This is a good point, and I'm not arguing with it, but I don't think the words "code cannot lie" are the right way to express it.

Code can deceive even if, definitionally, the code states what the computer will do. So code most certainly can lie.

[By analogy, you'd still feel lied to if someone told you something that is technically correct but very misleading: "(Me) It's going to rain tomorrow." → tomorrow comes → "(You) It isn't raining today!" → "(Me) It is raining, in Japan. I didn't say it would rain here."]

I suppose it depends on whether you're considering what the code communicates to the machine or what it communicates to a person.