std: Align `raw` modules with unsafe conventions

This commit is an implementation of [RFC 240][rfc] when applied to the standard
library. It primarily deprecates the entirety of `string::raw`, `vec::raw`,
`slice::raw`, and `str::raw` in favor of associated functions, methods, and
other free functions. The detailed renaming is:

* slice::raw::buf_as_slice => slice::with_raw_buf
* slice::raw::mut_buf_as_slice => slice::with_raw_mut_buf
* slice::shift_ptr => deprecated with no replacement
* slice::pop_ptr => deprecated with no replacement
* str::raw::from_utf8 => str::from_utf8_unchecked
* str::raw::c_str_to_static_slice => str::from_c_str
* str::raw::slice_bytes => deprecated for slice_unchecked (slight semantic diff)
* str::raw::slice_unchecked => str.slice_unchecked
* string::raw::from_parts => String::from_raw_parts
* string::raw::from_buf_len => String::from_raw_buf_len
* string::raw::from_buf => String::from_raw_buf
* string::raw::from_utf8 => String::from_utf8_unchecked
* vec::raw::from_buf => Vec::from_raw_buf

All previous functions exist in their `#[deprecated]` form, and the deprecation
messages indicate how to migrate to the newer variants.

[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0240-unsafe-api-location.md
[breaking-change]

Closes #17863

1 files changed, 3 insertions, 6 deletions

diff --git a/src/libserialize/base64.rs b/src/libserialize/base64.rs
index 9b1e285431f..41feee8257f 100644
--- a/src/libserialize/base64.rs
+++ b/src/libserialize/base64.rs
@@ -16,7 +16,6 @@ pub use self::FromBase64Error::*;
 pub use self::CharacterSet::*;
 
 use std::fmt;
-use std::string;
 use std::error;
 
 /// Available encoding character sets
@@ -152,9 +151,7 @@ impl ToBase64 for [u8] {
             _ => panic!("Algebra is broken, please alert the math police")
         }
 
-        unsafe {
-            string::raw::from_utf8(v)
-        }
+        unsafe { String::from_utf8_unchecked(v) }
     }
 }
 
@@ -201,8 +198,8 @@ impl FromBase64 for str {
      * Convert any base64 encoded string (literal, `@`, `&`, or `~`)
      * to the byte values it encodes.
      *
-     * You can use the `String::from_utf8` function in `std::string` to turn a
-     * `Vec<u8>` into a string with characters corresponding to those values.
+     * You can use the `String::from_utf8` function to turn a `Vec<u8>` into a
+     * string with characters corresponding to those values.
      *
      * # Example
      *