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Use @unchecked optionals for member references into AnyObject/AnyClass.

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This eliminates the need for a number of !'s when dealing with
Objective-C APIs. Now with actual executable behavior!


Swift SVN r13483
This commit is contained in:
Doug Gregor
2014-02-05 07:58:18 +00:00
parent 29af221df9
commit 04475c6a85
6 changed files with 54 additions and 23 deletions
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38
lib/Sema/ConstraintSystem.cpp
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@@ -959,13 +959,16 @@ ConstraintSystem::getTypeOfMemberReference(Type baseTy, ValueDecl *value,
// Compute the type of the reference.
Type type;
if (auto subscript = dyn_cast<SubscriptDecl>(value)) {
// For a subscript, turn the element type into an optional or lvalue,
// depending on whether the result type is optional/dynamic, is settable,
// or is not.
// For a subscript, turn the element type into an (@unchecked)
// optional or lvalue, depending on whether the result type is
// optional/dynamic, is settable, or is not.
auto fnType = openedFnType->getResult()->castTo<FunctionType>();
auto elementTy = fnType->getResult();
if (isDynamicResult || subscript->getAttrs().isOptional())
if (subscript->getAttrs().isOptional())
elementTy = OptionalType::get(elementTy->getRValueType());
else if (isDynamicResult)
elementTy = UncheckedOptionalType::get(elementTy->getRValueType());
type = FunctionType::get(fnType->getInput(), elementTy);
} else if (isa<ProtocolDecl>(value->getDeclContext()) &&
isa<AssociatedTypeDecl>(value)) {
@@ -1063,17 +1066,28 @@ void ConstraintSystem::resolveOverload(ConstraintLocator *locator,
isTypeReference,
choice.isSpecialized());
if (isDynamicResult || choice.getDecl()->getAttrs().isOptional()) {
// For a non-subscript declaration found via dynamic lookup or as an
// optional requirement in a protocol, strip off the lvalue-ness (one
// cannot assign to such declarations) and make a reference to that
// declaration be optional.
if (choice.getDecl()->getAttrs().isOptional() &&
!isa<SubscriptDecl>(choice.getDecl())) {
// For a non-subscript declaration that is an optional
// requirement in a protocol, strip off the lvalue-ness (FIXME:
// one cannot assign to such declarations for now) and make a
// reference to that declaration be optional.
//
// Subscript declarations are handled within
// getTypeOfMemberReference(); their result types are optional.
if (!isa<SubscriptDecl>(choice.getDecl()))
refType = OptionalType::get(refType->getRValueType());
}
refType = OptionalType::get(refType->getRValueType());
}
// For a non-subscript declaration found via dynamic lookup, strip
// off the lvalue-ness (FIXME: as a temporary hack. We eventually
// want this to work) and make a reference to that declaration be
// an unchecked optional.
//
// Subscript declarations are handled within
// getTypeOfMemberReference(); their result types are unchecked
// optional.
else if (isDynamicResult && !isa<SubscriptDecl>(choice.getDecl())) {
refType = UncheckedOptionalType::get(refType->getRValueType());
}
break;
}