xref: /openjdk10/langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/LambdaToMethod.java

/*
 * Copyright (c) 2010, 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.
 */
package com.sun.tools.javac.comp;

import com.sun.tools.javac.tree.*;
import com.sun.tools.javac.tree.JCTree.*;
import com.sun.tools.javac.tree.JCTree.JCMemberReference.ReferenceKind;
import com.sun.tools.javac.tree.TreeMaker;
import com.sun.tools.javac.tree.TreeTranslator;
import com.sun.tools.javac.code.Attribute;
import com.sun.tools.javac.code.Scope.WriteableScope;
import com.sun.tools.javac.code.Symbol;
import com.sun.tools.javac.code.Symbol.ClassSymbol;
import com.sun.tools.javac.code.Symbol.DynamicMethodSymbol;
import com.sun.tools.javac.code.Symbol.MethodSymbol;
import com.sun.tools.javac.code.Symbol.TypeSymbol;
import com.sun.tools.javac.code.Symbol.VarSymbol;
import com.sun.tools.javac.code.Symtab;
import com.sun.tools.javac.code.Type;
import com.sun.tools.javac.code.Type.MethodType;
import com.sun.tools.javac.code.Type.TypeVar;
import com.sun.tools.javac.code.Types;
import com.sun.tools.javac.comp.LambdaToMethod.LambdaAnalyzerPreprocessor.*;
import com.sun.tools.javac.comp.Lower.BasicFreeVarCollector;
import com.sun.tools.javac.jvm.*;
import com.sun.tools.javac.util.*;
import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
import com.sun.source.tree.MemberReferenceTree.ReferenceMode;

import java.util.EnumMap;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;

import static com.sun.tools.javac.comp.LambdaToMethod.LambdaSymbolKind.*;
import static com.sun.tools.javac.code.Flags.*;
import static com.sun.tools.javac.code.Kinds.Kind.*;
import static com.sun.tools.javac.code.TypeTag.*;
import static com.sun.tools.javac.tree.JCTree.Tag.*;
import javax.lang.model.type.TypeKind;

/**
 * This pass desugars lambda expressions into static methods
 *
 *  <p><b>This is NOT part of any supported API.
 *  If you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 */
public class LambdaToMethod extends TreeTranslator {

    private Attr attr;
    private JCDiagnostic.Factory diags;
    private Log log;
    private Lower lower;
    private Names names;
    private Symtab syms;
    private Resolve rs;
    private TreeMaker make;
    private Types types;
    private TransTypes transTypes;
    private Env<AttrContext> attrEnv;

    /** the analyzer scanner */
    private LambdaAnalyzerPreprocessor analyzer;

    /** map from lambda trees to translation contexts */
    private Map<JCTree, TranslationContext<?>> contextMap;

    /** current translation context (visitor argument) */
    private TranslationContext<?> context;

    /** info about the current class being processed */
    private KlassInfo kInfo;

    /** dump statistics about lambda code generation */
    private boolean dumpLambdaToMethodStats;

    /** force serializable representation, for stress testing **/
    private final boolean forceSerializable;

    /** Flag for alternate metafactories indicating the lambda object is intended to be serializable */
    public static final int FLAG_SERIALIZABLE = 1 << 0;

    /** Flag for alternate metafactories indicating the lambda object has multiple targets */
    public static final int FLAG_MARKERS = 1 << 1;

    /** Flag for alternate metafactories indicating the lambda object requires multiple bridges */
    public static final int FLAG_BRIDGES = 1 << 2;

    // <editor-fold defaultstate="collapsed" desc="Instantiating">
    protected static final Context.Key<LambdaToMethod> unlambdaKey = new Context.Key<>();

    public static LambdaToMethod instance(Context context) {
        LambdaToMethod instance = context.get(unlambdaKey);
        if (instance == null) {
            instance = new LambdaToMethod(context);
        }
        return instance;
    }
    private LambdaToMethod(Context context) {
        context.put(unlambdaKey, this);
        diags = JCDiagnostic.Factory.instance(context);
        log = Log.instance(context);
        lower = Lower.instance(context);
        names = Names.instance(context);
        syms = Symtab.instance(context);
        rs = Resolve.instance(context);
        make = TreeMaker.instance(context);
        types = Types.instance(context);
        transTypes = TransTypes.instance(context);
        analyzer = new LambdaAnalyzerPreprocessor();
        Options options = Options.instance(context);
        dumpLambdaToMethodStats = options.isSet("dumpLambdaToMethodStats");
        attr = Attr.instance(context);
        forceSerializable = options.isSet("forceSerializable");
    }
    // </editor-fold>

    private class KlassInfo {

        /**
         * list of methods to append
         */
        private ListBuffer<JCTree> appendedMethodList;

        /**
         * list of deserialization cases
         */
        private final Map<String, ListBuffer<JCStatement>> deserializeCases;

       /**
         * deserialize method symbol
         */
        private final MethodSymbol deserMethodSym;

        /**
         * deserialize method parameter symbol
         */
        private final VarSymbol deserParamSym;

        private final JCClassDecl clazz;

        private KlassInfo(JCClassDecl clazz) {
            this.clazz = clazz;
            appendedMethodList = new ListBuffer<>();
            deserializeCases = new HashMap<>();
            MethodType type = new MethodType(List.of(syms.serializedLambdaType), syms.objectType,
                    List.<Type>nil(), syms.methodClass);
            deserMethodSym = makePrivateSyntheticMethod(STATIC, names.deserializeLambda, type, clazz.sym);
            deserParamSym = new VarSymbol(FINAL, names.fromString("lambda"),
                    syms.serializedLambdaType, deserMethodSym);
        }

        private void addMethod(JCTree decl) {
            appendedMethodList = appendedMethodList.prepend(decl);
        }
    }

    // <editor-fold defaultstate="collapsed" desc="translate methods">
    @Override
    public <T extends JCTree> T translate(T tree) {
        TranslationContext<?> newContext = contextMap.get(tree);
        return translate(tree, newContext != null ? newContext : context);
    }

    <T extends JCTree> T translate(T tree, TranslationContext<?> newContext) {
        TranslationContext<?> prevContext = context;
        try {
            context = newContext;
            return super.translate(tree);
        }
        finally {
            context = prevContext;
        }
    }

    <T extends JCTree> List<T> translate(List<T> trees, TranslationContext<?> newContext) {
        ListBuffer<T> buf = new ListBuffer<>();
        for (T tree : trees) {
            buf.append(translate(tree, newContext));
        }
        return buf.toList();
    }

    public JCTree translateTopLevelClass(Env<AttrContext> env, JCTree cdef, TreeMaker make) {
        this.make = make;
        this.attrEnv = env;
        this.context = null;
        this.contextMap = new HashMap<>();
        return translate(cdef);
    }
    // </editor-fold>

    // <editor-fold defaultstate="collapsed" desc="visitor methods">
    /**
     * Visit a class.
     * Maintain the translatedMethodList across nested classes.
     * Append the translatedMethodList to the class after it is translated.
     * @param tree
     */
    @Override
    public void visitClassDef(JCClassDecl tree) {
        if (tree.sym.owner.kind == PCK) {
            //analyze class
            tree = analyzer.analyzeAndPreprocessClass(tree);
        }
        KlassInfo prevKlassInfo = kInfo;
        try {
            kInfo = new KlassInfo(tree);
            super.visitClassDef(tree);
            if (!kInfo.deserializeCases.isEmpty()) {
                int prevPos = make.pos;
                try {
                    make.at(tree);
                    kInfo.addMethod(makeDeserializeMethod(tree.sym));
                } finally {
                    make.at(prevPos);
                }
            }
            //add all translated instance methods here
            List<JCTree> newMethods = kInfo.appendedMethodList.toList();
            tree.defs = tree.defs.appendList(newMethods);
            for (JCTree lambda : newMethods) {
                tree.sym.members().enter(((JCMethodDecl)lambda).sym);
            }
            result = tree;
        } finally {
            kInfo = prevKlassInfo;
        }
    }

    /**
     * Translate a lambda into a method to be inserted into the class.
     * Then replace the lambda site with an invokedynamic call of to lambda
     * meta-factory, which will use the lambda method.
     * @param tree
     */
    @Override
    public void visitLambda(JCLambda tree) {
        LambdaTranslationContext localContext = (LambdaTranslationContext)context;
        MethodSymbol sym = localContext.translatedSym;
        MethodType lambdaType = (MethodType) sym.type;

        {
            Symbol owner = localContext.owner;
            ListBuffer<Attribute.TypeCompound> ownerTypeAnnos = new ListBuffer<>();
            ListBuffer<Attribute.TypeCompound> lambdaTypeAnnos = new ListBuffer<>();

            for (Attribute.TypeCompound tc : owner.getRawTypeAttributes()) {
                if (tc.position.onLambda == tree) {
                    lambdaTypeAnnos.append(tc);
                } else {
                    ownerTypeAnnos.append(tc);
                }
            }
            if (lambdaTypeAnnos.nonEmpty()) {
                owner.setTypeAttributes(ownerTypeAnnos.toList());
                sym.setTypeAttributes(lambdaTypeAnnos.toList());
            }
        }

        //create the method declaration hoisting the lambda body
        JCMethodDecl lambdaDecl = make.MethodDef(make.Modifiers(sym.flags_field),
                sym.name,
                make.QualIdent(lambdaType.getReturnType().tsym),
                List.<JCTypeParameter>nil(),
                localContext.syntheticParams,
                lambdaType.getThrownTypes() == null ?
                    List.<JCExpression>nil() :
                    make.Types(lambdaType.getThrownTypes()),
                null,
                null);
        lambdaDecl.sym = sym;
        lambdaDecl.type = lambdaType;

        //translate lambda body
        //As the lambda body is translated, all references to lambda locals,
        //captured variables, enclosing members are adjusted accordingly
        //to refer to the static method parameters (rather than i.e. acessing to
        //captured members directly).
        lambdaDecl.body = translate(makeLambdaBody(tree, lambdaDecl));

        //Add the method to the list of methods to be added to this class.
        kInfo.addMethod(lambdaDecl);

        //now that we have generated a method for the lambda expression,
        //we can translate the lambda into a method reference pointing to the newly
        //created method.
        //
        //Note that we need to adjust the method handle so that it will match the
        //signature of the SAM descriptor - this means that the method reference
        //should be added the following synthetic arguments:
        //
        // * the "this" argument if it is an instance method
        // * enclosing locals captured by the lambda expression

        ListBuffer<JCExpression> syntheticInits = new ListBuffer<>();

        if (localContext.methodReferenceReceiver != null) {
            syntheticInits.append(localContext.methodReferenceReceiver);
        } else if (!sym.isStatic()) {
            syntheticInits.append(makeThis(
                    sym.owner.enclClass().asType(),
                    localContext.owner.enclClass()));
        }

        //add captured locals
        for (Symbol fv : localContext.getSymbolMap(CAPTURED_VAR).keySet()) {
            if (fv != localContext.self) {
                JCTree captured_local = make.Ident(fv).setType(fv.type);
                syntheticInits.append((JCExpression) captured_local);
            }
        }

        //then, determine the arguments to the indy call
        List<JCExpression> indy_args = translate(syntheticInits.toList(), localContext.prev);

        //build a sam instance using an indy call to the meta-factory
        int refKind = referenceKind(sym);

        //convert to an invokedynamic call
        result = makeMetafactoryIndyCall(context, refKind, sym, indy_args);
    }

    private JCIdent makeThis(Type type, Symbol owner) {
        VarSymbol _this = new VarSymbol(PARAMETER | FINAL | SYNTHETIC,
                names._this,
                type,
                owner);
        return make.Ident(_this);
    }

    /**
     * Translate a method reference into an invokedynamic call to the
     * meta-factory.
     * @param tree
     */
    @Override
    public void visitReference(JCMemberReference tree) {
        ReferenceTranslationContext localContext = (ReferenceTranslationContext)context;

        //first determine the method symbol to be used to generate the sam instance
        //this is either the method reference symbol, or the bridged reference symbol
        Symbol refSym = localContext.isSignaturePolymorphic()
                ? localContext.sigPolySym
                : tree.sym;

        //the qualifying expression is treated as a special captured arg
        JCExpression init;
        switch(tree.kind) {

            case IMPLICIT_INNER:    /** Inner :: new */
            case SUPER:             /** super :: instMethod */
                init = makeThis(
                    localContext.owner.enclClass().asType(),
                    localContext.owner.enclClass());
                break;

            case BOUND:             /** Expr :: instMethod */
                init = tree.getQualifierExpression();
                init = attr.makeNullCheck(init);
                break;

            case UNBOUND:           /** Type :: instMethod */
            case STATIC:            /** Type :: staticMethod */
            case TOPLEVEL:          /** Top level :: new */
            case ARRAY_CTOR:        /** ArrayType :: new */
                init = null;
                break;

            default:
                throw new InternalError("Should not have an invalid kind");
        }

        List<JCExpression> indy_args = init==null? List.<JCExpression>nil() : translate(List.of(init), localContext.prev);


        //build a sam instance using an indy call to the meta-factory
        result = makeMetafactoryIndyCall(localContext, localContext.referenceKind(), refSym, indy_args);
    }

    /**
     * Translate identifiers within a lambda to the mapped identifier
     * @param tree
     */
    @Override
    public void visitIdent(JCIdent tree) {
        if (context == null || !analyzer.lambdaIdentSymbolFilter(tree.sym)) {
            super.visitIdent(tree);
        } else {
            int prevPos = make.pos;
            try {
                make.at(tree);

                LambdaTranslationContext lambdaContext = (LambdaTranslationContext) context;
                JCTree ltree = lambdaContext.translate(tree);
                if (ltree != null) {
                    result = ltree;
                } else {
                    //access to untranslated symbols (i.e. compile-time constants,
                    //members defined inside the lambda body, etc.) )
                    super.visitIdent(tree);
                }
            } finally {
                make.at(prevPos);
            }
        }
    }

    @Override
    public void visitVarDef(JCVariableDecl tree) {
        LambdaTranslationContext lambdaContext = (LambdaTranslationContext)context;
        if (context != null && lambdaContext.getSymbolMap(LOCAL_VAR).containsKey(tree.sym)) {
            tree.init = translate(tree.init);
            tree.sym = (VarSymbol) lambdaContext.getSymbolMap(LOCAL_VAR).get(tree.sym);
            result = tree;
        } else if (context != null && lambdaContext.getSymbolMap(TYPE_VAR).containsKey(tree.sym)) {
            JCExpression init = translate(tree.init);
            VarSymbol xsym = (VarSymbol)lambdaContext.getSymbolMap(TYPE_VAR).get(tree.sym);
            int prevPos = make.pos;
            try {
                result = make.at(tree).VarDef(xsym, init);
            } finally {
                make.at(prevPos);
            }
            // Replace the entered symbol for this variable
            WriteableScope sc = tree.sym.owner.members();
            if (sc != null) {
                sc.remove(tree.sym);
                sc.enter(xsym);
            }
        } else {
            super.visitVarDef(tree);
        }
    }

    // </editor-fold>

    // <editor-fold defaultstate="collapsed" desc="Translation helper methods">

    private JCBlock makeLambdaBody(JCLambda tree, JCMethodDecl lambdaMethodDecl) {
        return tree.getBodyKind() == JCLambda.BodyKind.EXPRESSION ?
                makeLambdaExpressionBody((JCExpression)tree.body, lambdaMethodDecl) :
                makeLambdaStatementBody((JCBlock)tree.body, lambdaMethodDecl, tree.canCompleteNormally);
    }

    private JCBlock makeLambdaExpressionBody(JCExpression expr, JCMethodDecl lambdaMethodDecl) {
        Type restype = lambdaMethodDecl.type.getReturnType();
        boolean isLambda_void = expr.type.hasTag(VOID);
        boolean isTarget_void = restype.hasTag(VOID);
        boolean isTarget_Void = types.isSameType(restype, types.boxedClass(syms.voidType).type);
        int prevPos = make.pos;
        try {
            if (isTarget_void) {
                //target is void:
                // BODY;
                JCStatement stat = make.at(expr).Exec(expr);
                return make.Block(0, List.<JCStatement>of(stat));
            } else if (isLambda_void && isTarget_Void) {
                //void to Void conversion:
                // BODY; return null;
                ListBuffer<JCStatement> stats = new ListBuffer<>();
                stats.append(make.at(expr).Exec(expr));
                stats.append(make.Return(make.Literal(BOT, null).setType(syms.botType)));
                return make.Block(0, stats.toList());
            } else {
                //non-void to non-void conversion:
                // return (TYPE)BODY;
                JCExpression retExpr = transTypes.coerce(attrEnv, expr, restype);
                return make.at(retExpr).Block(0, List.<JCStatement>of(make.Return(retExpr)));
            }
        } finally {
            make.at(prevPos);
        }
    }

    private JCBlock makeLambdaStatementBody(JCBlock block, final JCMethodDecl lambdaMethodDecl, boolean completeNormally) {
        final Type restype = lambdaMethodDecl.type.getReturnType();
        final boolean isTarget_void = restype.hasTag(VOID);
        boolean isTarget_Void = types.isSameType(restype, types.boxedClass(syms.voidType).type);

        class LambdaBodyTranslator extends TreeTranslator {

            @Override
            public void visitClassDef(JCClassDecl tree) {
                //do NOT recurse on any inner classes
                result = tree;
            }

            @Override
            public void visitLambda(JCLambda tree) {
                //do NOT recurse on any nested lambdas
                result = tree;
            }

            @Override
            public void visitReturn(JCReturn tree) {
                boolean isLambda_void = tree.expr == null;
                if (isTarget_void && !isLambda_void) {
                    //Void to void conversion:
                    // { TYPE $loc = RET-EXPR; return; }
                    VarSymbol loc = makeSyntheticVar(0, names.fromString("$loc"), tree.expr.type, lambdaMethodDecl.sym);
                    JCVariableDecl varDef = make.VarDef(loc, tree.expr);
                    result = make.Block(0, List.<JCStatement>of(varDef, make.Return(null)));
                } else if (!isTarget_void || !isLambda_void) {
                    //non-void to non-void conversion:
                    // return (TYPE)RET-EXPR;
                    tree.expr = transTypes.coerce(attrEnv, tree.expr, restype);
                    result = tree;
                } else {
                    result = tree;
                }

            }
        }

        JCBlock trans_block = new LambdaBodyTranslator().translate(block);
        if (completeNormally && isTarget_Void) {
            //there's no return statement and the lambda (possibly inferred)
            //return type is java.lang.Void; emit a synthetic return statement
            trans_block.stats = trans_block.stats.append(make.Return(make.Literal(BOT, null).setType(syms.botType)));
        }
        return trans_block;
    }

    private JCMethodDecl makeDeserializeMethod(Symbol kSym) {
        ListBuffer<JCCase> cases = new ListBuffer<>();
        ListBuffer<JCBreak> breaks = new ListBuffer<>();
        for (Map.Entry<String, ListBuffer<JCStatement>> entry : kInfo.deserializeCases.entrySet()) {
            JCBreak br = make.Break(null);
            breaks.add(br);
            List<JCStatement> stmts = entry.getValue().append(br).toList();
            cases.add(make.Case(make.Literal(entry.getKey()), stmts));
        }
        JCSwitch sw = make.Switch(deserGetter("getImplMethodName", syms.stringType), cases.toList());
        for (JCBreak br : breaks) {
            br.target = sw;
        }
        JCBlock body = make.Block(0L, List.<JCStatement>of(
                sw,
                make.Throw(makeNewClass(
                    syms.illegalArgumentExceptionType,
                    List.<JCExpression>of(make.Literal("Invalid lambda deserialization"))))));
        JCMethodDecl deser = make.MethodDef(make.Modifiers(kInfo.deserMethodSym.flags()),
                        names.deserializeLambda,
                        make.QualIdent(kInfo.deserMethodSym.getReturnType().tsym),
                        List.<JCTypeParameter>nil(),
                        List.of(make.VarDef(kInfo.deserParamSym, null)),
                        List.<JCExpression>nil(),
                        body,
                        null);
        deser.sym = kInfo.deserMethodSym;
        deser.type = kInfo.deserMethodSym.type;
        //System.err.printf("DESER: '%s'\n", deser);
        return deser;
    }

    /** Make an attributed class instance creation expression.
     *  @param ctype    The class type.
     *  @param args     The constructor arguments.
     *  @param cons     The constructor symbol
     */
    JCNewClass makeNewClass(Type ctype, List<JCExpression> args, Symbol cons) {
        JCNewClass tree = make.NewClass(null,
            null, make.QualIdent(ctype.tsym), args, null);
        tree.constructor = cons;
        tree.type = ctype;
        return tree;
    }

    /** Make an attributed class instance creation expression.
     *  @param ctype    The class type.
     *  @param args     The constructor arguments.
     */
    JCNewClass makeNewClass(Type ctype, List<JCExpression> args) {
        return makeNewClass(ctype, args,
                rs.resolveConstructor(null, attrEnv, ctype, TreeInfo.types(args), List.<Type>nil()));
     }

    private void addDeserializationCase(int implMethodKind, Symbol refSym, Type targetType, MethodSymbol samSym,
            DiagnosticPosition pos, List<Object> staticArgs, MethodType indyType) {
        String functionalInterfaceClass = classSig(targetType);
        String functionalInterfaceMethodName = samSym.getSimpleName().toString();
        String functionalInterfaceMethodSignature = typeSig(types.erasure(samSym.type));
        String implClass = classSig(types.erasure(refSym.owner.type));
        String implMethodName = refSym.getQualifiedName().toString();
        String implMethodSignature = typeSig(types.erasure(refSym.type));

        JCExpression kindTest = eqTest(syms.intType, deserGetter("getImplMethodKind", syms.intType), make.Literal(implMethodKind));
        ListBuffer<JCExpression> serArgs = new ListBuffer<>();
        int i = 0;
        for (Type t : indyType.getParameterTypes()) {
            List<JCExpression> indexAsArg = new ListBuffer<JCExpression>().append(make.Literal(i)).toList();
            List<Type> argTypes = new ListBuffer<Type>().append(syms.intType).toList();
            serArgs.add(make.TypeCast(types.erasure(t), deserGetter("getCapturedArg", syms.objectType, argTypes, indexAsArg)));
            ++i;
        }
        JCStatement stmt = make.If(
                deserTest(deserTest(deserTest(deserTest(deserTest(
                    kindTest,
                    "getFunctionalInterfaceClass", functionalInterfaceClass),
                    "getFunctionalInterfaceMethodName", functionalInterfaceMethodName),
                    "getFunctionalInterfaceMethodSignature", functionalInterfaceMethodSignature),
                    "getImplClass", implClass),
                    "getImplMethodSignature", implMethodSignature),
                make.Return(makeIndyCall(
                    pos,
                    syms.lambdaMetafactory,
                    names.altMetafactory,
                    staticArgs, indyType, serArgs.toList(), samSym.name)),
                null);
        ListBuffer<JCStatement> stmts = kInfo.deserializeCases.get(implMethodName);
        if (stmts == null) {
            stmts = new ListBuffer<>();
            kInfo.deserializeCases.put(implMethodName, stmts);
        }
        /****
        System.err.printf("+++++++++++++++++\n");
        System.err.printf("*functionalInterfaceClass: '%s'\n", functionalInterfaceClass);
        System.err.printf("*functionalInterfaceMethodName: '%s'\n", functionalInterfaceMethodName);
        System.err.printf("*functionalInterfaceMethodSignature: '%s'\n", functionalInterfaceMethodSignature);
        System.err.printf("*implMethodKind: %d\n", implMethodKind);
        System.err.printf("*implClass: '%s'\n", implClass);
        System.err.printf("*implMethodName: '%s'\n", implMethodName);
        System.err.printf("*implMethodSignature: '%s'\n", implMethodSignature);
        ****/
        stmts.append(stmt);
    }

    private JCExpression eqTest(Type argType, JCExpression arg1, JCExpression arg2) {
        JCBinary testExpr = make.Binary(JCTree.Tag.EQ, arg1, arg2);
        testExpr.operator = rs.resolveBinaryOperator(null, JCTree.Tag.EQ, attrEnv, argType, argType);
        testExpr.setType(syms.booleanType);
        return testExpr;
    }

    private JCExpression deserTest(JCExpression prev, String func, String lit) {
        MethodType eqmt = new MethodType(List.of(syms.objectType), syms.booleanType, List.<Type>nil(), syms.methodClass);
        Symbol eqsym = rs.resolveQualifiedMethod(null, attrEnv, syms.objectType, names.equals, List.of(syms.objectType), List.<Type>nil());
        JCMethodInvocation eqtest = make.Apply(
                List.<JCExpression>nil(),
                make.Select(deserGetter(func, syms.stringType), eqsym).setType(eqmt),
                List.<JCExpression>of(make.Literal(lit)));
        eqtest.setType(syms.booleanType);
        JCBinary compound = make.Binary(JCTree.Tag.AND, prev, eqtest);
        compound.operator = rs.resolveBinaryOperator(null, JCTree.Tag.AND, attrEnv, syms.booleanType, syms.booleanType);
        compound.setType(syms.booleanType);
        return compound;
    }

    private JCExpression deserGetter(String func, Type type) {
        return deserGetter(func, type, List.<Type>nil(), List.<JCExpression>nil());
    }

    private JCExpression deserGetter(String func, Type type, List<Type> argTypes, List<JCExpression> args) {
        MethodType getmt = new MethodType(argTypes, type, List.<Type>nil(), syms.methodClass);
        Symbol getsym = rs.resolveQualifiedMethod(null, attrEnv, syms.serializedLambdaType, names.fromString(func), argTypes, List.<Type>nil());
        return make.Apply(
                    List.<JCExpression>nil(),
                    make.Select(make.Ident(kInfo.deserParamSym).setType(syms.serializedLambdaType), getsym).setType(getmt),
                    args).setType(type);
    }

    /**
     * Create new synthetic method with given flags, name, type, owner
     */
    private MethodSymbol makePrivateSyntheticMethod(long flags, Name name, Type type, Symbol owner) {
        return new MethodSymbol(flags | SYNTHETIC | PRIVATE, name, type, owner);
    }

    /**
     * Create new synthetic variable with given flags, name, type, owner
     */
    private VarSymbol makeSyntheticVar(long flags, String name, Type type, Symbol owner) {
        return makeSyntheticVar(flags, names.fromString(name), type, owner);
    }

    /**
     * Create new synthetic variable with given flags, name, type, owner
     */
    private VarSymbol makeSyntheticVar(long flags, Name name, Type type, Symbol owner) {
        return new VarSymbol(flags | SYNTHETIC, name, type, owner);
    }

    /**
     * Set varargsElement field on a given tree (must be either a new class tree
     * or a method call tree)
     */
    private void setVarargsIfNeeded(JCTree tree, Type varargsElement) {
        if (varargsElement != null) {
            switch (tree.getTag()) {
                case APPLY: ((JCMethodInvocation)tree).varargsElement = varargsElement; break;
                case NEWCLASS: ((JCNewClass)tree).varargsElement = varargsElement; break;
                default: throw new AssertionError();
            }
        }
    }

    /**
     * Convert method/constructor arguments by inserting appropriate cast
     * as required by type-erasure - this is needed when bridging a lambda/method
     * reference, as the bridged signature might require downcast to be compatible
     * with the generated signature.
     */
    private List<JCExpression> convertArgs(Symbol meth, List<JCExpression> args, Type varargsElement) {
       Assert.check(meth.kind == MTH);
       List<Type> formals = types.erasure(meth.type).getParameterTypes();
       if (varargsElement != null) {
           Assert.check((meth.flags() & VARARGS) != 0);
       }
       return transTypes.translateArgs(args, formals, varargsElement, attrEnv);
    }

    // </editor-fold>

    /**
     * Converts a method reference which cannot be used directly into a lambda
     */
    private class MemberReferenceToLambda {

        private final JCMemberReference tree;
        private final ReferenceTranslationContext localContext;
        private final Symbol owner;
        private final ListBuffer<JCExpression> args = new ListBuffer<>();
        private final ListBuffer<JCVariableDecl> params = new ListBuffer<>();

        private JCExpression receiverExpression = null;

        MemberReferenceToLambda(JCMemberReference tree, ReferenceTranslationContext localContext, Symbol owner) {
            this.tree = tree;
            this.localContext = localContext;
            this.owner = owner;
        }

        JCLambda lambda() {
            int prevPos = make.pos;
            try {
                make.at(tree);

                //body generation - this can be either a method call or a
                //new instance creation expression, depending on the member reference kind
                VarSymbol rcvr = addParametersReturnReceiver();
                JCExpression expr = (tree.getMode() == ReferenceMode.INVOKE)
                        ? expressionInvoke(rcvr)
                        : expressionNew();

                JCLambda slam = make.Lambda(params.toList(), expr);
                slam.targets = tree.targets;
                slam.type = tree.type;
                slam.pos = tree.pos;
                return slam;
            } finally {
                make.at(prevPos);
            }
        }

        /**
         * Generate the parameter list for the converted member reference.
         *
         * @return The receiver variable symbol, if any
         */
        VarSymbol addParametersReturnReceiver() {
            Type samDesc = localContext.bridgedRefSig();
            List<Type> samPTypes = samDesc.getParameterTypes();
            List<Type> descPTypes = tree.getDescriptorType(types).getParameterTypes();

            // Determine the receiver, if any
            VarSymbol rcvr;
            switch (tree.kind) {
                case BOUND:
                    // The receiver is explicit in the method reference
                    rcvr = addParameter("rec$", tree.getQualifierExpression().type, false);
                    receiverExpression = attr.makeNullCheck(tree.getQualifierExpression());
                    break;
                case UNBOUND:
                    // The receiver is the first parameter, extract it and
                    // adjust the SAM and unerased type lists accordingly
                    rcvr = addParameter("rec$", samDesc.getParameterTypes().head, false);
                    samPTypes = samPTypes.tail;
                    descPTypes = descPTypes.tail;
                    break;
                default:
                    rcvr = null;
                    break;
            }
            List<Type> implPTypes = tree.sym.type.getParameterTypes();
            int implSize = implPTypes.size();
            int samSize = samPTypes.size();
            // Last parameter to copy from referenced method, exclude final var args
            int last = localContext.needsVarArgsConversion() ? implSize - 1 : implSize;

            // Failsafe -- assure match-up
            boolean checkForIntersection = tree.varargsElement != null || implSize == descPTypes.size();

            // Use parameter types of the implementation method unless the unerased
            // SAM parameter type is an intersection type, in that case use the
            // erased SAM parameter type so that the supertype relationship
            // the implementation method parameters is not obscured.
            // Note: in this loop, the lists implPTypes, samPTypes, and descPTypes
            // are used as pointers to the current parameter type information
            // and are thus not usable afterwards.
            for (int i = 0; implPTypes.nonEmpty() && i < last; ++i) {
                // By default use the implementation method parmeter type
                Type parmType = implPTypes.head;
                // If the unerased parameter type is a type variable whose
                // bound is an intersection (eg. <T extends A & B>) then
                // use the SAM parameter type
                if (checkForIntersection && descPTypes.head.getKind() == TypeKind.TYPEVAR) {
                    TypeVar tv = (TypeVar) descPTypes.head;
                    if (tv.bound.getKind() == TypeKind.INTERSECTION) {
                        parmType = samPTypes.head;
                    }
                }
                addParameter("x$" + i, parmType, true);

                // Advance to the next parameter
                implPTypes = implPTypes.tail;
                samPTypes = samPTypes.tail;
                descPTypes = descPTypes.tail;
            }
            // Flatten out the var args
            for (int i = last; i < samSize; ++i) {
                addParameter("xva$" + i, tree.varargsElement, true);
            }

            return rcvr;
        }

        JCExpression getReceiverExpression() {
            return receiverExpression;
        }

        private JCExpression makeReceiver(VarSymbol rcvr) {
            if (rcvr == null) return null;
            JCExpression rcvrExpr = make.Ident(rcvr);
            Type rcvrType = tree.sym.enclClass().type;
            if (rcvrType == syms.arrayClass.type) {
                // Map the receiver type to the actually type, not just "array"
                rcvrType = tree.getQualifierExpression().type;
            }
            if (!rcvr.type.tsym.isSubClass(rcvrType.tsym, types)) {
                rcvrExpr = make.TypeCast(make.Type(rcvrType), rcvrExpr).setType(rcvrType);
            }
            return rcvrExpr;
        }

        /**
         * determine the receiver of the method call - the receiver can
         * be a type qualifier, the synthetic receiver parameter or 'super'.
         */
        private JCExpression expressionInvoke(VarSymbol rcvr) {
            JCExpression qualifier =
                    tree.sym.isStatic() ?
                        make.Type(tree.sym.owner.type) :
                        (rcvr != null) ?
                            makeReceiver(rcvr) :
                            tree.getQualifierExpression();

            //create the qualifier expression
            JCFieldAccess select = make.Select(qualifier, tree.sym.name);
            select.sym = tree.sym;
            select.type = tree.sym.erasure(types);

            //create the method call expression
            JCExpression apply = make.Apply(List.<JCExpression>nil(), select,
                    convertArgs(tree.sym, args.toList(), tree.varargsElement)).
                    setType(tree.sym.erasure(types).getReturnType());

            apply = transTypes.coerce(apply, localContext.generatedRefSig().getReturnType());
            setVarargsIfNeeded(apply, tree.varargsElement);
            return apply;
        }

        /**
         * Lambda body to use for a 'new'.
         */
        private JCExpression expressionNew() {
            if (tree.kind == ReferenceKind.ARRAY_CTOR) {
                //create the array creation expression
                JCNewArray newArr = make.NewArray(
                        make.Type(types.elemtype(tree.getQualifierExpression().type)),
                        List.of(make.Ident(params.first())),
                        null);
                newArr.type = tree.getQualifierExpression().type;
                return newArr;
            } else {
                //create the instance creation expression
                //note that method reference syntax does not allow an explicit
                //enclosing class (so the enclosing class is null)
                JCNewClass newClass = make.NewClass(null,
                        List.<JCExpression>nil(),
                        make.Type(tree.getQualifierExpression().type),
                        convertArgs(tree.sym, args.toList(), tree.varargsElement),
                        null);
                newClass.constructor = tree.sym;
                newClass.constructorType = tree.sym.erasure(types);
                newClass.type = tree.getQualifierExpression().type;
                setVarargsIfNeeded(newClass, tree.varargsElement);
                return newClass;
            }
        }

        private VarSymbol addParameter(String name, Type p, boolean genArg) {
            VarSymbol vsym = new VarSymbol(PARAMETER | SYNTHETIC, names.fromString(name), p, owner);
            vsym.pos = tree.pos;
            params.append(make.VarDef(vsym, null));
            if (genArg) {
                args.append(make.Ident(vsym));
            }
            return vsym;
        }
    }

    private MethodType typeToMethodType(Type mt) {
        Type type = types.erasure(mt);
        return new MethodType(type.getParameterTypes(),
                        type.getReturnType(),
                        type.getThrownTypes(),
                        syms.methodClass);
    }

    /**
     * Generate an indy method call to the meta factory
     */
    private JCExpression makeMetafactoryIndyCall(TranslationContext<?> context,
            int refKind, Symbol refSym, List<JCExpression> indy_args) {
        JCFunctionalExpression tree = context.tree;
        //determine the static bsm args
        MethodSymbol samSym = (MethodSymbol) types.findDescriptorSymbol(tree.type.tsym);
        List<Object> staticArgs = List.<Object>of(
                typeToMethodType(samSym.type),
                new Pool.MethodHandle(refKind, refSym, types),
                typeToMethodType(tree.getDescriptorType(types)));

        //computed indy arg types
        ListBuffer<Type> indy_args_types = new ListBuffer<>();
        for (JCExpression arg : indy_args) {
            indy_args_types.append(arg.type);
        }

        //finally, compute the type of the indy call
        MethodType indyType = new MethodType(indy_args_types.toList(),
                tree.type,
                List.<Type>nil(),
                syms.methodClass);

        Name metafactoryName = context.needsAltMetafactory() ?
                names.altMetafactory : names.metafactory;

        if (context.needsAltMetafactory()) {
            ListBuffer<Object> markers = new ListBuffer<>();
            for (Type t : tree.targets.tail) {
                if (t.tsym != syms.serializableType.tsym) {
                    markers.append(t.tsym);
                }
            }
            int flags = context.isSerializable() ? FLAG_SERIALIZABLE : 0;
            boolean hasMarkers = markers.nonEmpty();
            boolean hasBridges = context.bridges.nonEmpty();
            if (hasMarkers) {
                flags |= FLAG_MARKERS;
            }
            if (hasBridges) {
                flags |= FLAG_BRIDGES;
            }
            staticArgs = staticArgs.append(flags);
            if (hasMarkers) {
                staticArgs = staticArgs.append(markers.length());
                staticArgs = staticArgs.appendList(markers.toList());
            }
            if (hasBridges) {
                staticArgs = staticArgs.append(context.bridges.length() - 1);
                for (Symbol s : context.bridges) {
                    Type s_erasure = s.erasure(types);
                    if (!types.isSameType(s_erasure, samSym.erasure(types))) {
                        staticArgs = staticArgs.append(s.erasure(types));
                    }
                }
            }
            if (context.isSerializable()) {
                int prevPos = make.pos;
                try {
                    make.at(kInfo.clazz);
                    addDeserializationCase(refKind, refSym, tree.type, samSym,
                            tree, staticArgs, indyType);
                } finally {
                    make.at(prevPos);
                }
            }
        }

        return makeIndyCall(tree, syms.lambdaMetafactory, metafactoryName, staticArgs, indyType, indy_args, samSym.name);
    }

    /**
     * Generate an indy method call with given name, type and static bootstrap
     * arguments types
     */
    private JCExpression makeIndyCall(DiagnosticPosition pos, Type site, Name bsmName,
            List<Object> staticArgs, MethodType indyType, List<JCExpression> indyArgs,
            Name methName) {
        int prevPos = make.pos;
        try {
            make.at(pos);
            List<Type> bsm_staticArgs = List.of(syms.methodHandleLookupType,
                    syms.stringType,
                    syms.methodTypeType).appendList(bsmStaticArgToTypes(staticArgs));

            Symbol bsm = rs.resolveInternalMethod(pos, attrEnv, site,
                    bsmName, bsm_staticArgs, List.<Type>nil());

            DynamicMethodSymbol dynSym =
                    new DynamicMethodSymbol(methName,
                                            syms.noSymbol,
                                            bsm.isStatic() ?
                                                ClassFile.REF_invokeStatic :
                                                ClassFile.REF_invokeVirtual,
                                            (MethodSymbol)bsm,
                                            indyType,
                                            staticArgs.toArray());

            JCFieldAccess qualifier = make.Select(make.QualIdent(site.tsym), bsmName);
            qualifier.sym = dynSym;
            qualifier.type = indyType.getReturnType();

            JCMethodInvocation proxyCall = make.Apply(List.<JCExpression>nil(), qualifier, indyArgs);
            proxyCall.type = indyType.getReturnType();
            return proxyCall;
        } finally {
            make.at(prevPos);
        }
    }
    //where
    private List<Type> bsmStaticArgToTypes(List<Object> args) {
        ListBuffer<Type> argtypes = new ListBuffer<>();
        for (Object arg : args) {
            argtypes.append(bsmStaticArgToType(arg));
        }
        return argtypes.toList();
    }

    private Type bsmStaticArgToType(Object arg) {
        Assert.checkNonNull(arg);
        if (arg instanceof ClassSymbol) {
            return syms.classType;
        } else if (arg instanceof Integer) {
            return syms.intType;
        } else if (arg instanceof Long) {
            return syms.longType;
        } else if (arg instanceof Float) {
            return syms.floatType;
        } else if (arg instanceof Double) {
            return syms.doubleType;
        } else if (arg instanceof String) {
            return syms.stringType;
        } else if (arg instanceof Pool.MethodHandle) {
            return syms.methodHandleType;
        } else if (arg instanceof MethodType) {
            return syms.methodTypeType;
        } else {
            Assert.error("bad static arg " + arg.getClass());
            return null;
        }
    }

    /**
     * Get the opcode associated with this method reference
     */
    private int referenceKind(Symbol refSym) {
        if (refSym.isConstructor()) {
            return ClassFile.REF_newInvokeSpecial;
        } else {
            if (refSym.isStatic()) {
                return ClassFile.REF_invokeStatic;
            } else if ((refSym.flags() & PRIVATE) != 0) {
                return ClassFile.REF_invokeSpecial;
            } else if (refSym.enclClass().isInterface()) {
                return ClassFile.REF_invokeInterface;
            } else {
                return ClassFile.REF_invokeVirtual;
            }
        }
    }

    // <editor-fold defaultstate="collapsed" desc="Lambda/reference analyzer">
    /**
     * This visitor collects information about translation of a lambda expression.
     * More specifically, it keeps track of the enclosing contexts and captured locals
     * accessed by the lambda being translated (as well as other useful info).
     * It also translates away problems for LambdaToMethod.
     */
    class LambdaAnalyzerPreprocessor extends TreeTranslator {

        /** the frame stack - used to reconstruct translation info about enclosing scopes */
        private List<Frame> frameStack;

        /**
         * keep the count of lambda expression (used to generate unambiguous
         * names)
         */
        private int lambdaCount = 0;

        /**
         * keep the count of lambda expression defined in given context (used to
         * generate unambiguous names for serializable lambdas)
         */
        private class SyntheticMethodNameCounter {
            private Map<String, Integer> map = new HashMap<>();
            int getIndex(StringBuilder buf) {
                String temp = buf.toString();
                Integer count = map.get(temp);
                if (count == null) {
                    count = 0;
                }
                ++count;
                map.put(temp, count);
                return count;
            }
        }
        private SyntheticMethodNameCounter syntheticMethodNameCounts =
                new SyntheticMethodNameCounter();

        private Map<Symbol, JCClassDecl> localClassDefs;

        /**
         * maps for fake clinit symbols to be used as owners of lambda occurring in
         * a static var init context
         */
        private Map<ClassSymbol, Symbol> clinits = new HashMap<>();

        private JCClassDecl analyzeAndPreprocessClass(JCClassDecl tree) {
            frameStack = List.nil();
            localClassDefs = new HashMap<>();
            return translate(tree);
        }

        @Override
        public void visitBlock(JCBlock tree) {
            List<Frame> prevStack = frameStack;
            try {
                if (frameStack.nonEmpty() && frameStack.head.tree.hasTag(CLASSDEF)) {
                    frameStack = frameStack.prepend(new Frame(tree));
                }
                super.visitBlock(tree);
            }
            finally {
                frameStack = prevStack;
            }
        }

        @Override
        public void visitClassDef(JCClassDecl tree) {
            List<Frame> prevStack = frameStack;
            int prevLambdaCount = lambdaCount;
            SyntheticMethodNameCounter prevSyntheticMethodNameCounts =
                    syntheticMethodNameCounts;
            Map<ClassSymbol, Symbol> prevClinits = clinits;
            DiagnosticSource prevSource = log.currentSource();
            try {
                log.useSource(tree.sym.sourcefile);
                lambdaCount = 0;
                syntheticMethodNameCounts = new SyntheticMethodNameCounter();
                prevClinits = new HashMap<>();
                if (tree.sym.owner.kind == MTH) {
                    localClassDefs.put(tree.sym, tree);
                }
                if (directlyEnclosingLambda() != null) {
                    tree.sym.owner = owner();
                    if (tree.sym.hasOuterInstance()) {
                        //if a class is defined within a lambda, the lambda must capture
                        //its enclosing instance (if any)
                        TranslationContext<?> localContext = context();
                        while (localContext != null) {
                            if (localContext.tree.getTag() == LAMBDA) {
                                ((LambdaTranslationContext)localContext)
                                        .addSymbol(tree.sym.type.getEnclosingType().tsym, CAPTURED_THIS);
                            }
                            localContext = localContext.prev;
                        }
                    }
                }
                frameStack = frameStack.prepend(new Frame(tree));
                super.visitClassDef(tree);
            }
            finally {
                log.useSource(prevSource.getFile());
                frameStack = prevStack;
                lambdaCount = prevLambdaCount;
                syntheticMethodNameCounts = prevSyntheticMethodNameCounts;
                clinits = prevClinits;
            }
        }

        @Override
        public void visitIdent(JCIdent tree) {
            if (context() != null && lambdaIdentSymbolFilter(tree.sym)) {
                if (tree.sym.kind == VAR &&
                        tree.sym.owner.kind == MTH &&
                        tree.type.constValue() == null) {
                    TranslationContext<?> localContext = context();
                    while (localContext != null) {
                        if (localContext.tree.getTag() == LAMBDA) {
                            JCTree block = capturedDecl(localContext.depth, tree.sym);
                            if (block == null) break;
                            ((LambdaTranslationContext)localContext)
                                    .addSymbol(tree.sym, CAPTURED_VAR);
                        }
                        localContext = localContext.prev;
                    }
                } else if (tree.sym.owner.kind == TYP) {
                    TranslationContext<?> localContext = context();
                    while (localContext != null) {
                        if (localContext.tree.hasTag(LAMBDA)) {
                            JCTree block = capturedDecl(localContext.depth, tree.sym);
                            if (block == null) break;
                            switch (block.getTag()) {
                                case CLASSDEF:
                                    JCClassDecl cdecl = (JCClassDecl)block;
                                    ((LambdaTranslationContext)localContext)
                                            .addSymbol(cdecl.sym, CAPTURED_THIS);
                                    break;
                                default:
                                    Assert.error("bad block kind");
                            }
                        }
                        localContext = localContext.prev;
                    }
                }
            }
            super.visitIdent(tree);
        }

        @Override
        public void visitLambda(JCLambda tree) {
            analyzeLambda(tree, "lambda.stat");
        }

        private void analyzeLambda(JCLambda tree, JCExpression methodReferenceReceiver) {
            // Translation of the receiver expression must occur first
            JCExpression rcvr = translate(methodReferenceReceiver);
            LambdaTranslationContext context = analyzeLambda(tree, "mref.stat.1");
            if (rcvr != null) {
                context.methodReferenceReceiver = rcvr;
            }
        }

        private LambdaTranslationContext analyzeLambda(JCLambda tree, String statKey) {
            List<Frame> prevStack = frameStack;
            try {
                LambdaTranslationContext context = new LambdaTranslationContext(tree);
                if (dumpLambdaToMethodStats) {
                    log.note(tree, statKey, context.needsAltMetafactory(), context.translatedSym);
                }
                frameStack = frameStack.prepend(new Frame(tree));
                for (JCVariableDecl param : tree.params) {
                    context.addSymbol(param.sym, PARAM);
                    frameStack.head.addLocal(param.sym);
                }
                contextMap.put(tree, context);
                super.visitLambda(tree);
                context.complete();
                return context;
            }
            finally {
                frameStack = prevStack;
            }
        }

        @Override
        public void visitMethodDef(JCMethodDecl tree) {
            List<Frame> prevStack = frameStack;
            try {
                frameStack = frameStack.prepend(new Frame(tree));
                super.visitMethodDef(tree);
            }
            finally {
                frameStack = prevStack;
            }
        }

        @Override
        public void visitNewClass(JCNewClass tree) {
            TypeSymbol def = tree.type.tsym;
            boolean inReferencedClass = currentlyInClass(def);
            boolean isLocal = def.isLocal();
            if ((inReferencedClass && isLocal || lambdaNewClassFilter(context(), tree))) {
                TranslationContext<?> localContext = context();
                while (localContext != null) {
                    if (localContext.tree.getTag() == LAMBDA) {
                        ((LambdaTranslationContext)localContext)
                                .addSymbol(tree.type.getEnclosingType().tsym, CAPTURED_THIS);
                    }
                    localContext = localContext.prev;
                }
            }
            if (context() != null && !inReferencedClass && isLocal) {
                LambdaTranslationContext lambdaContext = (LambdaTranslationContext)context();
                captureLocalClassDefs(def, lambdaContext);
            }
            super.visitNewClass(tree);
        }
        //where
            void captureLocalClassDefs(Symbol csym, final LambdaTranslationContext lambdaContext) {
                JCClassDecl localCDef = localClassDefs.get(csym);
                if (localCDef != null && lambdaContext.freeVarProcessedLocalClasses.add(csym)) {
                    BasicFreeVarCollector fvc = lower.new BasicFreeVarCollector() {
                        @Override
                        void addFreeVars(ClassSymbol c) {
                            captureLocalClassDefs(c, lambdaContext);
                        }
                        @Override
                        void visitSymbol(Symbol sym) {
                            if (sym.kind == VAR &&
                                    sym.owner.kind == MTH &&
                                    ((VarSymbol)sym).getConstValue() == null) {
                                TranslationContext<?> localContext = context();
                                while (localContext != null) {
                                    if (localContext.tree.getTag() == LAMBDA) {
                                        JCTree block = capturedDecl(localContext.depth, sym);
                                        if (block == null) break;
                                        ((LambdaTranslationContext)localContext).addSymbol(sym, CAPTURED_VAR);
                                    }
                                    localContext = localContext.prev;
                                }
                            }
                        }
                    };
                    fvc.scan(localCDef);
                }
        }
        //where
        boolean currentlyInClass(Symbol csym) {
            for (Frame frame : frameStack) {
                if (frame.tree.hasTag(JCTree.Tag.CLASSDEF)) {
                    JCClassDecl cdef = (JCClassDecl) frame.tree;
                    if (cdef.sym == csym) {
                        return true;
                    }
                }
            }
            return false;
        }

        /**
         * Method references to local class constructors, may, if the local
         * class references local variables, have implicit constructor
         * parameters added in Lower; As a result, the invokedynamic bootstrap
         * information added in the LambdaToMethod pass will have the wrong
         * signature. Hooks between Lower and LambdaToMethod have been added to
         * handle normal "new" in this case. This visitor converts potentially
         * affected method references into a lambda containing a normal
         * expression.
         *
         * @param tree
         */
        @Override
        public void visitReference(JCMemberReference tree) {
            ReferenceTranslationContext rcontext = new ReferenceTranslationContext(tree);
            contextMap.put(tree, rcontext);
            if (rcontext.needsConversionToLambda()) {
                 // Convert to a lambda, and process as such
                MemberReferenceToLambda conv = new MemberReferenceToLambda(tree, rcontext, owner());
                analyzeLambda(conv.lambda(), conv.getReceiverExpression());
            } else {
                super.visitReference(tree);
                if (dumpLambdaToMethodStats) {
                    log.note(tree, "mref.stat", rcontext.needsAltMetafactory(), null);
                }
            }
        }

        @Override
        public void visitSelect(JCFieldAccess tree) {
            if (context() != null && tree.sym.kind == VAR &&
                        (tree.sym.name == names._this ||
                         tree.sym.name == names._super)) {
                // A select of this or super means, if we are in a lambda,
                // we much have an instance context
                TranslationContext<?> localContext = context();
                while (localContext != null) {
                    if (localContext.tree.hasTag(LAMBDA)) {
                        JCClassDecl clazz = (JCClassDecl)capturedDecl(localContext.depth, tree.sym);
                        if (clazz == null) break;
                        ((LambdaTranslationContext)localContext).addSymbol(clazz.sym, CAPTURED_THIS);
                    }
                    localContext = localContext.prev;
                }
            }
            super.visitSelect(tree);
        }

        @Override
        public void visitVarDef(JCVariableDecl tree) {
            TranslationContext<?> context = context();
            LambdaTranslationContext ltc = (context != null && context instanceof LambdaTranslationContext)?
                    (LambdaTranslationContext)context :
                    null;
            if (ltc != null) {
                if (frameStack.head.tree.hasTag(LAMBDA)) {
                    ltc.addSymbol(tree.sym, LOCAL_VAR);
                }
                // Check for type variables (including as type arguments).
                // If they occur within class nested in a lambda, mark for erasure
                Type type = tree.sym.asType();
                if (inClassWithinLambda() && !types.isSameType(types.erasure(type), type)) {
                    ltc.addSymbol(tree.sym, TYPE_VAR);
                }
            }

            List<Frame> prevStack = frameStack;
            try {
                if (tree.sym.owner.kind == MTH) {
                    frameStack.head.addLocal(tree.sym);
                }
                frameStack = frameStack.prepend(new Frame(tree));
                super.visitVarDef(tree);
            }
            finally {
                frameStack = prevStack;
            }
        }

        /**
         * Return a valid owner given the current declaration stack
         * (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()) {
                    case VARDEF:
                        if (((JCVariableDecl)frameStack2.head.tree).sym.isLocal()) {
                            frameStack2 = frameStack2.tail;
                            break;
                        }
                        JCClassDecl cdecl = (JCClassDecl)frameStack2.tail.head.tree;
                        return initSym(cdecl.sym,
                                ((JCVariableDecl)frameStack2.head.tree).sym.flags() & STATIC);
                    case BLOCK:
                        JCClassDecl cdecl2 = (JCClassDecl)frameStack2.tail.head.tree;
                        return initSym(cdecl2.sym,
                                ((JCBlock)frameStack2.head.tree).flags & STATIC);
                    case CLASSDEF:
                        return ((JCClassDecl)frameStack2.head.tree).sym;
                    case METHODDEF:
                        return ((JCMethodDecl)frameStack2.head.tree).sym;
                    case LAMBDA:
                        if (!skipLambda)
                            return ((LambdaTranslationContext)contextMap
                                    .get(frameStack2.head.tree)).translatedSym;
                    default:
                        frameStack2 = frameStack2.tail;
                }
            }
            Assert.error();
            return null;
        }

        private Symbol initSym(ClassSymbol csym, long flags) {
            boolean isStatic = (flags & STATIC) != 0;
            if (isStatic) {
                /* static clinits are generated in Gen, so we need to use a fake
                 * one. Attr creates a fake clinit method while attributing
                 * lambda expressions used as initializers of static fields, so
                 * let's use that one.
                 */
                MethodSymbol clinit = attr.removeClinit(csym);
                if (clinit != null) {
                    clinits.put(csym, clinit);
                    return clinit;
                }

                /* if no clinit is found at Attr, then let's try at clinits.
                 */
                clinit = (MethodSymbol)clinits.get(csym);
                if (clinit == null) {
                    /* no luck, let's create a new one
                     */
                    clinit = makePrivateSyntheticMethod(STATIC,
                            names.clinit,
                            new MethodType(List.<Type>nil(), syms.voidType,
                                List.<Type>nil(), syms.methodClass),
                            csym);
                    clinits.put(csym, clinit);
                }
                return clinit;
            } else {
                //get the first constructor and treat it as the instance init sym
                for (Symbol s : csym.members_field.getSymbolsByName(names.init)) {
                    return s;
                }
            }
            Assert.error("init not found");
            return null;
        }

        private JCTree directlyEnclosingLambda() {
            if (frameStack.isEmpty()) {
                return null;
            }
            List<Frame> frameStack2 = frameStack;
            while (frameStack2.nonEmpty()) {
                switch (frameStack2.head.tree.getTag()) {
                    case CLASSDEF:
                    case METHODDEF:
                        return null;
                    case LAMBDA:
                        return frameStack2.head.tree;
                    default:
                        frameStack2 = frameStack2.tail;
                }
            }
            Assert.error();
            return null;
        }

        private boolean inClassWithinLambda() {
            if (frameStack.isEmpty()) {
                return false;
            }
            List<Frame> frameStack2 = frameStack;
            boolean classFound = false;
            while (frameStack2.nonEmpty()) {
                switch (frameStack2.head.tree.getTag()) {
                    case LAMBDA:
                        return classFound;
                    case CLASSDEF:
                        classFound = true;
                        frameStack2 = frameStack2.tail;
                        break;
                    default:
                        frameStack2 = frameStack2.tail;
                }
            }
            // No lambda
            return false;
        }

        /**
         * Return the declaration corresponding to a symbol in the enclosing
         * scope; the depth parameter is used to filter out symbols defined
         * in nested scopes (which do not need to undergo capture).
         */
        private JCTree capturedDecl(int depth, Symbol sym) {
            int currentDepth = frameStack.size() - 1;
            for (Frame block : frameStack) {
                switch (block.tree.getTag()) {
                    case CLASSDEF:
                        ClassSymbol clazz = ((JCClassDecl)block.tree).sym;
                        if (sym.isMemberOf(clazz, types)) {
                            return currentDepth > depth ? null : block.tree;
                        }
                        break;
                    case VARDEF:
                        if (((JCVariableDecl)block.tree).sym == sym &&
                                sym.owner.kind == MTH) { //only locals are captured
                            return currentDepth > depth ? null : block.tree;
                        }
                        break;
                    case BLOCK:
                    case METHODDEF:
                    case LAMBDA:
                        if (block.locals != null && block.locals.contains(sym)) {
                            return currentDepth > depth ? null : block.tree;
                        }
                        break;
                    default:
                        Assert.error("bad decl kind " + block.tree.getTag());
                }
                currentDepth--;
            }
            return null;
        }

        private TranslationContext<?> context() {
            for (Frame frame : frameStack) {
                TranslationContext<?> context = contextMap.get(frame.tree);
                if (context != null) {
                    return context;
                }
            }
            return null;
        }

        /**
         *  This is used to filter out those identifiers that needs to be adjusted
         *  when translating away lambda expressions
         */
        private boolean lambdaIdentSymbolFilter(Symbol sym) {
            return (sym.kind == VAR || sym.kind == MTH)
                    && !sym.isStatic()
                    && sym.name != names.init;
        }

        /**
         * This is used to filter out those new class expressions that need to
         * be qualified with an enclosing tree
         */
        private boolean lambdaNewClassFilter(TranslationContext<?> context, JCNewClass tree) {
            if (context != null
                    && tree.encl == null
                    && tree.def == null
                    && !tree.type.getEnclosingType().hasTag(NONE)) {
                Type encl = tree.type.getEnclosingType();
                Type current = context.owner.enclClass().type;
                while (!current.hasTag(NONE)) {
                    if (current.tsym.isSubClass(encl.tsym, types)) {
                        return true;
                    }
                    current = current.getEnclosingType();
                }
                return false;
            } else {
                return false;
            }
        }

        private class Frame {
            final JCTree tree;
            List<Symbol> locals;

            public Frame(JCTree tree) {
                this.tree = tree;
            }

            void addLocal(Symbol sym) {
                if (locals == null) {
                    locals = List.nil();
                }
                locals = locals.prepend(sym);
            }
        }

        /**
         * This class is used to store important information regarding translation of
         * lambda expression/method references (see subclasses).
         */
        private abstract class TranslationContext<T extends JCFunctionalExpression> {

            /** the underlying (untranslated) tree */
            final T tree;

            /** points to the adjusted enclosing scope in which this lambda/mref expression occurs */
            final Symbol owner;

            /** the depth of this lambda expression in the frame stack */
            final int depth;

            /** the enclosing translation context (set for nested lambdas/mref) */
            final TranslationContext<?> prev;

            /** list of methods to be bridged by the meta-factory */
            final List<Symbol> bridges;

            TranslationContext(T tree) {
                this.tree = tree;
                this.owner = owner();
                this.depth = frameStack.size() - 1;
                this.prev = context();
                ClassSymbol csym =
                        types.makeFunctionalInterfaceClass(attrEnv, names.empty, tree.targets, ABSTRACT | INTERFACE);
                this.bridges = types.functionalInterfaceBridges(csym);
            }

            /** does this functional expression need to be created using alternate metafactory? */
            boolean needsAltMetafactory() {
                return tree.targets.length() > 1 ||
                        isSerializable() ||
                        bridges.length() > 1;
            }

            /** does this functional expression require serialization support? */
            boolean isSerializable() {
                if (forceSerializable) {
                    return true;
                }
                for (Type target : tree.targets) {
                    if (types.asSuper(target, syms.serializableType.tsym) != null) {
                        return true;
                    }
                }
                return false;
            }

            /**
             * @return Name of the enclosing method to be folded into synthetic
             * method name
             */
            String enclosingMethodName() {
                return syntheticMethodNameComponent(owner.name);
            }

            /**
             * @return Method name in a form that can be folded into a
             * component of a synthetic method name
             */
            String syntheticMethodNameComponent(Name name) {
                if (name == null) {
                    return "null";
                }
                String methodName = name.toString();
                if (methodName.equals("<clinit>")) {
                    methodName = "static";
                } else if (methodName.equals("<init>")) {
                    methodName = "new";
                }
                return methodName;
            }
        }

        /**
         * This class retains all the useful information about a lambda expression;
         * the contents of this class are filled by the LambdaAnalyzer visitor,
         * and the used by the main translation routines in order to adjust references
         * to captured locals/members, etc.
         */
        private class LambdaTranslationContext extends TranslationContext<JCLambda> {

            /** variable in the enclosing context to which this lambda is assigned */
            final Symbol self;

            /** variable in the enclosing context to which this lambda is assigned */
            final Symbol assignedTo;

            Map<LambdaSymbolKind, Map<Symbol, Symbol>> translatedSymbols;

            /** the synthetic symbol for the method hoisting the translated lambda */
            MethodSymbol translatedSym;

            List<JCVariableDecl> syntheticParams;

            /**
             * to prevent recursion, track local classes processed
             */
            final Set<Symbol> freeVarProcessedLocalClasses;

            /**
             * For method references converted to lambdas.  The method
             * reference receiver expression. Must be treated like a captured
             * variable.
             */
            JCExpression methodReferenceReceiver;

            LambdaTranslationContext(JCLambda tree) {
                super(tree);
                Frame frame = frameStack.head;
                switch (frame.tree.getTag()) {
                    case VARDEF:
                        assignedTo = self = ((JCVariableDecl) frame.tree).sym;
                        break;
                    case ASSIGN:
                        self = null;
                        assignedTo = TreeInfo.symbol(((JCAssign) frame.tree).getVariable());
                        break;
                    default:
                        assignedTo = self = null;
                        break;
                 }

                // This symbol will be filled-in in complete
                this.translatedSym = makePrivateSyntheticMethod(0, null, null, owner.enclClass());

                translatedSymbols = new EnumMap<>(LambdaSymbolKind.class);

                translatedSymbols.put(PARAM, new LinkedHashMap<Symbol, Symbol>());
                translatedSymbols.put(LOCAL_VAR, new LinkedHashMap<Symbol, Symbol>());
                translatedSymbols.put(CAPTURED_VAR, new LinkedHashMap<Symbol, Symbol>());
                translatedSymbols.put(CAPTURED_THIS, new LinkedHashMap<Symbol, Symbol>());
                translatedSymbols.put(TYPE_VAR, new LinkedHashMap<Symbol, Symbol>());

                freeVarProcessedLocalClasses = new HashSet<>();
            }

             /**
             * For a serializable lambda, generate a disambiguating string
             * which maximizes stability across deserialization.
             *
             * @return String to differentiate synthetic lambda method names
             */
            private String serializedLambdaDisambiguation() {
                StringBuilder buf = new StringBuilder();
                // Append the enclosing method signature to differentiate
                // overloaded enclosing methods.  For lambdas enclosed in
                // lambdas, the generated lambda method will not have type yet,
                // but the enclosing method's name will have been generated
                // with this same method, so it will be unique and never be
                // overloaded.
                Assert.check(
                        owner.type != null ||
                        directlyEnclosingLambda() != null);
                if (owner.type != null) {
                    buf.append(typeSig(owner.type));
                    buf.append(":");
                }

                // Add target type info
                buf.append(types.findDescriptorSymbol(tree.type.tsym).owner.flatName());
                buf.append(" ");

                // Add variable assigned to
                if (assignedTo != null) {
                    buf.append(assignedTo.flatName());
                    buf.append("=");
                }
                //add captured locals info: type, name, order
                for (Symbol fv : getSymbolMap(CAPTURED_VAR).keySet()) {
                    if (fv != self) {
                        buf.append(typeSig(fv.type));
                        buf.append(" ");
                        buf.append(fv.flatName());
                        buf.append(",");
                    }
                }

                return buf.toString();
            }

            /**
             * For a non-serializable lambda, generate a simple method.
             *
             * @return Name to use for the synthetic lambda method name
             */
            private Name lambdaName() {
                return names.lambda.append(names.fromString(enclosingMethodName() + "$" + lambdaCount++));
            }

            /**
             * For a serializable lambda, generate a method name which maximizes
             * name stability across deserialization.
             *
             * @return Name to use for the synthetic lambda method name
             */
            private Name serializedLambdaName() {
                StringBuilder buf = new StringBuilder();
                buf.append(names.lambda);
                // Append the name of the method enclosing the lambda.
                buf.append(enclosingMethodName());
                buf.append('$');
                // Append a hash of the disambiguating string : enclosing method
                // signature, etc.
                String disam = serializedLambdaDisambiguation();
                buf.append(Integer.toHexString(disam.hashCode()));
                buf.append('$');
                // The above appended name components may not be unique, append
                // a count based on the above name components.
                buf.append(syntheticMethodNameCounts.getIndex(buf));
                String result = buf.toString();
                //System.err.printf("serializedLambdaName: %s -- %s\n", result, disam);
                return names.fromString(result);
            }

            /**
             * Translate a symbol of a given kind into something suitable for the
             * synthetic lambda body
             */
            Symbol translate(Name name, final Symbol sym, LambdaSymbolKind skind) {
                Symbol ret;
                switch (skind) {
                    case CAPTURED_THIS:
                        ret = sym;  // self represented
                        break;
                    case TYPE_VAR:
                        // Just erase the type var
                        ret = new VarSymbol(sym.flags(), name,
                                types.erasure(sym.type), sym.owner);

                        /* this information should also be kept for LVT generation at Gen
                         * a Symbol with pos < startPos won't be tracked.
                         */
                        ((VarSymbol)ret).pos = ((VarSymbol)sym).pos;
                        break;
                    case CAPTURED_VAR:
                        ret = new VarSymbol(SYNTHETIC | FINAL | PARAMETER, name, types.erasure(sym.type), translatedSym) {
                            @Override
                            public Symbol baseSymbol() {
                                //keep mapping with original captured symbol
                                return sym;
                            }
                        };
                        break;
                    case LOCAL_VAR:
                        ret = new VarSymbol(sym.flags() & FINAL, name, sym.type, translatedSym);
                        ((VarSymbol) ret).pos = ((VarSymbol) sym).pos;
                        break;
                    case PARAM:
                        ret = new VarSymbol((sym.flags() & FINAL) | PARAMETER, name, types.erasure(sym.type), translatedSym);
                        ((VarSymbol) ret).pos = ((VarSymbol) sym).pos;
                        break;
                    default:
                        ret = makeSyntheticVar(FINAL, name, types.erasure(sym.type), translatedSym);
                        ((VarSymbol) ret).pos = ((VarSymbol) sym).pos;
                }
                if (ret != sym) {
                    ret.setDeclarationAttributes(sym.getRawAttributes());
                    ret.setTypeAttributes(sym.getRawTypeAttributes());
                }
                return ret;
            }

            void addSymbol(Symbol sym, LambdaSymbolKind skind) {
                Map<Symbol, Symbol> transMap = getSymbolMap(skind);
                Name preferredName;
                switch (skind) {
                    case CAPTURED_THIS:
                        preferredName = names.fromString("encl$" + transMap.size());
                        break;
                    case CAPTURED_VAR:
                        preferredName = names.fromString("cap$" + transMap.size());
                        break;
                    case LOCAL_VAR:
                        preferredName = sym.name;
                        break;
                    case PARAM:
                        preferredName = sym.name;
                        break;
                    case TYPE_VAR:
                        preferredName = sym.name;
                        break;
                    default: throw new AssertionError();
                }
                if (!transMap.containsKey(sym)) {
                    transMap.put(sym, translate(preferredName, sym, skind));
                }
            }

            Map<Symbol, Symbol> getSymbolMap(LambdaSymbolKind skind) {
                Map<Symbol, Symbol> m = translatedSymbols.get(skind);
                Assert.checkNonNull(m);
                return m;
            }

            JCTree translate(JCIdent lambdaIdent) {
                for (Map<Symbol, Symbol> m : translatedSymbols.values()) {
                    if (m.containsKey(lambdaIdent.sym)) {
                        Symbol tSym = m.get(lambdaIdent.sym);
                        JCTree t = make.Ident(tSym).setType(lambdaIdent.type);
                        tSym.setTypeAttributes(lambdaIdent.sym.getRawTypeAttributes());
                        return t;
                    }
                }
                return null;
            }

            /**
             * The translatedSym is not complete/accurate until the analysis is
             * finished.  Once the analysis is finished, the translatedSym is
             * "completed" -- updated with type information, access modifiers,
             * and full parameter list.
             */
            void complete() {
                if (syntheticParams != null) {
                    return;
                }
                boolean inInterface = translatedSym.owner.isInterface();
                boolean thisReferenced = !getSymbolMap(CAPTURED_THIS).isEmpty();

                // If instance access isn't needed, make it static.
                // Interface instance methods must be default methods.
                // Lambda methods are private synthetic.
                // Inherit ACC_STRICT from the enclosing method, or, for clinit,
                // from the class.
                translatedSym.flags_field = SYNTHETIC | LAMBDA_METHOD |
                        owner.flags_field & STRICTFP |
                        owner.owner.flags_field & STRICTFP |
                        PRIVATE |
                        (thisReferenced? (inInterface? DEFAULT : 0) : STATIC);

                //compute synthetic params
                ListBuffer<JCVariableDecl> params = new ListBuffer<>();
                ListBuffer<VarSymbol> parameterSymbols = new ListBuffer<>();

                // The signature of the method is augmented with the following
                // synthetic parameters:
                //
                // 1) reference to enclosing contexts captured by the lambda expression
                // 2) enclosing locals captured by the lambda expression
                for (Symbol thisSym : getSymbolMap(CAPTURED_VAR).values()) {
                    params.append(make.VarDef((VarSymbol) thisSym, null));
                    parameterSymbols.append((VarSymbol) thisSym);
                }
                for (Symbol thisSym : getSymbolMap(PARAM).values()) {
                    params.append(make.VarDef((VarSymbol) thisSym, null));
                    parameterSymbols.append((VarSymbol) thisSym);
                }
                syntheticParams = params.toList();

                translatedSym.params = parameterSymbols.toList();

                // Compute and set the lambda name
                translatedSym.name = isSerializable()
                        ? serializedLambdaName()
                        : lambdaName();

                //prepend synthetic args to translated lambda method signature
                translatedSym.type = types.createMethodTypeWithParameters(
                        generatedLambdaSig(),
                        TreeInfo.types(syntheticParams));
            }

            Type generatedLambdaSig() {
                return types.erasure(tree.getDescriptorType(types));
            }
        }

        /**
         * This class retains all the useful information about a method reference;
         * the contents of this class are filled by the LambdaAnalyzer visitor,
         * and the used by the main translation routines in order to adjust method
         * references (i.e. in case a bridge is needed)
         */
        private final class ReferenceTranslationContext extends TranslationContext<JCMemberReference> {

            final boolean isSuper;
            final Symbol sigPolySym;

            ReferenceTranslationContext(JCMemberReference tree) {
                super(tree);
                this.isSuper = tree.hasKind(ReferenceKind.SUPER);
                this.sigPolySym = isSignaturePolymorphic()
                        ? makePrivateSyntheticMethod(tree.sym.flags(),
                                              tree.sym.name,
                                              bridgedRefSig(),
                                              tree.sym.enclClass())
                        : null;
            }

            /**
             * Get the opcode associated with this method reference
             */
            int referenceKind() {
                return LambdaToMethod.this.referenceKind(tree.sym);
            }

            boolean needsVarArgsConversion() {
                return tree.varargsElement != null;
            }

            /**
             * @return Is this an array operation like clone()
             */
            boolean isArrayOp() {
                return tree.sym.owner == syms.arrayClass;
            }

            boolean receiverAccessible() {
                //hack needed to workaround 292 bug (7087658)
                //when 292 issue is fixed we should remove this and change the backend
                //code to always generate a method handle to an accessible method
                return tree.ownerAccessible;
            }

            /**
             * The VM does not support access across nested classes (8010319).
             * Were that ever to change, this should be removed.
             */
            boolean isPrivateInOtherClass() {
                return  (tree.sym.flags() & PRIVATE) != 0 &&
                        !types.isSameType(
                              types.erasure(tree.sym.enclClass().asType()),
                              types.erasure(owner.enclClass().asType()));
            }

            /**
             * Signature polymorphic methods need special handling.
             * e.g. MethodHandle.invoke() MethodHandle.invokeExact()
             */
            final boolean isSignaturePolymorphic() {
                return  tree.sym.kind == MTH &&
                        types.isSignaturePolymorphic((MethodSymbol)tree.sym);
            }

            /**
             * Erasure destroys the implementation parameter subtype
             * relationship for intersection types
             */
            boolean interfaceParameterIsIntersectionType() {
                List<Type> tl = tree.getDescriptorType(types).getParameterTypes();
                if (tree.kind == ReferenceKind.UNBOUND) {
                    tl = tl.tail;
                }
                for (; tl.nonEmpty(); tl = tl.tail) {
                    Type pt = tl.head;
                    if (pt.getKind() == TypeKind.TYPEVAR) {
                        TypeVar tv = (TypeVar) pt;
                        if (tv.bound.getKind() == TypeKind.INTERSECTION) {
                            return true;
                        }
                    }
                }
                return false;
            }

            /**
             * Does this reference need to be converted to a lambda
             * (i.e. var args need to be expanded or "super" is used)
             */
            final boolean needsConversionToLambda() {
                return interfaceParameterIsIntersectionType() ||
                        isSuper ||
                        needsVarArgsConversion() ||
                        isArrayOp() ||
                        isPrivateInOtherClass() ||
                        !receiverAccessible() ||
                        (tree.getMode() == ReferenceMode.NEW &&
                          tree.kind != ReferenceKind.ARRAY_CTOR &&
                          (tree.sym.owner.isLocal() || tree.sym.owner.isInner()));
            }

            Type generatedRefSig() {
                return types.erasure(tree.sym.type);
            }

            Type bridgedRefSig() {
                return types.erasure(types.findDescriptorSymbol(tree.targets.head.tsym).type);
            }
        }
    }
    // </editor-fold>

    /*
     * These keys provide mappings for various translated lambda symbols
     * and the prevailing order must be maintained.
     */
    enum LambdaSymbolKind {
        PARAM,          // original to translated lambda parameters
        LOCAL_VAR,      // original to translated lambda locals
        CAPTURED_VAR,   // variables in enclosing scope to translated synthetic parameters
        CAPTURED_THIS,  // class symbols to translated synthetic parameters (for captured member access)
        TYPE_VAR       // original to translated lambda type variables
    }

    /**
     * ****************************************************************
     * Signature Generation
     * ****************************************************************
     */

    private String typeSig(Type type) {
        L2MSignatureGenerator sg = new L2MSignatureGenerator();
        sg.assembleSig(type);
        return sg.toString();
    }

    private String classSig(Type type) {
        L2MSignatureGenerator sg = new L2MSignatureGenerator();
        sg.assembleClassSig(type);
        return sg.toString();
    }

    /**
     * Signature Generation
     */
    private class L2MSignatureGenerator extends Types.SignatureGenerator {

        /**
         * An output buffer for type signatures.
         */
        StringBuilder sb = new StringBuilder();

        L2MSignatureGenerator() {
            super(types);
        }

        @Override
        protected void append(char ch) {
            sb.append(ch);
        }

        @Override
        protected void append(byte[] ba) {
            sb.append(new String(ba));
        }

        @Override
        protected void append(Name name) {
            sb.append(name.toString());
        }

        @Override
        public String toString() {
            return sb.toString();
        }
    }
}