1 /*
   2  * Copyright 2003 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  20  * CA 95054 USA or visit www.sun.com if you need additional information or
  21  * have any questions.
  22  */
  23 
  24 /*
  25  * @test
  26  * @bug 4916607
  27  * @summary Test casts (legal, warning, and errors)
  28  * @author gafter
  29  *
  30  * @compile/fail  -Werror -Xlint:unchecked CastWarn14.java
  31  */
  32 
  33 import java.util.*;
  34 
  35 class 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 = (AB<String>) (AA<Number>) null; // <<fail 1>>
  53         o = (AC<String>) (AA<Vector<String>>) null; // <<pass>>
  54         o = (AC<String>) (AA<Vector<Number>>) null; // <<fail 2>>
  55         o = (AC<String>) (AA<Stack<String>>) null; // <<fail 3>>
  56 
  57         o = (AD<Number>) (AA<Vector<? extends Number>>) null; // <<pass>>
  58         o = (AD<String>) (AA<Vector<? extends Number>>) null; // <<fail 4>>
  59         o = (AD<?>) (AA<Vector<? extends Object>>) null; // <<pass>>
  60         o = (AD<Object>) (AA<Vector<?>>) null; // <<pass>>
  61 
  62         o = (AE<String>) (AA<Vector<? super String>>) null; // <<pass>>
  63         o = (AE<Number>) (AA<Vector<? super String>>) null; // <<fail 5>>
  64 
  65         o = (AF<String>) (AA<String[]>) null; // <<pass>>
  66         o = (AF<String>) (AA<Number[]>) null; // <<fail 6>>
  67 
  68         o = (AG<?>) (AA<String>) null; // <<pass>>
  69         o = (AG<?>) (AA<Number>) null; // <<fail 7>>
  70     }
  71 
  72     // --- Inconsistent matches ---
  73 
  74     private class BA<T> { }
  75     private class BB<T, S> { }
  76 
  77     private class BC<T> extends BA<Integer> { }
  78     private class BD<T> extends BB<T, T> { }
  79 
  80     private void inconsistentMatches() {
  81         Object o;
  82 
  83         o = (BC<?>) (BA<Integer>) null; // <<pass>>
  84         o = (BC<?>) (BA<String>) null; // <<fail 8>>
  85         o = (BD<String>) (BB<String, String>) null; // <<pass>>
  86         o = (BD<String>) (BB<String, Number>) null; // <<fail 9>>
  87         o = (BD<String>) (BB<Number, String>) null; // <<fail 10>>
  88     }
  89 
  90     private void whyMustEverythingBeSo_______Complicated() {
  91         // This has to work...
  92         BD<Number> bd = new BD<Number>();
  93         BB<? extends Number, ? super Integer> bb = bd;
  94         // 4916620: wildcards: legal cast is rejected
  95         // bd = (BD<Number>) bb; // <<warn>> <<todo: cast-infer>>
  96     }
  97 
  98     // --- Transferring parameters via supertypes ---
  99 
 100     private interface CA<T> { }
 101     private interface CB<T> extends CA<T> { }
 102     private interface CC<T> extends CA<T> { }
 103 
 104     private class CD<T> implements CB<T> { }
 105     private interface CE<T> extends CC<T> { }
 106 
 107     private interface CF<S> { }
 108     private interface CG<T> { }
 109     private class CH<S, T> implements CF<S>, CG<T> { }
 110     private interface CI<S> extends CF<S> { }
 111     private interface CJ<T> extends CG<T> { }
 112     private interface CK<S, T> extends CI<S>, CJ<T> { }
 113 
 114     private void supertypeParameterTransfer() {
 115         Object o;
 116         CD<?> cd = (CE<?>) null; // <<fail 11>>
 117         CE<?> ce = (CD<?>) null; // <<fail 12>>
 118         o = (CE<String>) (CD<String>) null; // <<pass>>
 119         o = (CE<Number>) (CD<String>) null; // <<fail 13>>
 120 
 121         // 4916622: unnecessary warning with cast
 122         // o = (CH<String, Integer>) (CK<String, Integer>) null; // <<pass>> <<todo: cast-infer>>
 123     }
 124 
 125     // --- Disjoint ---
 126 
 127     private interface DA<T> { }
 128     private interface DB<T> extends DA<T> { }
 129     private interface DC<T> extends DA<Integer> { }
 130 
 131     private <N extends Number, I extends Integer, R extends Runnable, S extends String> void disjointness() {
 132         Object o;
 133 
 134         // Classes
 135         o = (DA<Number>) (DA<Integer>) null; // <<fail 14>>
 136         o = (DA<? extends Number>) (DA<Integer>) null; // <<pass>>
 137         o = (DA<? extends Integer>) (DA<Number>) null; // <<fail 15>>
 138         o = (DA<? super Integer>) (DA<Number>) null; // <<pass>>
 139         o = (DA<? super Number>) (DA<Integer>) null; // <<fail 16>>
 140         o = (DA<?>) (DA<Integer>) null; // <<pass>>
 141 
 142         o = (DA<? extends Runnable>) (DA<? extends Number>) null; // <<warn 2>>
 143         o = (DA<? extends Runnable>) (DA<? extends String>) null; // <<fail 17>>
 144 
 145         o = (DA<? super Integer>) (DA<? extends Number>) null; // <<warn 3>>
 146         o = (DA<? super Number>) (DA<? extends Integer>) null; // <<fail 18>>
 147         o = (DA<?>) (DA<? extends Integer>) null; // <<pass>>
 148 
 149         o = (DA<? super String>) (DA<? super Number>) null; // <<warn 4>>
 150         o = (DA<?>) (DA<? super String>) null; // <<pass>>
 151 
 152         o = (DA<?>) (DA<?>) null; // <<pass>>
 153 
 154         // Typevars
 155         o = (DA<? extends Number>) (DA<I>) null; // <<pass>>
 156         o = (DA<? extends Integer>) (DA<N>) null; // <<warn 5>>
 157         o = (DA<? extends String>) (DA<I>) null; // <<fail 19>>
 158 
 159         o = (DA<I>) (DA<? extends Number>) null; // <<warn 6>>
 160         o = (DA<N>) (DA<? extends Integer>) null; // <<warn 7>>
 161         o = (DA<N>) (DA<? extends Runnable>) null; // <<warn 8>>
 162 
 163         o = (DA<N>) (DA<I>) null; // <<warn 9>>
 164         o = (DA<N>) (DA<R>) null; // <<warn 10>>
 165         o = (DA<S>) (DA<R>) null; // <<fail 20>>
 166 
 167         // Raw (asymmetrical!)
 168         o = (DA) (DB<Number>) null; // <<pass>>
 169         o = (DA<Number>) (DB) null; // <<warn 11>>
 170         o = (DA<?>) (DB) null; // <<pass>>
 171         o = (DA<? extends Object>) (DB) null; // <<pass>>
 172         o = (DA<? extends Number>) (DB) null; // <<warn 12>>
 173 
 174         o = (DB) (DA<Number>) null; // <<pass>>
 175         o = (DB<Number>) (DA) null; // <<warn 13>>
 176         o = (DB<?>) (DA) null; // <<pass>>
 177         o = (DB<? extends Object>) (DA) null; // <<pass>>
 178         o = (DB<? extends Number>) (DA) null; // <<warn 14>>
 179 
 180         o = (DC<?>) (DA<?>) null; // <<pass>>
 181         o = (DC<?>) (DA<? super String>) null; // <<fail 21>>
 182     }
 183 
 184 }