We stored them as equations between terms, I think because terms are
easy to re-evaluate with new information, and because I thought we might
want to save them out. It's not usually a problem to do that. However...
Going back and forth between terms and values can be expensive if
we're stuck in the middle of a complicated unification problem, the like
of which can turn up a lot if your types are complicated. So, we need to
be able to handle this.
Now store the postponed problems as NF, rather than Term, and add a
fuction to resume evaluating a NF with an updated context.
This adds new `Int8`, `Int16`, `Int32` and `Int64` data types
to the compiler, thus working towards properly specified integer
types as discussed in #1048.
In addition, the following changes / corrections are made:
* Support casts from `Char`, `String`, and `Double` to all integer
types (and back). This fixes#1270.
* Make sure that all casts to limited-precision integers are properly
bounds checked (this was not the case so far for casts from `String`
and `Double` to `Int`)
* Add a thorough set of tests to make sure all bounds checks work
correctly for all supported casts and arithmetic operations
Including appropriate casts, and Num/Eq/Ord/Show implementations.
Also includes new primitives in Data.Buffer, and calls to foreign
functions in C as 'unsigned'.
Still a couple of things to resolve in coverage and totality checking
before we can switch on %default, so don't expect quite the right
behaviour just yet. More progress though!
Also working on this has caught a few totality errors in the Idris 2
code base that Idris 1 missed... so these are fixed on the way.