std: Remove deprecated/unstable num functionality

This commit removes all the old casting/generic traits from `std::num` that are
no longer in use by the standard library. This additionally removes the old
`strconv` module which has not seen much use in quite a long time. All generic
functionality has been supplanted with traits in the `num` crate and the
`strconv` module is supplanted with the [rust-strconv crate][rust-strconv].

[rust-strconv]: https://github.com/lifthrasiir/rust-strconv

This is a breaking change due to the removal of these deprecated crates, and the
alternative crates are listed above.

[breaking-change]

1 files changed, 0 insertions, 8 deletions

diff --git a/src/libcollections/string.rs b/src/libcollections/string.rs
index 384c049d386..07b99402cd2 100644
--- a/src/libcollections/string.rs
+++ b/src/libcollections/string.rs
@@ -1058,14 +1058,6 @@ impl<'a> IntoCow<'a, str> for &'a str {
     }
 }
 
-#[allow(deprecated)]
-impl<'a> Str for Cow<'a, str> {
-    #[inline]
-    fn as_slice<'b>(&'b self) -> &'b str {
-        &**self
-    }
-}
-
 #[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Write for String {
     #[inline]