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[Runtime] Have swift_dynamicCast unwrap multiple levels of optionals in the source. #16772

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Merged
merged 1 commit into from
May 23, 2018
Merged

[Runtime] Have swift_dynamicCast unwrap multiple levels of optionals in the source. #16772

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2 changes: 1 addition & 1 deletion stdlib/public/runtime/Casting.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1866,7 +1866,7 @@ checkDynamicCastFromOptional(OpaqueValue *dest,
// .Some
// Single payload enums are guaranteed layout compatible with their
// payload. Only the source's payload needs to be taken or destroyed.
return {false, payloadType};
return checkDynamicCastFromOptional(dest, src, payloadType, targetType, flags);
}

/******************************************************************************/
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20 changes: 20 additions & 0 deletions test/stdlib/Casts.swift
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Expand Up @@ -50,6 +50,26 @@ CastsTests.test("No overrelease of existential boxes in failed casts") {

extension Int : P {}

// Test for SR-7664: Inconsistent optional casting behaviour with generics
// Runtime failed to unwrap multiple levels of Optional when casting.
CastsTests.test("Multi-level optionals can be casted") {
func testSuccess<From, To>(_ x: From, from: From.Type, to: To.Type) {
expectNotNil(x as? To)
}
func testFailure<From, To>(_ x: From, from: From.Type, to: To.Type) {
expectNil(x as? To)
}
testSuccess(42, from: Int?.self, to: Int.self)
testSuccess(42, from: Int??.self, to: Int.self)
testSuccess(42, from: Int???.self, to: Int.self)
testSuccess(42, from: Int???.self, to: Int?.self)
testSuccess(42, from: Int???.self, to: Int??.self)
testSuccess(42, from: Int???.self, to: Int???.self)
testFailure(42, from: Int?.self, to: String.self)
testFailure(42, from: Int??.self, to: String.self)
testFailure(42, from: Int???.self, to: String.self)
}

#if _runtime(_ObjC)
extension CFBitVector : P {
static func makeImmutable(from values: Array<UInt8>) -> CFBitVector {
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