Implement Default for more types in the standard library

tbu- · tbu- · commit 3df35a01e982 · 2016-04-15T17:53:43.000+02:00
Also add `Hash` to `std::cmp::Ordering` and most possible traits to
`fmt::Error`.
diff --git a/src/libcore/cell.rs b/src/libcore/cell.rs
@@ -863,3 +863,10 @@ impl<T: ?Sized> UnsafeCell<T> {
         &self.value as *const T as *mut T
     }
 }
+
+#[stable(feature = "unsafe_cell_default", since = "1.9.0")]
+impl<T: Default> Default for UnsafeCell<T> {
+    fn default() -> UnsafeCell<T> {
+        UnsafeCell::new(Default::default())
+    }
+}
diff --git a/src/libcore/cmp.rs b/src/libcore/cmp.rs
@@ -128,7 +128,7 @@ pub trait Eq: PartialEq<Self> {
 /// let result = 2.cmp(&1);
 /// assert_eq!(Ordering::Greater, result);
 /// ```
-#[derive(Clone, Copy, PartialEq, Debug)]
+#[derive(Clone, Copy, PartialEq, Debug, Hash)]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub enum Ordering {
     /// An ordering where a compared value is less [than another].
diff --git a/src/libcore/fmt/mod.rs b/src/libcore/fmt/mod.rs
@@ -60,7 +60,7 @@ pub type Result = result::Result<(), Error>;
 /// occurred. Any extra information must be arranged to be transmitted through
 /// some other means.
 #[stable(feature = "rust1", since = "1.0.0")]
-#[derive(Copy, Clone, Debug)]
+#[derive(Copy, Clone, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)]
 pub struct Error;
 
 /// A collection of methods that are required to format a message into a stream.
diff --git a/src/libstd/sync/condvar.rs b/src/libstd/sync/condvar.rs
@@ -220,6 +220,13 @@ impl Condvar {
     pub fn notify_all(&self) { unsafe { self.inner.inner.notify_all() } }
 }
 
+#[stable(feature = "condvar_default", since = "1.9.0")]
+impl Default for Condvar {
+    fn default() -> Condvar {
+        Condvar::new()
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Drop for Condvar {
     fn drop(&mut self) {
diff --git a/src/libstd/sync/mutex.rs b/src/libstd/sync/mutex.rs
@@ -310,6 +310,13 @@ impl<T: ?Sized> Drop for Mutex<T> {
     }
 }
 
+#[stable(feature = "mutex_default", since = "1.9.0")]
+impl<T: ?Sized + Default> Default for Mutex<T> {
+    fn default() -> Mutex<T> {
+        Mutex::new(Default::default())
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized + fmt::Debug> fmt::Debug for Mutex<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
diff --git a/src/libstd/sync/rwlock.rs b/src/libstd/sync/rwlock.rs
@@ -346,6 +346,13 @@ impl<T: ?Sized + fmt::Debug> fmt::Debug for RwLock<T> {
     }
 }
 
+#[stable(feature = "rw_lock_default", since = "1.9.0")]
+impl<T: Default> Default for RwLock<T> {
+    fn default() -> RwLock<T> {
+        RwLock::new(Default::default())
+    }
+}
+
 struct Dummy(UnsafeCell<()>);
 unsafe impl Sync for Dummy {}
 static DUMMY: Dummy = Dummy(UnsafeCell::new(()));

Original file line number	Diff line number	Diff line change
`@@ -863,3 +863,10 @@ impl<T: ?Sized> UnsafeCell<T> {`
`863`	`863`	`&self.value as const T as mut T`
`864`	`864`	`}`
`865`	`865`	`}`
	`866`	`+`
	`867`	`+#[stable(feature = "unsafe_cell_default", since = "1.9.0")]`
	`868`	`+impl<T: Default> Default for UnsafeCell<T> {`
	`869`	`+ fn default() -> UnsafeCell<T> {`
	`870`	`+ UnsafeCell::new(Default::default())`
	`871`	`+ }`
	`872`	`+}`
Original file line number	Diff line number	Diff line change
`@@ -310,6 +310,13 @@ impl<T: ?Sized> Drop for Mutex<T> {`
`310`	`310`	`}`
`311`	`311`	`}`
`312`	`312`
	`313`	`+#[stable(feature = "mutex_default", since = "1.9.0")]`
	`314`	`+impl<T: ?Sized + Default> Default for Mutex<T> {`
	`315`	`+ fn default() -> Mutex<T> {`
	`316`	`+ Mutex::new(Default::default())`
	`317`	`+ }`
	`318`	`+}`
	`319`	`+`
`313`	`320`	`#[stable(feature = "rust1", since = "1.0.0")]`
`314`	`321`	`impl<T: ?Sized + fmt::Debug> fmt::Debug for Mutex<T> {`
`315`	`322`	`fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {`
Original file line number	Diff line number	Diff line change
`@@ -346,6 +346,13 @@ impl<T: ?Sized + fmt::Debug> fmt::Debug for RwLock<T> {`
`346`	`346`	`}`
`347`	`347`	`}`
`348`	`348`
	`349`	`+#[stable(feature = "rw_lock_default", since = "1.9.0")]`
	`350`	`+impl<T: Default> Default for RwLock<T> {`
	`351`	`+ fn default() -> RwLock<T> {`
	`352`	`+ RwLock::new(Default::default())`
	`353`	`+ }`
	`354`	`+}`
	`355`	`+`
`349`	`356`	`struct Dummy(UnsafeCell<()>);`
`350`	`357`	`unsafe impl Sync for Dummy {}`
`351`	`358`	`static DUMMY: Dummy = Dummy(UnsafeCell::new(()));`