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From the Swift documentation: "If you define an optional variable without providing a default value, the variable is automatically set to nil for you."
35 lines
779 B
Swift
35 lines
779 B
Swift
// RUN: %target-run-simple-swift | %FileCheck %s
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// REQUIRES: executable_test
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// REQUIRES: objc_interop
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import Foundation
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var str : NSString?
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var url : NSURL?
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print("\(str == nil) \(nil == url) \(str == url)")
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// CHECK: true true true
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str = "abc"
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url = NSURL(string: "file:///")
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print("\(str == nil) \(nil == url)")
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// CHECK: false false
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@inline(never)
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func isNilGeneric<T>(_ x: T?) -> Bool {
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if let x2 = x {
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return false
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} else {
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return true
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}
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}
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let noClass = NSClassFromString("A Class With This Name Should Not Exist!@#!")
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let yesClass = NSClassFromString("NSString")
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print(noClass == nil) // CHECK-NEXT: true
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print(yesClass == nil) // CHECK-NEXT: false
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print(isNilGeneric(noClass)) // CHECK-NEXT: true
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print(isNilGeneric(yesClass)) // CHECK-NEXT: false
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