Instead of local-expanding the entire top-level forms at
once, wrap expressions in a top-level begin in trampolining
macro forms. This allows the typechecker to trampoline back
to the evaluator, which is necessary to declare/register
declarations made in a top-level begin.
The point of this change is to eliminate top-level hacks
and faciliate various macros that need to communicate using
multiple top-level forms.
Previous version replaced calls to, e.g., `cadr` with calls to `cdr`
then `car`, called the typechecker to populate the type table, then
optimized the exploded operations. The call to the typechecker failed
on open terms, limiting the applicability of the optimization, and was
just generally brittle.
The new version instead explodes operations, then optimizes them inside
out for as long as the argument's type guarantees it's safe. This works
on open terms, and should be more robust.
In the case that a let rhs doesn't return and therefore the
bodies of the let are unreachable, the bodies need to be marked
as ignored for the optimizer.
In addition, don't attempt unboxed let optimization at all
if the return type is Nothing since it probably means some
body expressions have no type.
Closes GH issue #165
The old check was broken for cases with type constructors
with more than one type argument and was also too conservative
in some cases (e.g., when one cycle refers to another cycle of
aliases in a non-recursive manner).
The new check is still conservative, but it allows more types
than before.
Closes GH issue #157
This is the correct change for how attempting to bind AnyValues results
caused internal type-checking errors. The root cause was get-type/infer
violating its own contract by using the default return value from
tc-error/expr
This (partially) reverts 5e0e8ed713.
Because -let-internal wasn't rename-out'd, users would see its name in
syntax error messages. Adding #:context forces the error messages to be
phrased in terms of the given form.
Since these promises re-evaluate their bodies every time they
are forced, allowing them makes `force` not idempotent and not
safe to treat as a path.
This change is slightly backwards-incompatible, since programs
that previously passed `delay/name` promises across the typed
boundary will now fail at runtime. The alternative is also
incompatible: stop treating `force` as a path. Since `delay/name`
is quite obscure, this approach seems like the safer choice.
