Make type annotations abstract in type_check.mli

Rather than exporting the implementation of type annotations as

type tannot = (Env.t * typ * effect) option

we leave it abstract as

type tannot

Some additional functions have been added to type_check.mli to work
with these abstract type annotations. Most use cases where the type
was constructed explicitly can be handled by using either mk_tannot or
empty_tannot. For pattern matching on a tannot there is a function

val destruct_tannot : tannot -> (Env.t * typ * effect) option

Note that it is specifically not guaranteed that using mk_tannot on
the elements returned by destruct_tannot re-constructs the same
tannot, as destruct_tannot is only used to give the old view of a type
annotation, and we may add additional information that will not be
returned by destruct_tannot.

0 files changed, 0 insertions, 0 deletions