IDE functionality needs some internal type checking logics, e.g. checking
whether an extension is applicable to a concrete type. We used to directly
expose an header from sema called IDETypeChecking.h so that IDE functionalities
could invoke these APIs. The goal of the commit and following commits is to
expose evaluator requests instead of directly exposing function entry points from
sema so that we could later move IDETypeChecking.h to libIDE and implement these functions
by internally evaluating these requests.
This improves on the previous situation:
- The request ensures that the backing storage for lazy properties
and property wrappers gets synthesized first; previously it was
only somewhat guaranteed by callers.
- Instead of returning a range this just returns an ArrayRef,
which simplifies clients.
- Indexing into the ArrayRef is O(1), which addresses some FIXMEs
in the SIL optimizer.
Adds a NumStoredPropertiesQueries stat.
Adds a test case for an increasing number of lazy stored class
properties. Each property requires a formal access within the
initializer. This would manifest as cubic behavior in
AccessEnforcementOpts, which scales as O(1.5) in the above stat.
Sema no longer adds conformances to a per-SourceFile list that it thinks
are going to be "used" by SILGen, IRGen and the runtime. Instead, previous
commits already ensure that SILGen determines the set of conformances to be
emitted, triggering conformance checking as needed.
Introduce three new requests for name lookup operations that avoid performing
type checking/semantic analysis. They work using syntactic information
(e.g., TypeReprs) and AST-level name lookup operations that will (eventually)
avoid and calls back into type checking. The new requests are:
* Retrieve the superclass declaration of a protocol or class declaration. Use
this request for ClassDecl::getSuperclassDecl() and
ProtocolDecl::getSuperclassDecl().
* Retrieve the types “directly referenced” by a particular location in
an inheritance clause. This query is based on looking at the TypeReprs
and performing fairly-minimal lookup, so it does not involve any Type
computations.
* Retrieve the types “directly referenced” by the underlying type of
a typealias. This query allows us to desugar a typealias without forming
a type.
Along with these is a core operation to transform a set of TypeDecl*s
into a set of NominalTypeDecl*s, looking through typealiases, and
without involving Type at all. The superclass-decl request does this
to find a ClassDecl; other requests will eventually do this to (e.g.)
find all of the protocols mentioned in an inheritance clause.
Sink the type checker request classes into the AST library, so that
various functions in the AST library can form type-checking requests.
The actual evaluator functions for these requests continue to live
in the Sema library, called via indirection through the function
pointer tables registered with the request-evaluator.
