The simplest tool is to just grep for various constructs that copy or allocate. Clippy, the Rust linter, will find some of these (as well as other issues, some of which tend to cause performance problems).
The better tool is to profile the code, then optimize hotspots. There's a Rust Performance Book with a list of profilers known to work with Rust programs[1]. Rustc does support Profile Guided Optimization[2] which is often pretty good at speeding up the output even without any code changes.
For allocations (more expensive in many cases) the Rust container cheat sheet[1] is helpful. Box, Vec, Rc, Arc, and Mutex are the standard types which allocate.
Not sure of a list for things that copy their data. The Clone trait is the obvious one, and it requires calling clone() to make the copy. EG `val.clone()`. So searching for `.clone()` will get you those. But other things like to_string are expensive, and From/Into are sometimes expensive.
> The simplest tool is to just grep for various constructs that copy or allocate.
Do you happen to have a curated list somewhere?