private String prepareIndyCall(Expression receiver, boolean implicitThis) {
CompileStack compileStack = controller.getCompileStack();
OperandStack operandStack = controller.getOperandStack();
compileStack.pushLHS(false);
// load normal receiver as first argument
compileStack.pushImplicitThis(implicitThis);
receiver.visit(controller.getAcg());
compileStack.popImplicitThis();