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[Sema] Disregard reference storage types when inferring associated types from witnesses. #12444

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Merged
merged 1 commit into from
Oct 15, 2017
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[Sema] Disregard reference storage types when inferring associated types from witnesses. #12444

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2 changes: 1 addition & 1 deletion lib/Sema/TypeCheckProtocol.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3991,7 +3991,7 @@ static Type getWitnessTypeForMatching(TypeChecker &tc,
Type model = conformance->getType();
TypeSubstitutionMap substitutions = model->getMemberSubstitutions(witness);
if (substitutions.empty())
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What if the witness is in a generic context? Eg,

class G<T> : SomeProto where T : AnyObject {
  weak var t: T?
}

return witness->getInterfaceType();
return witness->getInterfaceType()->getReferenceStorageReferent();

Type type = witness->getInterfaceType();

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22 changes: 22 additions & 0 deletions test/Generics/associated_types.swift
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Expand Up @@ -199,3 +199,25 @@ extension M {
_ = B.A.isP
}
}

// SR-6097
protocol sr6097 {
associatedtype A : AnyObject
var aProperty: A { get }
}

class C1 {}
class C2 : sr6097 {
unowned let aProperty: C1 // should deduce A == C1 despite 'unowned'
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How do you actually know it's deducing this?

init() { fatalError() }
}

protocol sr6097_b {
associatedtype A : AnyObject
var aProperty: A? { get }
}
class C3 : sr6097_b {
weak var aProperty: C1? // and same here, despite 'weak'
init() { fatalError() }
}