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// RUN: %target-run-simple-swift( -enable-experimental-feature Embedded -wmo -Xfrontend -disable-access-control -runtime-compatibility-version none) | %FileCheck %s
// RUN: %target-run-simple-swift(-O -enable-experimental-feature Embedded -wmo -Xfrontend -disable-access-control -runtime-compatibility-version none) | %FileCheck %s
// REQUIRES: swift_in_compiler
// REQUIRES: executable_test
// REQUIRES: optimized_stdlib
// REQUIRES: OS=macosx || OS=linux-gnu
// REQUIRES: swift_feature_Embedded
@dynamicMemberLookup
public struct Box<T>: ~Copyable {
internal init(from t: T) {
self.value = UnsafeMutablePointer<InnerBox<T>>.allocate(capacity: 1)
self.value.pointee = .init(t)
}
public subscript<Value>(dynamicMember member: WritableKeyPath<InnerBox<T>, Value>) -> Value
{
@_transparent
@inline(__always)
get { return self.value.pointer(to: member)!.pointee }
@_transparent
@inline(__always)
set { self.value.pointer(to: member)!.pointee = newValue }
}
public struct InnerBox<V> {
public init(_ value: V) { self.innerValue = value }
public var innerValue: V
}
@usableFromInline
internal var value: UnsafeMutablePointer<InnerBox<T>>
}
struct Foo {
var a: Int
var b: Int
}
@inline(never)
public func test() -> Int {
var x = Box<Foo>(from: Foo(a: 0, b: 0))
x.innerValue.b = 42
return x.innerValue.b
}
precondition(test() == 42)
print("OK!")
// CHECK: OK!
public func test_read(x: inout Box<Foo>) -> Int {
return x.innerValue.b
}
public func test_write(x: inout Box<Foo>) {
x.innerValue.b = 42
}
var box = Box<Foo>(from: Foo(a: 0, b: 0))
_ = test_read(x: &box)
test_write(x: &box)
print(box.innerValue.b)
// CHECK: 42
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