private void Apply(Instruction instruction, Stack<Value> stack, ICollection<Value> values, IList<Value> locals)
        {
            // TODO: this method is a mess and needs to be refactored!!

            var pushCount = instruction.GetPushCount();
            var popCount = instruction.GetPopCount(_method);
            if (popCount == Int32.MaxValue)
                popCount = stack.Count;

            var isCall = instruction.OpCode.FlowControl == FlowControl.Call;
            var callParams = isCall ? (instruction.Operand as MethodReference).Parameters : NoParams;

            // List of all popped values
            var poppedValues = new List<Value>();

            var inputArguments = new List<Value>();
            for (var i = 0; i < popCount; i++)
            {
                // Instruction is a consumer
                var value = stack.Pop();
                poppedValues.Add(value);
                // If we popped a value for an out parameter, we're not a consumer!
                // Note that the first pop returns the last argument.
                if (isCall && i < callParams.Count && callParams[callParams.Count - i - 1].IsOut)
                {
                    inputArguments.Insert(0, null); // empty slot
                    continue;
                }
                value.Consumer = instruction;
                inputArguments.Insert(0, value); //TODO: not 'this'!?!?
            }
            int storeIndex;
            if (instruction.IsStoreLocal(out storeIndex))
            {
                Debug.Assert(popCount == 1);
                locals[storeIndex] = poppedValues[0];
            }
            for (var i = 0; i < pushCount; i++)
            {
                Value newValue;
                // Instruction is a producer
                int loadIndex;
                if (instruction.IsLoadLocal(out loadIndex))
                {
                    Debug.Assert(pushCount == 1);
                    newValue = new Value(instruction);
                    values.Add(newValue);
                    // The local value can be null if we're passing loading a reference
                    // destined for an out parameter. Note that we can get a non-null
                    // value as well, so we have to sort things out when we handle the
                    // call to the method with the out parameter.
                    var localValue = locals[loadIndex];
                    if (localValue != null)
                    {
                        newValue.AddParents(new[] { localValue });
                    }
                }
                else
                {
                    newValue = new Value(instruction);
                    values.Add(newValue);
                    newValue.AddParents(inputArguments.Where(a => a != null));
                }
                stack.Push(newValue);
            }
            if (isCall)
            {
                var argValues = new Value[callParams.Count];
                for (var i = 0; i < argValues.Length; i++)
                {
                    argValues[i] = poppedValues[argValues.Length - i - 1];
                }
                for (var i = 0; i < callParams.Count; i++)
                {
                    // First of poppedValues is last argument
                    var inputArgument = poppedValues[callParams.Count - i - 1];
                    if (!callParams[i].IsRef() && !callParams[i].IsOut)
                        continue;

                    var newValue = new Value(instruction);
                    var storeAtIndex = (inputArgument.Producer.Operand as VariableDefinition).Index;

                    // Add all input values (including any refs) as parents!
                    for (var j = 0; j < callParams.Count; j++)
                    {
                        if (callParams[j].IsOut)
                            continue;
                        newValue.AddParents(new[] { argValues[j] });
                    }

                    // Don't push onto the stack, but save the value and store
                    // it in the locals array.
                    values.Add(newValue);
                    locals[storeAtIndex] = newValue;
                }
            }
        }