746     }

   747 

   748     private Node leaveDELETE(final UnaryNode unaryNode) {

   749         final FunctionNode currentFunctionNode = lc.getCurrentFunction();

   750         final boolean      strictMode          = currentFunctionNode.isStrict();

   751         final Expression   rhs                 = unaryNode.getExpression();

   752         final Expression   strictFlagNode      = (Expression)LiteralNode.newInstance(unaryNode, strictMode).accept(this);

   753 

   754         Request request = Request.DELETE;

   755         final List<Expression> args = new ArrayList<>();

   756 

   757         if (rhs instanceof IdentNode) {

   758             final IdentNode ident = (IdentNode)rhs;

   759             // If this is a declared variable or a function parameter, delete always fails (except for globals).

   760             final String name = ident.getName();

   761             final Symbol symbol = ident.getSymbol();

   762 

   763             if (symbol.isThis()) {

   764                 // Can't delete "this", ignore and return true

   765                 return LiteralNode.newInstance(unaryNode, true);

   766             }

   767             final Expression literalNode = LiteralNode.newInstance(unaryNode, name);

   768             final boolean failDelete = strictMode || (!symbol.isScope() && (symbol.isParam() || (symbol.isVar() && !symbol.isProgramLevel())));

   769 

   770             if (!failDelete) {

   771                 args.add(compilerConstantIdentifier(SCOPE));

   772             }

   773             args.add(literalNode);

   774             args.add(strictFlagNode);

   775 

   776             if (failDelete) {

   777                 request = Request.FAIL_DELETE;

   778             } else if ((symbol.isGlobal() && !symbol.isFunctionDeclaration()) || symbol.isProgramLevel()) {

   779                 request = Request.SLOW_DELETE;

   780             }

   781         } else if (rhs instanceof AccessNode) {

   782             final Expression base     = ((AccessNode)rhs).getBase();

   783             final String     property = ((AccessNode)rhs).getProperty();

   784 

   785             args.add(base);

   786             args.add(LiteralNode.newInstance(unaryNode, property));

   787             args.add(strictFlagNode);

   788 

   789         } else if (rhs instanceof IndexNode) {

   790             final IndexNode indexNode = (IndexNode)rhs;

   791             final Expression base  = indexNode.getBase();

   792             final Expression index = indexNode.getIndex();

   793 

   794             args.add(base);

   795             args.add(index);

   796             args.add(strictFlagNode);

   797 

   798         } else {

   799             throw new AssertionError("Unexpected delete with " + rhs.getClass().getName() + " expression");

   800         }

   801         return new RuntimeNode(unaryNode, request, args);