From 096a28607fb80c91e6e2ca64d9ef44c4e550e96c Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Fri, 5 Dec 2014 17:01:33 -0800
Subject: librustc: Make `Copy` opt-in.

This change makes the compiler no longer infer whether types (structures
and enumerations) implement the `Copy` trait (and thus are implicitly
copyable). Rather, you must implement `Copy` yourself via `impl Copy for
MyType {}`.

A new warning has been added, `missing_copy_implementations`, to warn
you if a non-generic public type has been added that could have
implemented `Copy` but didn't.

For convenience, you may *temporarily* opt out of this behavior by using
`#![feature(opt_out_copy)]`. Note though that this feature gate will never be
accepted and will be removed by the time that 1.0 is released, so you should
transition your code away from using it.

This breaks code like:

    #[deriving(Show)]
    struct Point2D {
        x: int,
        y: int,
    }

    fn main() {
        let mypoint = Point2D {
            x: 1,
            y: 1,
        };
        let otherpoint = mypoint;
        println!("{}{}", mypoint, otherpoint);
    }

Change this code to:

    #[deriving(Show)]
    struct Point2D {
        x: int,
        y: int,
    }

    impl Copy for Point2D {}

    fn main() {
        let mypoint = Point2D {
            x: 1,
            y: 1,
        };
        let otherpoint = mypoint;
        println!("{}{}", mypoint, otherpoint);
    }

This is the backwards-incompatible part of #13231.

Part of RFC #3.

[breaking-change]
---
 src/librustdoc/html/format.rs    | 5 +++++
 src/librustdoc/html/item_type.rs | 2 ++
 src/librustdoc/html/render.rs    | 8 +++++++-
 3 files changed, 14 insertions(+), 1 deletion(-)

(limited to 'src/librustdoc/html')

diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs
index 0fca59962d4..68ff2ddbcb0 100644
--- a/src/librustdoc/html/format.rs
+++ b/src/librustdoc/html/format.rs
@@ -48,6 +48,11 @@ pub struct WhereClause<'a>(pub &'a clean::Generics);
 /// Wrapper struct for emitting type parameter bounds.
 pub struct TyParamBounds<'a>(pub &'a [clean::TyParamBound]);
 
+impl Copy for VisSpace {}
+impl Copy for FnStyleSpace {}
+impl Copy for MutableSpace {}
+impl Copy for RawMutableSpace {}
+
 impl VisSpace {
     pub fn get(&self) -> Option<ast::Visibility> {
         let VisSpace(v) = *self; v
diff --git a/src/librustdoc/html/item_type.rs b/src/librustdoc/html/item_type.rs
index 0ad12b957ba..86787e5c805 100644
--- a/src/librustdoc/html/item_type.rs
+++ b/src/librustdoc/html/item_type.rs
@@ -41,6 +41,8 @@ pub enum ItemType {
     Constant        = 18,
 }
 
+impl Copy for ItemType {}
+
 impl ItemType {
     pub fn from_item(item: &clean::Item) -> ItemType {
         match item.inner {
diff --git a/src/librustdoc/html/render.rs b/src/librustdoc/html/render.rs
index dab25c3b2ee..296493f3ba3 100644
--- a/src/librustdoc/html/render.rs
+++ b/src/librustdoc/html/render.rs
@@ -225,7 +225,13 @@ struct Source<'a>(&'a str);
 // Helper structs for rendering items/sidebars and carrying along contextual
 // information
 
-struct Item<'a> { cx: &'a Context, item: &'a clean::Item, }
+struct Item<'a> {
+    cx: &'a Context,
+    item: &'a clean::Item,
+}
+
+impl<'a> Copy for Item<'a> {}
+
 struct Sidebar<'a> { cx: &'a Context, item: &'a clean::Item, }
 
 /// Struct representing one entry in the JS search index. These are all emitted
-- 
cgit 1.4.1-3-g733a5