Thu, 30 Jul 2009 10:29:53 +0100
6827648: Extremely slow compilation time for visitor pattern code + generics
Summary: Javac unnecessarily recomputates type-substitutions multiple times
Reviewed-by: jjg
duke@1 | 1 | /* |
duke@1 | 2 | * Copyright 2002 Sun Microsystems, Inc. All Rights Reserved. |
duke@1 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@1 | 4 | * |
duke@1 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@1 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@1 | 7 | * published by the Free Software Foundation. |
duke@1 | 8 | * |
duke@1 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@1 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@1 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@1 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@1 | 13 | * accompanied this code). |
duke@1 | 14 | * |
duke@1 | 15 | * You should have received a copy of the GNU General Public License version |
duke@1 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@1 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@1 | 18 | * |
duke@1 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
duke@1 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
duke@1 | 21 | * have any questions. |
duke@1 | 22 | */ |
duke@1 | 23 | |
duke@1 | 24 | /* |
duke@1 | 25 | * @test |
duke@1 | 26 | * @bug 4698375 |
duke@1 | 27 | * @summary generics: subtyping problem when type parameters permuted |
duke@1 | 28 | * @author gafter |
duke@1 | 29 | * |
darcy@289 | 30 | * @compile PermuteBound.java |
duke@1 | 31 | */ |
duke@1 | 32 | |
duke@1 | 33 | package test.tools.javac.generics.PermuteBound; |
duke@1 | 34 | |
duke@1 | 35 | class C<X, Y> {} |
duke@1 | 36 | |
duke@1 | 37 | class D<X, Y> extends C<X, Y> |
duke@1 | 38 | { |
duke@1 | 39 | void f(C<X, Y> c) |
duke@1 | 40 | { |
duke@1 | 41 | D<X, Y> d = (D<X, Y>) c;// OK because D extends C |
duke@1 | 42 | } |
duke@1 | 43 | |
duke@1 | 44 | void g(C<Y, X> c)// parameters X and Y are now permuted |
duke@1 | 45 | { |
duke@1 | 46 | D<Y, X> d = (D<Y, X>) c;// should also be OK but is not !? |
duke@1 | 47 | // ^ |
duke@1 | 48 | // inconvertible types |
duke@1 | 49 | // found : C<Y,X> |
duke@1 | 50 | // required : D<Y,X> |
duke@1 | 51 | } |
duke@1 | 52 | /* |
duke@1 | 53 | void gWorkAround(C<Y, X> c)// but generates unchecked warning |
duke@1 | 54 | { |
duke@1 | 55 | D<Y, X> d = (D) ((C) c); |
duke@1 | 56 | } |
duke@1 | 57 | */ |
duke@1 | 58 | } |