liballoc: prefer imports of borrow from libcore.

src/liballoc/collections/btree/map.rs

@@ -1,4 +1,5 @@
 use core::{
+    borrow::Borrow,
     cmp::Ordering,
     fmt::Debug,
     hash::{Hash, Hasher},
@@ -11,8 +12,6 @@ use core::{
     fmt, intrinsics, mem, ptr,
 };
 
-use crate::borrow::Borrow;
-
 use super::{
     node::{self, Handle, NodeRef, marker, InsertResult::*, ForceResult::*},
     search::{self, SearchResult::*},

src/liballoc/collections/btree/search.rs

@@ -1,6 +1,7 @@
-use core::cmp::Ordering;
-
-use crate::borrow::Borrow;
+use core::{
+    borrow::Borrow,
+    cmp::Ordering,
+};
 
 use super::node::{Handle, NodeRef, marker, ForceResult::*};
 

src/liballoc/collections/btree/set.rs

@@ -2,6 +2,7 @@
 // to TreeMap
 
 use core::{
+    borrow::Borrow,
     cmp::{
         Ordering::{self, Less, Greater, Equal},
         min, max,
@@ -11,10 +12,7 @@ use core::{
     ops::{BitOr, BitAnd, BitXor, Sub, RangeBounds},
 };
 
-use crate::{
-    borrow::Borrow,
-    collections::btree_map::{self, BTreeMap, Keys},
-};
+use crate::collections::btree_map::{self, BTreeMap, Keys};
 use super::Recover;
 
 // FIXME(conventions): implement bounded iterators

src/liballoc/slice.rs

@@ -88,6 +88,7 @@
 #![cfg_attr(test, allow(unused_imports, dead_code))]
 
 use core::{
+    borrow::{Borrow, BorrowMut},
     cmp::Ordering::{self, Less},
     mem::{self, size_of},
     ptr,
@@ -95,7 +96,7 @@ use core::{
 };
 
 use crate::{
-    borrow::{Borrow, BorrowMut, ToOwned},
+    borrow::ToOwned,
     boxed::Box,
     vec::Vec,
 };

src/liballoc/str.rs

@@ -29,6 +29,7 @@
 #![allow(unused_imports)]
 
 use core::{
+    borrow::Borrow,
     fmt,
     str::{
         self as core_str,
@@ -41,7 +42,7 @@ use core::{
 };
 
 use crate::{
-    borrow::{Borrow, ToOwned},
+    borrow::ToOwned,
     boxed::Box,
     slice::{SliceConcatExt, SliceIndex},
     string::String,

src/liballoc/string.rs

@@ -64,8 +64,8 @@ use core::{
 };
 
 use crate::{
-    collections::CollectionAllocErr,
     borrow::{Cow, ToOwned},
+    collections::CollectionAllocErr,
     boxed::Box,
     str::{self, from_boxed_utf8_unchecked, FromStr, Utf8Error, Chars},
     vec::Vec,

src/liballoc/vec.rs

@@ -74,9 +74,8 @@ use core::{
 };
 
 use crate::{
+    borrow::{ToOwned, Cow},
     collections::CollectionAllocErr,
-    borrow::ToOwned,
-    borrow::Cow,
     boxed::Box,
     raw_vec::RawVec,
 };