Address fallout

16 files changed, 44 insertions, 83 deletions

diff --git a/src/liballoc/rc.rs b/src/liballoc/rc.rs
index 8d2b1a770b2..86f8c746646 100644
--- a/src/liballoc/rc.rs
+++ b/src/liballoc/rc.rs
@@ -320,7 +320,7 @@ impl<T> Rc<T> {
     #[inline]
     #[stable(feature = "rc_unique", since = "1.4.0")]
     pub fn try_unwrap(this: Self) -> Result<T, Self> {
-        if Rc::would_unwrap(&this) {
+        if Rc::strong_count(&this) == 1 {
             unsafe {
                 let val = ptr::read(&*this); // copy the contained object
 
@@ -343,23 +343,6 @@ impl<T> Rc<T> {
     ///
     /// [try_unwrap]: struct.Rc.html#method.try_unwrap
     /// [`Ok`]: ../../std/result/enum.Result.html#variant.Ok
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(rc_would_unwrap)]
-    ///
-    /// use std::rc::Rc;
-    ///
-    /// let x = Rc::new(3);
-    /// assert!(Rc::would_unwrap(&x));
-    /// assert_eq!(Rc::try_unwrap(x), Ok(3));
-    ///
-    /// let x = Rc::new(4);
-    /// let _y = x.clone();
-    /// assert!(!Rc::would_unwrap(&x));
-    /// assert_eq!(*Rc::try_unwrap(x).unwrap_err(), 4);
-    /// ```
     #[unstable(feature = "rc_would_unwrap",
                reason = "just added for niche usecase",
                issue = "28356")]
@@ -518,20 +501,8 @@ impl<T: ?Sized> Rc<T> {
     /// this inner value.
     ///
     /// [weak]: struct.Weak.html
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(rc_counts)]
-    ///
-    /// use std::rc::Rc;
-    ///
-    /// let five = Rc::new(5);
-    ///
-    /// assert!(Rc::is_unique(&five));
-    /// ```
     #[inline]
-    #[unstable(feature = "rc_counts", reason = "uniqueness has unclear meaning",
+    #[unstable(feature = "is_unique", reason = "uniqueness has unclear meaning",
                issue = "28356")]
     #[rustc_deprecated(since = "1.15.0",
                        reason = "too niche; use `strong_count` and `weak_count` instead")]
diff --git a/src/libcollectionstest/lib.rs b/src/libcollectionstest/lib.rs
index 0fe0a1bad64..d4fb5ea03ad 100644
--- a/src/libcollectionstest/lib.rs
+++ b/src/libcollectionstest/lib.rs
@@ -29,7 +29,6 @@
 #![feature(test)]
 #![feature(unboxed_closures)]
 #![feature(unicode)]
-#![feature(vec_into_iter_as_slice)]
 
 extern crate collections;
 extern crate test;
diff --git a/src/libcore/cell.rs b/src/libcore/cell.rs
index efba8798309..c3f862e7c54 100644
--- a/src/libcore/cell.rs
+++ b/src/libcore/cell.rs
@@ -394,6 +394,7 @@ pub struct RefCell<T: ?Sized> {
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 #[unstable(feature = "borrow_state", issue = "27733")]
 #[rustc_deprecated(since = "1.15.0", reason = "use `try_borrow` instead")]
+#[allow(deprecated)]
 pub enum BorrowState {
     /// The cell is currently being read, there is at least one active `borrow`.
     Reading,
@@ -513,6 +514,7 @@ impl<T: ?Sized> RefCell<T> {
     /// ```
     #[unstable(feature = "borrow_state", issue = "27733")]
     #[rustc_deprecated(since = "1.15.0", reason = "use `try_borrow` instead")]
+    #[allow(deprecated)]
     #[inline]
     pub fn borrow_state(&self) -> BorrowState {
         match self.borrow.get() {
diff --git a/src/libcore/fmt/mod.rs b/src/libcore/fmt/mod.rs
index 9167264ba9d..2ba7d6e8bd1 100644
--- a/src/libcore/fmt/mod.rs
+++ b/src/libcore/fmt/mod.rs
@@ -12,7 +12,7 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-use cell::{UnsafeCell, Cell, RefCell, Ref, RefMut, BorrowState};
+use cell::{UnsafeCell, Cell, RefCell, Ref, RefMut};
 use marker::PhantomData;
 use mem;
 use num::flt2dec;
@@ -1634,13 +1634,13 @@ impl<T: Copy + Debug> Debug for Cell<T> {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized + Debug> Debug for RefCell<T> {
     fn fmt(&self, f: &mut Formatter) -> Result {
-        match self.borrow_state() {
-            BorrowState::Unused | BorrowState::Reading => {
+        match self.try_borrow() {
+            Ok(borrow) => {
                 f.debug_struct("RefCell")
-                    .field("value", &self.borrow())
+                    .field("value", &borrow)
                     .finish()
             }
-            BorrowState::Writing => {
+            Err(_) => {
                 f.debug_struct("RefCell")
                     .field("value", &"<borrowed>")
                     .finish()
diff --git a/src/libcore/iter/iterator.rs b/src/libcore/iter/iterator.rs
index cdc804b9ad6..ec590d2bd06 100644
--- a/src/libcore/iter/iterator.rs
+++ b/src/libcore/iter/iterator.rs
@@ -1696,7 +1696,6 @@ pub trait Iterator {
     /// # Examples
     ///
     /// ```
-    /// #![feature(iter_max_by)]
     /// let a = [-3_i32, 0, 1, 5, -10];
     /// assert_eq!(*a.iter().max_by(|x, y| x.cmp(y)).unwrap(), 5);
     /// ```
@@ -1746,7 +1745,6 @@ pub trait Iterator {
     /// # Examples
     ///
     /// ```
-    /// #![feature(iter_min_by)]
     /// let a = [-3_i32, 0, 1, 5, -10];
     /// assert_eq!(*a.iter().min_by(|x, y| x.cmp(y)).unwrap(), -10);
     /// ```
diff --git a/src/libcoretest/cell.rs b/src/libcoretest/cell.rs
index a7c230ba979..724a312ea79 100644
--- a/src/libcoretest/cell.rs
+++ b/src/libcoretest/cell.rs
@@ -59,22 +59,22 @@ fn double_imm_borrow() {
 fn no_mut_then_imm_borrow() {
     let x = RefCell::new(0);
     let _b1 = x.borrow_mut();
-    assert_eq!(x.borrow_state(), BorrowState::Writing);
+    assert!(x.try_borrow().is_err());
 }
 
 #[test]
 fn no_imm_then_borrow_mut() {
     let x = RefCell::new(0);
     let _b1 = x.borrow();
-    assert_eq!(x.borrow_state(), BorrowState::Reading);
+    assert!(x.try_borrow_mut().is_err());
 }
 
 #[test]
 fn no_double_borrow_mut() {
     let x = RefCell::new(0);
-    assert_eq!(x.borrow_state(), BorrowState::Unused);
+    assert!(x.try_borrow().is_ok());
     let _b1 = x.borrow_mut();
-    assert_eq!(x.borrow_state(), BorrowState::Writing);
+    assert!(x.try_borrow().is_err());
 }
 
 #[test]
@@ -102,7 +102,8 @@ fn double_borrow_single_release_no_borrow_mut() {
     {
         let _b2 = x.borrow();
     }
-    assert_eq!(x.borrow_state(), BorrowState::Reading);
+    assert!(x.try_borrow().is_ok());
+    assert!(x.try_borrow_mut().is_err());
 }
 
 #[test]
@@ -119,14 +120,18 @@ fn ref_clone_updates_flag() {
     let x = RefCell::new(0);
     {
         let b1 = x.borrow();
-        assert_eq!(x.borrow_state(), BorrowState::Reading);
+        assert!(x.try_borrow().is_ok());
+        assert!(x.try_borrow_mut().is_err());
         {
             let _b2 = Ref::clone(&b1);
-            assert_eq!(x.borrow_state(), BorrowState::Reading);
+            assert!(x.try_borrow().is_ok());
+            assert!(x.try_borrow_mut().is_err());
         }
-        assert_eq!(x.borrow_state(), BorrowState::Reading);
+        assert!(x.try_borrow().is_ok());
+        assert!(x.try_borrow_mut().is_err());
     }
-    assert_eq!(x.borrow_state(), BorrowState::Unused);
+    assert!(x.try_borrow().is_ok());
+    assert!(x.try_borrow_mut().is_ok());
 }
 
 #[test]
@@ -134,15 +139,19 @@ fn ref_map_does_not_update_flag() {
     let x = RefCell::new(Some(5));
     {
         let b1: Ref<Option<u32>> = x.borrow();
-        assert_eq!(x.borrow_state(), BorrowState::Reading);
+        assert!(x.try_borrow().is_ok());
+        assert!(x.try_borrow_mut().is_err());
         {
             let b2: Ref<u32> = Ref::map(b1, |o| o.as_ref().unwrap());
             assert_eq!(*b2, 5);
-            assert_eq!(x.borrow_state(), BorrowState::Reading);
+            assert!(x.try_borrow().is_ok());
+            assert!(x.try_borrow_mut().is_err());
         }
-        assert_eq!(x.borrow_state(), BorrowState::Unused);
+        assert!(x.try_borrow().is_ok());
+        assert!(x.try_borrow_mut().is_ok());
     }
-    assert_eq!(x.borrow_state(), BorrowState::Unused);
+    assert!(x.try_borrow().is_ok());
+    assert!(x.try_borrow_mut().is_ok());
 }
 
 #[test]
@@ -247,5 +256,3 @@ fn refcell_ref_coercion() {
         assert_eq!(&*coerced, comp);
     }
 }
-
-
diff --git a/src/libcoretest/lib.rs b/src/libcoretest/lib.rs
index 05d98d4a212..d12616a97a6 100644
--- a/src/libcoretest/lib.rs
+++ b/src/libcoretest/lib.rs
@@ -10,9 +10,7 @@
 
 #![deny(warnings)]
 
-#![feature(borrow_state)]
 #![feature(box_syntax)]
-#![feature(cell_extras)]
 #![feature(char_escape_debug)]
 #![feature(const_fn)]
 #![feature(core_private_bignum)]
@@ -32,8 +30,6 @@
 #![feature(try_from)]
 #![feature(unicode)]
 #![feature(unique)]
-#![feature(iter_max_by)]
-#![feature(iter_min_by)]
 #![feature(ordering_chaining)]
 #![feature(result_unwrap_or_default)]
 #![feature(ptr_unaligned)]
diff --git a/src/librustc/dep_graph/shadow.rs b/src/librustc/dep_graph/shadow.rs
index 06def4bf19a..5d4190a8ae1 100644
--- a/src/librustc/dep_graph/shadow.rs
+++ b/src/librustc/dep_graph/shadow.rs
@@ -27,7 +27,7 @@
 //! created.  See `./README.md` for details.
 
 use hir::def_id::DefId;
-use std::cell::{BorrowState, RefCell};
+use std::cell::RefCell;
 use std::env;
 
 use super::DepNode;
@@ -71,15 +71,11 @@ impl ShadowGraph {
 
     pub fn enqueue(&self, message: &DepMessage) {
         if ENABLED {
-            match self.stack.borrow_state() {
-                BorrowState::Unused => {}
-                _ => {
-                    // When we apply edge filters, that invokes the
-                    // Debug trait on DefIds, which in turn reads from
-                    // various bits of state and creates reads! Ignore
-                    // those recursive reads.
-                    return;
-                }
+            if self.stack.try_borrow().is_err() {
+                // When we apply edge filters, that invokes the Debug trait on
+                // DefIds, which in turn reads from various bits of state and
+                // creates reads! Ignore those recursive reads.
+                return;
             }
 
             let mut stack = self.stack.borrow_mut();
diff --git a/src/librustc/lib.rs b/src/librustc/lib.rs
index 7c26b710a53..17cc34fcd83 100644
--- a/src/librustc/lib.rs
+++ b/src/librustc/lib.rs
@@ -24,7 +24,6 @@
 #![cfg_attr(not(stage0), deny(warnings))]
 
 #![feature(associated_consts)]
-#![feature(borrow_state)]
 #![feature(box_patterns)]
 #![feature(box_syntax)]
 #![feature(collections)]
diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index ea5aa5be013..509ee704e2e 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -18,7 +18,6 @@
 #![cfg_attr(not(stage0), deny(warnings))]
 
 #![feature(associated_consts)]
-#![feature(borrow_state)]
 #![feature(rustc_diagnostic_macros)]
 #![feature(rustc_private)]
 #![feature(staged_api)]
diff --git a/src/librustc_resolve/resolve_imports.rs b/src/librustc_resolve/resolve_imports.rs
index b634d57a842..890891fd090 100644
--- a/src/librustc_resolve/resolve_imports.rs
+++ b/src/librustc_resolve/resolve_imports.rs
@@ -144,11 +144,9 @@ impl<'a> Resolver<'a> {
                                   -> Result<&'a NameBinding<'a>, Determinacy> {
         self.populate_module_if_necessary(module);
 
-        let resolution = self.resolution(module, name, ns);
-        let resolution = match resolution.borrow_state() {
-            ::std::cell::BorrowState::Unused => resolution.borrow_mut(),
-            _ => return Err(Determined), // This happens when there is a cycle of imports
-        };
+        let resolution = self.resolution(module, name, ns)
+            .try_borrow_mut()
+            .map_err(|_| Determined)?; // This happens when there is a cycle of imports
 
         if let Some(span) = record_used {
             if let Some(binding) = resolution.binding {
diff --git a/src/librustc_trans/lib.rs b/src/librustc_trans/lib.rs
index e2da635b159..d842827b6fe 100644
--- a/src/librustc_trans/lib.rs
+++ b/src/librustc_trans/lib.rs
@@ -26,7 +26,6 @@
 #![feature(associated_consts)]
 #![feature(box_patterns)]
 #![feature(box_syntax)]
-#![feature(cell_extras)]
 #![feature(const_fn)]
 #![feature(custom_attribute)]
 #![allow(unused_attributes)]
diff --git a/src/libstd/io/stdio.rs b/src/libstd/io/stdio.rs
index 6419a9ff683..1a65bee13b8 100644
--- a/src/libstd/io/stdio.rs
+++ b/src/libstd/io/stdio.rs
@@ -10,7 +10,7 @@
 
 use io::prelude::*;
 
-use cell::{RefCell, BorrowState};
+use cell::RefCell;
 use fmt;
 use io::lazy::Lazy;
 use io::{self, BufReader, LineWriter};
@@ -638,8 +638,8 @@ pub fn _print(args: fmt::Arguments) {
         LocalKeyState::Destroyed => stdout().write_fmt(args),
         LocalKeyState::Valid => {
             LOCAL_STDOUT.with(|s| {
-                if s.borrow_state() == BorrowState::Unused {
-                    if let Some(w) = s.borrow_mut().as_mut() {
+                if let Ok(mut borrowed) = s.try_borrow_mut() {
+                    if let Some(w) = borrowed.as_mut() {
                         return w.write_fmt(args);
                     }
                 }
diff --git a/src/libstd/sys/redox/ext/process.rs b/src/libstd/sys/redox/ext/process.rs
index 1472242d3db..c59524974bf 100644
--- a/src/libstd/sys/redox/ext/process.rs
+++ b/src/libstd/sys/redox/ext/process.rs
@@ -56,7 +56,7 @@ pub trait CommandExt {
     /// When this closure is run, aspects such as the stdio file descriptors and
     /// working directory have successfully been changed, so output to these
     /// locations may not appear where intended.
-    #[unstable(feature = "process_exec", issue = "31398")]
+    #[stable(feature = "process_exec", since = "1.15.0")]
     fn before_exec<F>(&mut self, f: F) -> &mut process::Command
         where F: FnMut() -> io::Result<()> + Send + Sync + 'static;
 
diff --git a/src/libstd_unicode/char.rs b/src/libstd_unicode/char.rs
index b6a502e8c1a..53dafadb5d5 100644
--- a/src/libstd_unicode/char.rs
+++ b/src/libstd_unicode/char.rs
@@ -460,7 +460,6 @@ impl char {
     /// A buffer that's too small:
     ///
     /// ```
-    /// #![feature(unicode)]
     /// use std::thread;
     ///
     /// let result = thread::spawn(|| {
@@ -501,7 +500,6 @@ impl char {
     /// A buffer that's too small:
     ///
     /// ```
-    /// #![feature(unicode)]
     /// use std::thread;
     ///
     /// let result = thread::spawn(|| {
diff --git a/src/libstd_unicode/lib.rs b/src/libstd_unicode/lib.rs
index b086658ee0d..11724e74cda 100644
--- a/src/libstd_unicode/lib.rs
+++ b/src/libstd_unicode/lib.rs
@@ -39,7 +39,6 @@
 #![feature(lang_items)]
 #![feature(staged_api)]
 #![feature(try_from)]
-#![feature(unicode)]
 
 mod tables;
 mod u_str;