--- a/langtools/src/share/classes/com/sun/tools/javac/main/JavaCompiler.java	Fri Aug 08 17:43:24 2008 +0100
+++ b/langtools/src/share/classes/com/sun/tools/javac/main/JavaCompiler.java	Fri Aug 08 17:48:04 2008 +0100
@@ -27,6 +27,7 @@
 
 import java.io.*;
 import java.util.HashSet;
+import java.util.LinkedHashSet;
 import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.MissingResourceException;
@@ -1185,14 +1186,16 @@
          * are processed through attribute and flow before subtypes are translated.
          */
         class ScanNested extends TreeScanner {
-            Set<Env<AttrContext>> dependencies = new HashSet<Env<AttrContext>>();
+            Set<Env<AttrContext>> dependencies = new LinkedHashSet<Env<AttrContext>>();
             public void visitClassDef(JCClassDecl node) {
                 Type st = types.supertype(node.sym.type);
                 if (st.tag == TypeTags.CLASS) {
                     ClassSymbol c = st.tsym.outermostClass();
                     Env<AttrContext> stEnv = enter.getEnv(c);
-                    if (stEnv != null && env != stEnv)
-                        dependencies.add(stEnv);
+                    if (stEnv != null && env != stEnv) {
+                        if (dependencies.add(stEnv))
+                            scan(stEnv.tree);
+                    }
                 }
                 super.visitClassDef(node);
             }
@@ -1204,6 +1207,11 @@
                 flow(attribute(dep));
         }
 
+        //We need to check for error another time as more classes might
+        //have been attributed and analyzed at this stage
+        if (errorCount() > 0)
+            return;
+
         if (verboseCompilePolicy)
             log.printLines(log.noticeWriter, "[desugar " + env.enclClass.sym + "]");
 

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/6734819/T6734819a.java	Fri Aug 08 17:48:04 2008 +0100
@@ -0,0 +1,39 @@
+/*
+ * 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 6734819
+ * @summary Javac performs flows analysis on already translated classes
+ * @author Maurizio Cimadamore
+ *
+ * @compile/ref=T6734819a.out -XDrawDiagnostics -Xlint:all -XDverboseCompilePolicy T6734819a.java
+ */
+class Y extends W {}
+class W extends Z {}
+
+class Z {
+    void m(Z z) {
+        W w = (W)z;
+    }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/6734819/T6734819a.out	Fri Aug 08 17:48:04 2008 +0100
@@ -0,0 +1,12 @@
+[attribute Y]
+[flow Y]
+[attribute W]
+[flow W]
+[attribute Z]
+[flow Z]
+[desugar Y]
+[generate code Y]
+[desugar W]
+[generate code W]
+[desugar Z]
+[generate code Z]

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/6734819/T6734819b.java	Fri Aug 08 17:48:04 2008 +0100
@@ -0,0 +1,35 @@
+/*
+ * 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 6734819
+ * @summary Javac performs flows analysis on already translated classes
+ * @author Maurizio Cimadamore
+ *
+ * @compile/ref=T6734819b.out -XDrawDiagnostics -Xlint:all -XDverboseCompilePolicy T6734819b.java
+ */
+class A extends B {}
+class B {
+    class C extends B {}
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/6734819/T6734819b.out	Fri Aug 08 17:48:04 2008 +0100
@@ -0,0 +1,9 @@
+[attribute A]
+[flow A]
+[attribute B]
+[flow B]
+[desugar A]
+[generate code A]
+[desugar B]
+[generate code B]
+[generate code B]

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/6734819/T6734819c.java	Fri Aug 08 17:48:04 2008 +0100
@@ -0,0 +1,40 @@
+/*
+ * 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 6734819
+ * @summary Javac performs flows analysis on already translated classes
+ * @author Maurizio Cimadamore
+ *
+ * @compile/fail/ref=T6734819c.out -XDrawDiagnostics -Xlint:all -XDverboseCompilePolicy T6734819c.java
+ */
+class Y extends W {}
+class W extends Z {}
+
+class Z {
+    void m(Z z) {
+        return;
+        W w = (W)z;
+    }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/6734819/T6734819c.out	Fri Aug 08 17:48:04 2008 +0100
@@ -0,0 +1,8 @@
+[attribute Y]
+[flow Y]
+[attribute W]
+[flow W]
+[attribute Z]
+[flow Z]
+T6734819c.java:38:11: compiler.err.unreachable.stmt
+1 error