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618378ae48
These conditional conformances could not be properly evaluated at runtime, so ban them. We still allow conditional conformances to marker protocols.
66 lines
1.9 KiB
Swift
66 lines
1.9 KiB
Swift
// RUN: %target-typecheck-verify-swift
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// Marker protocol definition
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@_marker protocol P1 {
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func f() // expected-error{{marker protocol 'P1' cannot have any requirements}}
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}
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@_marker protocol P2 {
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associatedtype AT // expected-error{{marker protocol 'P2' cannot have any requirements}}
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}
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@_marker protocol P3 {
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typealias A = Int
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}
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protocol P4 { } // expected-note{{'P4' declared here}}
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@_marker protocol P5: P4 { } // expected-error{{marker protocol 'P5' cannot inherit non-marker protocol 'P4'}}
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// Legitimate uses of marker protocols.
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extension P3 {
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func f() { }
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}
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extension Int: P3 { }
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extension Array: P3 where Element: P3 { } // expected-note{{requirement from conditional conformance of '[Double]' to 'P3'}}
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protocol P6: P3 { } // okay
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@_marker protocol P7: P3 { } // okay
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func genericOk<T: P3>(_: T) { }
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func testGenericOk(i: Int, arr: [Int], nope: [Double], p3: P3, p3array: [P3]) {
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genericOk(i)
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genericOk(arr)
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genericOk(nope) // expected-error{{global function 'genericOk' requires that 'Double' conform to 'P3'}}
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genericOk(p3)
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genericOk(p3array)
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}
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// Incorrect uses of marker protocols in types.
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func testNotOkay(a: Any) {
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var mp1: P3 = 17
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_ = mp1
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mp1 = 17
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if let mp2 = a as? P3 { _ = mp2 } // expected-error{{marker protocol 'P3' cannot be used in a conditional cast}}
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if let mp3 = a as? AnyObject & P3 { _ = mp3 } // expected-error{{marker protocol 'P3' cannot be used in a conditional cast}}
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if a is AnyObject & P3 { } // expected-error{{marker protocol 'P3' cannot be used in a conditional cast}}
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func inner(p3: P3) { }
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}
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@_marker protocol P8 { }
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protocol P9: P8 { }
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// Implied conditional conformance to P8 is okay because P8 is a marker
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// protocol.
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extension Array: P9 where Element: P9 { }
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protocol P10 { }
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extension Array: P10 where Element: P10, Element: P8 { }
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// expected-error@-1{{conditional conformance to non-marker protocol 'P10' cannot depend on conformance of 'Element' to non-marker protocol 'P8'}}
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