Auto merge of #73692 - Dylan-DPC:rollup-ehzsbfw, r=Dylan-DPC

Rollup of 6 pull requests

Successful merges:

 - #73638 (Remove unused crate imports in 2018 edition crates)
 - #73639 (Change heuristic for determining range literal)
 - #73646 (Add some regression tests)
 - #73652 (Add re-exports to use suggestions)
 - #73667 (Update BTreeMap::new() doc)
 - #73675 (Update books)

Failed merges:

r? @ghost

7 files changed, 0 insertions, 10 deletions

diff --git a/src/libstd/sys/unix/ext/net.rs b/src/libstd/sys/unix/ext/net.rs
index cd24605ec7a..ada8eaa1c97 100644
--- a/src/libstd/sys/unix/ext/net.rs
+++ b/src/libstd/sys/unix/ext/net.rs
@@ -2,9 +2,6 @@
 
 //! Unix-specific networking functionality
 
-#[cfg(unix)]
-use libc;
-
 // FIXME(#43348): Make libc adapt #[doc(cfg(...))] so we don't need these fake definitions here?
 #[cfg(not(unix))]
 #[allow(non_camel_case_types)]
diff --git a/src/libstd/sys/vxworks/args.rs b/src/libstd/sys/vxworks/args.rs
index efd615f404d..adff6c489bb 100644
--- a/src/libstd/sys/vxworks/args.rs
+++ b/src/libstd/sys/vxworks/args.rs
@@ -56,7 +56,6 @@ mod imp {
     use crate::ffi::{CStr, OsString};
     use crate::marker::PhantomData;
     use crate::ptr;
-    use libc;
 
     use crate::sys_common::mutex::Mutex;
 
diff --git a/src/libstd/sys/vxworks/ext/fs.rs b/src/libstd/sys/vxworks/ext/fs.rs
index 9864a855df7..7cc64658ee1 100644
--- a/src/libstd/sys/vxworks/ext/fs.rs
+++ b/src/libstd/sys/vxworks/ext/fs.rs
@@ -6,7 +6,6 @@ use crate::path::Path;
 use crate::sys;
 use crate::sys::platform::fs::MetadataExt as UnixMetadataExt;
 use crate::sys_common::{AsInner, AsInnerMut, FromInner};
-use libc;
 
 /// Unix-specific extensions to [`File`].
 ///
diff --git a/src/libstd/sys/vxworks/rand.rs b/src/libstd/sys/vxworks/rand.rs
index 87ebd2c9593..3a1ff5fd3b9 100644
--- a/src/libstd/sys/vxworks/rand.rs
+++ b/src/libstd/sys/vxworks/rand.rs
@@ -13,7 +13,6 @@ pub fn hashmap_random_keys() -> (u64, u64) {
 mod imp {
     use crate::io;
     use core::sync::atomic::{AtomicBool, Ordering::Relaxed};
-    use libc;
 
     pub fn fill_bytes(v: &mut [u8]) {
         static RNG_INIT: AtomicBool = AtomicBool::new(false);
diff --git a/src/libstd/sys/vxworks/rwlock.rs b/src/libstd/sys/vxworks/rwlock.rs
index fd2e1a6e7bc..c90304c2b4a 100644
--- a/src/libstd/sys/vxworks/rwlock.rs
+++ b/src/libstd/sys/vxworks/rwlock.rs
@@ -1,6 +1,5 @@
 use crate::cell::UnsafeCell;
 use crate::sync::atomic::{AtomicUsize, Ordering};
-use libc;
 
 pub struct RWLock {
     inner: UnsafeCell<libc::pthread_rwlock_t>,
diff --git a/src/libstd/sys/vxworks/time.rs b/src/libstd/sys/vxworks/time.rs
index 8ebbf89213f..8365c9ee9c9 100644
--- a/src/libstd/sys/vxworks/time.rs
+++ b/src/libstd/sys/vxworks/time.rs
@@ -1,7 +1,6 @@
 use crate::cmp::Ordering;
 use crate::time::Duration;
 use ::core::hash::{Hash, Hasher};
-use libc;
 
 pub use self::inner::{Instant, SystemTime, UNIX_EPOCH};
 use crate::convert::TryInto;
@@ -104,7 +103,6 @@ mod inner {
     use crate::fmt;
     use crate::sys::cvt;
     use crate::time::Duration;
-    use libc;
 
     use super::Timespec;
 
diff --git a/src/libstd/sys/wasi/alloc.rs b/src/libstd/sys/wasi/alloc.rs
index bc614162784..57187851a14 100644
--- a/src/libstd/sys/wasi/alloc.rs
+++ b/src/libstd/sys/wasi/alloc.rs
@@ -1,7 +1,6 @@
 use crate::alloc::{GlobalAlloc, Layout, System};
 use crate::ptr;
 use crate::sys_common::alloc::{realloc_fallback, MIN_ALIGN};
-use libc;
 
 #[stable(feature = "alloc_system_type", since = "1.28.0")]
 unsafe impl GlobalAlloc for System {