auto merge of #13184 : alexcrichton/rust/priv-fields, r=brson

This is an implementation of a portion of [RFC #4](https://github.com/rust-lang/rfcs/blob/master/active/0004-private-fields.md). This PR makes named struct fields private by default (as opposed to inherited by default).

The only real meaty change is the first commit to `rustc`, all other commits are just fallout of that change.

Summary of changes made:

* Named fields are private by default *everywhere*
* The `priv` keyword is now default-deny on named fields (done in a "lint" pass in privacy)

Changes yet to be done (before the RFC is closed)

* Change tuple structs to have private fields by default
* Remove `priv` enum variants
* Make `priv` a reserved keyword

3 files changed, 11 insertions, 14 deletions

diff --git a/src/doc/guide-unsafe.md b/src/doc/guide-unsafe.md
index 2339f23f56e..4c8e32982c1 100644
--- a/src/doc/guide-unsafe.md
+++ b/src/doc/guide-unsafe.md
@@ -200,7 +200,7 @@ use std::ptr;
 // Unique<T> has the same semantics as ~T
 pub struct Unique<T> {
     // It contains a single raw, mutable pointer to the object in question.
-    priv ptr: *mut T
+    ptr: *mut T
 }
 
 // Implement methods for creating and using the values in the box.
diff --git a/src/doc/rust.md b/src/doc/rust.md
index 359a9c8052b..98db4cb5367 100644
--- a/src/doc/rust.md
+++ b/src/doc/rust.md
@@ -1527,12 +1527,9 @@ of an item to see whether it should be allowed or not. This is where privacy
 warnings are generated, or otherwise "you used a private item of another module
 and weren't allowed to."
 
-By default, everything in rust is *private*, with two exceptions. The first
-exception is that struct fields are public by default (but the struct itself is
-still private by default), and the remaining exception is that enum variants in
-a `pub` enum are the default visibility of the enum container itself.. You are
-allowed to alter this default visibility with the `pub` keyword (or `priv`
-keyword for struct fields and enum variants). When an item is declared as `pub`,
+By default, everything in rust is *private*, with one exception. Enum variants
+in a `pub` enum are also public by default. You are allowed to alter this
+default visibility with the `priv` keyword. When an item is declared as `pub`,
 it can be thought of as being accessible to the outside world. For example:
 
 ~~~~
@@ -1542,7 +1539,7 @@ struct Foo;
 
 // Declare a public struct with a private field
 pub struct Bar {
-    priv field: int
+    field: int
 }
 
 // Declare a public enum with public and private variants
@@ -2354,7 +2351,7 @@ The following are examples of structure expressions:
 ~~~~
 # struct Point { x: f64, y: f64 }
 # struct TuplePoint(f64, f64);
-# mod game { pub struct User<'a> { name: &'a str, age: uint, score: uint } }
+# mod game { pub struct User<'a> { pub name: &'a str, pub age: uint, pub score: uint } }
 # struct Cookie; fn some_fn<T>(t: T) {}
 Point {x: 10.0, y: 20.0};
 TuplePoint(10.0, 20.0);
@@ -3140,7 +3137,7 @@ The types `char` and `str` hold textual data.
 A value of type `char` is a [Unicode scalar value](
 http://www.unicode.org/glossary/#unicode_scalar_value)
 (ie. a code point that is not a surrogate),
-represented as a 32-bit unsigned word in the 0x0000 to 0xD7FF 
+represented as a 32-bit unsigned word in the 0x0000 to 0xD7FF
 or 0xE000 to 0x10FFFF range.
 A `[char]` vector is effectively an UCS-4 / UTF-32 string.
 
diff --git a/src/doc/tutorial.md b/src/doc/tutorial.md
index e15145e5f1d..3423a5e090e 100644
--- a/src/doc/tutorial.md
+++ b/src/doc/tutorial.md
@@ -2657,8 +2657,8 @@ Rust doesn't support encapsulation: both struct fields and methods can
 be private. But this encapsulation is at the module level, not the
 struct level.
 
-For convenience, fields are _public_ by default, and can be made _private_ with
-the `priv` keyword:
+Fields are _private_ by default, and can be made _public_ with
+the `pub` keyword:
 
 ~~~
 mod farm {
@@ -2667,8 +2667,8 @@ mod farm {
 # impl Human { pub fn rest(&self) { } }
 # pub fn make_me_a_farm() -> Farm { Farm { chickens: ~[], farmer: Human(0) } }
     pub struct Farm {
-        priv chickens: ~[Chicken],
-        farmer: Human
+        chickens: ~[Chicken],
+        pub farmer: Human
     }
 
     impl Farm {