---

yaml
---
r: 38791
b: refs/heads/incoming
c: 0ef75a6
h: refs/heads/master
i:
  38789: d475548
  38787: 6c0392f
  38783: a113211
v: v3

Author: catamorphism

[refs]

@@ -6,7 +6,7 @@ refs/heads/try: 3d5418789064fdb463e872a4e651af1c628a3650
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
 refs/heads/try2: a810c03263670238bccd64cabb12a23a46e3a278
-refs/heads/incoming: decbbaa182e488926d4ff7078a6be0b7dda45a41
+refs/heads/incoming: 0ef75a69659fa16604b0001afaa63f00fe18c36e
 refs/heads/dist-snap: 22efa39382d41b084fde1719df7ae8ce5697d8c9
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503

branches/incoming/doc/rust.md

@@ -2150,9 +2150,21 @@ match x {
 ~~~~
 
 Records and structures can also be pattern-matched and their fields bound to variables.
-When matching fields of a record, the fields being matched are specified
-first, then a placeholder (`_`) represents the remaining fields.
-
+When matching fields of a record,
+the fields being matched are specified first,
+then a placeholder (`_`) represents the remaining fields.
+
+A pattern that's just a variable binding,
+like `Nil` in the previous answer,
+could either refer to an enum variant that's in scope,
+or bind a new variable.
+The compiler resolves this ambiguity by forbidding variable bindings that occur in ```match``` patterns from shadowing names of variants that are in scope.
+For example, wherever ```List``` is in scope,
+a ```match``` pattern would not be able to bind ```Nil``` as a new name.
+The compiler interprets a variable pattern `x` as a binding _only_ if there is no variant named `x` in scope.
+A convention you can use to avoid conflicts is simply to name variants with upper-case letters,
+and local variables with lower-case letters.
+ 
 ~~~~
 # type options = {choose: bool, size: ~str};
 # type player = {player: ~str, stats: (), options: options};