diff --git a/src/libcore/iter/adapters/mod.rs b/src/libcore/iter/adapters/mod.rs
index 16738543eb3af57139ace44e1edd8bb4871e308e..e9fc1b612dd39aa385edd5a5912ae0a44acbadd5 100644
--- a/src/libcore/iter/adapters/mod.rs
+++ b/src/libcore/iter/adapters/mod.rs
@@ -2,7 +2,6 @@
 use crate::fmt;
 use crate::intrinsics;
 use crate::ops::{Add, AddAssign, Try};
-use crate::usize;
 
 use super::{from_fn, LoopState};
 use super::{DoubleEndedIterator, ExactSizeIterator, FusedIterator, Iterator, TrustedLen};
diff --git a/src/libcore/iter/range.rs b/src/libcore/iter/range.rs
index 28fbd00f36b33558e8f05ccf06632f9d299cf8fb..37369289c512e9b3314d1b7c1b79dc7d48bdb3d6 100644
--- a/src/libcore/iter/range.rs
+++ b/src/libcore/iter/range.rs
@@ -1,7 +1,6 @@
 use crate::convert::TryFrom;
 use crate::mem;
 use crate::ops::{self, Add, Sub, Try};
-use crate::usize;
 
 use super::{FusedIterator, TrustedLen};
 
diff --git a/src/libcore/iter/sources.rs b/src/libcore/iter/sources.rs
index a1d4e1b31e9b15f6c9cc77a557f67932247e5063..d76fa89bd012c22f4167b25e336a4aa917d321f0 100644
--- a/src/libcore/iter/sources.rs
+++ b/src/libcore/iter/sources.rs
@@ -1,6 +1,5 @@
 use crate::fmt;
 use crate::marker;
-use crate::usize;
 
 use super::{FusedIterator, TrustedLen};
 
diff --git a/src/libcore/num/flt2dec/mod.rs b/src/libcore/num/flt2dec/mod.rs
index 9adea94e87d1071646c9e4325c1c5c8db5e48fcd..9bf56e93d896f1d96db0c7de7b6e0053ea62b1e6 100644
--- a/src/libcore/num/flt2dec/mod.rs
+++ b/src/libcore/num/flt2dec/mod.rs
@@ -123,7 +123,6 @@
 )]
 
 pub use self::decoder::{decode, DecodableFloat, Decoded, FullDecoded};
-use crate::i16;
 
 pub mod decoder;
 pub mod estimator;
diff --git a/src/libcore/slice/memchr.rs b/src/libcore/slice/memchr.rs
index 2a2169dd348c211ec14edac3e33e5f5c886ac54e..3b13ed5fed396918ac7ab575eb6e17ba3a3ab54b 100644
--- a/src/libcore/slice/memchr.rs
+++ b/src/libcore/slice/memchr.rs
@@ -34,7 +34,7 @@ fn repeat_byte(b: u8) -> usize {
 #[cfg(not(target_pointer_width = "16"))]
 #[inline]
 fn repeat_byte(b: u8) -> usize {
-    (b as usize) * (crate::usize::MAX / 255)
+    (b as usize) * (usize::MAX / 255)
 }
 
 /// Returns the first index matching the byte `x` in `text`.
diff --git a/src/libcore/slice/mod.rs b/src/libcore/slice/mod.rs
index df976128b5efb7e92e6f6d5f9131432ab8835eed..dc395bcfba5ccf5be2d38f62cdf686da8bf27910 100644
--- a/src/libcore/slice/mod.rs
+++ b/src/libcore/slice/mod.rs
@@ -28,7 +28,6 @@
 use crate::cmp::Ordering::{self, Equal, Greater, Less};
 use crate::fmt;
 use crate::intrinsics::{assume, exact_div, is_aligned_and_not_null, unchecked_sub};
-use crate::isize;
 use crate::iter::*;
 use crate::marker::{self, Copy, Send, Sized, Sync};
 use crate::mem;
diff --git a/src/libcore/str/pattern.rs b/src/libcore/str/pattern.rs
index 708e4e5560ecd34106736aec2d166bb3fdd57b7b..ef0ec42bc8fcf1c7fec5ae7c3ed0a13a13cf538e 100644
--- a/src/libcore/str/pattern.rs
+++ b/src/libcore/str/pattern.rs
@@ -12,7 +12,6 @@
 use crate::cmp;
 use crate::fmt;
 use crate::slice::memchr;
-use crate::usize;
 
 // Pattern
 
diff --git a/src/libcore/time.rs b/src/libcore/time.rs
index 924a64847a794fa568ecba9f0e556c5faa361cbb..ed1d5d46db5c4c02c7b793f3ad240edb9f68d007 100644
--- a/src/libcore/time.rs
+++ b/src/libcore/time.rs
@@ -12,9 +12,9 @@
 //! assert_eq!(Duration::new(5, 0), Duration::from_secs(5));
 //! ```
 
+use crate::fmt;
 use crate::iter::Sum;
 use crate::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Sub, SubAssign};
-use crate::{fmt, u64};
 
 const NANOS_PER_SEC: u32 = 1_000_000_000;
 const NANOS_PER_MILLI: u32 = 1_000_000;
diff --git a/src/libstd/thread/mod.rs b/src/libstd/thread/mod.rs
index 282e268efd20686f35fba68a792d3f4f96ce432e..7a3cbbe4562ff70f8ff480c85e703ed2614d593e 100644
--- a/src/libstd/thread/mod.rs
+++ b/src/libstd/thread/mod.rs
@@ -1062,7 +1062,7 @@ fn new() -> ThreadId {
 
             // If we somehow use up all our bits, panic so that we're not
             // covering up subtle bugs of IDs being reused.
-            if COUNTER == crate::u64::MAX {
+            if COUNTER == u64::MAX {
                 panic!("failed to generate unique thread ID: bitspace exhausted");
             }