Since the return value of getAccessor() depends on mutable state, it
does not make sense in the request evaluator world. Let's begin by
removing some utility methods derived from getAccessor(), replacing
calls to them with calls to getAccessor().
This function was called on storage in primary files only. The only
remaining difference between this and addExpectedOpaqueAcessorsToStorage()
was setting the body synthesizer callback, but that's cheap so just do it
unconditionally when we synthesize an accessor.
Implicit accessors are sometimes transparent for performance reasons.
Previously this was done in Sema by maybeMarkTransparent(), which would
add a TransparentAttr. Replace this with a request.
Accessors logically belong to their storage and can be synthesized
on the fly, so removing them from the members list eliminates one
source of mutability (but doesn't eliminate it; there are also
witnesses for derived conformances, and implicit constructors).
Since a few ASTWalker implementations break in non-trivial ways when
the traversal is changed to visit accessors as children of the storage
rather than peers, I hacked up the ASTWalker to optionally preserve
the old traversal order for now. This is ugly and needs to be cleaned up,
but I want to avoid breaking _too_ much with this commit.
Fixes rdar://problem/53407949 | SR-11138. Previously, we'd only look at the outermost property wrapper to decide whether the wrapped property's getter and setter were `mutating` (or exist at all). In reality, this requires considering the semantics of the composed accesses of each wrapper layer's
`wrappedValue` property. Fixing this systematically addresses a number of issues:
- As SR-11138 reported, composing a nonmutating-get-set wrapper ought to produce a composed wrapper
that's nonmutating.
- We would previously allow a property wrapper with a mutating getter to be nested inside one with
only a getter, even though the resulting implementation was unsound (because there's no mutable
context for the inner wrapper to execute its get on.)
- Similarly, we would construct unsound setters in cases where the setter can't exist, such as when
the nested wrapper isn't settable but the outer wrapper is.
Fixes a regression where the compiler would reject something like:
@State var x: Int?
as not having an initializer, even though an Int? property ought to default to nil.
rdar://problem/53504653
This merges Sema's special logic for updating the ImplInfo of lazy properties
and property wrappers with the StorageImplInfoRequest.
I had to move some code from the parser into the StorageImplInfoRequest, to
avoid request cycles caused by hasStorage() calls; this is the right thing to
do anyway.
Since hasStorage() now answers false for lazy properties and property wrappers,
we have to move some diagnostic checks from checkDeclAttributesEarly() to
the StorageImplInfoRequest implementation itself.
Over time, I expect all of the checks currently in checkDeclAttributesEarly()
and checkDeclAttributes() to either migrate to requests, or typeCheckDecl().
This just moves the code from the parser into a request. Sema will
still overwrite the ImplInfo field for lazy properties and
property wrappers; refactoring that is next.
We want to compute the former independently of the latter.
It's only 16 bits so storing it inside the Decl is fine;
it also allows us to eliminate the 'compact' representation
where an AbstractStorageDecl without an accessor record is
assumed to be stored.
Since getStoredProperties() is a request that lowers lazy properties
and property wrappers to their underlying storage, and SIL can validate
stored property and enum element types, there's no longer any need for
Sema to explicitly finalize members of structs and enums. SILGen can
trigger any necessary type checkin work just by lowering a struct or
enum type.
Now the only remaining reason we need finalizeDecl() is adding implicit
methods to classes, and synthesizing accessors for storage in classes
and protocols.
The idea here is to split up the logic into three parts:
- computation of the final ImplInfo for lazy, property wrappers
and @NSManaged
- deciding if we should add accessors or not
- actually adding the accessors
Instead of requiring that function body synthesizers will always call
setBody(), which is annoyingly stateful, have function body synthesizers
always return the synthesized brace statement along with a bit that
indicates whether the body was already type-checked. This takes us a
step closer to centralizing the mutation of the body of a function.
Also since we're lazier about validating accessors now, relax some
checks in the ASTVerifier so that it can tolerate implicit accessors
without interface types. All other declarations must still have
interface types in verifyChecked().
ASTVerifier: Tolerate implicit accessors without interface types
Extend handling of enclosing-self subscripts by differentiating
between the original wrapped property (which now goes through
`subscript(_enclosingInstance:wrapped:storage:)`) and the projected
property (which goes through
`subscript(_enclosingInstance:projected:storage:)`). The new middle
argument provides a key path to the property that was accessed,
allowing one to distinguish the property being updated.
Allow property wrapper types to support a second access pattern for
instance properties of classes. When supported, the property wrapper's
static subscript(_enclosingInstance:storage:) is provided with the
enclosing "self" and a reference-writable key path referring to the
backing storage property.
Implements rdar://problem/52222560.
Fix a bug with cross-file uses of the synthesized _foo/$foo for
properties with attached wrappers by implicitly triggering the
appropriate synthesis during name lookup.
Fixes rdar://problem/51725203.
When the outermost property wrapper associated with a property has a
`wrapperValue`, create the projection property (with the `$` prefix)
at the same access level as the original property. This puts the
wrapped-value interface and the projection interface at the same level.
The newly-introduced @_projectionValueProperty attribute is implicitly
created to establish the link between the original property and the
projection value within module interfaces, where both properties will
be explicitly written out.
My recent refactoring of default arguments for the memberwise initializer
accidentally dropped support for getting a default argument when the
attached property wrapper has an init(). Reinstate that support,
fixing rdar://problem/52116923.
