Paul Berry
e933e91aaa
This is a reland of 6a1c54ec30
Original change's description:
> Flow analysis: promote to non-nullable on initialization
>
> When flow analysis encounters a variable declaration of the form `T? x
> = expr;`, if the type of `expr` is `T`, then the variable is
> immediately promoted to type `T`.
>
> Fixes #43099.
>
> Change-Id: Ia206fe0d50e2fdd9bdf637e13c85633d8490dbcc
> Bug: https://github.com/dart-lang/sdk/issues/43099
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/163841
> Commit-Queue: Paul Berry <paulberry@google.com>
> Reviewed-by: Bob Nystrom <rnystrom@google.com>
> Reviewed-by: Johnni Winther <johnniwinther@google.com>
> Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Bug: https://github.com/dart-lang/sdk/issues/43099
Change-Id: I7530bb0f7c24674a7b500558b89d50b35e045aca
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/166305
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>
60 lines
1.3 KiB
Dart
60 lines
1.3 KiB
Dart
// TODO(multitest): This was automatically migrated from a multitest and may
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// contain strange or dead code.
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// Copyright (c) 2015, 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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// Verify semantics of the ?. operator when it does not appear on the LHS of an
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// assignment.
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import "package:expect/expect.dart";
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import "conditional_access_helper.dart" as h;
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class B {}
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class C extends B {
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int? v;
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C(this.v);
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static int? staticInt;
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}
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C? nullC() => null;
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main() {
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// Make sure the "none" test fails if property access using "?." is not
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// implemented. This makes status files easier to maintain.
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nullC()?.v;
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// e1?.id is equivalent to ((x) => x == null ? null : x.id)(e1).
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var c = new C(1) as C?;
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Expect.equals(1, c?.v);
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// C?.id is equivalent to C.id.
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// The static type of e1?.d is the static type of e1.id.
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// Let T be the static type of e1 and let y be a fresh variable of type T.
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// Exactly the same static warnings that would be caused by y.id are also
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// generated in the case of e1?.id.
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// '?.' cannot be used to access toplevel properties in libraries imported via
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// prefix.
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// Nor can it be used to access the hashCode getter on the class Type.
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}
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