&gt; This is an insidious pitfall that may earn Rust the &quot;slow&quot; label, akin to what happened to Common Lisp.<p>This doesn&#x27;t match my experience at all with Rust, for what it&#x27;s worth. Not having copy constructors makes up for any difference in that regard: in C++ it&#x27;s way too easy to accidentally deep copy a vector and the entire object graph underneath it--all it takes is &quot;auto a = b&quot; as opposed to &quot;auto&amp; a = b&quot;--with very bad performance consequences. Rust, on the other hand, doesn&#x27;t let you deep copy unless you explicitly ask it to.