What is the difference between &Trait and impl Trait when used as method arguments?

Question

In my project so far, I use many traits to permit mocking/stubbing in unit tests for injected dependencies. However, one detail of what I\'m doing so far seems so suspicious

Answer 1

It is indeed different. The impl version is equivalent to the following:

fn confirm>(subject: M) ...

so unlike the first version, subject is moved (passed by value) into confirm, rather than passed by reference. So in the impl version, confirm takes ownership of this value.