A recent patch introduced custom terms in expressions manipulated by the
interpreter. For typing reasons, a traversal is done to extend the supplied
expression with these custom terms — it's functionally the identity, but, due to
the fact that the type-checker can't infer covariance of our AST terms on their
phantom parameter, playing by the rules imposes a full traversal + rebuild.
Without resorting to a (constrained) `Obj.magic`, this patch avoids extra
intermediate conversions, which is enough to cut out the huge extra cost we were
incurring.
Closes#516
rather than scattered in structures
The context is still hierarchical for defs though, so one needs to retrieve the
path to lookup in the correct context for info. Exceptions are enums and struct
defs, which are re-exposed at toplevel.
This makes sure `catala module` finds the local runtime when run from the catala
source tree; and fixes lookup of the catala exec on custom uses of `clerk runtest`.
... and add a custom printer
Since this is a very common bug, this patch should gain us a lot of time when
debugging uncaught Not_found errors, because the element not found can now be
printed straight away without the need for further debugging.
The small cost is that one should remember to catch the correct specialised
`Foo.Map.Not_found _` exception rather than the standard `Not_found` (which
would type-check but not catch the exception). Using `find_opt` should be
preferred anyway.
Note that the other functions from the module `Map` that raise `Not_found` are
not affected ; these functions are `choose`, `min/max_binding`,
`find_first/last` which either take a predicate or fail on the empty map, so it
wouldn't make sense for them (and we probably don't use them much).