6558559: Extra "unchecked" diagnostic

Summary: Fixed Types.sideCast in order to suppress redundant unchecked warnings
Reviewed-by: jjg

src/share/classes/com/sun/tools/javac/code/Types.java

@@ -3148,7 +3148,7 @@ public class Types {
             giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
             commonSupers = commonSupers.tail;
         }
-        if (giveWarning && !isReifiable(to))
+        if (giveWarning && !isReifiable(reverse ? from : to))
             warn.warnUnchecked();
         if (!source.allowCovariantReturns())
             // reject if there is a common method signature with

test/tools/javac/cast/6558559/T6558559a.java

+/*
+ * Copyright 2008 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * 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.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/*
+ * @test
+ * @bug 6558559
+ * @summary Extra "unchecked" diagnostic
+ * @author Maurizio Cimadamore
+ *
+ * @compile T6558559a.java -Xlint:unchecked -Werror
+ */
+
+class T6558559a {
+    interface A<T> {}
+
+    static class B<T> {}
+
+    A<?> x = null;
+    B<?> y = (B<?>)x;
+}
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test/tools/javac/cast/6558559/T6558559b.java

+/*
+ * Copyright 2008 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * 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.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/*
+ * @test
+ * @bug 6558559
+ * @summary Extra "unchecked" diagnostic
+ * @author Maurizio Cimadamore
+ *
+ * @compile T6558559b.java -Xlint:unchecked -Werror
+ */
+
+import java.util.*;
+
+class T6558559b {
+    void test(List rawList, List<?> unboundList) {
+        Throwable t0 = (Throwable) Collections.emptyList();
+        Throwable t1 = (Throwable) rawList;
+        Throwable t2 = (Throwable) unboundList;
+        Object o = unboundList;
+        Throwable t3 = (Throwable) o;
+    }
+}
\ No newline at end of file