Instead of visiting all members of all types and extensions, bail out
early if the type is not a class or protocol, or the extension is not
extending a class. This means we don't visit structs, enums or
protocol extensions at all, which will avoid delayed parsing.
Also, we were evaluating isObjC() on each member, which is an expensive
operation; if the member does not have an explicit @objc we would still
have to check if it overrides an @objc method or witnesses an @objc
protocol requirement.
Since most members are not ever found by dynamic lookup, this is wasted
work. Instead, let's rely on AnyObject lookup filtering non-@objc
members at the call site, which it was already doing anyway.
PatternBindingInitializer may not be attached to any
PatternBindingDecl. e.g.
struct S {
@CustomAttr(something)
}
In this case DeclContext for 'something' is PatternBindingInitializer,
but it doesn't have PatternBindingDecl because it's not written yet.
Fixes a crash in code-completion.
rdar://problem/53034550
If a var has optional type, e.g.
```
var x: Int?
```
It will be implicitly initialized to `nil`. However, there's a second,
undocumented behavior: tuples of optional type, potentially nested infinitely,
will also be initialized, to tuples of nil.
So this var
```
var w: ((Int?, (), Int?), (Int?, Int?))
```
Will be default-initialized to
```
((nil, (), nil), (nil, nil))
```
We need to handle this inside getDefaultValueStringRepresentation,
otherwise we will crash while emitting partial modules.
Fixes one instance of rdar://51560190
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().
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.
These are two slightly different operations. Make them share code and
prepare them for when we stop adding accessors to their parent
DeclContext.
Note the FIXMEs; this code could use additional attention.
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 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.
Previously we would copy this attribute from a superclass to the
subclass when validating a subclass. However, this is only correct
if the superclass is always guaranteed to have been validated
before the subclass.
Indeed, it appears this assumption is no longer true, so we would
sometimes lose track of the attribute, which would result in SILGen
failing to emit the ivar initializer entry point.
Instead, check for the attribute as part of the superclass walk
in checkAncestry(), ensuring the result is always up to date, correct,
and cached.
As a follow-up, we should also convert checkAncestry() into a
request, but I'm not doing that here to keep the fix short.
Fixes <rdar://problem/50845438>.
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.
Add the request `ExistentialConformsToSelfRequest` to lazily determine
if an existential conforming to a protocol can be matched with a
generic type parameter constrained to that protocol.
Add the request `ProtocolRequiresClassRequest` to lazily determine if a
`ProtocolDecl` requires conforming types to be a class.
Note that using the request evaluator to compute `requiresClass` introduces
cycle errors for protocol declarations, where this computation didn't
previously emit diagnostics. For now, we'll allow duplicate diagnostics in this
case, with the eventual goal of removing explicitly checking for cycles
via `checkCircularity` (instead letting the request evaluator handle cycle
diagnostics).
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.
