Rollup merge of #51807 - newpavlov:deprecate_str_slice, r=alexcrichton

Deprecation of str::slice_unchecked(_mut)

Closes #51715

I am not sure if 1.28.0 or 1.29.0 should be used for deprecation version, for now it's 1.28.0.

Additionally I've replaced `slice_unchecked` uses with `get_unchecked`. The only places where this method is still used are `src/liballoc/tests/str.rs` and `src/liballoc/tests/str.rs`.

3 files changed, 9 insertions, 9 deletions

diff --git a/src/liballoc/str.rs b/src/liballoc/str.rs
index 4d6434c378e..870bf971cd3 100644
--- a/src/liballoc/str.rs
+++ b/src/liballoc/str.rs
@@ -268,11 +268,11 @@ impl str {
         let mut result = String::new();
         let mut last_end = 0;
         for (start, part) in self.match_indices(from) {
-            result.push_str(unsafe { self.slice_unchecked(last_end, start) });
+            result.push_str(unsafe { self.get_unchecked(last_end..start) });
             result.push_str(to);
             last_end = start + part.len();
         }
-        result.push_str(unsafe { self.slice_unchecked(last_end, self.len()) });
+        result.push_str(unsafe { self.get_unchecked(last_end..self.len()) });
         result
     }
 
@@ -309,11 +309,11 @@ impl str {
         let mut result = String::with_capacity(32);
         let mut last_end = 0;
         for (start, part) in self.match_indices(pat).take(count) {
-            result.push_str(unsafe { self.slice_unchecked(last_end, start) });
+            result.push_str(unsafe { self.get_unchecked(last_end..start) });
             result.push_str(to);
             last_end = start + part.len();
         }
-        result.push_str(unsafe { self.slice_unchecked(last_end, self.len()) });
+        result.push_str(unsafe { self.get_unchecked(last_end..self.len()) });
         result
     }
 
diff --git a/src/liballoc/string.rs b/src/liballoc/string.rs
index 6b28687a060..631779a17a1 100644
--- a/src/liballoc/string.rs
+++ b/src/liballoc/string.rs
@@ -1222,7 +1222,7 @@ impl String {
 
         while idx < len {
             let ch = unsafe {
-                self.slice_unchecked(idx, len).chars().next().unwrap()
+                self.get_unchecked(idx..len).chars().next().unwrap()
             };
             let ch_len = ch.len_utf8();
 
diff --git a/src/liballoc/tests/str.rs b/src/liballoc/tests/str.rs
index 75306ac82df..6275c7bb112 100644
--- a/src/liballoc/tests/str.rs
+++ b/src/liballoc/tests/str.rs
@@ -177,9 +177,9 @@ fn test_join_for_different_lengths_with_long_separator() {
 
 #[test]
 fn test_unsafe_slice() {
-    assert_eq!("ab", unsafe {"abc".slice_unchecked(0, 2)});
-    assert_eq!("bc", unsafe {"abc".slice_unchecked(1, 3)});
-    assert_eq!("", unsafe {"abc".slice_unchecked(1, 1)});
+    assert_eq!("ab", unsafe {"abc".get_unchecked(0..2)});
+    assert_eq!("bc", unsafe {"abc".get_unchecked(1..3)});
+    assert_eq!("", unsafe {"abc".get_unchecked(1..1)});
     fn a_million_letter_a() -> String {
         let mut i = 0;
         let mut rs = String::new();
@@ -200,7 +200,7 @@ fn test_unsafe_slice() {
     }
     let letters = a_million_letter_a();
     assert_eq!(half_a_million_letter_a(),
-        unsafe { letters.slice_unchecked(0, 500000)});
+        unsafe { letters.get_unchecked(0..500000)});
 }
 
 #[test]