The 3rd kind of assignment kind (Bind) is gone and now reflected through a boolean parameter. Note that this parameter is completely erased by the type-checker so that the rest of the pipeline (i.e. code-generation) doesn't have to make any assumption. They simply can't see a backpassing let or expect.
This improves error messages for `a |> b(x)`.
We need to do a special check when looping over the args
and unifying. This information is within a function that does not belong
to pipe typer so I used a closure to forward along a way to add
metadata to the error when the first argument in the loop has a
unification error. Simply adding the metadata at the pipe typer
level is not good enough because then we may annotate regular
unification errors from the args.
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
KtorZ