# HG changeset patch
# User mcimadamore
# Date 1413284465 -3600
# Node ID 6c718c5086b320fa00d3a64b6e7853fb35bb812e
# Parent  5b69a74c224eda19e3f6476a1655d08939e58b2d
8058511: StackOverflowError at com.sun.tools.javac.code.Types.lub
Summary: Lub crashes when handling typevar with array bound
Reviewed-by: vromero, dlsmith

diff -r 5b69a74c224e -r 6c718c5086b3 langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Types.java
--- a/langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Types.java	Tue Oct 14 12:00:39 2014 +0100
+++ b/langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Types.java	Tue Oct 14 12:01:05 2014 +0100
@@ -1889,7 +1889,12 @@
      * Mapping to take element type of an arraytype
      */
     private Mapping elemTypeFun = new Mapping ("elemTypeFun") {
-        public Type apply(Type t) { return elemtype(t); }
+        public Type apply(Type t) {
+            while (t.hasTag(TYPEVAR)) {
+                t = t.getUpperBound();
+            }
+            return elemtype(t);
+        }
     };
 
     /**
@@ -3531,40 +3536,46 @@
     }
 
     /**
-     * Return the least upper bound of pair of types.  if the lub does
+     * Return the least upper bound of list of types.  if the lub does
      * not exist return null.
      */
-    public Type lub(Type t1, Type t2) {
-        return lub(List.of(t1, t2));
+    public Type lub(List<Type> ts) {
+        return lub(ts.toArray(new Type[ts.length()]));
     }
 
     /**
      * Return the least upper bound (lub) of set of types.  If the lub
      * does not exist return the type of null (bottom).
      */
-    public Type lub(List<Type> ts) {
+    public Type lub(Type... ts) {
+        final int UNKNOWN_BOUND = 0;
         final int ARRAY_BOUND = 1;
         final int CLASS_BOUND = 2;
-        int boundkind = 0;
-        for (Type t : ts) {
+
+        int[] kinds = new int[ts.length];
+
+        int boundkind = UNKNOWN_BOUND;
+        for (int i = 0 ; i < ts.length ; i++) {
+            Type t = ts[i];
             switch (t.getTag()) {
             case CLASS:
-                boundkind |= CLASS_BOUND;
+                boundkind |= kinds[i] = CLASS_BOUND;
                 break;
             case ARRAY:
-                boundkind |= ARRAY_BOUND;
+                boundkind |= kinds[i] = ARRAY_BOUND;
                 break;
             case  TYPEVAR:
                 do {
                     t = t.getUpperBound();
                 } while (t.hasTag(TYPEVAR));
                 if (t.hasTag(ARRAY)) {
-                    boundkind |= ARRAY_BOUND;
+                    boundkind |= kinds[i] = ARRAY_BOUND;
                 } else {
-                    boundkind |= CLASS_BOUND;
+                    boundkind |= kinds[i] = CLASS_BOUND;
                 }
                 break;
             default:
+                kinds[i] = UNKNOWN_BOUND;
                 if (t.isPrimitive())
                     return syms.errType;
             }
@@ -3575,15 +3586,16 @@
 
         case ARRAY_BOUND:
             // calculate lub(A[], B[])
-            List<Type> elements = Type.map(ts, elemTypeFun);
-            for (Type t : elements) {
-                if (t.isPrimitive()) {
+            Type[] elements = new Type[ts.length];
+            for (int i = 0 ; i < ts.length ; i++) {
+                Type elem = elements[i] = elemTypeFun.apply(ts[i]);
+                if (elem.isPrimitive()) {
                     // if a primitive type is found, then return
                     // arraySuperType unless all the types are the
                     // same
-                    Type first = ts.head;
-                    for (Type s : ts.tail) {
-                        if (!isSameType(first, s)) {
+                    Type first = ts[0];
+                    for (int j = 1 ; j < ts.length ; j++) {
+                        if (!isSameType(first, ts[j])) {
                              // lub(int[], B[]) is Cloneable & Serializable
                             return arraySuperType();
                         }
@@ -3598,13 +3610,20 @@
 
         case CLASS_BOUND:
             // calculate lub(A, B)
-            while (!ts.head.hasTag(CLASS) && !ts.head.hasTag(TYPEVAR)) {
-                ts = ts.tail;
+            int startIdx = 0;
+            for (int i = 0; i < ts.length ; i++) {
+                Type t = ts[i];
+                if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) {
+                    break;
+                } else {
+                    startIdx++;
+                }
             }
-            Assert.check(!ts.isEmpty());
+            Assert.check(startIdx < ts.length);
             //step 1 - compute erased candidate set (EC)
-            List<Type> cl = erasedSupertypes(ts.head);
-            for (Type t : ts.tail) {
+            List<Type> cl = erasedSupertypes(ts[startIdx]);
+            for (int i = startIdx + 1 ; i < ts.length ; i++) {
+                Type t = ts[i];
                 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR))
                     cl = intersect(cl, erasedSupertypes(t));
             }
@@ -3613,9 +3632,9 @@
             //step 3 - for each element G in MEC, compute lci(Inv(G))
             List<Type> candidates = List.nil();
             for (Type erasedSupertype : mec) {
-                List<Type> lci = List.of(asSuper(ts.head, erasedSupertype.tsym));
-                for (Type t : ts) {
-                    lci = intersect(lci, List.of(asSuper(t, erasedSupertype.tsym)));
+                List<Type> lci = List.of(asSuper(ts[startIdx], erasedSupertype.tsym));
+                for (int i = startIdx + 1 ; i < ts.length ; i++) {
+                    lci = intersect(lci, List.of(asSuper(ts[i], erasedSupertype.tsym)));
                 }
                 candidates = candidates.appendList(lci);
             }
@@ -3626,9 +3645,9 @@
         default:
             // calculate lub(A, B[])
             List<Type> classes = List.of(arraySuperType());
-            for (Type t : ts) {
-                if (!t.hasTag(ARRAY)) // Filter out any arrays
-                    classes = classes.prepend(t);
+            for (int i = 0 ; i < ts.length ; i++) {
+                if (kinds[i] != ARRAY_BOUND) // Filter out any arrays
+                    classes = classes.prepend(ts[i]);
             }
             // lub(A, B[]) is lub(A, arraySuperType)
             return lub(classes);
diff -r 5b69a74c224e -r 6c718c5086b3 langtools/test/tools/javac/generics/inference/8058511/T8058511a.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/generics/inference/8058511/T8058511a.java	Tue Oct 14 12:01:05 2014 +0100
@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8058511
+ * @summary StackOverflowError at com.sun.tools.javac.code.Types.lub
+ * @compile T8058511a.java
+ */
+class T8058511a {
+    <Z> void choose(Z z1, Z z2) { }
+
+    void test(Class<Double> cd, Class<? extends double[]> cdarr) {
+        choose(cd, cdarr);
+    }
+}
diff -r 5b69a74c224e -r 6c718c5086b3 langtools/test/tools/javac/generics/inference/8058511/T8058511b.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/generics/inference/8058511/T8058511b.java	Tue Oct 14 12:01:05 2014 +0100
@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8058511
+ * @summary StackOverflowError at com.sun.tools.javac.code.Types.lub
+ * @compile T8058511b.java
+ */
+class T8058511b {
+    void test(Class<Double> cd, Class<? extends double[]> cdarr) {
+        ((false) ? cd : cdarr).toString();
+    }
+}
diff -r 5b69a74c224e -r 6c718c5086b3 langtools/test/tools/javac/generics/inference/8058511/T8058511c.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/generics/inference/8058511/T8058511c.java	Tue Oct 14 12:01:05 2014 +0100
@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8058511
+ * @summary StackOverflowError at com.sun.tools.javac.code.Types.lub
+ * @compile T8058511c.java
+ */
+import java.util.List;
+
+class T8058511c {
+    void test(List<? extends double[]> l) {
+        (true ? l.get(0) : l.get(0)).toString();
+    }
+}