I don't know how complete this is, but it certainly detects some of the
most obvious cases which are most likely to be bugs.
While I'm at it, this is as good a time as any to add a general way of
reporting warnings, similar to the way of reporting errors.
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.
The hack (optimisation?) to normalise integer literals when below some
threshold is fine on the RHS, but on the LHS causes problems since we
need them in normal form for pattern matching. Fixes#112
This improves coverage checking, because it can now see that things like
(Z = S x) and (x = S x) are empty. Previously, it only checked that all
possible constructors had a disjoint index. Now, it looks for matches
and checks for disjointness in the matches, which catches a lot more
things especially with equality.
As in Idris 1 - if an interface declares a method as total or covering,
then all implementations have to satisfy that.
Temporarily turn off %default directive again, at least until totality
checking works as it should (this is probably better than removing it
from various places because I'll forget to put them back)
This means temporarily removing some '%default total' from the libraries
and tests, since the input for codata checking isn't right yet (it needs
appropriate use of inlining)
Should have done this ages ago, it was much easier than I expected...
this adds an explicit error clause before running the pattern match
compiler for runtime case trees, but only if the coverage checker finds
there are missing cases.
