1/*
2 * Copyright (c) 2003, 2004, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
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22 */
23
24/*
25 * @test
26 * @bug 4916607
27 * @summary Test casts (legal, warning, and errors)
28 * @author gafter
29 *
30 * @compile  -Werror CastTest.java
31 */
32
33import java.util.*;
34
35class CastTest {
36
37    // --- Directly transferring parameters ---
38
39    private class AA<T> { }
40
41    private class AB<T> extends AA<T> { }
42    private class AC<T> extends AA<Vector<T>> { }
43    private class AD<T> extends AA<Vector<? extends T>> { }
44    private class AE<T> extends AA<Vector<? super T>> { }
45    private class AF<T> extends AA<T[]> { }
46    private class AG<T> extends AA<String> { }
47
48    private void parameterTransfer() {
49        Object o;
50
51        o = (AB<String>) (AA<String>) null; // <<pass>>
52        o = (AC<String>) (AA<Vector<String>>) null; // <<pass>>
53
54        o = (AD<Number>) (AA<Vector<? extends Number>>) null; // <<pass>>
55        o = (AD<?>) (AA<Vector<? extends Object>>) null; // <<pass>>
56        o = (AD<Object>) (AA<Vector<?>>) null; // <<pass>>
57
58        o = (AE<String>) (AA<Vector<? super String>>) null; // <<pass>>
59
60        o = (AF<String>) (AA<String[]>) null; // <<pass>>
61
62        o = (AG<?>) (AA<String>) null; // <<pass>>
63    }
64
65    // --- Inconsistent matches ---
66
67    private class BA<T> { }
68    private class BB<T, S> { }
69
70    private class BC<T> extends BA<Integer> { }
71    private class BD<T> extends BB<T, T> { }
72
73    private void inconsistentMatches() {
74        Object o;
75
76        o = (BC<?>) (BA<Integer>) null; // <<pass>>
77        o = (BD<String>) (BB<String, String>) null; // <<pass>>
78    }
79
80    private void whyMustEverythingBeSo_______Complicated() {
81        // This has to work...
82        BD<Number> bd = new BD<Number>();
83        BB<? extends Number, ? super Integer> bb = bd;
84
85        // 4916620: wildcards: legal cast is rejected
86        // bd = (BD<Number>) bb; // <<warn>> <<todo: cast-infer>>
87    }
88
89    // --- Transferring parameters via supertypes ---
90
91    private interface CA<T> { }
92    private interface CB<T> extends CA<T> { }
93    private interface CC<T> extends CA<T> { }
94
95    private class CD<T> implements CB<T> { }
96    private interface CE<T> extends CC<T> { }
97
98    private interface CF<S> { }
99    private interface CG<T> { }
100    private class CH<S, T> implements CF<S>, CG<T> { }
101    private interface CI<S> extends CF<S> { }
102    private interface CJ<T> extends CG<T> { }
103    private interface CK<S, T> extends CI<S>, CJ<T> { }
104
105    private void supertypeParameterTransfer() {
106        Object o;
107        o = (CE<String>) (CD<String>) null; // <<pass>>
108
109        // 4916622: unnecessary warning with cast
110        // o = (CH<String, Integer>) (CK<String, Integer>) null; // <<pass>> <<todo: cast-infer>>
111    }
112
113    // --- Disjoint ---
114
115    private interface DA<T> { }
116    private interface DB<T> extends DA<T> { }
117    private interface DC<T> extends DA<Integer> { }
118
119    private <N extends Number, I extends Integer, R extends Runnable, S extends String> void disjointness() {
120        Object o;
121
122        // Classes
123        o = (DA<? extends Number>) (DA<Integer>) null; // <<pass>>
124        o = (DA<? super Integer>) (DA<Number>) null; // <<pass>>
125        o = (DA<?>) (DA<Integer>) null; // <<pass>>
126
127        o = (DA<?>) (DA<? extends Integer>) null; // <<pass>>
128
129        o = (DA<?>) (DA<? super String>) null; // <<pass>>
130
131        o = (DA<?>) (DA<?>) null; // <<pass>>
132
133        // Typevars
134        o = (DA<? extends Number>) (DA<I>) null; // <<pass>>
135
136        // Raw (asymmetrical!)
137        o = (DA) (DB<Number>) null; // <<pass>>
138        o = (DA<?>) (DB) null; // <<pass>>
139        o = (DA<? extends Object>) (DB) null; // <<pass>>
140
141        o = (DB) (DA<Number>) null; // <<pass>>
142        o = (DB<?>) (DA) null; // <<pass>>
143        o = (DB<? extends Object>) (DA) null; // <<pass>>
144
145        // reported broken (5034609)
146        // o = (DC<?>) (DA<?>) null; // <<pass>>
147    }
148
149}
150