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>
104 lines
2.0 KiB
Dart
104 lines
2.0 KiB
Dart
// 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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//
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// VMOptions=--optimization_counter_threshold=5
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//
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// Basic null-aware operator test that invokes the optimizing compiler.
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import "package:expect/expect.dart";
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class C {
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C(this.f);
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var f;
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m(a) => a;
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}
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bomb() {
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Expect.fail('Should not be executed');
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return 100;
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}
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getNull() => null;
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test() {
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var c;
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var d = new C(5) as C?;
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Expect.equals(null, c?.m(bomb()));
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Expect.equals(null, getNull()?.anything(bomb()));
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Expect.equals(1, d?.m(1));
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var c2 = new C(1) as C?;
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Expect.equals(1, c2?.f);
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Expect.equals(null, c?.v);
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Expect.equals(10, c ?? 10);
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Expect.equals(d, d ?? bomb());
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var list = [[3]] as List<List<int>>?;
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Expect.equals(
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3,
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list?.expand((i) => i).toList()[0]);
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Expect.equals(null, (null as dynamic)?.expand((i) => i)?.toList());
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var e;
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// The assignment to e is not executed since d != null.
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d ??= e ??= new C(100);
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Expect.equals(null, e);
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e ??= new C(100);
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Expect.equals(100, e?.f);
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e?.f ??= 200;
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Expect.equals(100, e?.f);
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e.f = null;
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e?.f ??= 200;
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Expect.equals(200, e?.f);
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c?.f ??= 400;
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Expect.equals(null, c?.f);
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Expect.equals(null, c?.f++);
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e?.f++;
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Expect.equals(201, e.f);
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var five = 5 as int?;
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var x = five ?? bomb();
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}
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// Check that instructions without result do not crash.
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test2() {
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var c;
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c?.v;
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c?.m(bomb());
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}
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class Bar {
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String? s;
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}
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class Foo {
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Bar? _bar;
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String? str;
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Foo(this._bar) : str = _bar?.s;
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}
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// Check that ?? isn't incorrectly optimized as non-nullable
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// (DDC regression test)
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test3() {
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List? n = null;
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var func = n?.add;
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var result = func ?? 1;
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Expect.equals(result, 1);
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String? x = null;
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Expect.equals(x?.split(',') ?? 'hello', 'hello');
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}
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main() {
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for (int i = 0; i < 10; i++) {
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test();
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test2();
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test3();
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}
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Expect.equals(null, new Foo(new Bar()).str);
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}
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