We already did this, but missed a few cases due to the way arguments are
elaborated. So now, when checking an LHS, we don't allow LHS argument
types to be inferred from the pattern, but rather they must be inferred
from elsewhere. To do this, we keep track of the constraints which would
be solved when inferring the type, and make sure they don't solve any
new metavariables. Fixes#1510, and also now gets the error location
right as a bonus!
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.
