test/tools/javac/generics/wildcards/pos/CastTest.java

Thu, 31 Aug 2017 15:17:03 +0800

author
aoqi
date
Thu, 31 Aug 2017 15:17:03 +0800
changeset 2525
2eb010b6cb22
parent 554
9d9f26857129
parent 0
959103a6100f
permissions
-rw-r--r--

merge

aoqi@0 1 /*
aoqi@0 2 * Copyright (c) 2003, 2004, Oracle and/or its affiliates. All rights reserved.
aoqi@0 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0 4 *
aoqi@0 5 * This code is free software; you can redistribute it and/or modify it
aoqi@0 6 * under the terms of the GNU General Public License version 2 only, as
aoqi@0 7 * published by the Free Software Foundation.
aoqi@0 8 *
aoqi@0 9 * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
aoqi@0 12 * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0 13 * accompanied this code).
aoqi@0 14 *
aoqi@0 15 * You should have received a copy of the GNU General Public License version
aoqi@0 16 * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0 18 *
aoqi@0 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0 20 * or visit www.oracle.com if you need additional information or have any
aoqi@0 21 * questions.
aoqi@0 22 */
aoqi@0 23
aoqi@0 24 /*
aoqi@0 25 * @test
aoqi@0 26 * @bug 4916607
aoqi@0 27 * @summary Test casts (legal, warning, and errors)
aoqi@0 28 * @author gafter
aoqi@0 29 *
aoqi@0 30 * @compile -Werror CastTest.java
aoqi@0 31 */
aoqi@0 32
aoqi@0 33 import java.util.*;
aoqi@0 34
aoqi@0 35 class CastTest {
aoqi@0 36
aoqi@0 37 // --- Directly transferring parameters ---
aoqi@0 38
aoqi@0 39 private class AA<T> { }
aoqi@0 40
aoqi@0 41 private class AB<T> extends AA<T> { }
aoqi@0 42 private class AC<T> extends AA<Vector<T>> { }
aoqi@0 43 private class AD<T> extends AA<Vector<? extends T>> { }
aoqi@0 44 private class AE<T> extends AA<Vector<? super T>> { }
aoqi@0 45 private class AF<T> extends AA<T[]> { }
aoqi@0 46 private class AG<T> extends AA<String> { }
aoqi@0 47
aoqi@0 48 private void parameterTransfer() {
aoqi@0 49 Object o;
aoqi@0 50
aoqi@0 51 o = (AB<String>) (AA<String>) null; // <<pass>>
aoqi@0 52 o = (AC<String>) (AA<Vector<String>>) null; // <<pass>>
aoqi@0 53
aoqi@0 54 o = (AD<Number>) (AA<Vector<? extends Number>>) null; // <<pass>>
aoqi@0 55 o = (AD<?>) (AA<Vector<? extends Object>>) null; // <<pass>>
aoqi@0 56 o = (AD<Object>) (AA<Vector<?>>) null; // <<pass>>
aoqi@0 57
aoqi@0 58 o = (AE<String>) (AA<Vector<? super String>>) null; // <<pass>>
aoqi@0 59
aoqi@0 60 o = (AF<String>) (AA<String[]>) null; // <<pass>>
aoqi@0 61
aoqi@0 62 o = (AG<?>) (AA<String>) null; // <<pass>>
aoqi@0 63 }
aoqi@0 64
aoqi@0 65 // --- Inconsistent matches ---
aoqi@0 66
aoqi@0 67 private class BA<T> { }
aoqi@0 68 private class BB<T, S> { }
aoqi@0 69
aoqi@0 70 private class BC<T> extends BA<Integer> { }
aoqi@0 71 private class BD<T> extends BB<T, T> { }
aoqi@0 72
aoqi@0 73 private void inconsistentMatches() {
aoqi@0 74 Object o;
aoqi@0 75
aoqi@0 76 o = (BC<?>) (BA<Integer>) null; // <<pass>>
aoqi@0 77 o = (BD<String>) (BB<String, String>) null; // <<pass>>
aoqi@0 78 }
aoqi@0 79
aoqi@0 80 private void whyMustEverythingBeSo_______Complicated() {
aoqi@0 81 // This has to work...
aoqi@0 82 BD<Number> bd = new BD<Number>();
aoqi@0 83 BB<? extends Number, ? super Integer> bb = bd;
aoqi@0 84
aoqi@0 85 // 4916620: wildcards: legal cast is rejected
aoqi@0 86 // bd = (BD<Number>) bb; // <<warn>> <<todo: cast-infer>>
aoqi@0 87 }
aoqi@0 88
aoqi@0 89 // --- Transferring parameters via supertypes ---
aoqi@0 90
aoqi@0 91 private interface CA<T> { }
aoqi@0 92 private interface CB<T> extends CA<T> { }
aoqi@0 93 private interface CC<T> extends CA<T> { }
aoqi@0 94
aoqi@0 95 private class CD<T> implements CB<T> { }
aoqi@0 96 private interface CE<T> extends CC<T> { }
aoqi@0 97
aoqi@0 98 private interface CF<S> { }
aoqi@0 99 private interface CG<T> { }
aoqi@0 100 private class CH<S, T> implements CF<S>, CG<T> { }
aoqi@0 101 private interface CI<S> extends CF<S> { }
aoqi@0 102 private interface CJ<T> extends CG<T> { }
aoqi@0 103 private interface CK<S, T> extends CI<S>, CJ<T> { }
aoqi@0 104
aoqi@0 105 private void supertypeParameterTransfer() {
aoqi@0 106 Object o;
aoqi@0 107 o = (CE<String>) (CD<String>) null; // <<pass>>
aoqi@0 108
aoqi@0 109 // 4916622: unnecessary warning with cast
aoqi@0 110 // o = (CH<String, Integer>) (CK<String, Integer>) null; // <<pass>> <<todo: cast-infer>>
aoqi@0 111 }
aoqi@0 112
aoqi@0 113 // --- Disjoint ---
aoqi@0 114
aoqi@0 115 private interface DA<T> { }
aoqi@0 116 private interface DB<T> extends DA<T> { }
aoqi@0 117 private interface DC<T> extends DA<Integer> { }
aoqi@0 118
aoqi@0 119 private <N extends Number, I extends Integer, R extends Runnable, S extends String> void disjointness() {
aoqi@0 120 Object o;
aoqi@0 121
aoqi@0 122 // Classes
aoqi@0 123 o = (DA<? extends Number>) (DA<Integer>) null; // <<pass>>
aoqi@0 124 o = (DA<? super Integer>) (DA<Number>) null; // <<pass>>
aoqi@0 125 o = (DA<?>) (DA<Integer>) null; // <<pass>>
aoqi@0 126
aoqi@0 127 o = (DA<?>) (DA<? extends Integer>) null; // <<pass>>
aoqi@0 128
aoqi@0 129 o = (DA<?>) (DA<? super String>) null; // <<pass>>
aoqi@0 130
aoqi@0 131 o = (DA<?>) (DA<?>) null; // <<pass>>
aoqi@0 132
aoqi@0 133 // Typevars
aoqi@0 134 o = (DA<? extends Number>) (DA<I>) null; // <<pass>>
aoqi@0 135
aoqi@0 136 // Raw (asymmetrical!)
aoqi@0 137 o = (DA) (DB<Number>) null; // <<pass>>
aoqi@0 138 o = (DA<?>) (DB) null; // <<pass>>
aoqi@0 139 o = (DA<? extends Object>) (DB) null; // <<pass>>
aoqi@0 140
aoqi@0 141 o = (DB) (DA<Number>) null; // <<pass>>
aoqi@0 142 o = (DB<?>) (DA) null; // <<pass>>
aoqi@0 143 o = (DB<? extends Object>) (DA) null; // <<pass>>
aoqi@0 144
aoqi@0 145 // reported broken (5034609)
aoqi@0 146 // o = (DC<?>) (DA<?>) null; // <<pass>>
aoqi@0 147 }
aoqi@0 148
aoqi@0 149 }

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