---

yaml
---
r: 236103
b: refs/heads/stable
c: 99043dd
h: refs/heads/master
i:
  236101: 88b8cb4
  236099: b44a960
  236095: 23a57a0
v: v3

Author: Gankra

[refs]

@@ -29,7 +29,7 @@ refs/heads/tmp: afae2ff723393b3ab4ccffef6ac7c6d1809e2da0
 refs/tags/1.0.0-alpha.2: 4c705f6bc559886632d3871b04f58aab093bfa2f
 refs/tags/homu-tmp: f859507de8c410b648d934d8f5ec1c52daac971d
 refs/tags/1.0.0-beta: 8cbb92b53468ee2b0c2d3eeb8567005953d40828
-refs/heads/stable: 5f6e0abe27aa6632f95492ad8864d8084c1bacef
+refs/heads/stable: 99043dde9dd2d0507ad2e3cda65b9d3e9244f13f
 refs/tags/1.0.0: 55bd4f8ff2b323f317ae89e254ce87162d52a375
 refs/tags/1.1.0: bc3c16f09287e5545c1d3f76b7abd54f2eca868b
 refs/tags/1.2.0: f557861f822c34f07270347b94b5280de20a597e

branches/stable/src/doc/tarpl/exotic-sizes.md

@@ -95,10 +95,9 @@ actually possible to communicate this at the type level by returning a
 knowing that it's *statically impossible* for this value to be an `Err`, as
 this would require providing a value of type Void.
 
-In principle, Rust can do some interesting analysees and optimizations based
+In principle, Rust can do some interesting analyses and optimizations based
 on this fact. For instance, `Result<T, Void>` could be represented as just `T`,
-because the Err case doesn't actually exist. Also in principle the following
-could compile:
+because the Err case doesn't actually exist. The following *could* also compile:
 
 ```rust,ignore
 enum Void {}
@@ -111,3 +110,9 @@ let Ok(num) = res;
 
 But neither of these tricks work today, so all Void types get you today is
 the ability to be confident that certain situations are statically impossible.
+
+One final subtle detail about empty types is that raw pointers to them are
+actually valid to construct, but dereferencing them is Undefined Behaviour
+because that doesn't actually make sense. That is, you could model C's `void *`
+type with `*const Void`, but this doesn't necessarily gain anything over using
+e.g. `*const ()`, which *is* safe to randomly dereference.