they come up# Please enter the commit message
for your changes. Lines starting
This is a bit annoying as we are forced to use #[related] here which isn't quite what we want.
Ideally, this would use #[diagnostic_source] but, there's a bug upstream. See: zkat/miette#172.
Due to how PlutusData works it doesn't make sense
to allow user defined types to contain
functions.
```
type Foo {
bar: fn(Int) -> Int
}
```
The above definition will now return an error.
KtorZ