The CastWarn14.java Java example source code
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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/*
* @test
* @bug 4916607
* @summary Test casts (legal, warning, and errors)
* @author gafter
*
* @compile/fail -Werror -Xlint:unchecked CastWarn14.java
*/
import java.util.*;
class CastTest {
// --- Directly transferring parameters ---
private class AA<T> { }
private class AB<T> extends AA { }
private class AC<T> extends AA> { }
private class AD<T> extends AA> { }
private class AE<T> extends AA> { }
private class AF<T> extends AA { }
private class AG<T> extends AA { }
private void parameterTransfer() {
Object o;
o = (AB<String>) (AA) null; // <>
o = (AB<String>) (AA) null; // <>
o = (AC<String>) (AA>) null; // <>
o = (AC<String>) (AA>) null; // <>
o = (AC<String>) (AA>) null; // <>
o = (AD<Number>) (AA>) null; // <>
o = (AD<String>) (AA>) null; // <>
o = (AD<?>) (AA>) null; // <>
o = (AD<Object>) (AA>) null; // <>
o = (AE<String>) (AA>) null; // <>
o = (AE<Number>) (AA>) null; // <>
o = (AF<String>) (AA) null; // <>
o = (AF<String>) (AA) null; // <>
o = (AG<?>) (AA) null; // <>
o = (AG<?>) (AA) null; // <>
}
// --- Inconsistent matches ---
private class BA<T> { }
private class BB<T, S> { }
private class BC<T> extends BA { }
private class BD<T> extends BB { }
private void inconsistentMatches() {
Object o;
o = (BC<?>) (BA) null; // <>
o = (BC<?>) (BA) null; // <>
o = (BD<String>) (BB) null; // <>
o = (BD<String>) (BB) null; // <>
o = (BD<String>) (BB) null; // <>
}
private void whyMustEverythingBeSo_______Complicated() {
// This has to work...
BD<Number> bd = new BD();
BB<? extends Number, ? super Integer> bb = bd;
// 4916620: wildcards: legal cast is rejected
// bd = (BD<Number>) bb; // <> <>
}
// --- Transferring parameters via supertypes ---
private interface CA<T> { }
private interface CB<T> extends CA { }
private interface CC<T> extends CA { }
private class CD<T> implements CB { }
private interface CE<T> extends CC { }
private interface CF<S> { }
private interface CG<T> { }
private class CH<S, T> implements CF, CG { }
private interface CI<S> extends CF { }
private interface CJ<T> extends CG { }
private interface CK<S, T> extends CI, CJ { }
private void supertypeParameterTransfer() {
Object o;
CD<?> cd = (CE) null; // <>
CE<?> ce = (CD) null; // <>
o = (CE<String>) (CD) null; // <>
o = (CE<Number>) (CD) null; // <>
// 4916622: unnecessary warning with cast
// o = (CH<String, Integer>) (CK) null; // <> <>
}
// --- Disjoint ---
private interface DA<T> { }
private interface DB<T> extends DA { }
private interface DC<T> extends DA { }
private <N extends Number, I extends Integer, R extends Runnable, S extends String> void disjointness() {
Object o;
// Classes
o = (DA<Number>) (DA) null; // <>
o = (DA<? extends Number>) (DA) null; // <>
o = (DA<? extends Integer>) (DA) null; // <>
o = (DA<? super Integer>) (DA) null; // <>
o = (DA<? super Number>) (DA) null; // <>
o = (DA<?>) (DA) null; // <>
o = (DA<? extends Runnable>) (DA) null; // <>
o = (DA<? extends Runnable>) (DA) null; // <>
o = (DA<? super Integer>) (DA) null; // <>
o = (DA<? super Number>) (DA) null; // <>
o = (DA<?>) (DA) null; // <>
o = (DA<? super String>) (DA) null; // <>
o = (DA<?>) (DA) null; // <>
o = (DA<?>) (DA) null; // <>
// Typevars
o = (DA<? extends Number>) (DA) null; // <>
o = (DA<? extends Integer>) (DA) null; // <>
o = (DA<? extends String>) (DA) null; // <>
o = (DA<I>) (DA) null; // <>
o = (DA<N>) (DA) null; // <>
o = (DA<N>) (DA) null; // <>
o = (DA<N>) (DA) null; // <>
o = (DA<N>) (DA) null; // <>
o = (DA<S>) (DA) null; // <>
// Raw (asymmetrical!)
o = (DA) (DB<Number>) null; // <>
o = (DA<Number>) (DB) null; // <>
o = (DA<?>) (DB) null; // <>
o = (DA<? extends Object>) (DB) null; // <>
o = (DA<? extends Number>) (DB) null; // <>
o = (DB) (DA<Number>) null; // <>
o = (DB<Number>) (DA) null; // <>
o = (DB<?>) (DA) null; // <>
o = (DB<? extends Object>) (DA) null; // <>
o = (DB<? extends Number>) (DA) null; // <>
o = (DC<?>) (DA) null; // <>
o = (DC<?>) (DA) null; // <>
}
}
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