Buggy code:
//*  * Copyright 2004 The Closure Compiler Authors.  *  * Licensed under the Apache License, Version 2.0 (the "License");  * you may not use this file except in compliance with the License.  * You may obtain a copy of the License at  *  *     http: *  * Unless required by applicable law or agreed to in writing, software  * distributed under the License is distributed on an "AS IS" BASIS,  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  * See the License for the specific language governing permissions and  * limitations under the License.  *//  package com.google.javascript.jscomp;  import com.google.common.base.Charsets; import com.google.common.base.Preconditions; import com.google.common.collect.Maps; import com.google.javascript.jscomp.NodeUtil.MatchNotFunction; import com.google.javascript.rhino.Node; import com.google.javascript.rhino.Token; import com.google.javascript.rhino.TokenStream;  import java.io.IOException; import java.nio.charset.Charset; import java.nio.charset.CharsetEncoder; import java.util.Map;  //**  * CodeGenerator generates codes from a parse tree, sending it to the specified  * CodeConsumer.  *  *// class CodeGenerator {     private final Map<String, String> ESCAPED_JS_STRINGS = Maps.newHashMap();    private static final char[] HEX_CHARS       = { '0', '1', '2', '3', '4', '5', '6', '7',           '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };    private final CodeConsumer cc;    private final CharsetEncoder outputCharsetEncoder;    CodeGenerator(       CodeConsumer consumer, Charset outputCharset) {     cc = consumer;     if (outputCharset == null || outputCharset == Charsets.US_ASCII) {                               this.outputCharsetEncoder = null;     } else {       this.outputCharsetEncoder = outputCharset.newEncoder();     }   }    CodeGenerator(CodeConsumer consumer) {     this(consumer, null);   }    //**    * Insert a ECMASCRIPT 5 strict annotation.    *//   public void tagAsStrict() {     add("'use strict';");   }    void add(String str) {     cc.add(str);   }    private void addIdentifier(String identifier) {     cc.addIdentifier(identifierEscape(identifier));   }    void add(Node n) {     add(n, Context.OTHER);   }    void add(Node n, Context context) {     if (!cc.continueProcessing()) {       return;     }      int type = n.getType();     String opstr = NodeUtil.opToStr(type);     int childCount = n.getChildCount();     Node first = n.getFirstChild();     Node last = n.getLastChild();          if (opstr != null && first != last) {       Preconditions.checkState(           childCount == 2,           "Bad binary operator \"%s\": expected 2 arguments but got %s",           opstr, childCount);       int p = NodeUtil.precedence(type);       addLeftExpr(first, p, context);       cc.addOp(opstr, true);                    Context rhsContext = getContextForNoInOperator(context);                          if (last.getType() == type &&           NodeUtil.isAssociative(type)) {         addExpr(last, p, rhsContext);       } else if (NodeUtil.isAssignmentOp(n) && NodeUtil.isAssignmentOp(last)) {                 addExpr(last, p, rhsContext);       } else {         addExpr(last, p + 1, rhsContext);       }       return;     }      cc.startSourceMapping(n);      switch (type) {       case Token.TRY: {         Preconditions.checkState(first.getNext().getType() == Token.BLOCK &&                 !first.getNext().hasMoreThanOneChild());         Preconditions.checkState(childCount >= 2 && childCount <= 3);          add("try");         add(first, Context.PRESERVE_BLOCK);                          Node catchblock = first.getNext().getFirstChild();         if (catchblock != null) {           add(catchblock);         }          if (childCount == 3) {           add("finally");           add(last, Context.PRESERVE_BLOCK);         }         break;       }        case Token.CATCH:         Preconditions.checkState(childCount == 2);         add("catch(");         add(first);         add(")");         add(last, Context.PRESERVE_BLOCK);         break;        case Token.THROW:         Preconditions.checkState(childCount == 1);         add("throw");         add(first);                          cc.endStatement(true);         break;        case Token.RETURN:         add("return");         if (childCount == 1) {           add(first);         } else {           Preconditions.checkState(childCount == 0);         }         cc.endStatement();         break;        case Token.VAR:         if (first != null) {           add("var ");           addList(first, false, getContextForNoInOperator(context));         }         break;        case Token.LABEL_NAME:         Preconditions.checkState(!n.getString().isEmpty());         addIdentifier(n.getString());         break;        case Token.NAME:         if (first == null || first.getType() == Token.EMPTY) {           addIdentifier(n.getString());         } else {           Preconditions.checkState(childCount == 1);           addIdentifier(n.getString());           cc.addOp("=", true);           if (first.getType() == Token.COMMA) {             addExpr(first, NodeUtil.precedence(Token.ASSIGN));           } else {                                     addExpr(first, 0, getContextForNoInOperator(context));           }         }         break;        case Token.ARRAYLIT:         add("[");         addArrayList(first);         add("]");         break;        case Token.LP:         add("(");         addList(first);         add(")");         break;        case Token.COMMA:         Preconditions.checkState(childCount == 2);         addList(first, false, context);         break;        case Token.NUMBER:         Preconditions.checkState(childCount == 0);         cc.addNumber(n.getDouble());         break;        case Token.TYPEOF:       case Token.VOID:       case Token.NOT:       case Token.BITNOT:       case Token.POS: {                 Preconditions.checkState(childCount == 1);         cc.addOp(NodeUtil.opToStrNoFail(type), false);         addExpr(first, NodeUtil.precedence(type));         break;       }        case Token.NEG: {         Preconditions.checkState(childCount == 1);                                  if (n.getFirstChild().getType() == Token.NUMBER) {           cc.addNumber(-n.getFirstChild().getDouble());         } else {           cc.addOp(NodeUtil.opToStrNoFail(type), false);           addExpr(first, NodeUtil.precedence(type));         }          break;       }        case Token.HOOK: {         Preconditions.checkState(childCount == 3);         int p = NodeUtil.precedence(type);         addLeftExpr(first, p + 1, context);         cc.addOp("?", true);         addExpr(first.getNext(), 1);         cc.addOp(":", true);         addExpr(last, 1);         break;       }        case Token.REGEXP:         if (first.getType() != Token.STRING ||             last.getType() != Token.STRING) {           throw new Error("Expected children to be strings");         }          String regexp = regexpEscape(first.getString(), outputCharsetEncoder);                  if (childCount == 2) {           add(regexp + last.getString());         } else {           Preconditions.checkState(childCount == 1);           add(regexp);         }         break;        case Token.GET_REF:         add(first);         break;        case Token.REF_SPECIAL:         Preconditions.checkState(childCount == 1);         add(first);         add(".");         add((String) n.getProp(Node.NAME_PROP));         break;        case Token.FUNCTION:         if (n.getClass() != Node.class) {           throw new Error("Unexpected Node subclass.");         }         Preconditions.checkState(childCount == 3);         boolean funcNeedsParens = (context == Context.START_OF_EXPR);         if (funcNeedsParens) {           add("(");         }          add("function");         add(first);          add(first.getNext());         add(last, Context.PRESERVE_BLOCK);         cc.endFunction(context == Context.STATEMENT);          if (funcNeedsParens) {           add(")");         }         break;        case Token.GET:       case Token.SET:         Preconditions.checkState(n.getParent().getType() == Token.OBJECTLIT);         Preconditions.checkState(childCount == 1);         Preconditions.checkState(first.getType() == Token.FUNCTION);                  Preconditions.checkState(first.getFirstChild().getString().isEmpty());         if (type == Token.GET) {                     Preconditions.checkState(!first.getChildAtIndex(1).hasChildren());           add("get ");         } else {                     Preconditions.checkState(first.getChildAtIndex(1).hasOneChild());           add("set ");         }                  String name = n.getString();         Node fn = first;         Node parameters = fn.getChildAtIndex(1);         Node body = fn.getLastChild();                  if (!n.isQuotedString() &&             TokenStream.isJSIdentifier(name) &&                                     NodeUtil.isLatin(name)) {           add(name);         } else {                     double d = getSimpleNumber(name);           if (!Double.isNaN(d)) {             cc.addNumber(d);           } else {             addJsString(n.getString());           }         }          add(parameters);         add(body, Context.PRESERVE_BLOCK);         break;        case Token.SCRIPT:       case Token.BLOCK: {         if (n.getClass() != Node.class) {           throw new Error("Unexpected Node subclass.");         }         boolean preserveBlock = context == Context.PRESERVE_BLOCK;         if (preserveBlock) {           cc.beginBlock();         }          boolean preferLineBreaks =             type == Token.SCRIPT ||             (type == Token.BLOCK &&                 !preserveBlock &&                 n.getParent() != null &&                 n.getParent().getType() == Token.SCRIPT);         for (Node c = first; c != null; c = c.getNext()) {           add(c, Context.STATEMENT);                      if (c.getType() == Token.VAR) {             cc.endStatement();           }            if (c.getType() == Token.FUNCTION) {             cc.maybeLineBreak();           }                                if (preferLineBreaks) {             cc.notePreferredLineBreak();           }         }         if (preserveBlock) {           cc.endBlock(cc.breakAfterBlockFor(n, context == Context.STATEMENT));         }         break;       }        case Token.FOR:         if (childCount == 4) {           add("for(");           if (first.getType() == Token.VAR) {             add(first, Context.IN_FOR_INIT_CLAUSE);           } else {             addExpr(first, 0, Context.IN_FOR_INIT_CLAUSE);           }           add(";");           add(first.getNext());           add(";");           add(first.getNext().getNext());           add(")");           addNonEmptyStatement(               last, getContextForNonEmptyExpression(context), false);         } else {           Preconditions.checkState(childCount == 3);           add("for(");           add(first);           add("in");           add(first.getNext());           add(")");           addNonEmptyStatement(               last, getContextForNonEmptyExpression(context), false);         }         break;        case Token.DO:         Preconditions.checkState(childCount == 2);         add("do");         addNonEmptyStatement(first, Context.OTHER, false);         add("while(");         add(last);         add(")");         cc.endStatement();         break;        case Token.WHILE:         Preconditions.checkState(childCount == 2);         add("while(");         add(first);         add(")");         addNonEmptyStatement(             last, getContextForNonEmptyExpression(context), false);         break;        case Token.EMPTY:         Preconditions.checkState(childCount == 0);         break;        case Token.GETPROP: {         Preconditions.checkState(             childCount == 2,             "Bad GETPROP: expected 2 children, but got %s", childCount);         Preconditions.checkState(             last.getType() == Token.STRING,             "Bad GETPROP: RHS should be STRING");         boolean needsParens = (first.getType() == Token.NUMBER);         if (needsParens) {           add("(");         }         addLeftExpr(first, NodeUtil.precedence(type), context);         if (needsParens) {           add(")");         }         add(".");         addIdentifier(last.getString());         break;       }        case Token.GETELEM:         Preconditions.checkState(             childCount == 2,             "Bad GETELEM: expected 2 children but got %s", childCount);         addLeftExpr(first, NodeUtil.precedence(type), context);         add("[");         add(first.getNext());         add("]");         break;        case Token.WITH:         Preconditions.checkState(childCount == 2);         add("with(");         add(first);         add(")");         addNonEmptyStatement(             last, getContextForNonEmptyExpression(context), false);         break;        case Token.INC:       case Token.DEC: {         Preconditions.checkState(childCount == 1);         String o = type == Token.INC ? "++" : "--";         int postProp = n.getIntProp(Node.INCRDECR_PROP);                         if (postProp != 0) {           addLeftExpr(first, NodeUtil.precedence(type), context);           cc.addOp(o, false);         } else {           cc.addOp(o, false);           add(first);         }         break;       }        case Token.CALL:                                                                                 if (isIndirectEval(first)             || n.getBooleanProp(Node.FREE_CALL) && NodeUtil.isGet(first)) {           add("(0,");           addExpr(first, NodeUtil.precedence(Token.COMMA));           add(")");         } else {           addLeftExpr(first, NodeUtil.precedence(type), context);         }         add("(");         addList(first.getNext());         add(")");         break;        case Token.IF:         boolean hasElse = childCount == 3;         boolean ambiguousElseClause =             context == Context.BEFORE_DANGLING_ELSE && !hasElse;         if (ambiguousElseClause) {           cc.beginBlock();         }          add("if(");         add(first);         add(")");          if (hasElse) {           addNonEmptyStatement(               first.getNext(), Context.BEFORE_DANGLING_ELSE, false);           add("else");           addNonEmptyStatement(               last, getContextForNonEmptyExpression(context), false);         } else {           addNonEmptyStatement(first.getNext(), Context.OTHER, false);           Preconditions.checkState(childCount == 2);         }          if (ambiguousElseClause) {           cc.endBlock();         }         break;        case Token.NULL:       case Token.THIS:       case Token.FALSE:       case Token.TRUE:         Preconditions.checkState(childCount == 0);         add(Node.tokenToName(type));         break;        case Token.CONTINUE:         Preconditions.checkState(childCount <= 1);         add("continue");         if (childCount == 1) {           if (first.getType() != Token.LABEL_NAME) {             throw new Error("Unexpected token type. Should be LABEL_NAME.");           }           add(" ");           add(first);         }         cc.endStatement();         break;        case Token.DEBUGGER:         Preconditions.checkState(childCount == 0);         add("debugger");         cc.endStatement();         break;        case Token.BREAK:         Preconditions.checkState(childCount <= 1);         add("break");         if (childCount == 1) {           if (first.getType() != Token.LABEL_NAME) {             throw new Error("Unexpected token type. Should be LABEL_NAME.");           }           add(" ");           add(first);         }         cc.endStatement();         break;        case Token.EXPR_VOID:         throw new Error("Unexpected EXPR_VOID. Should be EXPR_RESULT.");        case Token.EXPR_RESULT:         Preconditions.checkState(childCount == 1);         add(first, Context.START_OF_EXPR);         cc.endStatement();         break;        case Token.NEW:         add("new ");         int precedence = NodeUtil.precedence(type);                                  if (NodeUtil.containsType(first, Token.CALL, new MatchNotFunction())) {           precedence = NodeUtil.precedence(first.getType()) + 1;         }         addExpr(first, precedence);                  Node next = first.getNext();         if (next != null) {           add("(");           addList(next);           add(")");         }         break;        case Token.STRING:         if (childCount !=             ((n.getParent() != null &&               n.getParent().getType() == Token.OBJECTLIT) ? 1 : 0)) {           throw new IllegalStateException(               "Unexpected String children: " + n.getParent().toStringTree());         }         addJsString(n.getString());         break;        case Token.DELPROP:         Preconditions.checkState(childCount == 1);         add("delete ");         add(first);         break;        case Token.OBJECTLIT: {         boolean needsParens = (context == Context.START_OF_EXPR);         if (needsParens) {           add("(");         }         add("{");         for (Node c = first; c != null; c = c.getNext()) {           if (c != first) {             cc.listSeparator();           }            if (c.getType() == Token.GET || c.getType() == Token.SET) {             add(c);           } else {             Preconditions.checkState(c.getType() == Token.STRING);             String key = c.getString();                                     if (!c.isQuotedString() &&                 !TokenStream.isKeyword(key) &&                 TokenStream.isJSIdentifier(key) &&                                                 NodeUtil.isLatin(key)) {               add(key);             } else {                             double d = getSimpleNumber(key);               if (!Double.isNaN(d)) {                 cc.addNumber(d);               } else {                 addExpr(c, 1);               }             }             add(":");             addExpr(c.getFirstChild(), 1);           }         }         add("}");         if (needsParens) {           add(")");         }         break;       }        case Token.SWITCH:         add("switch(");         add(first);         add(")");         cc.beginBlock();         addAllSiblings(first.getNext());         cc.endBlock(context == Context.STATEMENT);         break;        case Token.CASE:         Preconditions.checkState(childCount == 2);         add("case ");         add(first);         addCaseBody(last);         break;        case Token.DEFAULT:         Preconditions.checkState(childCount == 1);         add("default");         addCaseBody(first);         break;        case Token.LABEL:         Preconditions.checkState(childCount == 2);         if (first.getType() != Token.LABEL_NAME) {           throw new Error("Unexpected token type. Should be LABEL_NAME.");         }         add(first);         add(":");         addNonEmptyStatement(             last, getContextForNonEmptyExpression(context), true);         break;                    case Token.SETNAME:         break;        default:         throw new Error("Unknown type " + type + "\n" + n.toStringTree());     }      cc.endSourceMapping(n);   }    static boolean isSimpleNumber(String s) {     int len = s.length();     for (int index = 0; index < len; index++) {       char c = s.charAt(index);       if (c < '0' || c > '9') {        return false;       }     }    <START_BUG> return (len > 0); <END_BUG>   }    static double getSimpleNumber(String s) {     if (isSimpleNumber(s)) {       try {         long l = Long.parseLong(s);         if (l < NodeUtil.MAX_POSITIVE_INTEGER_NUMBER) {           return l;         }       } catch (NumberFormatException e) {               }     }     return Double.NaN;   }    //**    * @return Whether the name is an indirect eval.    *//   private boolean isIndirectEval(Node n) {     return n.getType() == Token.NAME && "eval".equals(n.getString()) &&         !n.getBooleanProp(Node.DIRECT_EVAL);   }    //**    * Adds a block or expression, substituting a VOID with an empty statement.    * This is used for "for (...);" and "if (...);" type statements.    *    * @param n The node to print.    * @param context The context to determine how the node should be printed.    *//   private void addNonEmptyStatement(       Node n, Context context, boolean allowNonBlockChild) {     Node nodeToProcess = n;      if (!allowNonBlockChild && n.getType() != Token.BLOCK) {       throw new Error("Missing BLOCK child.");     }              if (n.getType() == Token.BLOCK) {       int count = getNonEmptyChildCount(n, 2);       if (count == 0) {         if (cc.shouldPreserveExtraBlocks()) {           cc.beginBlock();           cc.endBlock(cc.breakAfterBlockFor(n, context == Context.STATEMENT));         } else {           cc.endStatement(true);         }         return;       }        if (count == 1) {                                 Node firstAndOnlyChild = getFirstNonEmptyChild(n);         boolean alwaysWrapInBlock = cc.shouldPreserveExtraBlocks();         if (alwaysWrapInBlock || isOneExactlyFunctionOrDo(firstAndOnlyChild)) {           cc.beginBlock();           add(firstAndOnlyChild, Context.STATEMENT);           cc.maybeLineBreak();           cc.endBlock(cc.breakAfterBlockFor(n, context == Context.STATEMENT));           return;         } else {                     nodeToProcess = firstAndOnlyChild;         }       }        if (count > 1) {         context = Context.PRESERVE_BLOCK;       }     }      if (nodeToProcess.getType() == Token.EMPTY) {       cc.endStatement(true);     } else {       add(nodeToProcess, context);                    if (nodeToProcess.getType() == Token.VAR) {         cc.endStatement();       }     }   }    //**    * @return Whether the Node is a DO or FUNCTION (with or without    * labels).    *//   private boolean isOneExactlyFunctionOrDo(Node n) {     if (n.getType() == Token.LABEL) {       Node labeledStatement = n.getLastChild();       if (labeledStatement.getType() != Token.BLOCK) {         return isOneExactlyFunctionOrDo(labeledStatement);       } else {                                 if (getNonEmptyChildCount(n, 2) == 1) {           return isOneExactlyFunctionOrDo(getFirstNonEmptyChild(n));         } else {                                return len > 0;         }       }     } else {       return (n.getType() == Token.FUNCTION || n.getType() == Token.DO);     }   }    //**    * Adds a node at the left-hand side of an expression. Unlike    * {@link #addExpr(Node,int)}, this preserves information about the context.    *    * The left side of an expression is special because in the JavaScript    * grammar, certain tokens may be parsed differently when they are at    * the beginning of a statement. For example, "{}" is parsed as a block,    * but "{'x': 'y'}" is parsed as an object literal.    *//   void addLeftExpr(Node n, int minPrecedence, Context context) {     addExpr(n, minPrecedence, context);   }    void addExpr(Node n, int minPrecedence) {     addExpr(n, minPrecedence, Context.OTHER);   }    private void addExpr(Node n, int minPrecedence, Context context) {     if ((NodeUtil.precedence(n.getType()) < minPrecedence) ||         ((context == Context.IN_FOR_INIT_CLAUSE) &&         (n.getType() == Token.IN))){       add("(");       add(n, clearContextForNoInOperator(context));       add(")");     } else {       add(n, context);     }   }    void addList(Node firstInList) {     addList(firstInList, true, Context.OTHER);   }    void addList(Node firstInList, boolean isArrayOrFunctionArgument) {     addList(firstInList, isArrayOrFunctionArgument, Context.OTHER);   }    void addList(Node firstInList, boolean isArrayOrFunctionArgument,                Context lhsContext) {     for (Node n = firstInList; n != null; n = n.getNext()) {       boolean isFirst = n == firstInList;       if (isFirst) {         addLeftExpr(n, isArrayOrFunctionArgument ? 1 : 0, lhsContext);       } else {         cc.listSeparator();         addExpr(n, isArrayOrFunctionArgument ? 1 : 0);       }     }   }    //**    * This function adds a comma-separated list as is specified by an ARRAYLIT    * node with the associated skipIndexes array.  This is a space optimization    * since we avoid creating a whole Node object for each empty array literal    * slot.    * @param firstInList The first in the node list (chained through the next    * property).    *//   void addArrayList(Node firstInList) {     boolean lastWasEmpty = false;     for (Node n = firstInList; n != null; n = n.getNext()) {       if (n != firstInList) {         cc.listSeparator();       }       addExpr(n, 1);       lastWasEmpty = n.getType() == Token.EMPTY;     }      if (lastWasEmpty) {       cc.listSeparator();     }   }    void addCaseBody(Node caseBody) {     cc.beginCaseBody();     add(caseBody);     cc.endCaseBody();   }    void addAllSiblings(Node n) {     for (Node c = n; c != null; c = c.getNext()) {       add(c);     }   }    //** Outputs a js string, using the optimal (single//double) quote character *//   void addJsString(String s) {     String cached = ESCAPED_JS_STRINGS.get(s);     if (cached == null) {       cached = jsString(s);       ESCAPED_JS_STRINGS.put(s, cached);     }     add(cached);   }    String jsString(String s) {     int singleq = 0, doubleq = 0;          for (int i = 0; i < s.length(); i++) {       switch (s.charAt(i)) {         case '"': doubleq++; break;         case '\'': singleq++; break;       }     }      String doublequote, singlequote;     char quote;     if (singleq < doubleq) {             quote = '\'';       doublequote = "\"";       singlequote = "\\\'";     } else {             quote = '\"';       doublequote = "\\\"";       singlequote = "\'";     }      return strEscape(s, quote, doublequote, singlequote, "\\\\",         outputCharsetEncoder);   }    //** Escapes regular expression *//   static String regexpEscape(String s, CharsetEncoder outputCharsetEncoder) {     return strEscape(s, '//', "\"", "'", "\\", outputCharsetEncoder);   }    //**    * Escapes the given string to a double quoted (") JavaScript//JSON string    *//   static String escapeToDoubleQuotedJsString(String s) {     return strEscape(s, '"',  "\\\"", "\'", "\\\\", null);   }    //* If the user doesn't want to specify an output charset encoder, assume      they want Latin//ASCII characters only.    *//   static String regexpEscape(String s) {     return regexpEscape(s, null);   }    //** Helper to escape javascript string as well as regular expression *//   static String strEscape(String s, char quote,                           String doublequoteEscape,                           String singlequoteEscape,                           String backslashEscape,                           CharsetEncoder outputCharsetEncoder) {     StringBuilder sb = new StringBuilder(s.length() + 2);     sb.append(quote);     for (int i = 0; i < s.length(); i++) {       char c = s.charAt(i);       switch (c) {         case '\0': sb.append("\\x00"); break;         case '\n': sb.append("\\n"); break;         case '\r': sb.append("\\r"); break;         case '\t': sb.append("\\t"); break;         case '\\': sb.append(backslashEscape); break;         case '\"': sb.append(doublequoteEscape); break;         case '\'': sb.append(singlequoteEscape); break;         case '>':                                 if (i >= 2 &&               ((s.charAt(i - 1) == '-' && s.charAt(i - 2) == '-') ||                (s.charAt(i - 1) == ']' && s.charAt(i - 2) == ']'))) {             sb.append("\\>");           } else {             sb.append(c);           }           break;         case '<':                     final String END_SCRIPT = "//script";                      final String START_COMMENT = "!--";            if (s.regionMatches(true, i + 1, END_SCRIPT, 0,                               END_SCRIPT.length())) {             sb.append("<\\");           } else if (s.regionMatches(false, i + 1, START_COMMENT, 0,                                      START_COMMENT.length())) {             sb.append("<\\");           } else {             sb.append(c);           }           break;         default:                               if (outputCharsetEncoder != null) {             if (outputCharsetEncoder.canEncode(c)) {               sb.append(c);             } else {                             appendHexJavaScriptRepresentation(sb, c);             }           } else {                                                 if (c > 0x1f && c < 0x7f) {               sb.append(c);             } else {                                                         appendHexJavaScriptRepresentation(sb, c);             }           }       }     }     sb.append(quote);     return sb.toString();   }    static String identifierEscape(String s) {         if (NodeUtil.isLatin(s)) {       return s;     }          StringBuilder sb = new StringBuilder();     for (int i = 0; i < s.length(); i++) {       char c = s.charAt(i);                         if (c > 0x1F && c < 0x7F) {         sb.append(c);       } else {         appendHexJavaScriptRepresentation(sb, c);       }     }     return sb.toString();   }   //**    * @param maxCount The maximum number of children to look for.    * @return The number of children of this node that are non empty up to    * maxCount.    *//   private static int getNonEmptyChildCount(Node n, int maxCount) {     int i = 0;     Node c = n.getFirstChild();     for (; c != null && i < maxCount; c = c.getNext()) {       if (c.getType() == Token.BLOCK) {         i += getNonEmptyChildCount(c, maxCount-i);       } else if (c.getType() != Token.EMPTY) {         i++;       }     }     return i;   }    //** Gets the first non-empty child of the given node. *//   private static Node getFirstNonEmptyChild(Node n) {     for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {       if (c.getType() == Token.BLOCK) {         Node result = getFirstNonEmptyChild(c);         if (result != null) {           return result;         }       } else if (c.getType() != Token.EMPTY) {         return c;       }     }     return null;   }          enum Context {     STATEMENT,     BEFORE_DANGLING_ELSE,     START_OF_EXPR,     PRESERVE_BLOCK,                 IN_FOR_INIT_CLAUSE,     OTHER   }    private Context getContextForNonEmptyExpression(Context currentContext) {     return currentContext == Context.BEFORE_DANGLING_ELSE ?         Context.BEFORE_DANGLING_ELSE : Context.OTHER;   }    //**    * If we're in a IN_FOR_INIT_CLAUSE, we can't permit in operators in the    * expression.  Pass on the IN_FOR_INIT_CLAUSE flag through subexpressions.    *//   private  Context getContextForNoInOperator(Context context) {     return (context == Context.IN_FOR_INIT_CLAUSE         ? Context.IN_FOR_INIT_CLAUSE : Context.OTHER);   }    //**    * If we're in a IN_FOR_INIT_CLAUSE, (and thus can't permit in operators    * in the expression), but have added parentheses, the expressions within    * the parens have no limits.  Clear the context flag  Be safe and don't    * clear the flag if it held another value.    *//   private  Context clearContextForNoInOperator(Context context) {     return (context == Context.IN_FOR_INIT_CLAUSE         ? Context.OTHER : context);   }    //**    * @see #appendHexJavaScriptRepresentation(int, Appendable)    *//   private static void appendHexJavaScriptRepresentation(       StringBuilder sb, char c) {     try {       appendHexJavaScriptRepresentation(c, sb);     } catch (IOException ex) {             throw new RuntimeException(ex);     }   }    //**    * Returns a javascript representation of the character in a hex escaped    * format.    *    * @param codePoint The codepoint to append.    * @param out The buffer to which the hex representation should be appended.    *//   private static void appendHexJavaScriptRepresentation(       int codePoint, Appendable out)       throws IOException {     if (Character.isSupplementaryCodePoint(codePoint)) {                               char[] surrogates = Character.toChars(codePoint);       appendHexJavaScriptRepresentation(surrogates[0], out);       appendHexJavaScriptRepresentation(surrogates[1], out);       return;     }     out.append("\\u")         .append(HEX_CHARS[(codePoint >>> 12) & 0xf])         .append(HEX_CHARS[(codePoint >>> 8) & 0xf])         .append(HEX_CHARS[(codePoint >>> 4) & 0xf])         .append(HEX_CHARS[codePoint & 0xf]);   } } 


Fix:
return len > 0 && s.charAt(0) != '0';