Does <'a, 'b: 'a> mean that the lifetime 'b must outlive the lifetime 'a?

Question

I want to implement a builder similar to the debug builders defined by the standard library. They are defined using structures like the following:

struct Deb         


        

Answer 1

Yes, you're broadly right.

A bound <...: 'a> means that ... (either a type or another lifetime) needs to be able to outlive 'a. E.g. 'b: 'a means that "'b must live at least as long as 'a" (not strictly outlives, though: they can be the same).

Answer 2

The colon is read "outlives", so

'long: 'short

is read "'long outlives 'short".

As for an official doc on the topic, the only place I've seen it documented so far is in the RFC on lifetime bounds.