averello/swift-mirror
1
0
Fork 0
mirror of https://github.com/apple/swift.git synced 2025-12-21 12:14:44 +01:00
Code Issues Packages Projects Releases Wiki Activity

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

Browse Source 
The real work is done in checkDynamicCastFromOptional. This code tried to unwrap the source and returned the payload on success. It only did this once, so a type like Optional<Optional<Int>> would come out as Optional<Int> and then a cast to Int would fail.

This change makes checkDynamicCastFromOptional recursive, which makes it unwrap as many levels of Optional as it encounters.

Fixes rdar://problem/40171034 and SR-7664.
This commit is contained in:
Mike Ash
2018-05-22 15:05:09 -04:00
parent c23942012a
commit 0dae9b3dc0
2 changed files with 21 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
test/stdlib/Casts.swift
View File

@@ -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 {