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8de8a1c226
They are all errors now. Change-Id: If48d38e38e845fd5b5a950dd5514bf1cbbce03d8 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/155880 Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
61 lines
2.2 KiB
Dart
61 lines
2.2 KiB
Dart
// Copyright (c) 2019, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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// Tests local inference errors for the `out` variance modifier.
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// SharedOptions=--enable-experiment=variance
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class Covariant<out T> {}
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class Exactly<inout T> {}
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class Upper {}
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class Middle extends Upper {}
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class Lower extends Middle {}
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class CovBound<out T> {
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CovBound(T x, void Function(T) y) {}
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}
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Exactly<T> inferCovCov<T>(Covariant<T> x, Covariant<T> y) => new Exactly<T>();
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Exactly<T> inferCovBound<T>(CovBound<T> x) => new Exactly<T>();
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main() {
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Exactly<Upper> upper;
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Exactly<Middle> middle;
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Exactly<Lower> lower;
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// Lower <: T <: Middle.
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// We choose Middle.
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var inferredMiddle = inferCovCov(Covariant<Lower>(), Covariant<Middle>());
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lower = inferredMiddle;
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// ^^^^^^^^^^^^^^
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// [analyzer] COMPILE_TIME_ERROR.INVALID_ASSIGNMENT
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// [cfe] A value of type 'Exactly<Middle>' can't be assigned to a variable of type 'Exactly<Lower>'.
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// Lower <: T <: Upper.
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// We choose Upper.
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var inferredUpper = inferCovCov(Covariant<Lower>(), Covariant<Upper>());
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lower = inferredUpper;
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// ^^^^^^^^^^^^^
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// [analyzer] COMPILE_TIME_ERROR.INVALID_ASSIGNMENT
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// [cfe] A value of type 'Exactly<Upper>' can't be assigned to a variable of type 'Exactly<Lower>'.
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// Inference for Covbound(...) produces Lower <: T <: Upper.
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// Since T is covariant, we choose Lower as the solution.
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var inferredCovLower = inferCovBound(CovBound(Lower(), (Upper x) {}));
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upper = inferredCovLower;
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// ^^^^^^^^^^^^^^^^
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// [analyzer] COMPILE_TIME_ERROR.INVALID_ASSIGNMENT
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// [cfe] A value of type 'Exactly<Lower>' can't be assigned to a variable of type 'Exactly<Upper>'.
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// Inference for Covbound(...) produces Lower <: T <: Middle.
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// Since T is covariant, we choose Lower as the solution.
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var inferredCovLower2 = inferCovBound(CovBound(Lower(), (Middle x) {}));
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middle = inferredCovLower2;
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// ^^^^^^^^^^^^^^^^^
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// [analyzer] COMPILE_TIME_ERROR.INVALID_ASSIGNMENT
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// [cfe] A value of type 'Exactly<Lower>' can't be assigned to a variable of type 'Exactly<Middle>'.
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}
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