The first rule of Rust references is that you don’t talk about Rust references

References must always be valid

The first rule of references is that they must always be valid - that is to say you can’t create a reference to a variable that will go out of scope or be destroyed before the reference does. Imagine a function that returns the address of a local variable or a use-after-free bug.

Seems simple enough however, this introduces complications related to lifetimes of data that we’ll talk about in another post. For example, if you want a struct to contain a reference, then you will have to describe the lifetimes involved so that the compiler can ensure that an instance of your struct - which contains a reference - does not outlast the value that is being referenced. This introduces a whole layer of lifetime syntax, not present in a language like C or C++, whose purpose is to describe the needed lifetimes.

Lifetimes