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// Copyright (c) 2018, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
// @dart = 2.9
import "package:expect/expect.dart";
// Class hierarchy on an abstract class
// that defines a "next" structure.
abstract class A {
A next;
}
class B extends A {
B(A n) {
this.next = n;
}
}
// Method that counts length of list.
// With only Bs, the getter can be
// inlined without check class.
int countMe(A i) {
int x = 0;
while (i != null) {
A next = i.next;
x++;
i = next;
}
return x;
}
int doitHot(A a) {
// Warm up the JIT.
int d = 0;
for (int i = 0; i < 1000; i++) {
d += countMe(a);
}
return d;
}
// Nasty class that overrides the getter.
class C extends A {
C(A n) {
this.next = n;
}
// New override.
A get next => null;
}
int bringInC(A a) {
// Introduce C to compiler.
a = new C(a);
return doitHot(a);
}
main() {
// Make a list with just Bs.
A a = null;
for (int i = 0; i < 1000; i++) {
a = new B(a);
}
Expect.equals(1000 * 1000, doitHot(a));
Expect.equals(1000, bringInC(a));
}