---

yaml
---
r: 195302
b: refs/heads/snap-stage3
c: e2fd2df
h: refs/heads/master
v: v3

Author: alexcrichton

[refs]

@@ -1,7 +1,7 @@
 ---
 refs/heads/master: 14192d6df5cc714e5c9a3ca70b08f2514d977be2
 refs/heads/snap-stage1: e33de59e47c5076a89eadeb38f4934f58a3618a6
-refs/heads/snap-stage3: e58f05717d49a4404638da81cb5ae431d2c7a6b6
+refs/heads/snap-stage3: e2fd2dffde52a59f7d59d67460aeb2ebf33f77dd
 refs/heads/try: 961e0358e1a5c0faaef606e31e9965742c1643bf
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/dist-snap: ba4081a5a8573875fed17545846f6f6902c8ba8d

branches/snap-stage3/src/libcore/iter.rs

@@ -244,20 +244,6 @@ pub trait IteratorExt: Iterator + Sized {
     /// assert_eq!(it.next().unwrap(), (&0, &1));
     /// assert!(it.next().is_none());
     /// ```
-    ///
-    /// `zip` can provide similar functionality to `enumerate`:
-    ///
-    /// ```
-    /// for pair in "foo".chars().enumerate() {
-    ///     println!("{:?}", pair);
-    /// }
-    ///
-    /// for pair in (0..).zip("foo".chars()) {
-    ///     println!("{:?}", pair);
-    /// }
-    /// ```
-    ///
-    /// both produce the same output.
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     fn zip<U: Iterator>(self, other: U) -> Zip<Self, U> {
@@ -327,9 +313,6 @@ pub trait IteratorExt: Iterator + Sized {
     /// Creates an iterator that yields a pair of the value returned by this
     /// iterator plus the current index of iteration.
     ///
-    /// `enumerate` keeps its count as a `usize`. If you want to count by a
-    /// different sized integer, the `zip` function provides similar functionality.
-    ///
     /// # Examples
     ///
     /// ```

branches/snap-stage3/src/libstd/io/stdio.rs

@@ -11,7 +11,7 @@
 use prelude::v1::*;
 use io::prelude::*;
 
-use cell::RefCell;
+use cell::{RefCell, BorrowState};
 use cmp;
 use fmt;
 use io::lazy::Lazy;
@@ -264,9 +264,8 @@ impl Write for Stdout {
     fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
         self.lock().write_all(buf)
     }
-    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
-        self.lock().write_fmt(fmt)
-    }
+    // Don't override write_fmt as it's possible to run arbitrary code during a
+    // write_fmt, allowing the possibility of a recursive lock (aka deadlock)
 }
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a> Write for StdoutLock<'a> {
@@ -334,9 +333,7 @@ impl Write for Stderr {
     fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
         self.lock().write_all(buf)
     }
-    fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
-        self.lock().write_fmt(fmt)
-    }
+    // Don't override write_fmt for the same reasons as Stdout
 }
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a> Write for StderrLock<'a> {
@@ -395,10 +392,15 @@ pub fn set_print(sink: Box<Write + Send>) -> Option<Box<Write + Send>> {
            reason = "implementation detail which may disappear or be replaced at any time")]
 #[doc(hidden)]
 pub fn _print(args: fmt::Arguments) {
-    if let Err(e) = LOCAL_STDOUT.with(|s| match s.borrow_mut().as_mut() {
-        Some(w) => w.write_fmt(args),
-        None => stdout().write_fmt(args)
-    }) {
+    let result = LOCAL_STDOUT.with(|s| {
+        if s.borrow_state() == BorrowState::Unused {
+            if let Some(w) = s.borrow_mut().as_mut() {
+                return w.write_fmt(args);
+            }
+        }
+        stdout().write_fmt(args)
+    });
+    if let Err(e) = result {
         panic!("failed printing to stdout: {}", e);
     }
 }

branches/snap-stage3/src/libstd/lib.rs

@@ -127,6 +127,7 @@
 #![feature(str_char)]
 #![feature(into_cow)]
 #![feature(slice_patterns)]
+#![feature(std_misc)]
 #![cfg_attr(test, feature(test, rustc_private, std_misc))]
 
 // Don't link to std. We are std.

branches/snap-stage3/src/test/run-pass/issue-23781.rs

@@ -0,0 +1,38 @@
+// 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.
+
+use std::fmt;
+
+struct Foo;
+impl fmt::Debug for Foo {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        println!("<Foo as Debug>::fmt()");
+
+        write!(fmt, "")
+    }
+}
+
+fn test1() {
+    let foo_str = format!("{:?}", Foo);
+
+    println!("{}", foo_str);
+}
+
+fn test2() {
+    println!("{:?}", Foo);
+}
+
+fn main() {
+    // This works fine
+    test1();
+
+    // This fails
+    test2();
+}