By the way, I recently tried to get rid of some `vec!`s in the benchmarksgame entries (well, to see if I could), but got into trouble with IntoIterator implementations, so an extension of EscapeAnalysis would be great!
I suspect that the escape analysis lint will never be as powerful as a human looking in a reasonably small region of code to remove specific allocations, so it wouldn't be able to help here. Probably. Its power is in that it can find unnecessary allocations in a large codebase.