将非转义值转换为 'T' 可能允许它转义 Xcode 10 Swift CGPath

Question

我有这段代码，它在 Xcode 9 中运行良好，但在 Xcode 10 中我收到此错误。 将非转义值转换为 'T' 可能会使其转义

这是代码：

extension CGPath {

    func forEach( body: @convention(block) (CGPathElement) -> Void) {
        typealias Body = @convention(block) (CGPathElement) -> Void
        let callback: @convention(c) (UnsafeMutableRawPointer, UnsafePointer<CGPathElement>) -> Void = { (info, element) in
            let body = unsafeBitCast(info, to: Body.self)
            body(element.pointee)
        }
        print(MemoryLayout.size(ofValue: body))
        let unsafeBody = unsafeBitCast(body, to: UnsafeMutableRawPointer.self)
        self.apply(info: unsafeBody, function: unsafeBitCast(callback, to: CGPathApplierFunction.self))
    }

我收到这 2 行代码的错误

 print(MemoryLayout.size(ofValue: body))
            let unsafeBody = unsafeBitCast(body, to: UnsafeMutableRawPointer.self)

对于 MemoryLayout 和 unsafeBitCast

Answer 1

您将添加 @escaping

func forEach( body: @escaping @convention(block) (CGPathElement) -> Void) {

}

将非转义值转换为 'T' 可能允许它转义 Xcode 10 Swift CGPath

Converting non-escaping value to 'T' may allow it to escape Xcode 10 Swift CGPath

swift4

cgpath

xcode10

ios12