5053846: javac: MethodRef entries are duplicated in the constant pool

Reviewed-by: mcimadamore

langtools/src/share/classes/com/sun/tools/javac/comp/Lower.java

@@ -3434,14 +3434,16 @@ public class Lower extends TreeTranslator {
                 tree.expr = make.TypeCast(types.erasure(iterableType), tree.expr);
             Symbol iterator = lookupMethod(tree.expr.pos(),
                                            names.iterator,
-                                           types.erasure(syms.iterableType),
+                                           eType,
                                            List.<Type>nil());
             VarSymbol itvar = new VarSymbol(0, names.fromString("i" + target.syntheticNameChar()),
                                             types.erasure(iterator.type.getReturnType()),
                                             currentMethodSym);
+
              JCStatement init = make.
-                VarDef(itvar,
+                VarDef(itvar, make.App(make.Select(tree.expr, iterator)
-                       make.App(make.Select(tree.expr, iterator)));
+                     .setType(types.erasure(iterator.type))));
+
             Symbol hasNext = lookupMethod(tree.expr.pos(),
                                           names.hasNext,
                                           itvar.type,

langtools/test/tools/javac/T5053846/MethodRefDupInConstantPoolTest.java

@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2013, 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.
+ *
+ * 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 5053846
+ * @summary javac: MethodRef entries are duplicated in the constant pool
+ */
+
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.nio.file.Paths;
+import java.util.*;
+
+public class MethodRefDupInConstantPoolTest {
+
+    private static final String methodToLookFor =
+            "java/util/Vector.iterator:()Ljava/util/Iterator;";
+
+    public static void main(String[] args) {
+        new MethodRefDupInConstantPoolTest().run();
+    }
+
+    void run() {
+        check("-v", Paths.get(System.getProperty("test.classes"),
+                "TestHelper1.class").toString());
+        check("-v", Paths.get(System.getProperty("test.classes"),
+                "TestHelper2.class").toString());
+    }
+
+    void check(String... params) {
+        StringWriter s;
+        String out;
+        try (PrintWriter pw = new PrintWriter(s = new StringWriter())) {
+            com.sun.tools.javap.Main.run(params, pw);
+            out = s.toString();
+        }
+        String constantPool = getConstantPool(out);
+        if (constantPool.indexOf(methodToLookFor) !=
+                constantPool.lastIndexOf(methodToLookFor)) {
+            throw new AssertionError("There is more than one entry for the method seek "  +
+                    methodToLookFor);
+        }
+    }
+
+    String getConstantPool(String out) {
+        int start = out.indexOf("Constant pool:");
+        int end = out.indexOf("{");
+        return out.substring(start, end);
+    }
+}
+
+class TestHelper1 {
+    void m() {
+        Vector v = new Vector();
+        Iterator iter = v.iterator();
+        while (iter.hasNext()) {
+            Object o = iter.next();
+            Object o2 = o;
+        }
+        for (Object o: v) {
+            Object o2 = o;
+        }
+    }
+}
+
+class TestHelper2<X extends Number & Iterable<String>> {
+    void test(X x) {
+        for (String s : x) { }
+    }
+}