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 ...)`.
In conjunction with a small change to syntax/parse, this means
that `typed/racket/base` no longer depends on `racket/set`,
`racket/contract/base`, or `racket/generic`.
Timings on my machine go from ~200ms for `#lang typed/racket/base`
as the whole file, to ~100ms. For comparison, `racket/base` is 30ms
and `#lang racket` is 150ms. `#lang typed/racket` is ~200ms with
this change.
Changes include:
- not using `in-syntax`
- switching to `syntax/parse/pre`
- avoiding `template` from `syntax/parse`
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.
