8006684: Compiler produces java.lang.VerifyError: Bad type on operand stack

Summary: Lambda desugaring generates spurious references to 'this' in static contexts
Reviewed-by: jjg

src/share/classes/com/sun/tools/javac/comp/LambdaToMethod.java

@@ -859,8 +859,8 @@ public class LambdaToMethod extends TreeTranslator {
             finally {
                 frameStack = prevStack;
             }
-            if (frameStack.nonEmpty() && enclosingLambda() != null) {
-                // Any class defined within a lambda is an implicit 'this' reference
+            if (!tree.sym.isStatic() && frameStack.nonEmpty() && enclosingLambda() != null) {
+                // Any (non-static) class defined within a lambda is an implicit 'this' reference
                 // because its constructor will reference the enclosing class
                 ((LambdaTranslationContext) context()).addSymbol(tree.sym.type.getEnclosingType().tsym, CAPTURED_THIS);
             }
@@ -994,6 +994,11 @@ public class LambdaToMethod extends TreeTranslator {
          * (required to skip synthetic lambda symbols)
          */
         private Symbol owner() {
+            return owner(false);
+        }
+
+        @SuppressWarnings("fallthrough")
+        private Symbol owner(boolean skipLambda) {
             List<Frame> frameStack2 = frameStack;
             while (frameStack2.nonEmpty()) {
                 switch (frameStack2.head.tree.getTag()) {
@@ -1012,7 +1017,8 @@ public class LambdaToMethod extends TreeTranslator {
                     case METHODDEF:
                         return ((JCMethodDecl)frameStack2.head.tree).sym;
                     case LAMBDA:
-                        return ((LambdaTranslationContext)contextMap.get(frameStack2.head.tree)).translatedSym;
+                        if (!skipLambda)
+                            return ((LambdaTranslationContext)contextMap.get(frameStack2.head.tree)).translatedSym;
                     default:
                         frameStack2 = frameStack2.tail;
                 }
@@ -1311,8 +1317,9 @@ public class LambdaToMethod extends TreeTranslator {
             }
 
             Type enclosingType() {
-                //local inner classes defined inside a lambda are always non-static
-                return owner.enclClass().type;
+                return owner.isStatic() ?
+                        Type.noType :
+                        owner.enclClass().type;
             }
 
             Type generatedLambdaSig() {

test/tools/javac/lambda/LambdaExpr21.java

+/*
+ * 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 8006684
+ * @summary Compiler produces java.lang.VerifyError: Bad type on operand stack
+ * @run main LambdaExpr21
+ */
+public class LambdaExpr21 {
+
+    static int assertionCount = 0;
+
+    static void assertTrue(boolean cond) {
+        assertionCount++;
+        if (!cond)
+            throw new AssertionError();
+    }
+
+    interface SAM {
+        void foo();
+    }
+
+    static class Checker {
+        Checker(boolean cond) {
+            assertTrue(cond);
+        }
+    }
+
+    static {
+        SAM s = ()-> { new Checker(true) { }; };
+        s.foo();
+    }
+
+    static void test(){
+        SAM s = ()-> { new Checker(true) { }; };
+        s.foo();
+    }
+
+    static SAM s = ()-> { new Checker(true) { }; };
+
+    public static void main(String[] args) {
+        test();
+        s.foo();
+        assertTrue(assertionCount == 3);
+    }
+}