Add "early-bound lifetime" and "late-bound lifetime" to the glossary

Author: varkor

src/appendix/glossary.md

@@ -20,6 +20,7 @@ data-flow analysis      |  a static analysis that figures out what properties ar
 DefId                   |  an index identifying a definition (see `librustc/hir/def_id.rs`). Uniquely identifies a `DefPath`.
 Double pointer          |  a pointer with additional metadata. See "fat pointer" for more.
 DST                     |  Dynamically-Sized Type. A type for which the compiler cannot statically know the size in memory (e.g. `str` or `[u8]`). Such types don't implement `Sized` and cannot be allocated on the stack. They can only occur as the last field in a struct. They can only be used behind a pointer (e.g. `&str` or `&[u8]`).
+early-bound lifetime    |  a lifetime region, which is bound in an item's `Generics` and substituted using a `Substs`. Contrast with **late-bound lifetime**. ([see more](https://doc.rust-lang.org/nightly/nightly-rustc/rustc/ty/enum.RegionKind.html#bound-regions))
 empty type              |  see "uninhabited type".
 Fat pointer             |  a two word value carrying the address of some value, along with some further information necessary to put the value to use. Rust includes two kinds of "fat pointers": references to slices, and trait objects. A reference to a slice carries the starting address of the slice and its length. A trait object carries a value's address and a pointer to the trait's implementation appropriate to that value. "Fat pointers" are also known as "wide pointers", and "double pointers".
 free variable           |  a "free variable" is one that is not bound within an expression or term; see [the background chapter for more](./background.html#free-vs-bound)
@@ -36,6 +37,7 @@ IR                      |  Intermediate Representation. A general term in compil
 IRLO                    |  `IRLO` or `irlo` is sometimes used as an abbreviation for [internals.rust-lang.org](https://internals.rust-lang.org).
 item                    |  a kind of "definition" in the language, such as a static, const, use statement, module, struct, etc. Concretely, this corresponds to the `Item` type.
 lang item               |  items that represent concepts intrinsic to the language itself, such as special built-in traits like `Sync` and `Send`; or traits representing operations such as `Add`; or functions that are called by the compiler. ([see more](https://doc.rust-lang.org/1.9.0/book/lang-items.html))
+late-bound lifetime     |  a lifetime region, which is bound in a HRTB and substituted with specific functions in the compiler, such as `liberate_late_bound_regions`. Contrast with **early-bound lifetime**. ([see more](https://doc.rust-lang.org/nightly/nightly-rustc/rustc/ty/enum.RegionKind.html#bound-regions))
 local crate             |  the crate currently being compiled.
 LTO                     |  Link-Time Optimizations. A set of optimizations offered by LLVM that occur just before the final binary is linked. These include optimizations like removing functions that are never used in the final program, for example. _ThinLTO_ is a variant of LTO that aims to be a bit more scalable and efficient, but possibly sacrifices some optimizations. You may also read issues in the Rust repo about "FatLTO", which is the loving nickname given to non-Thin LTO. LLVM documentation: [here][lto] and [here][thinlto]
 [LLVM]                  |  (actually not an acronym :P) an open-source compiler backend. It accepts LLVM IR and outputs native binaries. Various languages (e.g. Rust) can then implement a compiler front-end that output LLVM IR and use LLVM to compile to all the platforms LLVM supports.