It's a big patch, but the summary is that it's okay to use a pattern in
an erased position if either:
- the pattern can also be solved by unification (this is the same as
'dot patterns' for matching on non-constructor forms)
- the argument position is detaggable w.r.t. non-erased arguments, which
means we can tell which pattern it is without pattern matching
The second case, in particular, means we can still pattern match on
proof terms which turn out to be irrelevant, especially Refl.
Fixes#178
This is the result of running the command:
$ find . -name '*.idr' -type f -exec sed -i -E 's/\s+$//' {} +
I confirmed before running it that this would not affect any markdown
formatting in documentation comments.
This is part of what we used to have in Enum but I think it's better to
separate the two. Added implementations for Nat, and anything in
Integral/Ord/Neg, so that we get range syntax (at least when its
implemeted) for the most useful cases.
There's a bit of a trade off here. It would be better to report the
ambiguity but this would lead to a need for (I think) excessive
precision in types which would impact usability. It will always take the
leftmost interface.
Chapter 7 tests added.
Idris 1 will fill in the last metavariables by matching rather than
unification, as a convenience. I still think this is okay, even if it's
a bit hacky, because it's a huge convenience and doesn't affect other
unification problems.
Also abstract over lets in guesses, like in delayed elaborators, to
avoid any difficulties when linearity checking and to make sure that let
bound things don't get reevaluated.
This is enough to get the Chapter 6 TypeDD tests working
