---

yaml
---
r: 172269
b: refs/heads/master
c: a96a8b2
h: refs/heads/master
i:
  172267: 5bb3f23
v: v3

Author: Keegan McAllister

[refs]

@@ -1,5 +1,5 @@
 ---
-refs/heads/master: 128e7ff53b9e7330ca78f961030ac307f5a6fc47
+refs/heads/master: a96a8b2b2526aaa631183f71aef9acf390b61f48
 refs/heads/snap-stage1: e33de59e47c5076a89eadeb38f4934f58a3618a6
 refs/heads/snap-stage3: 5b3cd3900ceda838f5798c30ab96ceb41f962534
 refs/heads/try: 705b92bdfe33d0d6febdf945340262514e1b3b5c

trunk/src/doc/trpl/macros.md

@@ -440,14 +440,18 @@ to print "I am never printed" and to run forever.
 
 # Scoping and macro import/export
 
-Macros occupy a single global namespace. The interaction with Rust's system of
-modules and crates is somewhat complex.
+Macros are expanded at an early stage in compilation, before name resolution.
+One downside is that scoping works differently for macros, compared to other
+constructs in the language.
 
 Definition and expansion of macros both happen in a single depth-first,
 lexical-order traversal of a crate's source. So a macro defined at module scope
 is visible to any subsequent code in the same module, which includes the body
 of any subsequent child `mod` items.
 
+A macro defined within the body of a single `fn`, or anywhere else not at
+module scope, is visible only within that item.
+
 If a module has the `macro_use` attribute, its macros are also visible in its
 parent module after the child's `mod` item. If the parent also has `macro_use`
 then the macros will be visible in the grandparent after the parent's `mod`