liballoc: revert nested imports style changes.

34 files changed, 305 insertions, 406 deletions

diff --git a/src/liballoc/alloc.rs b/src/liballoc/alloc.rs
index 515de9852d1..ec652df3b37 100644
--- a/src/liballoc/alloc.rs
+++ b/src/liballoc/alloc.rs
@@ -2,11 +2,9 @@
 
 #![stable(feature = "alloc_module", since = "1.28.0")]
 
-use core::{
-    intrinsics::{min_align_of_val, size_of_val},
-    ptr::{NonNull, Unique},
-    usize,
-};
+use core::intrinsics::{min_align_of_val, size_of_val};
+use core::ptr::{NonNull, Unique};
+use core::usize;
 
 #[stable(feature = "alloc_module", since = "1.28.0")]
 #[doc(inline)]
@@ -230,10 +228,8 @@ pub fn handle_alloc_error(layout: Layout) -> ! {
 mod tests {
     extern crate test;
     use test::Bencher;
-    use crate::{
-        boxed::Box,
-        alloc::{Global, Alloc, Layout, handle_alloc_error},
-    };
+    use crate::boxed::Box;
+    use crate::alloc::{Global, Alloc, Layout, handle_alloc_error};
 
     #[test]
     fn allocate_zeroed() {
diff --git a/src/liballoc/benches/btree/map.rs b/src/liballoc/benches/btree/map.rs
index 3865ec866ae..4c17bdc3e9e 100644
--- a/src/liballoc/benches/btree/map.rs
+++ b/src/liballoc/benches/btree/map.rs
@@ -1,8 +1,7 @@
-use std::{
-    iter::Iterator,
-    vec::Vec,
-    collections::BTreeMap,
-};
+use std::iter::Iterator;
+use std::vec::Vec;
+use std::collections::BTreeMap;
+
 use rand::{Rng, seq::SliceRandom, thread_rng};
 use test::{Bencher, black_box};
 
diff --git a/src/liballoc/benches/slice.rs b/src/liballoc/benches/slice.rs
index d87b70f2d93..f17fb8212ce 100644
--- a/src/liballoc/benches/slice.rs
+++ b/src/liballoc/benches/slice.rs
@@ -1,8 +1,7 @@
 use std::{mem, ptr};
-use rand::{
-    thread_rng, Rng, SeedableRng,
-    distributions::{Standard, Alphanumeric},
-};
+
+use rand::{thread_rng, Rng, SeedableRng};
+use rand::distributions::{Standard, Alphanumeric};
 use rand_xorshift::XorShiftRng;
 use test::{Bencher, black_box};
 
diff --git a/src/liballoc/borrow.rs b/src/liballoc/borrow.rs
index 1fda36778f4..270f48e8083 100644
--- a/src/liballoc/borrow.rs
+++ b/src/liballoc/borrow.rs
@@ -2,16 +2,15 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-use core::{
-    cmp::Ordering,
-    hash::{Hash, Hasher},
-    ops::{Add, AddAssign, Deref},
-};
+use core::cmp::Ordering;
+use core::hash::{Hash, Hasher};
+use core::ops::{Add, AddAssign, Deref};
 
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use core::borrow::{Borrow, BorrowMut};
 
-use crate::{fmt, string::String};
+use crate::fmt;
+use crate::string::String;
 
 use Cow::*;
 
diff --git a/src/liballoc/boxed.rs b/src/liballoc/boxed.rs
index 40b091b92c1..8e01e12e0b8 100644
--- a/src/liballoc/boxed.rs
+++ b/src/liballoc/boxed.rs
@@ -56,28 +56,26 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-use core::{
-    any::Any,
-    borrow,
-    cmp::Ordering,
-    convert::From,
-    fmt,
-    future::Future,
-    hash::{Hash, Hasher},
-    iter::{Iterator, FromIterator, FusedIterator},
-    marker::{Unpin, Unsize},
-    mem,
-    pin::Pin,
-    ops::{CoerceUnsized, DispatchFromDyn, Deref, DerefMut, Receiver, Generator, GeneratorState},
-    ptr::{self, NonNull, Unique},
-    task::{LocalWaker, Poll},
+use core::any::Any;
+use core::borrow;
+use core::cmp::Ordering;
+use core::convert::From;
+use core::fmt;
+use core::future::Future;
+use core::hash::{Hash, Hasher};
+use core::iter::{Iterator, FromIterator, FusedIterator};
+use core::marker::{Unpin, Unsize};
+use core::mem;
+use core::pin::Pin;
+use core::ops::{
+    CoerceUnsized, DispatchFromDyn, Deref, DerefMut, Receiver, Generator, GeneratorState
 };
+use core::ptr::{self, NonNull, Unique};
+use core::task::{LocalWaker, Poll};
 
-use crate::{
-    vec::Vec,
-    raw_vec::RawVec,
-    str::from_boxed_utf8_unchecked,
-};
+use crate::vec::Vec;
+use crate::raw_vec::RawVec;
+use crate::str::from_boxed_utf8_unchecked;
 
 /// A pointer type for heap allocation.
 ///
diff --git a/src/liballoc/boxed_test.rs b/src/liballoc/boxed_test.rs
index 6fb01fbc6a1..654eabd0703 100644
--- a/src/liballoc/boxed_test.rs
+++ b/src/liballoc/boxed_test.rs
@@ -1,13 +1,11 @@
 //! Test for `boxed` mod.
 
-use core::{
-    any::Any,
-    ops::Deref,
-    result::Result::{Err, Ok},
-    clone::Clone,
-    f64,
-    i64,
-};
+use core::any::Any;
+use core::ops::Deref;
+use core::result::Result::{Err, Ok};
+use core::clone::Clone;
+use core::f64;
+use core::i64;
 
 use std::boxed::Box;
 
diff --git a/src/liballoc/collections/binary_heap.rs b/src/liballoc/collections/binary_heap.rs
index 5f0386400d7..f97522140a8 100644
--- a/src/liballoc/collections/binary_heap.rs
+++ b/src/liballoc/collections/binary_heap.rs
@@ -145,18 +145,14 @@
 #![allow(missing_docs)]
 #![stable(feature = "rust1", since = "1.0.0")]
 
-use core::{
-    ops::{Deref, DerefMut},
-    iter::{FromIterator, FusedIterator},
-    mem::{swap, size_of, ManuallyDrop},
-    ptr,
-    fmt,
-};
-
-use crate::{
-    slice,
-    vec::{self, Vec},
-};
+use core::ops::{Deref, DerefMut};
+use core::iter::{FromIterator, FusedIterator};
+use core::mem::{swap, size_of, ManuallyDrop};
+use core::ptr;
+use core::fmt;
+
+use crate::slice;
+use crate::vec::{self, Vec};
 
 use super::SpecExtend;
 
diff --git a/src/liballoc/collections/btree/map.rs b/src/liballoc/collections/btree/map.rs
index fe6b5fef210..aaaa419dcb8 100644
--- a/src/liballoc/collections/btree/map.rs
+++ b/src/liballoc/collections/btree/map.rs
@@ -1,21 +1,15 @@
-use core::{
-    borrow::Borrow,
-    cmp::Ordering,
-    fmt::Debug,
-    hash::{Hash, Hasher},
-    iter::{FromIterator, Peekable, FusedIterator},
-    marker::PhantomData,
-    ops::{
-        Bound::{Excluded, Included, Unbounded},
-        Index, RangeBounds,
-    },
-    fmt, intrinsics, mem, ptr,
-};
-
-use super::{
-    node::{self, Handle, NodeRef, marker, InsertResult::*, ForceResult::*},
-    search::{self, SearchResult::*},
-};
+use core::borrow::Borrow;
+use core::cmp::Ordering;
+use core::fmt::Debug;
+use core::hash::{Hash, Hasher};
+use core::iter::{FromIterator, Peekable, FusedIterator};
+use core::marker::PhantomData;
+use core::ops::Bound::{Excluded, Included, Unbounded};
+use core::ops::{Index, RangeBounds};
+use core::{fmt, intrinsics, mem, ptr};
+
+use super::node::{self, Handle, NodeRef, marker, InsertResult::*, ForceResult::*};
+use super::search::{self, SearchResult::*};
 
 use UnderflowResult::*;
 use Entry::*;
diff --git a/src/liballoc/collections/btree/node.rs b/src/liballoc/collections/btree/node.rs
index a5f90aa8974..c4f39430533 100644
--- a/src/liballoc/collections/btree/node.rs
+++ b/src/liballoc/collections/btree/node.rs
@@ -31,17 +31,13 @@
 // - A node of length `n` has `n` keys, `n` values, and (in an internal node) `n + 1` edges.
 //   This implies that even an empty internal node has at least one edge.
 
-use core::{
-    marker::PhantomData,
-    mem::{self, MaybeUninit},
-    ptr::{self, Unique, NonNull},
-    slice,
-};
+use core::marker::PhantomData;
+use core::mem::{self, MaybeUninit};
+use core::ptr::{self, Unique, NonNull};
+use core::slice;
 
-use crate::{
-    alloc::{Global, Alloc, Layout},
-    boxed::Box,
-};
+use crate::alloc::{Global, Alloc, Layout};
+use crate::boxed::Box;
 
 const B: usize = 6;
 pub const MIN_LEN: usize = B - 1;
diff --git a/src/liballoc/collections/btree/search.rs b/src/liballoc/collections/btree/search.rs
index 1645e48cb52..dfb67d2ea57 100644
--- a/src/liballoc/collections/btree/search.rs
+++ b/src/liballoc/collections/btree/search.rs
@@ -1,7 +1,5 @@
-use core::{
-    borrow::Borrow,
-    cmp::Ordering,
-};
+use core::borrow::Borrow;
+use core::cmp::Ordering;
 
 use super::node::{Handle, NodeRef, marker, ForceResult::*};
 
diff --git a/src/liballoc/collections/btree/set.rs b/src/liballoc/collections/btree/set.rs
index ba3b3ed76c8..78cd21dd411 100644
--- a/src/liballoc/collections/btree/set.rs
+++ b/src/liballoc/collections/btree/set.rs
@@ -1,16 +1,12 @@
 // This is pretty much entirely stolen from TreeSet, since BTreeMap has an identical interface
 // to TreeMap
 
-use core::{
-    borrow::Borrow,
-    cmp::{
-        Ordering::{self, Less, Greater, Equal},
-        min, max,
-    },
-    fmt::{self, Debug},
-    iter::{Peekable, FromIterator, FusedIterator},
-    ops::{BitOr, BitAnd, BitXor, Sub, RangeBounds},
-};
+use core::borrow::Borrow;
+use core::cmp::Ordering::{self, Less, Greater, Equal};
+use core::cmp::{min, max};
+use core::fmt::{self, Debug};
+use core::iter::{Peekable, FromIterator, FusedIterator};
+use core::ops::{BitOr, BitAnd, BitXor, Sub, RangeBounds};
 
 use crate::collections::btree_map::{self, BTreeMap, Keys};
 use super::Recover;
diff --git a/src/liballoc/collections/linked_list.rs b/src/liballoc/collections/linked_list.rs
index f601fa2c8d1..afd8078cdd7 100644
--- a/src/liballoc/collections/linked_list.rs
+++ b/src/liballoc/collections/linked_list.rs
@@ -12,15 +12,13 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-use core::{
-    cmp::Ordering,
-    fmt,
-    hash::{Hasher, Hash},
-    iter::{FromIterator, FusedIterator},
-    marker::PhantomData,
-    mem,
-    ptr::NonNull,
-};
+use core::cmp::Ordering;
+use core::fmt;
+use core::hash::{Hasher, Hash};
+use core::iter::{FromIterator, FusedIterator};
+use core::marker::PhantomData;
+use core::mem;
+use core::ptr::NonNull;
 
 use crate::boxed::Box;
 use super::SpecExtend;
@@ -1215,8 +1213,11 @@ unsafe impl<'a, T: Sync> Sync for IterMut<'a, T> {}
 
 #[cfg(test)]
 mod tests {
-    use std::{thread, vec::Vec};
+    use std::thread;
+    use std::vec::Vec;
+
     use rand::{thread_rng, RngCore};
+
     use super::{LinkedList, Node};
 
     #[cfg(test)]
diff --git a/src/liballoc/collections/vec_deque.rs b/src/liballoc/collections/vec_deque.rs
index f92c7ed04f4..99fa54acb08 100644
--- a/src/liballoc/collections/vec_deque.rs
+++ b/src/liballoc/collections/vec_deque.rs
@@ -7,25 +7,19 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-use core::{
-    cmp::{self, Ordering},
-    fmt,
-    iter::{repeat_with, FromIterator, FusedIterator},
-    mem,
-    ops::{
-        Bound::{Excluded, Included, Unbounded},
-        Index, IndexMut, RangeBounds, Try,
-    },
-    ptr::{self, NonNull},
-    slice,
-    hash::{Hash, Hasher},
-};
-
-use crate::{
-    collections::CollectionAllocErr,
-    raw_vec::RawVec,
-    vec::Vec,
-};
+use core::cmp::{self, Ordering};
+use core::fmt;
+use core::iter::{repeat_with, FromIterator, FusedIterator};
+use core::mem;
+use core::ops::Bound::{Excluded, Included, Unbounded};
+use core::ops::{Index, IndexMut, RangeBounds, Try};
+use core::ptr::{self, NonNull};
+use core::slice;
+use core::hash::{Hash, Hasher};
+
+use crate::collections::CollectionAllocErr;
+use crate::raw_vec::RawVec;
+use crate::vec::Vec;
 
 const INITIAL_CAPACITY: usize = 7; // 2^3 - 1
 const MINIMUM_CAPACITY: usize = 1; // 2 - 1
diff --git a/src/liballoc/fmt.rs b/src/liballoc/fmt.rs
index a8a99c7e7a3..9bda7034a62 100644
--- a/src/liballoc/fmt.rs
+++ b/src/liballoc/fmt.rs
@@ -509,16 +509,21 @@
 #[unstable(feature = "fmt_internals", issue = "0")]
 pub use core::fmt::rt;
 #[stable(feature = "rust1", since = "1.0.0")]
-pub use core::fmt::{
-    Formatter, Result, Write,
-    Binary, Octal,
-    Debug, Display,
-    LowerHex, Pointer, UpperHex,
-    LowerExp, UpperExp,
-    Error,
-    write, ArgumentV1, Arguments,
-    DebugList, DebugMap, DebugSet, DebugStruct, DebugTuple
-};
+pub use core::fmt::{Formatter, Result, Write};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{Binary, Octal};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{Debug, Display};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{LowerHex, Pointer, UpperHex};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{LowerExp, UpperExp};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::Error;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{write, ArgumentV1, Arguments};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{DebugList, DebugMap, DebugSet, DebugStruct, DebugTuple};
 #[stable(feature = "fmt_flags_align", since = "1.28.0")]
 pub use core::fmt::{Alignment};
 
diff --git a/src/liballoc/prelude.rs b/src/liballoc/prelude.rs
index 3f1d6ded66d..6767cf89f73 100644
--- a/src/liballoc/prelude.rs
+++ b/src/liballoc/prelude.rs
@@ -12,11 +12,8 @@
 
 #![unstable(feature = "alloc", issue = "27783")]
 
-#[unstable(feature = "alloc", issue = "27783")]
-pub use crate::{
-    borrow::ToOwned,
-    boxed::Box,
-    slice::SliceConcatExt,
-    string::{String, ToString},
-    vec::Vec,
-};
+#[unstable(feature = "alloc", issue = "27783")] pub use crate::borrow::ToOwned;
+#[unstable(feature = "alloc", issue = "27783")] pub use crate::boxed::Box;
+#[unstable(feature = "alloc", issue = "27783")] pub use crate::slice::SliceConcatExt;
+#[unstable(feature = "alloc", issue = "27783")] pub use crate::string::{String, ToString};
+#[unstable(feature = "alloc", issue = "27783")] pub use crate::vec::Vec;
diff --git a/src/liballoc/raw_vec.rs b/src/liballoc/raw_vec.rs
index f1839f73634..dcecf9bc76d 100644
--- a/src/liballoc/raw_vec.rs
+++ b/src/liballoc/raw_vec.rs
@@ -1,19 +1,15 @@
 #![unstable(feature = "raw_vec_internals", reason = "implementation detail", issue = "0")]
 #![doc(hidden)]
 
-use core::{
-    cmp,
-    mem,
-    ops::Drop,
-    ptr::{self, NonNull, Unique},
-    slice,
-};
-
-use crate::{
-    alloc::{Alloc, Layout, Global, handle_alloc_error},
-    collections::CollectionAllocErr::{self, *},
-    boxed::Box,
-};
+use core::cmp;
+use core::mem;
+use core::ops::Drop;
+use core::ptr::{self, NonNull, Unique};
+use core::slice;
+
+use crate::alloc::{Alloc, Layout, Global, handle_alloc_error};
+use crate::collections::CollectionAllocErr::{self, *};
+use crate::boxed::Box;
 
 /// A low-level utility for more ergonomically allocating, reallocating, and deallocating
 /// a buffer of memory on the heap without having to worry about all the corner cases
diff --git a/src/liballoc/rc.rs b/src/liballoc/rc.rs
index 01a26b6f423..d78869270d5 100644
--- a/src/liballoc/rc.rs
+++ b/src/liballoc/rc.rs
@@ -231,29 +231,25 @@ use crate::boxed::Box;
 #[cfg(test)]
 use std::boxed::Box;
 
-use core::{
-    any::Any,
-    borrow,
-    cell::Cell,
-    cmp::Ordering,
-    fmt,
-    hash::{Hash, Hasher},
-    intrinsics::abort,
-    marker::{self, Unpin, Unsize, PhantomData},
-    mem::{self, align_of_val, forget, size_of_val},
-    ops::{Deref, Receiver, CoerceUnsized, DispatchFromDyn},
-    pin::Pin,
-    ptr::{self, NonNull},
-    slice::from_raw_parts_mut,
-    convert::From,
-    usize,
-};
-
-use crate::{
-    alloc::{Global, Alloc, Layout, box_free, handle_alloc_error},
-    string::String,
-    vec::Vec,
-};
+use core::any::Any;
+use core::borrow;
+use core::cell::Cell;
+use core::cmp::Ordering;
+use core::fmt;
+use core::hash::{Hash, Hasher};
+use core::intrinsics::abort;
+use core::marker::{self, Unpin, Unsize, PhantomData};
+use core::mem::{self, align_of_val, forget, size_of_val};
+use core::ops::{Deref, Receiver, CoerceUnsized, DispatchFromDyn};
+use core::pin::Pin;
+use core::ptr::{self, NonNull};
+use core::slice::from_raw_parts_mut;
+use core::convert::From;
+use core::usize;
+
+use crate::alloc::{Global, Alloc, Layout, box_free, handle_alloc_error};
+use crate::string::String;
+use crate::vec::Vec;
 
 struct RcBox<T: ?Sized> {
     strong: Cell<usize>,
@@ -1563,15 +1559,13 @@ impl<T: ?Sized> RcBoxPtr<T> for RcBox<T> {
 #[cfg(test)]
 mod tests {
     use super::{Rc, Weak};
-    use std::{
-        boxed::Box,
-        cell::RefCell,
-        option::Option::{self, None, Some},
-        result::Result::{Err, Ok},
-        mem::drop,
-        clone::Clone,
-        convert::From,
-    };
+    use std::boxed::Box;
+    use std::cell::RefCell;
+    use std::option::Option::{self, None, Some};
+    use std::result::Result::{Err, Ok};
+    use std::mem::drop;
+    use std::clone::Clone;
+    use std::convert::From;
 
     #[test]
     fn test_clone() {
@@ -1735,7 +1729,8 @@ mod tests {
 
     #[test]
     fn test_into_from_raw_unsized() {
-        use std::{fmt::Display, string::ToString};
+        use std::fmt::Display;
+        use std::string::ToString;
 
         let rc: Rc<str> = Rc::from("foo");
 
@@ -1943,7 +1938,8 @@ mod tests {
 
     #[test]
     fn test_from_box_trait() {
-        use std::{fmt::Display, string::ToString};
+        use std::fmt::Display;
+        use std::string::ToString;
 
         let b: Box<dyn Display> = box 123;
         let r: Rc<dyn Display> = Rc::from(b);
diff --git a/src/liballoc/slice.rs b/src/liballoc/slice.rs
index 9d1197117bb..479959deeb1 100644
--- a/src/liballoc/slice.rs
+++ b/src/liballoc/slice.rs
@@ -87,19 +87,15 @@
 // It's cleaner to just turn off the unused_imports warning than to fix them.
 #![cfg_attr(test, allow(unused_imports, dead_code))]
 
-use core::{
-    borrow::{Borrow, BorrowMut},
-    cmp::Ordering::{self, Less},
-    mem::{self, size_of},
-    ptr,
-    u8, u16, u32,
-};
-
-use crate::{
-    borrow::ToOwned,
-    boxed::Box,
-    vec::Vec,
-};
+use core::borrow::{Borrow, BorrowMut};
+use core::cmp::Ordering::{self, Less};
+use core::mem::{self, size_of};
+use core::ptr;
+use core::{u8, u16, u32};
+
+use crate::borrow::ToOwned;
+use crate::boxed::Box;
+use crate::vec::Vec;
 
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use core::slice::{Chunks, Windows};
@@ -142,8 +138,9 @@ pub use hack::to_vec;
 // `test_permutations` test
 mod hack {
     use core::mem;
-    use crate::{boxed::Box, vec::Vec};
 
+    use crate::boxed::Box;
+    use crate::vec::Vec;
     #[cfg(test)]
     use crate::string::ToString;
 
diff --git a/src/liballoc/str.rs b/src/liballoc/str.rs
index 9681572d883..211e75bd915 100644
--- a/src/liballoc/str.rs
+++ b/src/liballoc/str.rs
@@ -28,26 +28,20 @@
 // It's cleaner to just turn off the unused_imports warning than to fix them.
 #![allow(unused_imports)]
 
-use core::{
-    borrow::Borrow,
-    fmt,
-    str::{
-        self as core_str,
-        pattern::{Pattern, Searcher, ReverseSearcher, DoubleEndedSearcher},
-    },
-    mem,
-    ptr,
-    iter::FusedIterator,
-    unicode::conversions,
-};
-
-use crate::{
-    borrow::ToOwned,
-    boxed::Box,
-    slice::{SliceConcatExt, SliceIndex},
-    string::String,
-    vec::Vec,
-};
+use core::borrow::Borrow;
+use core::fmt;
+use core::str as core_str;
+use core::str::pattern::{Pattern, Searcher, ReverseSearcher, DoubleEndedSearcher};
+use core::mem;
+use core::ptr;
+use core::iter::FusedIterator;
+use core::unicode::conversions;
+
+use crate::borrow::ToOwned;
+use crate::boxed::Box;
+use crate::slice::{SliceConcatExt, SliceIndex};
+use crate::string::String;
+use crate::vec::Vec;
 
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use core::str::{FromStr, Utf8Error};
diff --git a/src/liballoc/string.rs b/src/liballoc/string.rs
index cb497f5bde2..73f67e98f36 100644
--- a/src/liballoc/string.rs
+++ b/src/liballoc/string.rs
@@ -46,30 +46,20 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-use core::{
-    char::{decode_utf16, REPLACEMENT_CHARACTER},
-    fmt,
-    hash,
-    iter::{FromIterator, FusedIterator},
-    ops::{
-        self,
-        Bound::{Excluded, Included, Unbounded},
-        Add, AddAssign, Index, IndexMut, RangeBounds,
-    },
-    ptr,
-    str::{
-        pattern::Pattern,
-        lossy,
-    }
-};
-
-use crate::{
-    borrow::{Cow, ToOwned},
-    collections::CollectionAllocErr,
-    boxed::Box,
-    str::{self, from_boxed_utf8_unchecked, FromStr, Utf8Error, Chars},
-    vec::Vec,
-};
+use core::char::{decode_utf16, REPLACEMENT_CHARACTER};
+use core::fmt;
+use core::hash;
+use core::iter::{FromIterator, FusedIterator};
+use core::ops::{self, Add, AddAssign, Index, IndexMut, RangeBounds};
+use core::ops::Bound::{Excluded, Included, Unbounded};
+use core::ptr;
+use core::str::{pattern::Pattern, lossy};
+
+use crate::borrow::{Cow, ToOwned};
+use crate::collections::CollectionAllocErr;
+use crate::boxed::Box;
+use crate::str::{self, from_boxed_utf8_unchecked, FromStr, Utf8Error, Chars};
+use crate::vec::Vec;
 
 /// A UTF-8 encoded, growable string.
 ///
diff --git a/src/liballoc/sync.rs b/src/liballoc/sync.rs
index 52f8879d184..5bdb3616ed2 100644
--- a/src/liballoc/sync.rs
+++ b/src/liballoc/sync.rs
@@ -6,34 +6,28 @@
 //!
 //! [arc]: struct.Arc.html
 
-use core::{
-    any::Any,
-    sync::atomic::{
-        self,
-        Ordering::{Acquire, Relaxed, Release, SeqCst}
-    },
-    borrow,
-    fmt,
-    cmp::{self, Ordering},
-    intrinsics::abort,
-    mem::{self, align_of_val, size_of_val},
-    ops::{Deref, Receiver, CoerceUnsized, DispatchFromDyn},
-    pin::Pin,
-    ptr::{self, NonNull},
-    marker::{Unpin, Unsize, PhantomData},
-    hash::{Hash, Hasher},
-    isize, usize,
-    convert::From,
-    slice::from_raw_parts_mut,
-};
-
-use crate::{
-    alloc::{Global, Alloc, Layout, box_free, handle_alloc_error},
-    boxed::Box,
-    rc::is_dangling,
-    string::String,
-    vec::Vec,
-};
+use core::any::Any;
+use core::sync::atomic;
+use core::sync::atomic::Ordering::{Acquire, Relaxed, Release, SeqCst};
+use core::borrow;
+use core::fmt;
+use core::cmp::{self, Ordering};
+use core::intrinsics::abort;
+use core::mem::{self, align_of_val, size_of_val};
+use core::ops::{Deref, Receiver, CoerceUnsized, DispatchFromDyn};
+use core::pin::Pin;
+use core::ptr::{self, NonNull};
+use core::marker::{Unpin, Unsize, PhantomData};
+use core::hash::{Hash, Hasher};
+use core::{isize, usize};
+use core::convert::From;
+use core::slice::from_raw_parts_mut;
+
+use crate::alloc::{Global, Alloc, Layout, box_free, handle_alloc_error};
+use crate::boxed::Box;
+use crate::rc::is_dangling;
+use crate::string::String;
+use crate::vec::Vec;
 
 /// A soft limit on the amount of references that may be made to an `Arc`.
 ///
@@ -1654,18 +1648,16 @@ impl<T> From<Vec<T>> for Arc<[T]> {
 
 #[cfg(test)]
 mod tests {
-    use std::{
-        boxed::Box,
-        clone::Clone,
-        sync::mpsc::channel,
-        mem::drop,
-        ops::Drop,
-        option::Option::{self, None, Some},
-        sync::atomic::{self, Ordering::{Acquire, SeqCst}},
-        thread,
-        sync::Mutex,
-        convert::From,
-    };
+    use std::boxed::Box;
+    use std::clone::Clone;
+    use std::sync::mpsc::channel;
+    use std::mem::drop;
+    use std::ops::Drop;
+    use std::option::Option::{self, None, Some};
+    use std::sync::atomic::{self, Ordering::{Acquire, SeqCst}};
+    use std::thread;
+    use std::sync::Mutex;
+    use std::convert::From;
 
     use super::{Arc, Weak};
     use crate::vec::Vec;
@@ -1774,7 +1766,8 @@ mod tests {
 
     #[test]
     fn test_into_from_raw_unsized() {
-        use std::{fmt::Display, string::ToString};
+        use std::fmt::Display;
+        use std::string::ToString;
 
         let arc: Arc<str> = Arc::from("foo");
 
@@ -2086,7 +2079,8 @@ mod tests {
 
     #[test]
     fn test_from_box_trait() {
-        use std::{fmt::Display, string::ToString};
+        use std::fmt::Display;
+        use std::string::ToString;
 
         let b: Box<dyn Display> = box 123;
         let r: Arc<dyn Display> = Arc::from(b);
diff --git a/src/liballoc/task.rs b/src/liballoc/task.rs
index 0bf1ff35cc1..2261dabe277 100644
--- a/src/liballoc/task.rs
+++ b/src/liballoc/task.rs
@@ -8,11 +8,9 @@ pub use if_arc::*;
 #[cfg(all(target_has_atomic = "ptr", target_has_atomic = "cas"))]
 mod if_arc {
     use super::*;
-    use core::{
-        marker::PhantomData,
-        mem,
-        ptr::{self, NonNull},
-    };
+    use core::marker::PhantomData;
+    use core::mem;
+    use core::ptr::{self, NonNull};
     use crate::sync::Arc;
 
     /// A way of waking up a specific task.
diff --git a/src/liballoc/tests/arc.rs b/src/liballoc/tests/arc.rs
index b71cf3bd477..2759b1b1cac 100644
--- a/src/liballoc/tests/arc.rs
+++ b/src/liballoc/tests/arc.rs
@@ -1,9 +1,7 @@
-use std::{
-    any::Any,
-    sync::{Arc, Weak},
-    cell::RefCell,
-    cmp::PartialEq,
-};
+use std::any::Any;
+use std::sync::{Arc, Weak};
+use std::cell::RefCell;
+use std::cmp::PartialEq;
 
 #[test]
 fn uninhabited() {
diff --git a/src/liballoc/tests/binary_heap.rs b/src/liballoc/tests/binary_heap.rs
index f19d641fe83..94ae43237d1 100644
--- a/src/liballoc/tests/binary_heap.rs
+++ b/src/liballoc/tests/binary_heap.rs
@@ -1,9 +1,8 @@
-use std::{
-    cmp,
-    collections::{BinaryHeap, binary_heap::{Drain, PeekMut}},
-    panic::{self, AssertUnwindSafe},
-    sync::atomic::{AtomicUsize, Ordering},
-};
+use std::cmp;
+use std::collections::BinaryHeap;
+use std::collections::binary_heap::{Drain, PeekMut};
+use std::panic::{self, AssertUnwindSafe};
+use std::sync::atomic::{AtomicUsize, Ordering};
 
 use rand::{thread_rng, seq::SliceRandom};
 
diff --git a/src/liballoc/tests/btree/map.rs b/src/liballoc/tests/btree/map.rs
index 6859b0138b5..aaf50407328 100644
--- a/src/liballoc/tests/btree/map.rs
+++ b/src/liballoc/tests/btree/map.rs
@@ -1,9 +1,8 @@
-use std::{
-    collections::{BTreeMap, btree_map::Entry::{Occupied, Vacant}},
-    ops::Bound::{self, Excluded, Included, Unbounded},
-    rc::Rc,
-    iter::FromIterator,
-};
+use std::collections::BTreeMap;
+use std::collections::btree_map::Entry::{Occupied, Vacant};
+use std::ops::Bound::{self, Excluded, Included, Unbounded};
+use std::rc::Rc;
+use std::iter::FromIterator;
 
 use super::DeterministicRng;
 
diff --git a/src/liballoc/tests/btree/set.rs b/src/liballoc/tests/btree/set.rs
index b90ecd9e3f1..4f5168f1ce5 100644
--- a/src/liballoc/tests/btree/set.rs
+++ b/src/liballoc/tests/btree/set.rs
@@ -1,7 +1,6 @@
-use std::{
-    collections::BTreeSet,
-    iter::FromIterator
-};
+use std::collections::BTreeSet;
+use std::iter::FromIterator;
+
 use super::DeterministicRng;
 
 #[test]
diff --git a/src/liballoc/tests/lib.rs b/src/liballoc/tests/lib.rs
index 100b3986370..a76fd87a1a9 100644
--- a/src/liballoc/tests/lib.rs
+++ b/src/liballoc/tests/lib.rs
@@ -13,10 +13,8 @@
 extern crate core;
 extern crate rand;
 
-use std::{
-    hash::{Hash, Hasher},
-    collections::hash_map::DefaultHasher,
-};
+use std::hash::{Hash, Hasher};
+use std::collections::hash_map::DefaultHasher;
 
 mod arc;
 mod binary_heap;
diff --git a/src/liballoc/tests/rc.rs b/src/liballoc/tests/rc.rs
index caa3c914fc2..18f82e80410 100644
--- a/src/liballoc/tests/rc.rs
+++ b/src/liballoc/tests/rc.rs
@@ -1,9 +1,7 @@
-use std::{
-    any::Any,
-    rc::{Rc, Weak},
-    cell::RefCell,
-    cmp::PartialEq,
-};
+use std::any::Any;
+use std::rc::{Rc, Weak};
+use std::cell::RefCell;
+use std::cmp::PartialEq;
 
 #[test]
 fn uninhabited() {
diff --git a/src/liballoc/tests/slice.rs b/src/liballoc/tests/slice.rs
index d0a8b65ae8b..334466dfb25 100644
--- a/src/liballoc/tests/slice.rs
+++ b/src/liballoc/tests/slice.rs
@@ -1,18 +1,14 @@
-use std::{
-    cell::Cell,
-    cmp::Ordering::{self, Equal, Greater, Less},
-    mem,
-    panic,
-    rc::Rc,
-    sync::atomic::{Ordering::Relaxed, AtomicUsize},
-    thread,
-};
-
-use rand::{
-    Rng, RngCore, thread_rng,
-    seq::SliceRandom,
-    distributions::Standard,
-};
+use std::cell::Cell;
+use std::cmp::Ordering::{self, Equal, Greater, Less};
+use std::mem;
+use std::panic;
+use std::rc::Rc;
+use std::sync::atomic::{Ordering::Relaxed, AtomicUsize};
+use std::thread;
+
+use rand::{Rng, RngCore, thread_rng};
+use rand::seq::SliceRandom;
+use rand::distributions::Standard;
 
 fn square(n: usize) -> usize {
     n * n
diff --git a/src/liballoc/tests/str.rs b/src/liballoc/tests/str.rs
index b1586558713..1bc1bd8d78c 100644
--- a/src/liballoc/tests/str.rs
+++ b/src/liballoc/tests/str.rs
@@ -1,8 +1,6 @@
-use std::{
-    borrow::Cow,
-    cmp::Ordering::{Equal, Greater, Less},
-    str::from_utf8,
-};
+use std::borrow::Cow;
+use std::cmp::Ordering::{Equal, Greater, Less};
+use std::str::from_utf8;
 
 #[test]
 fn test_le() {
@@ -1601,10 +1599,8 @@ fn test_repeat() {
 }
 
 mod pattern {
-    use std::str::pattern::{
-        Pattern, Searcher, ReverseSearcher,
-        SearchStep::{self, Match, Reject, Done},
-    };
+    use std::str::pattern::{Pattern, Searcher, ReverseSearcher};
+    use std::str::pattern::SearchStep::{self, Match, Reject, Done};
 
     macro_rules! make_test {
         ($name:ident, $p:expr, $h:expr, [$($e:expr,)*]) => {
diff --git a/src/liballoc/tests/string.rs b/src/liballoc/tests/string.rs
index 14f70fdf303..e5ce51a36ee 100644
--- a/src/liballoc/tests/string.rs
+++ b/src/liballoc/tests/string.rs
@@ -1,9 +1,7 @@
-use std::{
-    borrow::Cow,
-    collections::CollectionAllocErr::*,
-    mem::size_of,
-    usize, isize,
-};
+use std::borrow::Cow;
+use std::collections::CollectionAllocErr::*;
+use std::mem::size_of;
+use std::{usize, isize};
 
 pub trait IntoCow<'a, B: ?Sized> where B: ToOwned {
     fn into_cow(self) -> Cow<'a, B>;
diff --git a/src/liballoc/tests/vec.rs b/src/liballoc/tests/vec.rs
index e8fea287e1c..89f2e0a046d 100644
--- a/src/liballoc/tests/vec.rs
+++ b/src/liballoc/tests/vec.rs
@@ -1,10 +1,8 @@
-use std::{
-    borrow::Cow,
-    mem::size_of,
-    usize, isize,
-    vec::{Drain, IntoIter},
-    collections::CollectionAllocErr::*,
-};
+use std::borrow::Cow;
+use std::mem::size_of;
+use std::{usize, isize};
+use std::vec::{Drain, IntoIter};
+use std::collections::CollectionAllocErr::*;
 
 struct DropCounter<'a> {
     count: &'a mut u32,
diff --git a/src/liballoc/tests/vec_deque.rs b/src/liballoc/tests/vec_deque.rs
index 313aa55a2b2..aa49bdb0090 100644
--- a/src/liballoc/tests/vec_deque.rs
+++ b/src/liballoc/tests/vec_deque.rs
@@ -1,12 +1,8 @@
-use std::{
-    fmt::Debug,
-    collections::{
-        VecDeque, vec_deque::Drain,
-        CollectionAllocErr::*,
-    },
-    mem::size_of,
-    usize, isize,
-};
+use std::fmt::Debug;
+use std::collections::{VecDeque, vec_deque::Drain};
+use std::collections::CollectionAllocErr::*;
+use std::mem::size_of;
+use std::{usize, isize};
 
 use crate::hash;
 
diff --git a/src/liballoc/vec.rs b/src/liballoc/vec.rs
index 66a73e75799..57e10498b92 100644
--- a/src/liballoc/vec.rs
+++ b/src/liballoc/vec.rs
@@ -56,29 +56,22 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-use core::{
-    cmp::{self, Ordering},
-    fmt,
-    hash::{self, Hash},
-    intrinsics::{arith_offset, assume},
-    iter::{FromIterator, FusedIterator, TrustedLen},
-    marker::PhantomData,
-    mem,
-    ops::{
-        self,
-        Bound::{Excluded, Included, Unbounded},
-        Index, IndexMut, RangeBounds,
-    },
-    ptr::{self, NonNull},
-    slice::{self, SliceIndex},
-};
-
-use crate::{
-    borrow::{ToOwned, Cow},
-    collections::CollectionAllocErr,
-    boxed::Box,
-    raw_vec::RawVec,
-};
+use core::cmp::{self, Ordering};
+use core::fmt;
+use core::hash::{self, Hash};
+use core::intrinsics::{arith_offset, assume};
+use core::iter::{FromIterator, FusedIterator, TrustedLen};
+use core::marker::PhantomData;
+use core::mem;
+use core::ops::{self, Index, IndexMut, RangeBounds};
+use core::ops::Bound::{Excluded, Included, Unbounded};
+use core::ptr::{self, NonNull};
+use core::slice::{self, SliceIndex};
+
+use crate::borrow::{ToOwned, Cow};
+use crate::collections::CollectionAllocErr;
+use crate::boxed::Box;
+use crate::raw_vec::RawVec;
 
 /// A contiguous growable array type, written `Vec<T>` but pronounced 'vector'.
 ///