* Add field for universe level to TType
This doesn't do anything yet, other than introduce new universe
variables whenever we introduce a new type, but it's the first step
towards checking the universe hierarchy. Next step is to add constraints
when checking pi, unifying/converting types, and when adding data
constructors.
* TTC version increment
Thought I'd done this, but apparently I didn't save the file. Oops!
* Add structure for universe constraints
* Fix display of ambiguity errors
We need to store the Context in errors at the point where the error
occurs, or we might get some nonsense in the message. There's still a
couple of places in Error where we don't do this right. This fixes one
of them, and improves a few messages in the process.
While the discussion about how to refactor test framework is not
finished (#1654), make this change: move `rm -rf build` in the
beginning of the test. For these reasons:
* it is useful to inspect the contents of the `build` directory
especially after the test failure
* if build crashes mid-test (e.g. process killed), next run should
not be affected by the `build` directory from the previous run
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.
helps with readability since these, especially named-IPi, come up a lot
didn't change everything that could need it like PiInfo or BindMode
PiInfo rarely has DefImplicit (so far) and BindMode hasn't come up a lot (so far)
reduced indentation for TTImp Show implementation
This is mostly to make it easier to write linear function types without
having to invent names for everything, which might be noisy. Also it
improves the display of linear function types when the name isn't used
in the scope.
