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.
The `identifier-binding` function is now senstive to the "macro
introduction" scope that's on an indentifier provided to a currently
expanding macro. Unit tests for TR need to use
`syntax-local-intorduce` to remove it, in the same way that `tc-setup`
already does.
Also, recognize a class expansion when it's wrapped with
`#%expression`, since `class` now expands that way sometimes.
This enables contract generation in the negative
direction (untyped->typed) for row polymorphic types
(basically mixin types).
Depends on `class-seal` and `class-unseal` in
the racket/class library.
This patch addresses two issues with `typed/racket/class`:
1. For multiple private fields declared with `define-values`, type
information does not propagate from the values produced by the
initialization expression to the declared fields. This breaks soundness
of private fields: A field can be annotated with a type that does not
contain the field's initial value.
This was resolved by keeping a table of temporary bindings introduced in
the expansion of the initializer along with their types. The field
setter's type is then checked against that of the corresponding
temporary.
2. The class body typechecker assumes that the `expr` of
a `define-values` clause will expand to a bare `(values vs ...)`.
This was resolved by generalizing the template for matching an expanded
`define-values` initializer and extracting the type information from the
`expr` instead of each element in `(vs ...)`.
Previously the restriction didn't account for traversing
the object type with the given path. This also relies on
the previous commit that adds subtyping on filters.
(because this change seems to introduce filters which
only differ by an unrolling of a recursive type, but
the old subtyping only worked for identical types)
This makes a type like
(-> Any Boolean : #:+ Integer)
a subtype of a type like
(-> Any Boolean : #:+ Number)
For not filters, the direction is reversed.
