rollup merge of rust-lang#20723: pnkfelix/feature-gate-box-syntax

Conflicts:
	src/compiletest/compiletest.rs
	src/libcollections/lib.rs
	src/libserialize/lib.rs
	src/libsyntax/feature_gate.rs

src/compiletest/compiletest.rs

@@ -9,7 +9,9 @@
 // except according to those terms.
 
 #![crate_type = "bin"]
-#![feature(slicing_syntax)]
+#![allow(unknown_features)]
+#![feature(slicing_syntax, unboxed_closures)]
+#![feature(box_syntax)]
 
 #![deny(warnings)]
 

src/liballoc/boxed.rs

@@ -49,6 +49,15 @@ pub static HEAP: () = ();
 #[stable]
 pub struct Box<T>(Unique<T>);
 
+#[unstable]
+impl<T> Box<T> {
+    /// Moves `x` into a freshly allocated box on the global exchange heap.
+    #[unstable]
+    pub fn new(x: T) -> Box<T> {
+        box x
+    }
+}
+
 #[stable]
 impl<T: Default> Default for Box<T> {
     #[stable]
@@ -186,36 +195,36 @@ impl<T: ?Sized> DerefMut for Box<T> {
 mod test {
     #[test]
     fn test_owned_clone() {
-        let a = box 5i;
+        let a = Box::new(5i);
         let b: Box<int> = a.clone();
         assert!(a == b);
     }
 
     #[test]
     fn any_move() {
-        let a = box 8u as Box<Any>;
-        let b = box Test as Box<Any>;
+        let a = Box::new(8u) as Box<Any>;
+        let b = Box::new(Test) as Box<Any>;
 
         match a.downcast::<uint>() {
-            Ok(a) => { assert!(a == box 8u); }
+            Ok(a) => { assert!(a == Box::new(8u)); }
             Err(..) => panic!()
         }
         match b.downcast::<Test>() {
-            Ok(a) => { assert!(a == box Test); }
+            Ok(a) => { assert!(a == Box::new(Test)); }
             Err(..) => panic!()
         }
 
-        let a = box 8u as Box<Any>;
-        let b = box Test as Box<Any>;
+        let a = Box::new(8u) as Box<Any>;
+        let b = Box::new(Test) as Box<Any>;
 
         assert!(a.downcast::<Box<Test>>().is_err());
         assert!(b.downcast::<Box<uint>>().is_err());
     }
 
     #[test]
     fn test_show() {
-        let a = box 8u as Box<Any>;
-        let b = box Test as Box<Any>;
+        let a = Box::new(8u) as Box<Any>;
+        let b = Box::new(Test) as Box<Any>;
         let a_str = a.to_str();
         let b_str = b.to_str();
         assert_eq!(a_str, "Box<Any>");
@@ -232,6 +241,6 @@ mod test {
     #[test]
     fn deref() {
         fn homura<T: Deref<Target=i32>>(_: T) { }
-        homura(box 765i32);
+        homura(Box::new(765i32));
     }
 }

src/liballoc/lib.rs

@@ -67,6 +67,7 @@
 #![no_std]
 #![allow(unknown_features)]
 #![feature(lang_items, unsafe_destructor)]
+#![feature(box_syntax)]
 
 #[macro_use]
 extern crate core;

src/libcollections/lib.rs

@@ -24,6 +24,7 @@
 
 #![allow(unknown_features)]
 #![feature(unsafe_destructor, slicing_syntax)]
+#![feature(box_syntax)]
 #![feature(unboxed_closures)]
 #![feature(old_impl_check)]
 #![no_std]

src/liblog/lib.rs

@@ -164,7 +164,10 @@
        html_favicon_url = "http://www.rust-lang.org/favicon.ico",
        html_root_url = "http://doc.rust-lang.org/nightly/",
        html_playground_url = "http://play.rust-lang.org/")]
+
+#![allow(unknown_features)]
 #![feature(slicing_syntax)]
+#![feature(box_syntax)]
 #![deny(missing_docs)]
 
 extern crate regex;

src/libregex/lib.rs

@@ -25,6 +25,7 @@
 
 #![allow(unknown_features)]
 #![feature(slicing_syntax)]
+#![feature(box_syntax)]
 #![deny(missing_docs)]
 
 #[cfg(test)]

src/librustc/lib.rs

@@ -26,6 +26,7 @@
 #![allow(unknown_features)]
 #![feature(quote)]
 #![feature(slicing_syntax, unsafe_destructor)]
+#![feature(box_syntax)]
 #![feature(rustc_diagnostic_macros)]
 #![feature(old_impl_check)]
 

src/librustc_driver/lib.rs

@@ -23,8 +23,10 @@
       html_favicon_url = "http://www.rust-lang.org/favicon.ico",
       html_root_url = "http://doc.rust-lang.org/nightly/")]
 
+#![allow(unknown_features)]
 #![feature(quote)]
 #![feature(slicing_syntax, unsafe_destructor)]
+#![feature(box_syntax)]
 #![feature(rustc_diagnostic_macros)]
 
 extern crate arena;

src/librustc_llvm/lib.rs

@@ -22,7 +22,9 @@
        html_favicon_url = "http://www.rust-lang.org/favicon.ico",
        html_root_url = "http://doc.rust-lang.org/nightly/")]
 
+#![allow(unknown_features)]
 #![feature(link_args)]
+#![feature(box_syntax)]
 
 extern crate libc;
 

src/librustc_trans/lib.rs

@@ -23,8 +23,10 @@
       html_favicon_url = "http://www.rust-lang.org/favicon.ico",
       html_root_url = "http://doc.rust-lang.org/nightly/")]
 
+#![allow(unknown_features)]
 #![feature(quote)]
 #![feature(slicing_syntax, unsafe_destructor)]
+#![feature(box_syntax)]
 #![feature(rustc_diagnostic_macros)]
 
 extern crate arena;

src/librustc_typeck/lib.rs

@@ -72,8 +72,10 @@ This API is completely unstable and subject to change.
       html_favicon_url = "http://www.rust-lang.org/favicon.ico",
       html_root_url = "http://doc.rust-lang.org/nightly/")]
 
+#![allow(unknown_features)]
 #![feature(quote)]
 #![feature(slicing_syntax, unsafe_destructor)]
+#![feature(box_syntax)]
 #![feature(rustc_diagnostic_macros)]
 #![allow(non_camel_case_types)]
 

src/librustdoc/lib.rs

@@ -18,6 +18,7 @@
        html_root_url = "http://doc.rust-lang.org/nightly/",
        html_playground_url = "http://play.rust-lang.org/")]
 #![feature(slicing_syntax)]
+#![feature(box_syntax)]
 
 extern crate arena;
 extern crate getopts;

src/libserialize/lib.rs

@@ -25,6 +25,7 @@ Core encoding and decoding interfaces.
        html_playground_url = "http://play.rust-lang.org/")]
 #![allow(unknown_features)]
 #![cfg_attr(stage0, allow(unused_attributes))]
+#![feature(box_syntax)]
 #![feature(old_impl_check)]
 #![feature(slicing_syntax)]
 

src/libstd/lib.rs

@@ -108,6 +108,7 @@
 #![feature(linkage, thread_local, asm)]
 #![feature(lang_items, unsafe_destructor)]
 #![feature(slicing_syntax, unboxed_closures)]
+#![feature(box_syntax)]
 #![feature(old_impl_check)]
 
 // Don't link to std. We are std.

src/libsyntax/feature_gate.rs

@@ -69,7 +69,8 @@ static KNOWN_FEATURES: &'static [(&'static str, Status)] = &[
     ("tuple_indexing", Accepted),
     ("associated_types", Accepted),
     ("visible_private_types", Active),
-    ("slicing_syntax", Accepted),
+    ("slicing_syntax", Active),
+    ("box_syntax", Active),
 
     ("if_let", Accepted),
     ("while_let", Accepted),
@@ -337,6 +338,15 @@ impl<'a, 'v> Visitor<'v> for PostExpansionVisitor<'a> {
     }
 
     fn visit_expr(&mut self, e: &ast::Expr) {
+        match e.node {
+            ast::ExprBox(..) | ast::ExprUnary(ast::UnOp::UnUniq, _) => {
+                self.gate_feature("box_syntax",
+                                  e.span,
+                                  "box expression syntax is experimental in alpha release; \
+                                   you can call `Box::new` instead.");
+            }
+            _ => {}
+        }
         visit::walk_expr(self, e);
     }
 
@@ -357,6 +367,11 @@ impl<'a, 'v> Visitor<'v> for PostExpansionVisitor<'a> {
                                    but at the end of a slice (e.g. \
                                    `[0, ..xs, 0]` are experimental")
             }
+            ast::PatBox(..) => {
+                self.gate_feature("box_syntax",
+                                  pattern.span,
+                                  "box pattern syntax is experimental in alpha release");
+            }
             _ => {}
         }
         visit::walk_pat(self, pattern)

src/libsyntax/lib.rs

@@ -25,6 +25,7 @@
 
 #![allow(unknown_features)]
 #![feature(slicing_syntax)]
+#![feature(box_syntax)]
 #![feature(quote, unsafe_destructor)]
 
 extern crate arena;

src/libterm/lib.rs

@@ -50,6 +50,7 @@
 
 #![allow(unknown_features)]
 #![feature(slicing_syntax)]
+#![feature(box_syntax)]
 #![deny(missing_docs)]
 
 #[macro_use] extern crate log;

src/libtest/lib.rs

@@ -31,7 +31,9 @@
 #![doc(html_logo_url = "http://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "http://www.rust-lang.org/favicon.ico",
        html_root_url = "http://doc.rust-lang.org/nightly/")]
+#![allow(unknown_features)]
 #![feature(asm, slicing_syntax)]
+#![feature(box_syntax)]
 
 extern crate getopts;
 extern crate regex;

src/test/auxiliary/cci_nested_lib.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![allow(unknown_features)]
+#![feature(box_syntax)]
 
 use std::cell::RefCell;
 

src/test/auxiliary/issue-2380.rs

@@ -11,6 +11,8 @@
 #![crate_name="a"]
 #![crate_type = "lib"]
 
+#![allow(unknown_features)]
+#![feature(box_syntax)]
 
 pub trait i<T> { }
 

src/test/auxiliary/method_self_arg1.rs

@@ -10,6 +10,9 @@
 
 #![crate_type = "lib"]
 
+#![allow(unknown_features)]
+#![feature(box_syntax)]
+
 static mut COUNT: u64 = 1;
 
 pub fn get_count() -> u64 { unsafe { COUNT } }

src/test/auxiliary/method_self_arg2.rs

@@ -10,6 +10,9 @@
 
 #![crate_type = "lib"]
 
+#![allow(unknown_features)]
+#![feature(box_syntax)]
+
 static mut COUNT: u64 = 1;
 
 pub fn get_count() -> u64 { unsafe { COUNT } }

src/test/compile-fail/autoderef-full-lval.rs

@@ -8,6 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![allow(unknown_features)]
+#![feature(box_syntax)]
+
 struct clam {
     x: Box<isize>,
     y: Box<isize>,

src/test/compile-fail/borrow-tuple-fields.rs

@@ -8,6 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![allow(unknown_features)]
+#![feature(box_syntax)]
+
 struct Foo(Box<int>, int);
 
 struct Bar(int, int);

src/test/compile-fail/borrowck-array-double-move.rs

@@ -8,6 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![allow(unknown_features)]
+#![feature(box_syntax)]
+
 fn f() {
     let mut a = [box 0i, box 1i];
     drop(a[0]);

src/test/compile-fail/borrowck-loan-in-overloaded-op.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![feature(box_syntax)]
+
 use std::ops::Add;
 
 #[derive(Clone)]

src/test/compile-fail/borrowck-vec-pattern-nesting.rs

@@ -9,6 +9,7 @@
 // except according to those terms.
 
 #![feature(advanced_slice_patterns)]
+#![feature(box_syntax)]
 
 fn a() {
     let mut vec = [box 1i, box 2, box 3];

src/test/compile-fail/destructure-trait-ref.rs

@@ -11,6 +11,8 @@
 // The regression test for #15031 to make sure destructuring trait
 // reference work properly.
 
+#![feature(box_syntax)]
+
 trait T {}
 impl T for int {}
 

src/test/compile-fail/feature-gate-box-expr.rs

@@ -0,0 +1,23 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn main() {
+    use std::boxed::HEAP;
+
+    let x = box 'c'; //~ ERROR box expression syntax is experimental in alpha release
+    println!("x: {}", x);
+
+    let x = box () 'c'; //~ ERROR box expression syntax is experimental in alpha release
+    println!("x: {}", x);
+
+    let x = box (HEAP) 'c'; //~ ERROR box expression syntax is experimental in alpha release
+    println!("x: {}", x);
+}
+

src/test/compile-fail/feature-gate-box-pat.rs

@@ -0,0 +1,14 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn main() {
+    let box x = Box::new('c'); //~ ERROR box pattern syntax is experimental in alpha release
+    println!("x: {}", x);
+}

src/test/compile-fail/issue-12116.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![feature(box_syntax)]
+
 enum IntList {
     Cons(int, Box<IntList>),
     Nil