//@ are used correctly, *while looking only at the function type*. At no point in our analysis of `rust_foo` did
//@ we have to look *into* `head`. That's, of course, crucial if we want to separate library code from application code.
//@ Most of the time, we don't have to explicitly add lifetimes to function types. This is thanks to *lifetimes elision*,
//@ are used correctly, *while looking only at the function type*. At no point in our analysis of `rust_foo` did
//@ we have to look *into* `head`. That's, of course, crucial if we want to separate library code from application code.
//@ Most of the time, we don't have to explicitly add lifetimes to function types. This is thanks to *lifetimes elision*,