8334121: Anonymous class capturing two enclosing instances fails to compile

Reviewed-by: jlahoda, vromero

Author: mcimadamore

src/jdk.compiler/share/classes/com/sun/tools/javac/code/Symbol.java

@@ -358,7 +358,7 @@ public Type erasure(Types types) {
     public Type externalType(Types types) {
         Type t = erasure(types);
         if (name == name.table.names.init && owner.hasOuterInstance()) {
-            Type outerThisType = types.erasure(owner.type.getEnclosingType());
+            Type outerThisType = owner.innermostAccessibleEnclosingClass().erasure(types);
             return new MethodType(t.getParameterTypes().prepend(outerThisType),
                                   t.getReturnType(),
                                   t.getThrownTypes(),
@@ -506,7 +506,23 @@ public boolean isInner() {
      */
     public boolean hasOuterInstance() {
         return
-            type.getEnclosingType().hasTag(CLASS) && (flags() & (INTERFACE | ENUM | RECORD | NOOUTERTHIS)) == 0;
+            type.getEnclosingType().hasTag(CLASS) && (flags() & (INTERFACE | ENUM | RECORD)) == 0 &&
+                    ((flags() & NOOUTERTHIS) == 0 || type.getEnclosingType().tsym.hasOuterInstance());
+    }
+
+    /** If the class containing this symbol is a local or an anonymous class, then it might be
+     *  defined inside one or more pre-construction contexts, for which the corresponding enclosing
+     *  instance is considered inaccessible. This method return the class symbol corresponding to the
+     *  innermost enclosing type that is accessible from this symbol's class. Note: this method should
+     *  only be called after checking that {@link #hasOuterInstance()} returns {@code true}.
+     */
+    public ClassSymbol innermostAccessibleEnclosingClass() {
+        Assert.check(enclClass().hasOuterInstance());
+        Type current = enclClass().type;
+        while ((current.tsym.flags() & NOOUTERTHIS) != 0) {
+            current = current.getEnclosingType();
+        }
+        return (ClassSymbol) current.getEnclosingType().tsym;
     }
 
     /** The closest enclosing class of this symbol's declaration.

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

@@ -366,53 +366,9 @@ void visitSymbol(Symbol _sym) {
                     if (v.getConstValue() == null) {
                         addFreeVar(v);
                     }
-                } else {
-                    if (outerThisStack.head != null &&
-                        outerThisStack.head != _sym)
-                        visitSymbol(outerThisStack.head);
                 }
             }
         }
-
-        /** If tree refers to a class instance creation expression
-         *  add all free variables of the freshly created class.
-         */
-        public void visitNewClass(JCNewClass tree) {
-            ClassSymbol c = (ClassSymbol)tree.constructor.owner;
-            if (tree.encl == null &&
-                c.hasOuterInstance() &&
-                outerThisStack.head != null)
-                visitSymbol(outerThisStack.head);
-            super.visitNewClass(tree);
-        }
-
-        /** If tree refers to a qualified this or super expression
-         *  for anything but the current class, add the outer this
-         *  stack as a free variable.
-         */
-        public void visitSelect(JCFieldAccess tree) {
-            if ((tree.name == names._this || tree.name == names._super) &&
-                tree.selected.type.tsym != clazz &&
-                outerThisStack.head != null)
-                visitSymbol(outerThisStack.head);
-            super.visitSelect(tree);
-        }
-
-        /** If tree refers to a superclass constructor call,
-         *  add all free variables of the superclass.
-         */
-        public void visitApply(JCMethodInvocation tree) {
-            if (TreeInfo.name(tree.meth) == names._super) {
-                Symbol constructor = TreeInfo.symbol(tree.meth);
-                ClassSymbol c = (ClassSymbol)constructor.owner;
-                if (c.hasOuterInstance() &&
-                    !tree.meth.hasTag(SELECT) &&
-                    outerThisStack.head != null)
-                    visitSymbol(outerThisStack.head);
-            }
-            super.visitApply(tree);
-        }
-
     }
 
     ClassSymbol ownerToCopyFreeVarsFrom(ClassSymbol c) {
@@ -1586,7 +1542,7 @@ Name outerThisName(Type type, Symbol owner) {
     }
 
     private VarSymbol makeOuterThisVarSymbol(Symbol owner, long flags) {
-        Type target = types.erasure(owner.enclClass().type.getEnclosingType());
+        Type target = owner.innermostAccessibleEnclosingClass().erasure(types);
         // Set NOOUTERTHIS for all synthetic outer instance variables, and unset
         // it when the variable is accessed. If the variable is never accessed,
         // we skip creating an outer instance field and saving the constructor
@@ -3097,7 +3053,7 @@ public void visitNewClass(JCNewClass tree) {
                 thisArg.type = tree.encl.type;
             } else if (c.isDirectlyOrIndirectlyLocal()) {
                 // local class
-                thisArg = makeThis(tree.pos(), c.type.getEnclosingType().tsym);
+                thisArg = makeThis(tree.pos(), c.innermostAccessibleEnclosingClass());
             } else {
                 // nested class
                 thisArg = makeOwnerThis(tree.pos(), c, false);
@@ -3303,7 +3259,7 @@ public void visitApply(JCMethodInvocation tree) {
                     ((JCIdent) tree.meth).name = methName;
                 } else if (c.isDirectlyOrIndirectlyLocal() || methName == names._this){
                     // local class or this() call
-                    thisArg = makeThis(tree.meth.pos(), c.type.getEnclosingType().tsym);
+                    thisArg = makeThis(tree.meth.pos(), c.innermostAccessibleEnclosingClass());
                 } else if (currentClass.isStatic()) {
                     // super() call from static nested class - invalid
                     log.error(tree.pos(),

test/langtools/tools/javac/MethodParameters/LocalClassTest.out

@@ -1,7 +1,7 @@
 class LocalClassTest$1 -- anon
 LocalClassTest$1.<init>(final this$0/*implicit*/, final j, final val$i/*synthetic*/)
 class LocalClassTest$1CapturingLocal$1 -- anon
-LocalClassTest$1CapturingLocal$1.<init>(final val$this$0/*synthetic*/, final val$val$i/*synthetic*/)
+LocalClassTest$1CapturingLocal$1.<init>(final this$0/*implicit*/, final val$val$i/*synthetic*/)
 LocalClassTest$1CapturingLocal$1.test()
 class LocalClassTest$1CapturingLocal -- inner
 LocalClassTest$1CapturingLocal.<init>(final this$0/*implicit*/, final j, final val$i/*synthetic*/)

test/langtools/tools/javac/SuperInit/MultiLevelOuterInstance.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2024, 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 8334121
+ * @summary Anonymous class capturing two enclosing instances fails to compile
+ * @enablePreview
+ */
+
+public class MultiLevelOuterInstance {
+
+    interface A {
+        void run();
+    }
+    interface B {
+        void run();
+    }
+
+    class Inner1 {
+        Inner1() {
+            this(new A() {
+                class Inner2 {
+                    Inner2() {
+                        this(new B() {
+                            public void run() {
+                                m();
+                                g();
+                            }
+                        });
+                    }
+
+                    Inner2(B o) {
+                        o.run();
+                    }
+                }
+
+                public void run() {
+                    new Inner2();
+                }
+
+                void m() { }
+            });
+        }
+
+        Inner1(A o) { }
+    }
+    void g() { }
+
+    public static void main(String[] args) {
+        new MultiLevelOuterInstance().new Inner1();
+    }
+}