Rollup merge of #49426 - lukaslueg:patch-1, r=kennytm

Update CONTRIBUTING.md

The current link is a 404, just link to the main repo page

4 files changed, 23 insertions, 6 deletions

diff --git a/src/libstd/error.rs b/src/libstd/error.rs
index 79bb6af168f..3d0c96585b5 100644
--- a/src/libstd/error.rs
+++ b/src/libstd/error.rs
@@ -275,14 +275,14 @@ impl Error for num::ParseIntError {
     }
 }
 
-#[unstable(feature = "try_from", issue = "33417")]
+#[stable(feature = "try_from", since = "1.26.0")]
 impl Error for num::TryFromIntError {
     fn description(&self) -> &str {
         self.__description()
     }
 }
 
-#[unstable(feature = "try_from", issue = "33417")]
+#[stable(feature = "try_from", since = "1.26.0")]
 impl Error for array::TryFromSliceError {
     fn description(&self) -> &str {
         self.__description()
@@ -356,7 +356,7 @@ impl Error for cell::BorrowMutError {
     }
 }
 
-#[unstable(feature = "try_from", issue = "33417")]
+#[stable(feature = "try_from", since = "1.26.0")]
 impl Error for char::CharTryFromError {
     fn description(&self) -> &str {
         "converted integer out of range for `char`"
diff --git a/src/libstd/io/cursor.rs b/src/libstd/io/cursor.rs
index 76bcb5fedc9..2673f3ccfa3 100644
--- a/src/libstd/io/cursor.rs
+++ b/src/libstd/io/cursor.rs
@@ -10,7 +10,6 @@
 
 use io::prelude::*;
 
-use core::convert::TryInto;
 use cmp;
 use io::{self, Initializer, SeekFrom, Error, ErrorKind};
 
@@ -260,9 +259,26 @@ fn slice_write(pos_mut: &mut u64, slice: &mut [u8], buf: &[u8]) -> io::Result<us
     Ok(amt)
 }
 
+/// Compensate removal of some impls per
+/// https://github.com/rust-lang/rust/pull/49305#issuecomment-376293243
+#[cfg(any(target_pointer_width = "16",
+          target_pointer_width = "32"))]
+fn try_into(n: u64) -> Result<usize, ()> {
+    if n <= (<usize>::max_value() as u64) {
+        Ok(n as usize)
+    } else {
+        Err(())
+    }
+}
+
+#[cfg(any(target_pointer_width = "64"))]
+fn try_into(n: u64) -> Result<usize, ()> {
+    Ok(n as usize)
+}
+
 // Resizing write implementation
 fn vec_write(pos_mut: &mut u64, vec: &mut Vec<u8>, buf: &[u8]) -> io::Result<usize> {
-    let pos: usize = (*pos_mut).try_into().map_err(|_| {
+    let pos: usize = try_into(*pos_mut).map_err(|_| {
         Error::new(ErrorKind::InvalidInput,
                     "cursor position exceeds maximum possible vector length")
     })?;
diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index 93996868f16..15a22443b6a 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -310,7 +310,6 @@
 #![feature(test, rustc_private)]
 #![feature(thread_local)]
 #![feature(toowned_clone_into)]
-#![feature(try_from)]
 #![feature(try_reserve)]
 #![feature(unboxed_closures)]
 #![feature(unicode)]
diff --git a/src/libstd/prelude/v1.rs b/src/libstd/prelude/v1.rs
index feedd4e1abe..d5b7c68a3fa 100644
--- a/src/libstd/prelude/v1.rs
+++ b/src/libstd/prelude/v1.rs
@@ -35,6 +35,8 @@
 #[doc(no_inline)] pub use cmp::{PartialEq, PartialOrd, Eq, Ord};
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(no_inline)] pub use convert::{AsRef, AsMut, Into, From};
+#[stable(feature = "try_from", since = "1.26.0")]
+#[doc(no_inline)] pub use convert::{TryFrom, TryInto};
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(no_inline)] pub use default::Default;
 #[stable(feature = "rust1", since = "1.0.0")]