Fix imports

Author: Fedor Ryabinin

library/core/src/hint.rs

@@ -4,13 +4,13 @@
 //!
 //! Hints may be compile time or runtime.
 
-use safety::requires;
 #[cfg(kani)]
 use crate::kani;
-
 use crate::mem::MaybeUninit;
 use crate::{intrinsics, ub_checks};
 
+use safety::requires;
+
 /// Informs the compiler that the site which is calling this function is not
 /// reachable, possibly enabling further optimizations.
 ///

library/core/src/iter/adapters/step_by.rs

@@ -1,12 +1,12 @@
-use safety::requires;
-#[cfg(kani)]
-use crate::kani;
-
 use crate::intrinsics;
 use crate::iter::{TrustedLen, TrustedRandomAccess, from_fn};
+#[cfg(kani)]
+use crate::kani;
 use crate::num::NonZero;
 use crate::ops::{Range, Try};
 
+use safety::requires;
+
 /// An iterator for stepping iterators by a custom amount.
 ///
 /// This `struct` is created by the [`step_by`] method on [`Iterator`]. See

library/core/src/ops/index_range.rs

@@ -1,12 +1,12 @@
-use safety::requires;
+use crate::iter::{FusedIterator, TrustedLen};
 #[cfg(kani)]
 use crate::kani;
-
-use crate::iter::{FusedIterator, TrustedLen};
 use crate::num::NonZero;
 use crate::ops::{NeverShortCircuit, Try};
 use crate::ub_checks;
 
+use safety::requires;
+
 /// Like a `Range<usize>`, but with a safety invariant that `start <= end`.
 ///
 /// This means that `end - start` cannot overflow, allowing some μoptimizations.

library/std/src/sync/mpmc/context.rs

@@ -1,9 +1,8 @@
 //! Thread-local channel context.
 
 #[cfg(kani)]
-#[unstable(feature="kani", issue="none")]
+#[unstable(feature = "kani", issue="none")]
 use core::kani;
-use safety::requires;
 
 use super::select::Selected;
 use super::waker::current_thread_id;
@@ -14,6 +13,8 @@ use crate::sync::atomic::{Atomic, AtomicPtr, AtomicUsize, Ordering};
 use crate::thread::{self, Thread};
 use crate::time::Instant;
 
+use safety::requires;
+
 /// Thread-local context.
 #[derive(Debug, Clone)]
 pub struct Context {