Auto merge of #136658 - matthiaskrgr:rollup-tg1vmex, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #133925 (disallow `repr()` on invalid items)
 - #136069 (Simplify slice indexing in next trait solver)
 - #136152 (Stabilize `map_many_mut` feature)
 - #136219 (Misc. `rustc_hir` cleanups 🧹)
 - #136580 (Couple of changes to run rustc in miri)
 - #136636 (Couple of minor cleanups to the diagnostic infrastructure)
 - #136645 (Clippy subtree update)

r? `@ghost`
`@rustbot` modify labels: rollup

47 files changed, 1527 insertions, 249 deletions

diff --git a/src/tools/clippy/tests/ui/cmp_null.fixed b/src/tools/clippy/tests/ui/cmp_null.fixed
new file mode 100644
index 00000000000..e5ab765bc86
--- /dev/null
+++ b/src/tools/clippy/tests/ui/cmp_null.fixed
@@ -0,0 +1,32 @@
+#![warn(clippy::cmp_null)]
+#![allow(unused_mut)]
+
+use std::ptr;
+
+fn main() {
+    let x = 0;
+    let p: *const usize = &x;
+    if p.is_null() {
+        //~^ ERROR: comparing with null is better expressed by the `.is_null()` method
+        //~| NOTE: `-D clippy::cmp-null` implied by `-D warnings`
+        println!("This is surprising!");
+    }
+    if p.is_null() {
+        //~^ ERROR: comparing with null is better expressed by the `.is_null()` method
+        println!("This is surprising!");
+    }
+
+    let mut y = 0;
+    let mut m: *mut usize = &mut y;
+    if m.is_null() {
+        //~^ ERROR: comparing with null is better expressed by the `.is_null()` method
+        println!("This is surprising, too!");
+    }
+    if m.is_null() {
+        //~^ ERROR: comparing with null is better expressed by the `.is_null()` method
+        println!("This is surprising, too!");
+    }
+
+    let _ = (x as *const ()).is_null();
+    //~^ ERROR: comparing with null is better expressed by the `.is_null()` method
+}
diff --git a/src/tools/clippy/tests/ui/cmp_null.rs b/src/tools/clippy/tests/ui/cmp_null.rs
index ef1d93940aa..257f7ba2662 100644
--- a/src/tools/clippy/tests/ui/cmp_null.rs
+++ b/src/tools/clippy/tests/ui/cmp_null.rs
@@ -11,10 +11,22 @@ fn main() {
         //~| NOTE: `-D clippy::cmp-null` implied by `-D warnings`
         println!("This is surprising!");
     }
+    if ptr::null() == p {
+        //~^ ERROR: comparing with null is better expressed by the `.is_null()` method
+        println!("This is surprising!");
+    }
+
     let mut y = 0;
     let mut m: *mut usize = &mut y;
     if m == ptr::null_mut() {
         //~^ ERROR: comparing with null is better expressed by the `.is_null()` method
         println!("This is surprising, too!");
     }
+    if ptr::null_mut() == m {
+        //~^ ERROR: comparing with null is better expressed by the `.is_null()` method
+        println!("This is surprising, too!");
+    }
+
+    let _ = x as *const () == ptr::null();
+    //~^ ERROR: comparing with null is better expressed by the `.is_null()` method
 }
diff --git a/src/tools/clippy/tests/ui/cmp_null.stderr b/src/tools/clippy/tests/ui/cmp_null.stderr
index 8362904a5ba..f3b35f3afba 100644
--- a/src/tools/clippy/tests/ui/cmp_null.stderr
+++ b/src/tools/clippy/tests/ui/cmp_null.stderr
@@ -2,16 +2,34 @@ error: comparing with null is better expressed by the `.is_null()` method
   --> tests/ui/cmp_null.rs:9:8
    |
 LL |     if p == ptr::null() {
-   |        ^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^^ help: try: `p.is_null()`
    |
    = note: `-D clippy::cmp-null` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::cmp_null)]`
 
 error: comparing with null is better expressed by the `.is_null()` method
-  --> tests/ui/cmp_null.rs:16:8
+  --> tests/ui/cmp_null.rs:14:8
+   |
+LL |     if ptr::null() == p {
+   |        ^^^^^^^^^^^^^^^^ help: try: `p.is_null()`
+
+error: comparing with null is better expressed by the `.is_null()` method
+  --> tests/ui/cmp_null.rs:21:8
    |
 LL |     if m == ptr::null_mut() {
-   |        ^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^^^^^^ help: try: `m.is_null()`
+
+error: comparing with null is better expressed by the `.is_null()` method
+  --> tests/ui/cmp_null.rs:25:8
+   |
+LL |     if ptr::null_mut() == m {
+   |        ^^^^^^^^^^^^^^^^^^^^ help: try: `m.is_null()`
+
+error: comparing with null is better expressed by the `.is_null()` method
+  --> tests/ui/cmp_null.rs:30:13
+   |
+LL |     let _ = x as *const () == ptr::null();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `(x as *const ()).is_null()`
 
-error: aborting due to 2 previous errors
+error: aborting due to 5 previous errors
 
diff --git a/src/tools/clippy/tests/ui/eta.fixed b/src/tools/clippy/tests/ui/eta.fixed
index f1baf28200e..abccc30ef87 100644
--- a/src/tools/clippy/tests/ui/eta.fixed
+++ b/src/tools/clippy/tests/ui/eta.fixed
@@ -116,6 +116,11 @@ fn test_redundant_closures_containing_method_calls() {
         t.iter().filter(|x| x.trait_foo_ref());
         t.iter().map(|x| x.trait_foo_ref());
     }
+
+    fn issue14096() {
+        let x = Some("42");
+        let _ = x.map(str::parse::<i16>);
+    }
 }
 
 struct Thunk<T>(Box<dyn FnMut() -> T>);
diff --git a/src/tools/clippy/tests/ui/eta.rs b/src/tools/clippy/tests/ui/eta.rs
index c52a51880bf..9bcee4eba34 100644
--- a/src/tools/clippy/tests/ui/eta.rs
+++ b/src/tools/clippy/tests/ui/eta.rs
@@ -116,6 +116,11 @@ fn test_redundant_closures_containing_method_calls() {
         t.iter().filter(|x| x.trait_foo_ref());
         t.iter().map(|x| x.trait_foo_ref());
     }
+
+    fn issue14096() {
+        let x = Some("42");
+        let _ = x.map(|x| x.parse::<i16>());
+    }
 }
 
 struct Thunk<T>(Box<dyn FnMut() -> T>);
diff --git a/src/tools/clippy/tests/ui/eta.stderr b/src/tools/clippy/tests/ui/eta.stderr
index 1731a4377f5..ac58e87bc5e 100644
--- a/src/tools/clippy/tests/ui/eta.stderr
+++ b/src/tools/clippy/tests/ui/eta.stderr
@@ -71,142 +71,148 @@ LL |     let e: std::vec::Vec<char> = vec!['a', 'b', 'c'].iter().map(|c| c.to_as
    |                                                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `char::to_ascii_uppercase`
 
 error: redundant closure
-  --> tests/ui/eta.rs:169:22
+  --> tests/ui/eta.rs:122:23
+   |
+LL |         let _ = x.map(|x| x.parse::<i16>());
+   |                       ^^^^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `str::parse::<i16>`
+
+error: redundant closure
+  --> tests/ui/eta.rs:174:22
    |
 LL |     requires_fn_once(|| x());
    |                      ^^^^^^ help: replace the closure with the function itself: `x`
 
 error: redundant closure
-  --> tests/ui/eta.rs:176:27
+  --> tests/ui/eta.rs:181:27
    |
 LL |     let a = Some(1u8).map(|a| foo_ptr(a));
    |                           ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `foo_ptr`
 
 error: redundant closure
-  --> tests/ui/eta.rs:181:27
+  --> tests/ui/eta.rs:186:27
    |
 LL |     let a = Some(1u8).map(|a| closure(a));
    |                           ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `closure`
 
 error: redundant closure
-  --> tests/ui/eta.rs:213:28
+  --> tests/ui/eta.rs:218:28
    |
 LL |     x.into_iter().for_each(|x| add_to_res(x));
    |                            ^^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `&mut add_to_res`
 
 error: redundant closure
-  --> tests/ui/eta.rs:214:28
+  --> tests/ui/eta.rs:219:28
    |
 LL |     y.into_iter().for_each(|x| add_to_res(x));
    |                            ^^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `&mut add_to_res`
 
 error: redundant closure
-  --> tests/ui/eta.rs:215:28
+  --> tests/ui/eta.rs:220:28
    |
 LL |     z.into_iter().for_each(|x| add_to_res(x));
    |                            ^^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `add_to_res`
 
 error: redundant closure
-  --> tests/ui/eta.rs:222:21
+  --> tests/ui/eta.rs:227:21
    |
 LL |         Some(1).map(|n| closure(n));
    |                     ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `&mut closure`
 
 error: redundant closure
-  --> tests/ui/eta.rs:226:21
+  --> tests/ui/eta.rs:231:21
    |
 LL |         Some(1).map(|n| in_loop(n));
    |                     ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `in_loop`
 
 error: redundant closure
-  --> tests/ui/eta.rs:319:18
+  --> tests/ui/eta.rs:324:18
    |
 LL |     takes_fn_mut(|| f());
    |                  ^^^^^^ help: replace the closure with the function itself: `&mut f`
 
 error: redundant closure
-  --> tests/ui/eta.rs:322:19
+  --> tests/ui/eta.rs:327:19
    |
 LL |     takes_fn_once(|| f());
    |                   ^^^^^^ help: replace the closure with the function itself: `&mut f`
 
 error: redundant closure
-  --> tests/ui/eta.rs:326:26
+  --> tests/ui/eta.rs:331:26
    |
 LL |     move || takes_fn_mut(|| f_used_once())
    |                          ^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `&mut f_used_once`
 
 error: redundant closure
-  --> tests/ui/eta.rs:338:19
+  --> tests/ui/eta.rs:343:19
    |
 LL |     array_opt.map(|a| a.as_slice());
    |                   ^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `<[u8; 3]>::as_slice`
 
 error: redundant closure
-  --> tests/ui/eta.rs:341:19
+  --> tests/ui/eta.rs:346:19
    |
 LL |     slice_opt.map(|s| s.len());
    |                   ^^^^^^^^^^^ help: replace the closure with the method itself: `<[u8]>::len`
 
 error: redundant closure
-  --> tests/ui/eta.rs:344:17
+  --> tests/ui/eta.rs:349:17
    |
 LL |     ptr_opt.map(|p| p.is_null());
    |                 ^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `<*const usize>::is_null`
 
 error: redundant closure
-  --> tests/ui/eta.rs:348:17
+  --> tests/ui/eta.rs:353:17
    |
 LL |     dyn_opt.map(|d| d.method_on_dyn());
    |                 ^^^^^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `<dyn TestTrait>::method_on_dyn`
 
 error: redundant closure
-  --> tests/ui/eta.rs:408:19
+  --> tests/ui/eta.rs:413:19
    |
 LL |     let _ = f(&0, |x, y| f2(x, y));
    |                   ^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `f2`
 
 error: redundant closure
-  --> tests/ui/eta.rs:436:22
+  --> tests/ui/eta.rs:441:22
    |
 LL |             test.map(|t| t.method())
    |                      ^^^^^^^^^^^^^^ help: replace the closure with the method itself: `Test::method`
 
 error: redundant closure
-  --> tests/ui/eta.rs:440:22
+  --> tests/ui/eta.rs:445:22
    |
 LL |             test.map(|t| t.method())
    |                      ^^^^^^^^^^^^^^ help: replace the closure with the method itself: `super::Outer::method`
 
 error: redundant closure
-  --> tests/ui/eta.rs:453:18
+  --> tests/ui/eta.rs:458:18
    |
 LL |         test.map(|t| t.method())
    |                  ^^^^^^^^^^^^^^ help: replace the closure with the method itself: `test_mod::Test::method`
 
 error: redundant closure
-  --> tests/ui/eta.rs:460:30
+  --> tests/ui/eta.rs:465:30
    |
 LL |                     test.map(|t| t.method())
    |                              ^^^^^^^^^^^^^^ help: replace the closure with the method itself: `crate::issue_10854::d::Test::method`
 
 error: redundant closure
-  --> tests/ui/eta.rs:479:38
+  --> tests/ui/eta.rs:484:38
    |
 LL |         let x = Box::new(|| None.map(|x| f(x)));
    |                                      ^^^^^^^^ help: replace the closure with the function itself: `&f`
 
 error: redundant closure
-  --> tests/ui/eta.rs:483:38
+  --> tests/ui/eta.rs:488:38
    |
 LL |         let x = Box::new(|| None.map(|x| f(x)));
    |                                      ^^^^^^^^ help: replace the closure with the function itself: `f`
 
 error: redundant closure
-  --> tests/ui/eta.rs:500:35
+  --> tests/ui/eta.rs:505:35
    |
 LL |         let _field = bind.or_else(|| get_default()).unwrap();
    |                                   ^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `get_default`
 
-error: aborting due to 34 previous errors
+error: aborting due to 35 previous errors
 
diff --git a/src/tools/clippy/tests/ui/ignored_unit_patterns.fixed b/src/tools/clippy/tests/ui/ignored_unit_patterns.fixed
index fde40437309..118f0b48895 100644
--- a/src/tools/clippy/tests/ui/ignored_unit_patterns.fixed
+++ b/src/tools/clippy/tests/ui/ignored_unit_patterns.fixed
@@ -21,12 +21,15 @@ fn main() {
     let _ = foo().map_err(|()| todo!());
     //~^ ERROR: matching over `()` is more explicit
 
-    println!("{:?}", match foo() {
-        Ok(()) => {},
-        //~^ ERROR: matching over `()` is more explicit
-        Err(()) => {},
-        //~^ ERROR: matching over `()` is more explicit
-    });
+    println!(
+        "{:?}",
+        match foo() {
+            Ok(()) => {},
+            //~^ ERROR: matching over `()` is more explicit
+            Err(()) => {},
+            //~^ ERROR: matching over `()` is more explicit
+        }
+    );
 }
 
 // ignored_unit_patterns in derive macro should be ok
diff --git a/src/tools/clippy/tests/ui/ignored_unit_patterns.rs b/src/tools/clippy/tests/ui/ignored_unit_patterns.rs
index 528844d76e0..92feb9e6c28 100644
--- a/src/tools/clippy/tests/ui/ignored_unit_patterns.rs
+++ b/src/tools/clippy/tests/ui/ignored_unit_patterns.rs
@@ -21,12 +21,15 @@ fn main() {
     let _ = foo().map_err(|_| todo!());
     //~^ ERROR: matching over `()` is more explicit
 
-    println!("{:?}", match foo() {
-        Ok(_) => {},
-        //~^ ERROR: matching over `()` is more explicit
-        Err(_) => {},
-        //~^ ERROR: matching over `()` is more explicit
-    });
+    println!(
+        "{:?}",
+        match foo() {
+            Ok(_) => {},
+            //~^ ERROR: matching over `()` is more explicit
+            Err(_) => {},
+            //~^ ERROR: matching over `()` is more explicit
+        }
+    );
 }
 
 // ignored_unit_patterns in derive macro should be ok
diff --git a/src/tools/clippy/tests/ui/ignored_unit_patterns.stderr b/src/tools/clippy/tests/ui/ignored_unit_patterns.stderr
index 54ff4454d6b..00a254e3919 100644
--- a/src/tools/clippy/tests/ui/ignored_unit_patterns.stderr
+++ b/src/tools/clippy/tests/ui/ignored_unit_patterns.stderr
@@ -26,31 +26,31 @@ LL |     let _ = foo().map_err(|_| todo!());
    |                            ^ help: use `()` instead of `_`: `()`
 
 error: matching over `()` is more explicit
-  --> tests/ui/ignored_unit_patterns.rs:25:12
+  --> tests/ui/ignored_unit_patterns.rs:27:16
    |
-LL |         Ok(_) => {},
-   |            ^ help: use `()` instead of `_`: `()`
+LL |             Ok(_) => {},
+   |                ^ help: use `()` instead of `_`: `()`
 
 error: matching over `()` is more explicit
-  --> tests/ui/ignored_unit_patterns.rs:27:13
+  --> tests/ui/ignored_unit_patterns.rs:29:17
    |
-LL |         Err(_) => {},
-   |             ^ help: use `()` instead of `_`: `()`
+LL |             Err(_) => {},
+   |                 ^ help: use `()` instead of `_`: `()`
 
 error: matching over `()` is more explicit
-  --> tests/ui/ignored_unit_patterns.rs:38:9
+  --> tests/ui/ignored_unit_patterns.rs:41:9
    |
 LL |     let _ = foo().unwrap();
    |         ^ help: use `()` instead of `_`: `()`
 
 error: matching over `()` is more explicit
-  --> tests/ui/ignored_unit_patterns.rs:47:13
+  --> tests/ui/ignored_unit_patterns.rs:50:13
    |
 LL |         (1, _) => unimplemented!(),
    |             ^ help: use `()` instead of `_`: `()`
 
 error: matching over `()` is more explicit
-  --> tests/ui/ignored_unit_patterns.rs:54:13
+  --> tests/ui/ignored_unit_patterns.rs:57:13
    |
 LL |     for (x, _) in v {
    |             ^ help: use `()` instead of `_`: `()`
diff --git a/src/tools/clippy/tests/ui/manual_memcpy/without_loop_counters.rs b/src/tools/clippy/tests/ui/manual_memcpy/without_loop_counters.rs
index c917fa7f2d0..2f8640cd3f5 100644
--- a/src/tools/clippy/tests/ui/manual_memcpy/without_loop_counters.rs
+++ b/src/tools/clippy/tests/ui/manual_memcpy/without_loop_counters.rs
@@ -1,5 +1,10 @@
 #![warn(clippy::manual_memcpy)]
-#![allow(clippy::assigning_clones, clippy::useless_vec, clippy::needless_range_loop)]
+#![allow(
+    clippy::assigning_clones,
+    clippy::useless_vec,
+    clippy::needless_range_loop,
+    clippy::manual_slice_fill
+)]
 
 //@no-rustfix
 const LOOP_OFFSET: usize = 5000;
diff --git a/src/tools/clippy/tests/ui/manual_memcpy/without_loop_counters.stderr b/src/tools/clippy/tests/ui/manual_memcpy/without_loop_counters.stderr
index 803053b2db2..c881e3fac76 100644
--- a/src/tools/clippy/tests/ui/manual_memcpy/without_loop_counters.stderr
+++ b/src/tools/clippy/tests/ui/manual_memcpy/without_loop_counters.stderr
@@ -1,5 +1,5 @@
 error: it looks like you're manually copying between slices
-  --> tests/ui/manual_memcpy/without_loop_counters.rs:9:5
+  --> tests/ui/manual_memcpy/without_loop_counters.rs:14:5
    |
 LL | /     for i in 0..src.len() {
 LL | |
@@ -12,7 +12,7 @@ LL | |     }
    = help: to override `-D warnings` add `#[allow(clippy::manual_memcpy)]`
 
 error: it looks like you're manually copying between slices
-  --> tests/ui/manual_memcpy/without_loop_counters.rs:16:5
+  --> tests/ui/manual_memcpy/without_loop_counters.rs:21:5
    |
 LL | /     for i in 0..src.len() {
 LL | |
@@ -21,7 +21,7 @@ LL | |     }
    | |_____^ help: try replacing the loop by: `dst[10..(src.len() + 10)].copy_from_slice(&src[..]);`
 
 error: it looks like you're manually copying between slices
-  --> tests/ui/manual_memcpy/without_loop_counters.rs:22:5
+  --> tests/ui/manual_memcpy/without_loop_counters.rs:27:5
    |
 LL | /     for i in 0..src.len() {
 LL | |
@@ -30,7 +30,7 @@ LL | |     }
    | |_____^ help: try replacing the loop by: `dst[..src.len()].copy_from_slice(&src[10..(src.len() + 10)]);`
 
 error: it looks like you're manually copying between slices
-  --> tests/ui/manual_memcpy/without_loop_counters.rs:28:5
+  --> tests/ui/manual_memcpy/without_loop_counters.rs:33:5
    |
 LL | /     for i in 11..src.len() {
 LL | |
@@ -39,7 +39,7 @@ LL | |     }
    | |_____^ help: try replacing the loop by: `dst[11..src.len()].copy_from_slice(&src[(11 - 10)..(src.len() - 10)]);`
 
 error: it looks like you're manually copying between slices
-  --> tests/ui/manual_memcpy/without_loop_counters.rs:34:5
+  --> tests/ui/manual_memcpy/without_loop_counters.rs:39:5
    |
 LL | /     for i in 0..dst.len() {
 LL | |
@@ -48,7 +48,7 @@ LL | |     }
    | |_____^ help: try replacing the loop by: `dst.copy_from_slice(&src[..dst.len()]);`
 
 error: it looks like you're manually copying between slices
-  --> tests/ui/manual_memcpy/without_loop_counters.rs:48:5
+  --> tests/ui/manual_memcpy/without_loop_counters.rs:53:5
    |
 LL | /     for i in 10..256 {
 LL | |
@@ -64,7 +64,7 @@ LL +     dst2[(10 + 500)..(256 + 500)].copy_from_slice(&src[10..256]);
    |
 
 error: it looks like you're manually copying between slices
-  --> tests/ui/manual_memcpy/without_loop_counters.rs:61:5
+  --> tests/ui/manual_memcpy/without_loop_counters.rs:66:5
    |
 LL | /     for i in 10..LOOP_OFFSET {
 LL | |
@@ -73,7 +73,7 @@ LL | |     }
    | |_____^ help: try replacing the loop by: `dst[(10 + LOOP_OFFSET)..(LOOP_OFFSET + LOOP_OFFSET)].copy_from_slice(&src[(10 - some_var)..(LOOP_OFFSET - some_var)]);`
 
 error: it looks like you're manually copying between slices
-  --> tests/ui/manual_memcpy/without_loop_counters.rs:75:5
+  --> tests/ui/manual_memcpy/without_loop_counters.rs:80:5
    |
 LL | /     for i in 0..src_vec.len() {
 LL | |
@@ -82,7 +82,7 @@ LL | |     }
    | |_____^ help: try replacing the loop by: `dst_vec[..src_vec.len()].copy_from_slice(&src_vec[..]);`
 
 error: it looks like you're manually copying between slices
-  --> tests/ui/manual_memcpy/without_loop_counters.rs:105:5
+  --> tests/ui/manual_memcpy/without_loop_counters.rs:110:5
    |
 LL | /     for i in from..from + src.len() {
 LL | |
@@ -91,7 +91,7 @@ LL | |     }
    | |_____^ help: try replacing the loop by: `dst[from..(from + src.len())].copy_from_slice(&src[..(from + src.len() - from)]);`
 
 error: it looks like you're manually copying between slices
-  --> tests/ui/manual_memcpy/without_loop_counters.rs:110:5
+  --> tests/ui/manual_memcpy/without_loop_counters.rs:115:5
    |
 LL | /     for i in from..from + 3 {
 LL | |
@@ -100,7 +100,7 @@ LL | |     }
    | |_____^ help: try replacing the loop by: `dst[from..(from + 3)].copy_from_slice(&src[..(from + 3 - from)]);`
 
 error: it looks like you're manually copying between slices
-  --> tests/ui/manual_memcpy/without_loop_counters.rs:116:5
+  --> tests/ui/manual_memcpy/without_loop_counters.rs:121:5
    |
 LL | /     for i in 0..5 {
 LL | |
@@ -109,7 +109,7 @@ LL | |     }
    | |_____^ help: try replacing the loop by: `dst[..5].copy_from_slice(&src);`
 
 error: it looks like you're manually copying between slices
-  --> tests/ui/manual_memcpy/without_loop_counters.rs:122:5
+  --> tests/ui/manual_memcpy/without_loop_counters.rs:127:5
    |
 LL | /     for i in 0..0 {
 LL | |
@@ -118,7 +118,7 @@ LL | |     }
    | |_____^ help: try replacing the loop by: `dst[..0].copy_from_slice(&src[..0]);`
 
 error: it looks like you're manually copying between slices
-  --> tests/ui/manual_memcpy/without_loop_counters.rs:146:5
+  --> tests/ui/manual_memcpy/without_loop_counters.rs:151:5
    |
 LL | /     for i in 0..4 {
 LL | |
@@ -127,7 +127,7 @@ LL | |     }
    | |_____^ help: try replacing the loop by: `dst.copy_from_slice(&src[..4]);`
 
 error: it looks like you're manually copying between slices
-  --> tests/ui/manual_memcpy/without_loop_counters.rs:152:5
+  --> tests/ui/manual_memcpy/without_loop_counters.rs:157:5
    |
 LL | /     for i in 0..5 {
 LL | |
@@ -136,7 +136,7 @@ LL | |     }
    | |_____^ help: try replacing the loop by: `dst[..5].copy_from_slice(&src);`
 
 error: it looks like you're manually copying between slices
-  --> tests/ui/manual_memcpy/without_loop_counters.rs:158:5
+  --> tests/ui/manual_memcpy/without_loop_counters.rs:163:5
    |
 LL | /     for i in 0..5 {
 LL | |
@@ -145,7 +145,7 @@ LL | |     }
    | |_____^ help: try replacing the loop by: `dst.copy_from_slice(&src);`
 
 error: it looks like you're manually copying between slices
-  --> tests/ui/manual_memcpy/without_loop_counters.rs:205:5
+  --> tests/ui/manual_memcpy/without_loop_counters.rs:210:5
    |
 LL | /     for i in 0..5 {
 LL | |
@@ -154,7 +154,7 @@ LL | |     }
    | |_____^ help: try replacing the loop by: `dst.copy_from_slice(&src[0]);`
 
 error: it looks like you're manually copying between slices
-  --> tests/ui/manual_memcpy/without_loop_counters.rs:211:5
+  --> tests/ui/manual_memcpy/without_loop_counters.rs:216:5
    |
 LL | /     for i in 0..5 {
 LL | |
@@ -163,7 +163,7 @@ LL | |     }
    | |_____^ help: try replacing the loop by: `dst.copy_from_slice(&src[0][1]);`
 
 error: it looks like you're manually copying between slices
-  --> tests/ui/manual_memcpy/without_loop_counters.rs:219:5
+  --> tests/ui/manual_memcpy/without_loop_counters.rs:224:5
    |
 LL | /     for i in 0..src.len() {
 LL | |
diff --git a/src/tools/clippy/tests/ui/manual_option_as_slice.fixed b/src/tools/clippy/tests/ui/manual_option_as_slice.fixed
new file mode 100644
index 00000000000..48337d7654d
--- /dev/null
+++ b/src/tools/clippy/tests/ui/manual_option_as_slice.fixed
@@ -0,0 +1,62 @@
+#![warn(clippy::manual_option_as_slice)]
+#![allow(clippy::redundant_closure, clippy::unwrap_or_default)]
+
+fn check(x: Option<u32>) {
+    _ = x.as_slice();
+
+    _ = x.as_slice();
+
+    _ = x.as_slice();
+    //~^ manual_option_as_slice
+
+    _ = x.as_slice();
+    //~^ manual_option_as_slice
+
+    _ = x.as_slice();
+    //~^ manual_option_as_slice
+
+    _ = x.as_slice();
+    //~^ manual_option_as_slice
+
+    {
+        use std::slice::from_ref;
+        _ = x.as_slice();
+        //~^ manual_option_as_slice
+    }
+
+    // possible false positives
+    let y = x.as_ref();
+    _ = match y {
+        // as_ref outside
+        Some(f) => &[f][..],
+        None => &[][..],
+    };
+    _ = match x.as_ref() {
+        Some(f) => std::slice::from_ref(f),
+        None => &[0],
+    };
+    _ = match x.as_ref() {
+        Some(42) => &[23],
+        Some(f) => std::slice::from_ref(f),
+        None => &[],
+    };
+    let b = &[42];
+    _ = if let Some(_f) = x.as_ref() {
+        std::slice::from_ref(b)
+    } else {
+        &[]
+    };
+    _ = x.as_ref().map_or(&[42][..], std::slice::from_ref);
+    _ = x.as_ref().map_or_else(|| &[42][..1], std::slice::from_ref);
+    _ = x.as_ref().map(|f| std::slice::from_ref(f)).unwrap_or_default();
+}
+
+#[clippy::msrv = "1.74"]
+fn check_msrv(x: Option<u32>) {
+    _ = x.as_ref().map_or(&[][..], std::slice::from_ref);
+}
+
+fn main() {
+    check(Some(1));
+    check_msrv(Some(175));
+}
diff --git a/src/tools/clippy/tests/ui/manual_option_as_slice.rs b/src/tools/clippy/tests/ui/manual_option_as_slice.rs
new file mode 100644
index 00000000000..561a8b53401
--- /dev/null
+++ b/src/tools/clippy/tests/ui/manual_option_as_slice.rs
@@ -0,0 +1,71 @@
+#![warn(clippy::manual_option_as_slice)]
+#![allow(clippy::redundant_closure, clippy::unwrap_or_default)]
+
+fn check(x: Option<u32>) {
+    _ = match x.as_ref() {
+        //~^ manual_option_as_slice
+        Some(f) => std::slice::from_ref(f),
+        None => &[],
+    };
+
+    _ = if let Some(f) = x.as_ref() {
+        //~^ manual_option_as_slice
+        std::slice::from_ref(f)
+    } else {
+        &[]
+    };
+
+    _ = x.as_ref().map_or(&[][..], std::slice::from_ref);
+    //~^ manual_option_as_slice
+
+    _ = x.as_ref().map_or_else(Default::default, std::slice::from_ref);
+    //~^ manual_option_as_slice
+
+    _ = x.as_ref().map(std::slice::from_ref).unwrap_or_default();
+    //~^ manual_option_as_slice
+
+    _ = x.as_ref().map_or_else(|| &[42][..0], std::slice::from_ref);
+    //~^ manual_option_as_slice
+
+    {
+        use std::slice::from_ref;
+        _ = x.as_ref().map_or_else(<&[_]>::default, from_ref);
+        //~^ manual_option_as_slice
+    }
+
+    // possible false positives
+    let y = x.as_ref();
+    _ = match y {
+        // as_ref outside
+        Some(f) => &[f][..],
+        None => &[][..],
+    };
+    _ = match x.as_ref() {
+        Some(f) => std::slice::from_ref(f),
+        None => &[0],
+    };
+    _ = match x.as_ref() {
+        Some(42) => &[23],
+        Some(f) => std::slice::from_ref(f),
+        None => &[],
+    };
+    let b = &[42];
+    _ = if let Some(_f) = x.as_ref() {
+        std::slice::from_ref(b)
+    } else {
+        &[]
+    };
+    _ = x.as_ref().map_or(&[42][..], std::slice::from_ref);
+    _ = x.as_ref().map_or_else(|| &[42][..1], std::slice::from_ref);
+    _ = x.as_ref().map(|f| std::slice::from_ref(f)).unwrap_or_default();
+}
+
+#[clippy::msrv = "1.74"]
+fn check_msrv(x: Option<u32>) {
+    _ = x.as_ref().map_or(&[][..], std::slice::from_ref);
+}
+
+fn main() {
+    check(Some(1));
+    check_msrv(Some(175));
+}
diff --git a/src/tools/clippy/tests/ui/manual_option_as_slice.stderr b/src/tools/clippy/tests/ui/manual_option_as_slice.stderr
new file mode 100644
index 00000000000..569269d3e2b
--- /dev/null
+++ b/src/tools/clippy/tests/ui/manual_option_as_slice.stderr
@@ -0,0 +1,58 @@
+error: use `Option::as_slice`
+  --> tests/ui/manual_option_as_slice.rs:5:9
+   |
+LL |       _ = match x.as_ref() {
+   |  _________^
+LL | |
+LL | |         Some(f) => std::slice::from_ref(f),
+LL | |         None => &[],
+LL | |     };
+   | |_____^ help: use: `x.as_slice()`
+   |
+   = note: `-D clippy::manual-option-as-slice` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::manual_option_as_slice)]`
+
+error: use `Option::as_slice`
+  --> tests/ui/manual_option_as_slice.rs:11:9
+   |
+LL |       _ = if let Some(f) = x.as_ref() {
+   |  _________^
+LL | |
+LL | |         std::slice::from_ref(f)
+LL | |     } else {
+LL | |         &[]
+LL | |     };
+   | |_____^ help: use: `x.as_slice()`
+
+error: use `Option::as_slice`
+  --> tests/ui/manual_option_as_slice.rs:18:9
+   |
+LL |     _ = x.as_ref().map_or(&[][..], std::slice::from_ref);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `x.as_slice()`
+
+error: use `Option::as_slice`
+  --> tests/ui/manual_option_as_slice.rs:21:9
+   |
+LL |     _ = x.as_ref().map_or_else(Default::default, std::slice::from_ref);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `x.as_slice()`
+
+error: use `Option::as_slice`
+  --> tests/ui/manual_option_as_slice.rs:24:9
+   |
+LL |     _ = x.as_ref().map(std::slice::from_ref).unwrap_or_default();
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `x.as_slice()`
+
+error: use `Option::as_slice`
+  --> tests/ui/manual_option_as_slice.rs:27:9
+   |
+LL |     _ = x.as_ref().map_or_else(|| &[42][..0], std::slice::from_ref);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `x.as_slice()`
+
+error: use `Option::as_slice`
+  --> tests/ui/manual_option_as_slice.rs:32:13
+   |
+LL |         _ = x.as_ref().map_or_else(<&[_]>::default, from_ref);
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `x.as_slice()`
+
+error: aborting due to 7 previous errors
+
diff --git a/src/tools/clippy/tests/ui/manual_slice_fill.fixed b/src/tools/clippy/tests/ui/manual_slice_fill.fixed
new file mode 100644
index 00000000000..397a156a2dc
--- /dev/null
+++ b/src/tools/clippy/tests/ui/manual_slice_fill.fixed
@@ -0,0 +1,101 @@
+#![warn(clippy::manual_slice_fill)]
+#![allow(clippy::needless_range_loop)]
+
+macro_rules! assign_element {
+    ($slice:ident, $index:expr) => {
+        $slice[$index] = 0;
+    };
+}
+
+macro_rules! assign_element_2 {
+    ($i:expr) => {
+        $i = 0;
+    };
+}
+
+struct NoClone;
+
+fn num() -> usize {
+    5
+}
+
+fn should_lint() {
+    let mut some_slice = [1, 2, 3, 4, 5];
+
+    some_slice.fill(0);
+
+    let x = 5;
+    some_slice.fill(x);
+
+    some_slice.fill(0);
+
+    // This should trigger `manual_slice_fill`, but the applicability is `MaybeIncorrect` since comments
+    // within the loop might be purely informational.
+    some_slice.fill(0);
+}
+
+fn should_not_lint() {
+    let mut some_slice = [1, 2, 3, 4, 5];
+
+    // Should not lint because we can't determine if the scope of the loop is intended to access all the
+    // elements of the slice.
+    for i in 0..5 {
+        some_slice[i] = 0;
+    }
+
+    // Should not lint, as using a function to assign values to elements might be
+    // intentional. For example, the contents of `num()` could be temporary and subject to change
+    // later.
+    for i in 0..some_slice.len() {
+        some_slice[i] = num();
+    }
+
+    // Should not lint because this loop isn't equivalent to `fill`.
+    for i in 0..some_slice.len() {
+        some_slice[i] = 0;
+        println!("foo");
+    }
+
+    // Should not lint because it may be intentional to use a macro to perform an operation equivalent
+    // to `fill`.
+    for i in 0..some_slice.len() {
+        assign_element!(some_slice, i);
+    }
+
+    let another_slice = [1, 2, 3];
+    // Should not lint because the range is not for `some_slice`.
+    for i in 0..another_slice.len() {
+        some_slice[i] = 0;
+    }
+
+    let mut vec: Vec<Option<NoClone>> = Vec::with_capacity(5);
+    // Should not lint because `NoClone` does not have `Clone` trait.
+    for i in 0..vec.len() {
+        vec[i] = None;
+    }
+
+    // Should not lint, as using a function to assign values to elements might be
+    // intentional. For example, the contents of `num()` could be temporary and subject to change
+    // later.
+    for i in &mut some_slice {
+        *i = num();
+    }
+
+    // Should not lint because this loop isn't equivalent to `fill`.
+    for i in &mut some_slice {
+        *i = 0;
+        println!("foo");
+    }
+
+    // Should not lint because it may be intentional to use a macro to perform an operation equivalent
+    // to `fill`.
+    for i in &mut some_slice {
+        assign_element_2!(*i);
+    }
+
+    let mut vec: Vec<Option<NoClone>> = Vec::with_capacity(5);
+    // Should not lint because `NoClone` does not have `Clone` trait.
+    for i in &mut vec {
+        *i = None;
+    }
+}
diff --git a/src/tools/clippy/tests/ui/manual_slice_fill.rs b/src/tools/clippy/tests/ui/manual_slice_fill.rs
new file mode 100644
index 00000000000..c25127ca613
--- /dev/null
+++ b/src/tools/clippy/tests/ui/manual_slice_fill.rs
@@ -0,0 +1,110 @@
+#![warn(clippy::manual_slice_fill)]
+#![allow(clippy::needless_range_loop)]
+
+macro_rules! assign_element {
+    ($slice:ident, $index:expr) => {
+        $slice[$index] = 0;
+    };
+}
+
+macro_rules! assign_element_2 {
+    ($i:expr) => {
+        $i = 0;
+    };
+}
+
+struct NoClone;
+
+fn num() -> usize {
+    5
+}
+
+fn should_lint() {
+    let mut some_slice = [1, 2, 3, 4, 5];
+
+    for i in 0..some_slice.len() {
+        some_slice[i] = 0;
+    }
+
+    let x = 5;
+    for i in 0..some_slice.len() {
+        some_slice[i] = x;
+    }
+
+    for i in &mut some_slice {
+        *i = 0;
+    }
+
+    // This should trigger `manual_slice_fill`, but the applicability is `MaybeIncorrect` since comments
+    // within the loop might be purely informational.
+    for i in 0..some_slice.len() {
+        some_slice[i] = 0;
+        // foo
+    }
+}
+
+fn should_not_lint() {
+    let mut some_slice = [1, 2, 3, 4, 5];
+
+    // Should not lint because we can't determine if the scope of the loop is intended to access all the
+    // elements of the slice.
+    for i in 0..5 {
+        some_slice[i] = 0;
+    }
+
+    // Should not lint, as using a function to assign values to elements might be
+    // intentional. For example, the contents of `num()` could be temporary and subject to change
+    // later.
+    for i in 0..some_slice.len() {
+        some_slice[i] = num();
+    }
+
+    // Should not lint because this loop isn't equivalent to `fill`.
+    for i in 0..some_slice.len() {
+        some_slice[i] = 0;
+        println!("foo");
+    }
+
+    // Should not lint because it may be intentional to use a macro to perform an operation equivalent
+    // to `fill`.
+    for i in 0..some_slice.len() {
+        assign_element!(some_slice, i);
+    }
+
+    let another_slice = [1, 2, 3];
+    // Should not lint because the range is not for `some_slice`.
+    for i in 0..another_slice.len() {
+        some_slice[i] = 0;
+    }
+
+    let mut vec: Vec<Option<NoClone>> = Vec::with_capacity(5);
+    // Should not lint because `NoClone` does not have `Clone` trait.
+    for i in 0..vec.len() {
+        vec[i] = None;
+    }
+
+    // Should not lint, as using a function to assign values to elements might be
+    // intentional. For example, the contents of `num()` could be temporary and subject to change
+    // later.
+    for i in &mut some_slice {
+        *i = num();
+    }
+
+    // Should not lint because this loop isn't equivalent to `fill`.
+    for i in &mut some_slice {
+        *i = 0;
+        println!("foo");
+    }
+
+    // Should not lint because it may be intentional to use a macro to perform an operation equivalent
+    // to `fill`.
+    for i in &mut some_slice {
+        assign_element_2!(*i);
+    }
+
+    let mut vec: Vec<Option<NoClone>> = Vec::with_capacity(5);
+    // Should not lint because `NoClone` does not have `Clone` trait.
+    for i in &mut vec {
+        *i = None;
+    }
+}
diff --git a/src/tools/clippy/tests/ui/manual_slice_fill.stderr b/src/tools/clippy/tests/ui/manual_slice_fill.stderr
new file mode 100644
index 00000000000..3aa980f6919
--- /dev/null
+++ b/src/tools/clippy/tests/ui/manual_slice_fill.stderr
@@ -0,0 +1,38 @@
+error: manually filling a slice
+  --> tests/ui/manual_slice_fill.rs:25:5
+   |
+LL | /     for i in 0..some_slice.len() {
+LL | |         some_slice[i] = 0;
+LL | |     }
+   | |_____^ help: try: `some_slice.fill(0);`
+   |
+   = note: `-D clippy::manual-slice-fill` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::manual_slice_fill)]`
+
+error: manually filling a slice
+  --> tests/ui/manual_slice_fill.rs:30:5
+   |
+LL | /     for i in 0..some_slice.len() {
+LL | |         some_slice[i] = x;
+LL | |     }
+   | |_____^ help: try: `some_slice.fill(x);`
+
+error: manually filling a slice
+  --> tests/ui/manual_slice_fill.rs:34:5
+   |
+LL | /     for i in &mut some_slice {
+LL | |         *i = 0;
+LL | |     }
+   | |_____^ help: try: `some_slice.fill(0);`
+
+error: manually filling a slice
+  --> tests/ui/manual_slice_fill.rs:40:5
+   |
+LL | /     for i in 0..some_slice.len() {
+LL | |         some_slice[i] = 0;
+LL | |         // foo
+LL | |     }
+   | |_____^ help: try: `some_slice.fill(0);`
+
+error: aborting due to 4 previous errors
+
diff --git a/src/tools/clippy/tests/ui/manual_unwrap_or_default_unfixable.rs b/src/tools/clippy/tests/ui/manual_unwrap_or_default_unfixable.rs
new file mode 100644
index 00000000000..acc54b52816
--- /dev/null
+++ b/src/tools/clippy/tests/ui/manual_unwrap_or_default_unfixable.rs
@@ -0,0 +1,15 @@
+//@no-rustfix
+fn issue_12670() {
+    // no auto: type not found
+    #[allow(clippy::match_result_ok)]
+    let _ = if let Some(x) = "1".parse().ok() {
+        x
+    } else {
+        i32::default()
+    };
+    let _ = if let Some(x) = None { x } else { i32::default() };
+    // auto fix with unwrap_or_default
+    let a: Option<i32> = None;
+    let _ = if let Some(x) = a { x } else { i32::default() };
+    let _ = if let Some(x) = Some(99) { x } else { i32::default() };
+}
diff --git a/src/tools/clippy/tests/ui/manual_unwrap_or_default_unfixable.stderr b/src/tools/clippy/tests/ui/manual_unwrap_or_default_unfixable.stderr
new file mode 100644
index 00000000000..3849d33cf25
--- /dev/null
+++ b/src/tools/clippy/tests/ui/manual_unwrap_or_default_unfixable.stderr
@@ -0,0 +1,34 @@
+error: if let can be simplified with `.unwrap_or_default()`
+  --> tests/ui/manual_unwrap_or_default_unfixable.rs:5:13
+   |
+LL |       let _ = if let Some(x) = "1".parse().ok() {
+   |  _____________^
+LL | |         x
+LL | |     } else {
+LL | |         i32::default()
+LL | |     };
+   | |_____^ help: ascribe the type i32 and replace your expression with: `"1".parse().ok().unwrap_or_default()`
+   |
+   = note: `-D clippy::manual-unwrap-or-default` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::manual_unwrap_or_default)]`
+
+error: if let can be simplified with `.unwrap_or_default()`
+  --> tests/ui/manual_unwrap_or_default_unfixable.rs:10:13
+   |
+LL |     let _ = if let Some(x) = None { x } else { i32::default() };
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `None::<i32>.unwrap_or_default()`
+
+error: if let can be simplified with `.unwrap_or_default()`
+  --> tests/ui/manual_unwrap_or_default_unfixable.rs:13:13
+   |
+LL |     let _ = if let Some(x) = a { x } else { i32::default() };
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `a.unwrap_or_default()`
+
+error: if let can be simplified with `.unwrap_or_default()`
+  --> tests/ui/manual_unwrap_or_default_unfixable.rs:14:13
+   |
+LL |     let _ = if let Some(x) = Some(99) { x } else { i32::default() };
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `Some(99).unwrap_or_default()`
+
+error: aborting due to 4 previous errors
+
diff --git a/src/tools/clippy/tests/ui/needless_option_take.fixed b/src/tools/clippy/tests/ui/needless_option_take.fixed
new file mode 100644
index 00000000000..6514b67ef7a
--- /dev/null
+++ b/src/tools/clippy/tests/ui/needless_option_take.fixed
@@ -0,0 +1,58 @@
+struct MyStruct;
+
+impl MyStruct {
+    pub fn get_option() -> Option<Self> {
+        todo!()
+    }
+}
+
+fn return_option() -> Option<i32> {
+    todo!()
+}
+
+fn main() {
+    println!("Testing non erroneous option_take_on_temporary");
+    let mut option = Some(1);
+    let _ = Box::new(move || option.take().unwrap());
+
+    println!("Testing non erroneous option_take_on_temporary");
+    let x = Some(3);
+    x.as_ref();
+
+    let x = Some(3);
+    x.as_ref();
+    //~^ ERROR: called `Option::take()` on a temporary value
+
+    println!("Testing non erroneous option_take_on_temporary");
+    let mut x = Some(3);
+    let y = x.as_mut();
+
+    let mut x = Some(3);
+    let y = x.as_mut();
+    //~^ ERROR: called `Option::take()` on a temporary value
+    let y = x.replace(289);
+    //~^ ERROR: called `Option::take()` on a temporary value
+
+    let y = Some(3).as_mut();
+    //~^ ERROR: called `Option::take()` on a temporary value
+
+    let y = Option::as_mut(&mut x);
+    //~^ ERROR: called `Option::take()` on a temporary value
+
+    let x = return_option();
+    let x = return_option();
+    //~^ ERROR: called `Option::take()` on a temporary value
+
+    let x = MyStruct::get_option();
+    let x = MyStruct::get_option();
+    //~^ ERROR: called `Option::take()` on a temporary value
+
+    let mut my_vec = vec![1, 2, 3];
+    my_vec.push(4);
+    let y = my_vec.first();
+    let y = my_vec.first();
+    //~^ ERROR: called `Option::take()` on a temporary value
+
+    let y = my_vec.first();
+    //~^ ERROR: called `Option::take()` on a temporary value
+}
diff --git a/src/tools/clippy/tests/ui/needless_option_take.stderr b/src/tools/clippy/tests/ui/needless_option_take.stderr
index e036bd53170..3fc339ed79e 100644
--- a/src/tools/clippy/tests/ui/needless_option_take.stderr
+++ b/src/tools/clippy/tests/ui/needless_option_take.stderr
@@ -2,7 +2,9 @@ error: called `Option::take()` on a temporary value
   --> tests/ui/needless_option_take.rs:23:5
    |
 LL |     x.as_ref().take();
-   |     ^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^-------
+   |               |
+   |               help: remove
    |
    = note: `as_ref` creates a temporary value, so calling take() has no effect
    = note: `-D clippy::needless-option-take` implied by `-D warnings`
@@ -12,7 +14,9 @@ error: called `Option::take()` on a temporary value
   --> tests/ui/needless_option_take.rs:31:13
    |
 LL |     let y = x.as_mut().take();
-   |             ^^^^^^^^^^^^^^^^^
+   |             ^^^^^^^^^^-------
+   |                       |
+   |                       help: remove
    |
    = note: `as_mut` creates a temporary value, so calling take() has no effect
 
@@ -20,7 +24,9 @@ error: called `Option::take()` on a temporary value
   --> tests/ui/needless_option_take.rs:33:13
    |
 LL |     let y = x.replace(289).take();
-   |             ^^^^^^^^^^^^^^^^^^^^^
+   |             ^^^^^^^^^^^^^^-------
+   |                           |
+   |                           help: remove
    |
    = note: `replace` creates a temporary value, so calling take() has no effect
 
@@ -28,7 +34,9 @@ error: called `Option::take()` on a temporary value
   --> tests/ui/needless_option_take.rs:36:13
    |
 LL |     let y = Some(3).as_mut().take();
-   |             ^^^^^^^^^^^^^^^^^^^^^^^
+   |             ^^^^^^^^^^^^^^^^-------
+   |                             |
+   |                             help: remove
    |
    = note: `as_mut` creates a temporary value, so calling take() has no effect
 
@@ -36,7 +44,9 @@ error: called `Option::take()` on a temporary value
   --> tests/ui/needless_option_take.rs:39:13
    |
 LL |     let y = Option::as_mut(&mut x).take();
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |             ^^^^^^^^^^^^^^^^^^^^^^-------
+   |                                   |
+   |                                   help: remove
    |
    = note: `as_mut` creates a temporary value, so calling take() has no effect
 
@@ -44,7 +54,9 @@ error: called `Option::take()` on a temporary value
   --> tests/ui/needless_option_take.rs:43:13
    |
 LL |     let x = return_option().take();
-   |             ^^^^^^^^^^^^^^^^^^^^^^
+   |             ^^^^^^^^^^^^^^^-------
+   |                            |
+   |                            help: remove
    |
    = note: `return_option` creates a temporary value, so calling take() has no effect
 
@@ -52,7 +64,9 @@ error: called `Option::take()` on a temporary value
   --> tests/ui/needless_option_take.rs:47:13
    |
 LL |     let x = MyStruct::get_option().take();
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |             ^^^^^^^^^^^^^^^^^^^^^^-------
+   |                                   |
+   |                                   help: remove
    |
    = note: `get_option` creates a temporary value, so calling take() has no effect
 
@@ -60,7 +74,9 @@ error: called `Option::take()` on a temporary value
   --> tests/ui/needless_option_take.rs:53:13
    |
 LL |     let y = my_vec.first().take();
-   |             ^^^^^^^^^^^^^^^^^^^^^
+   |             ^^^^^^^^^^^^^^-------
+   |                           |
+   |                           help: remove
    |
    = note: `first` creates a temporary value, so calling take() has no effect
 
@@ -68,7 +84,9 @@ error: called `Option::take()` on a temporary value
   --> tests/ui/needless_option_take.rs:56:13
    |
 LL |     let y = my_vec.first().take();
-   |             ^^^^^^^^^^^^^^^^^^^^^
+   |             ^^^^^^^^^^^^^^-------
+   |                           |
+   |                           help: remove
    |
    = note: `first` creates a temporary value, so calling take() has no effect
 
diff --git a/src/tools/clippy/tests/ui/needless_range_loop.rs b/src/tools/clippy/tests/ui/needless_range_loop.rs
index 3f242195330..75f1896eded 100644
--- a/src/tools/clippy/tests/ui/needless_range_loop.rs
+++ b/src/tools/clippy/tests/ui/needless_range_loop.rs
@@ -2,7 +2,8 @@
 #![allow(
     clippy::uninlined_format_args,
     clippy::unnecessary_literal_unwrap,
-    clippy::useless_vec
+    clippy::useless_vec,
+    clippy::manual_slice_fill
 )]
 //@no-rustfix
 static STATIC: [usize; 4] = [0, 1, 8, 16];
diff --git a/src/tools/clippy/tests/ui/needless_range_loop.stderr b/src/tools/clippy/tests/ui/needless_range_loop.stderr
index dc2cf437e02..503d796e5e8 100644
--- a/src/tools/clippy/tests/ui/needless_range_loop.stderr
+++ b/src/tools/clippy/tests/ui/needless_range_loop.stderr
@@ -1,5 +1,5 @@
 error: the loop variable `i` is only used to index `vec`
-  --> tests/ui/needless_range_loop.rs:15:14
+  --> tests/ui/needless_range_loop.rs:16:14
    |
 LL |     for i in 0..vec.len() {
    |              ^^^^^^^^^^^^
@@ -12,7 +12,7 @@ LL |     for <item> in &vec {
    |         ~~~~~~    ~~~~
 
 error: the loop variable `i` is only used to index `vec`
-  --> tests/ui/needless_range_loop.rs:26:14
+  --> tests/ui/needless_range_loop.rs:27:14
    |
 LL |     for i in 0..vec.len() {
    |              ^^^^^^^^^^^^
@@ -23,7 +23,7 @@ LL |     for <item> in &vec {
    |         ~~~~~~    ~~~~
 
 error: the loop variable `j` is only used to index `STATIC`
-  --> tests/ui/needless_range_loop.rs:32:14
+  --> tests/ui/needless_range_loop.rs:33:14
    |
 LL |     for j in 0..4 {
    |              ^^^^
@@ -34,7 +34,7 @@ LL |     for <item> in &STATIC {
    |         ~~~~~~    ~~~~~~~
 
 error: the loop variable `j` is only used to index `CONST`
-  --> tests/ui/needless_range_loop.rs:37:14
+  --> tests/ui/needless_range_loop.rs:38:14
    |
 LL |     for j in 0..4 {
    |              ^^^^
@@ -45,7 +45,7 @@ LL |     for <item> in &CONST {
    |         ~~~~~~    ~~~~~~
 
 error: the loop variable `i` is used to index `vec`
-  --> tests/ui/needless_range_loop.rs:42:14
+  --> tests/ui/needless_range_loop.rs:43:14
    |
 LL |     for i in 0..vec.len() {
    |              ^^^^^^^^^^^^
@@ -56,7 +56,7 @@ LL |     for (i, <item>) in vec.iter().enumerate() {
    |         ~~~~~~~~~~~    ~~~~~~~~~~~~~~~~~~~~~~
 
 error: the loop variable `i` is only used to index `vec2`
-  --> tests/ui/needless_range_loop.rs:51:14
+  --> tests/ui/needless_range_loop.rs:52:14
    |
 LL |     for i in 0..vec.len() {
    |              ^^^^^^^^^^^^
@@ -67,7 +67,7 @@ LL |     for <item> in vec2.iter().take(vec.len()) {
    |         ~~~~~~    ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: the loop variable `i` is only used to index `vec`
-  --> tests/ui/needless_range_loop.rs:56:14
+  --> tests/ui/needless_range_loop.rs:57:14
    |
 LL |     for i in 5..vec.len() {
    |              ^^^^^^^^^^^^
@@ -78,7 +78,7 @@ LL |     for <item> in vec.iter().skip(5) {
    |         ~~~~~~    ~~~~~~~~~~~~~~~~~~
 
 error: the loop variable `i` is only used to index `vec`
-  --> tests/ui/needless_range_loop.rs:61:14
+  --> tests/ui/needless_range_loop.rs:62:14
    |
 LL |     for i in 0..MAX_LEN {
    |              ^^^^^^^^^^
@@ -89,7 +89,7 @@ LL |     for <item> in vec.iter().take(MAX_LEN) {
    |         ~~~~~~    ~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: the loop variable `i` is only used to index `vec`
-  --> tests/ui/needless_range_loop.rs:66:14
+  --> tests/ui/needless_range_loop.rs:67:14
    |
 LL |     for i in 0..=MAX_LEN {
    |              ^^^^^^^^^^^
@@ -100,7 +100,7 @@ LL |     for <item> in vec.iter().take(MAX_LEN + 1) {
    |         ~~~~~~    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: the loop variable `i` is only used to index `vec`
-  --> tests/ui/needless_range_loop.rs:71:14
+  --> tests/ui/needless_range_loop.rs:72:14
    |
 LL |     for i in 5..10 {
    |              ^^^^^
@@ -111,7 +111,7 @@ LL |     for <item> in vec.iter().take(10).skip(5) {
    |         ~~~~~~    ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: the loop variable `i` is only used to index `vec`
-  --> tests/ui/needless_range_loop.rs:76:14
+  --> tests/ui/needless_range_loop.rs:77:14
    |
 LL |     for i in 5..=10 {
    |              ^^^^^^
@@ -122,7 +122,7 @@ LL |     for <item> in vec.iter().take(10 + 1).skip(5) {
    |         ~~~~~~    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: the loop variable `i` is used to index `vec`
-  --> tests/ui/needless_range_loop.rs:81:14
+  --> tests/ui/needless_range_loop.rs:82:14
    |
 LL |     for i in 5..vec.len() {
    |              ^^^^^^^^^^^^
@@ -133,7 +133,7 @@ LL |     for (i, <item>) in vec.iter().enumerate().skip(5) {
    |         ~~~~~~~~~~~    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: the loop variable `i` is used to index `vec`
-  --> tests/ui/needless_range_loop.rs:86:14
+  --> tests/ui/needless_range_loop.rs:87:14
    |
 LL |     for i in 5..10 {
    |              ^^^^^
@@ -144,7 +144,7 @@ LL |     for (i, <item>) in vec.iter().enumerate().take(10).skip(5) {
    |         ~~~~~~~~~~~    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: the loop variable `i` is used to index `vec`
-  --> tests/ui/needless_range_loop.rs:92:14
+  --> tests/ui/needless_range_loop.rs:93:14
    |
 LL |     for i in 0..vec.len() {
    |              ^^^^^^^^^^^^
diff --git a/src/tools/clippy/tests/ui/precedence.fixed b/src/tools/clippy/tests/ui/precedence.fixed
index 9864dd2550b..52144a18bac 100644
--- a/src/tools/clippy/tests/ui/precedence.fixed
+++ b/src/tools/clippy/tests/ui/precedence.fixed
@@ -20,10 +20,10 @@ fn main() {
     1 ^ (1 - 1);
     3 | (2 - 1);
     3 & (5 - 2);
-    0x0F00 & (0x00F0 << 4);
-    0x0F00 & (0xF000 >> 4);
-    (0x0F00 << 1) ^ 3;
-    (0x0F00 << 1) | 2;
+    0x0F00 & 0x00F0 << 4;
+    0x0F00 & 0xF000 >> 4;
+    0x0F00 << 1 ^ 3;
+    0x0F00 << 1 | 2;
 
     let b = 3;
     trip!(b * 8);
diff --git a/src/tools/clippy/tests/ui/precedence.stderr b/src/tools/clippy/tests/ui/precedence.stderr
index 329422cb8a6..68ad5cb4829 100644
--- a/src/tools/clippy/tests/ui/precedence.stderr
+++ b/src/tools/clippy/tests/ui/precedence.stderr
@@ -43,29 +43,5 @@ error: operator precedence might not be obvious
 LL |     3 & 5 - 2;
    |     ^^^^^^^^^ help: consider parenthesizing your expression: `3 & (5 - 2)`
 
-error: operator precedence might not be obvious
-  --> tests/ui/precedence.rs:23:5
-   |
-LL |     0x0F00 & 0x00F0 << 4;
-   |     ^^^^^^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `0x0F00 & (0x00F0 << 4)`
-
-error: operator precedence might not be obvious
-  --> tests/ui/precedence.rs:24:5
-   |
-LL |     0x0F00 & 0xF000 >> 4;
-   |     ^^^^^^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `0x0F00 & (0xF000 >> 4)`
-
-error: operator precedence might not be obvious
-  --> tests/ui/precedence.rs:25:5
-   |
-LL |     0x0F00 << 1 ^ 3;
-   |     ^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `(0x0F00 << 1) ^ 3`
-
-error: operator precedence might not be obvious
-  --> tests/ui/precedence.rs:26:5
-   |
-LL |     0x0F00 << 1 | 2;
-   |     ^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `(0x0F00 << 1) | 2`
-
-error: aborting due to 11 previous errors
+error: aborting due to 7 previous errors
 
diff --git a/src/tools/clippy/tests/ui/precedence_bits.fixed b/src/tools/clippy/tests/ui/precedence_bits.fixed
new file mode 100644
index 00000000000..82fea0d14e4
--- /dev/null
+++ b/src/tools/clippy/tests/ui/precedence_bits.fixed
@@ -0,0 +1,35 @@
+#![warn(clippy::precedence_bits)]
+#![allow(
+    unused_must_use,
+    clippy::no_effect,
+    clippy::unnecessary_operation,
+    clippy::precedence
+)]
+#![allow(clippy::identity_op)]
+#![allow(clippy::eq_op)]
+
+macro_rules! trip {
+    ($a:expr) => {
+        match $a & 0b1111_1111u8 {
+            0 => println!("a is zero ({})", $a),
+            _ => println!("a is {}", $a),
+        }
+    };
+}
+
+fn main() {
+    1 << 2 + 3;
+    1 + 2 << 3;
+    4 >> 1 + 1;
+    1 + 3 >> 2;
+    1 ^ 1 - 1;
+    3 | 2 - 1;
+    3 & 5 - 2;
+    0x0F00 & (0x00F0 << 4);
+    0x0F00 & (0xF000 >> 4);
+    (0x0F00 << 1) ^ 3;
+    (0x0F00 << 1) | 2;
+
+    let b = 3;
+    trip!(b * 8);
+}
diff --git a/src/tools/clippy/tests/ui/precedence_bits.rs b/src/tools/clippy/tests/ui/precedence_bits.rs
new file mode 100644
index 00000000000..9b353308b6e
--- /dev/null
+++ b/src/tools/clippy/tests/ui/precedence_bits.rs
@@ -0,0 +1,35 @@
+#![warn(clippy::precedence_bits)]
+#![allow(
+    unused_must_use,
+    clippy::no_effect,
+    clippy::unnecessary_operation,
+    clippy::precedence
+)]
+#![allow(clippy::identity_op)]
+#![allow(clippy::eq_op)]
+
+macro_rules! trip {
+    ($a:expr) => {
+        match $a & 0b1111_1111u8 {
+            0 => println!("a is zero ({})", $a),
+            _ => println!("a is {}", $a),
+        }
+    };
+}
+
+fn main() {
+    1 << 2 + 3;
+    1 + 2 << 3;
+    4 >> 1 + 1;
+    1 + 3 >> 2;
+    1 ^ 1 - 1;
+    3 | 2 - 1;
+    3 & 5 - 2;
+    0x0F00 & 0x00F0 << 4;
+    0x0F00 & 0xF000 >> 4;
+    0x0F00 << 1 ^ 3;
+    0x0F00 << 1 | 2;
+
+    let b = 3;
+    trip!(b * 8);
+}
diff --git a/src/tools/clippy/tests/ui/precedence_bits.stderr b/src/tools/clippy/tests/ui/precedence_bits.stderr
new file mode 100644
index 00000000000..f468186b363
--- /dev/null
+++ b/src/tools/clippy/tests/ui/precedence_bits.stderr
@@ -0,0 +1,29 @@
+error: operator precedence might not be obvious
+  --> tests/ui/precedence_bits.rs:28:5
+   |
+LL |     0x0F00 & 0x00F0 << 4;
+   |     ^^^^^^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `0x0F00 & (0x00F0 << 4)`
+   |
+   = note: `-D clippy::precedence-bits` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::precedence_bits)]`
+
+error: operator precedence might not be obvious
+  --> tests/ui/precedence_bits.rs:29:5
+   |
+LL |     0x0F00 & 0xF000 >> 4;
+   |     ^^^^^^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `0x0F00 & (0xF000 >> 4)`
+
+error: operator precedence might not be obvious
+  --> tests/ui/precedence_bits.rs:30:5
+   |
+LL |     0x0F00 << 1 ^ 3;
+   |     ^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `(0x0F00 << 1) ^ 3`
+
+error: operator precedence might not be obvious
+  --> tests/ui/precedence_bits.rs:31:5
+   |
+LL |     0x0F00 << 1 | 2;
+   |     ^^^^^^^^^^^^^^^ help: consider parenthesizing your expression: `(0x0F00 << 1) | 2`
+
+error: aborting due to 4 previous errors
+
diff --git a/src/tools/clippy/tests/ui/print_literal.fixed b/src/tools/clippy/tests/ui/print_literal.fixed
index 1705a7ff01b..328e9a9b999 100644
--- a/src/tools/clippy/tests/ui/print_literal.fixed
+++ b/src/tools/clippy/tests/ui/print_literal.fixed
@@ -66,3 +66,17 @@ fn main() {
 
     println!("mixed: {{hello}} {world}");
 }
+
+fn issue_13959() {
+    println!("\"");
+    println!(
+        "
+        foo
+        \\
+        \\\\
+        \"
+        \\\"
+        bar
+"
+    );
+}
diff --git a/src/tools/clippy/tests/ui/print_literal.rs b/src/tools/clippy/tests/ui/print_literal.rs
index d10b26b5887..3130d0b6998 100644
--- a/src/tools/clippy/tests/ui/print_literal.rs
+++ b/src/tools/clippy/tests/ui/print_literal.rs
@@ -66,3 +66,18 @@ fn main() {
 
     println!("mixed: {} {world}", "{hello}");
 }
+
+fn issue_13959() {
+    println!("{}", r#"""#);
+    println!(
+        "{}",
+        r#"
+        foo
+        \
+        \\
+        "
+        \"
+        bar
+"#
+    );
+}
diff --git a/src/tools/clippy/tests/ui/print_literal.stderr b/src/tools/clippy/tests/ui/print_literal.stderr
index c4cbb8bed70..d967b7c2407 100644
--- a/src/tools/clippy/tests/ui/print_literal.stderr
+++ b/src/tools/clippy/tests/ui/print_literal.stderr
@@ -192,5 +192,41 @@ LL -     println!("mixed: {} {world}", "{hello}");
 LL +     println!("mixed: {{hello}} {world}");
    |
 
-error: aborting due to 16 previous errors
+error: literal with an empty format string
+  --> tests/ui/print_literal.rs:71:20
+   |
+LL |     println!("{}", r#"""#);
+   |                    ^^^^^^
+   |
+help: try
+   |
+LL -     println!("{}", r#"""#);
+LL +     println!("\"");
+   |
+
+error: literal with an empty format string
+  --> tests/ui/print_literal.rs:74:9
+   |
+LL | /         r#"
+LL | |         foo
+LL | |         \
+LL | |         \\
+...  |
+LL | |         bar
+LL | | "#
+   | |__^
+   |
+help: try
+   |
+LL ~         "
+LL +         foo
+LL +         \\
+LL +         \\\\
+LL +         \"
+LL +         \\\"
+LL +         bar
+LL ~ "
+   |
+
+error: aborting due to 18 previous errors
 
diff --git a/src/tools/clippy/tests/ui/redundant_else.fixed b/src/tools/clippy/tests/ui/redundant_else.fixed
new file mode 100644
index 00000000000..47aa79302d2
--- /dev/null
+++ b/src/tools/clippy/tests/ui/redundant_else.fixed
@@ -0,0 +1,154 @@
+#![warn(clippy::redundant_else)]
+#![allow(clippy::needless_return, clippy::if_same_then_else, clippy::needless_late_init)]
+
+fn main() {
+    loop {
+        // break
+        if foo() {
+            println!("Love your neighbor;");
+            break;
+        }
+        //~^ ERROR: redundant else block
+        println!("yet don't pull down your hedge.");
+        // continue
+        if foo() {
+            println!("He that lies down with Dogs,");
+            continue;
+        }
+        //~^ ERROR: redundant else block
+        println!("shall rise up with fleas.");
+        // match block
+        if foo() {
+            match foo() {
+                1 => break,
+                _ => return,
+            }
+        }
+        //~^ ERROR: redundant else block
+        println!("You may delay, but time will not.");
+    }
+    // else if
+    if foo() {
+        return;
+    } else if foo() {
+        return;
+    }
+    //~^ ERROR: redundant else block
+    println!("A fat kitchen makes a lean will.");
+    // let binding outside of block
+    let _ = {
+        if foo() {
+            return;
+        }
+        //~^ ERROR: redundant else block
+        1
+    };
+    // else if with let binding outside of block
+    let _ = {
+        if foo() {
+            return;
+        } else if foo() {
+            return;
+        }
+        //~^ ERROR: redundant else block
+        2
+    };
+    // inside if let
+    let _ = if let Some(1) = foo() {
+        let _ = 1;
+        if foo() {
+            return;
+        }
+        //~^ ERROR: redundant else block
+        1
+    } else {
+        1
+    };
+
+    //
+    // non-lint cases
+    //
+
+    // sanity check
+    if foo() {
+        let _ = 1;
+    } else {
+        println!("Who is wise? He that learns from every one.");
+    }
+    // else if without else
+    if foo() {
+        return;
+    } else if foo() {
+        foo()
+    };
+    // nested if return
+    if foo() {
+        if foo() {
+            return;
+        }
+    } else {
+        foo()
+    };
+    // match with non-breaking branch
+    if foo() {
+        match foo() {
+            1 => foo(),
+            _ => return,
+        }
+    } else {
+        println!("Three may keep a secret, if two of them are dead.");
+    }
+    // let binding
+    let _ = if foo() {
+        return;
+    } else {
+        1
+    };
+    // assign
+    let mut a;
+    a = if foo() {
+        return;
+    } else {
+        1
+    };
+    // assign-op
+    a += if foo() {
+        return;
+    } else {
+        1
+    };
+    // if return else if else
+    if foo() {
+        return;
+    } else if foo() {
+        1
+    } else {
+        2
+    };
+    // if else if return else
+    if foo() {
+        1
+    } else if foo() {
+        return;
+    } else {
+        2
+    };
+    // else if with let binding
+    let _ = if foo() {
+        return;
+    } else if foo() {
+        return;
+    } else {
+        2
+    };
+    // inside function call
+    Box::new(if foo() {
+        return;
+    } else {
+        1
+    });
+}
+
+fn foo<T>() -> T {
+    unimplemented!("I'm not Santa Claus")
+}
diff --git a/src/tools/clippy/tests/ui/redundant_else.stderr b/src/tools/clippy/tests/ui/redundant_else.stderr
index b649a210b5f..ecc16f7cda5 100644
--- a/src/tools/clippy/tests/ui/redundant_else.stderr
+++ b/src/tools/clippy/tests/ui/redundant_else.stderr
@@ -1,88 +1,123 @@
 error: redundant else block
-  --> tests/ui/redundant_else.rs:10:16
+  --> tests/ui/redundant_else.rs:10:10
    |
 LL |           } else {
-   |  ________________^
+   |  __________^
 LL | |
 LL | |             println!("yet don't pull down your hedge.");
 LL | |         }
    | |_________^
    |
-   = help: remove the `else` block and move the contents out
    = note: `-D clippy::redundant-else` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::redundant_else)]`
+help: remove the `else` block and move the contents out
+   |
+LL ~         }
+LL +
+LL +         println!("yet don't pull down your hedge.");
+   |
 
 error: redundant else block
-  --> tests/ui/redundant_else.rs:18:16
+  --> tests/ui/redundant_else.rs:18:10
    |
 LL |           } else {
-   |  ________________^
+   |  __________^
 LL | |
 LL | |             println!("shall rise up with fleas.");
 LL | |         }
    | |_________^
    |
-   = help: remove the `else` block and move the contents out
+help: remove the `else` block and move the contents out
+   |
+LL ~         }
+LL +
+LL +         println!("shall rise up with fleas.");
+   |
 
 error: redundant else block
-  --> tests/ui/redundant_else.rs:28:16
+  --> tests/ui/redundant_else.rs:28:10
    |
 LL |           } else {
-   |  ________________^
+   |  __________^
 LL | |
 LL | |             println!("You may delay, but time will not.");
 LL | |         }
    | |_________^
    |
-   = help: remove the `else` block and move the contents out
+help: remove the `else` block and move the contents out
+   |
+LL ~         }
+LL +
+LL +         println!("You may delay, but time will not.");
+   |
 
 error: redundant else block
-  --> tests/ui/redundant_else.rs:38:12
+  --> tests/ui/redundant_else.rs:38:6
    |
 LL |       } else {
-   |  ____________^
+   |  ______^
 LL | |
 LL | |         println!("A fat kitchen makes a lean will.");
 LL | |     }
    | |_____^
    |
-   = help: remove the `else` block and move the contents out
+help: remove the `else` block and move the contents out
+   |
+LL ~     }
+LL +
+LL +     println!("A fat kitchen makes a lean will.");
+   |
 
 error: redundant else block
-  --> tests/ui/redundant_else.rs:46:16
+  --> tests/ui/redundant_else.rs:46:10
    |
 LL |           } else {
-   |  ________________^
+   |  __________^
 LL | |
 LL | |             1
 LL | |         }
    | |_________^
    |
-   = help: remove the `else` block and move the contents out
+help: remove the `else` block and move the contents out
+   |
+LL ~         }
+LL +
+LL +         1
+   |
 
 error: redundant else block
-  --> tests/ui/redundant_else.rs:57:16
+  --> tests/ui/redundant_else.rs:57:10
    |
 LL |           } else {
-   |  ________________^
+   |  __________^
 LL | |
 LL | |             2
 LL | |         }
    | |_________^
    |
-   = help: remove the `else` block and move the contents out
+help: remove the `else` block and move the contents out
+   |
+LL ~         }
+LL +
+LL +         2
+   |
 
 error: redundant else block
-  --> tests/ui/redundant_else.rs:67:16
+  --> tests/ui/redundant_else.rs:67:10
    |
 LL |           } else {
-   |  ________________^
+   |  __________^
 LL | |
 LL | |             1
 LL | |         }
    | |_________^
    |
-   = help: remove the `else` block and move the contents out
+help: remove the `else` block and move the contents out
+   |
+LL ~         }
+LL +
+LL +         1
+   |
 
 error: aborting due to 7 previous errors
 
diff --git a/src/tools/clippy/tests/ui/return_and_then.fixed b/src/tools/clippy/tests/ui/return_and_then.fixed
new file mode 100644
index 00000000000..9736a51ac86
--- /dev/null
+++ b/src/tools/clippy/tests/ui/return_and_then.fixed
@@ -0,0 +1,67 @@
+#![warn(clippy::return_and_then)]
+
+fn main() {
+    fn test_opt_block(opt: Option<i32>) -> Option<i32> {
+        let n = opt?;
+        let mut ret = n + 1;
+        ret += n;
+        if n > 1 { Some(ret) } else { None }
+    }
+
+    fn test_opt_func(opt: Option<i32>) -> Option<i32> {
+        let n = opt?;
+        test_opt_block(Some(n))
+    }
+
+    fn test_call_chain() -> Option<i32> {
+        let n = gen_option(1)?;
+        test_opt_block(Some(n))
+    }
+
+    fn test_res_block(opt: Result<i32, i32>) -> Result<i32, i32> {
+        let n = opt?;
+        if n > 1 { Ok(n + 1) } else { Err(n) }
+    }
+
+    fn test_res_func(opt: Result<i32, i32>) -> Result<i32, i32> {
+        let n = opt?;
+        test_res_block(Ok(n))
+    }
+
+    fn test_ref_only() -> Option<i32> {
+        // ref: empty string
+        let x = Some("")?;
+        if x.len() > 2 { Some(3) } else { None }
+    }
+
+    fn test_tmp_only() -> Option<i32> {
+        // unused temporary: vec![1, 2, 4]
+        let x = Some(match (vec![1, 2, 3], vec![1, 2, 4]) {
+            (a, _) if a.len() > 1 => a,
+            (_, b) => b,
+        })?;
+        if x.len() > 2 { Some(3) } else { None }
+    }
+
+    // should not lint
+    fn test_tmp_ref() -> Option<String> {
+        String::from("<BOOM>")
+            .strip_prefix("<")
+            .and_then(|s| s.strip_suffix(">").map(String::from))
+    }
+
+    // should not lint
+    fn test_unconsumed_tmp() -> Option<i32> {
+        [1, 2, 3]
+            .iter()
+            .map(|x| x + 1)
+            .collect::<Vec<_>>() // temporary Vec created here
+            .as_slice() // creates temporary slice
+            .first() // creates temporary reference
+            .and_then(|x| test_opt_block(Some(*x)))
+    }
+}
+
+fn gen_option(n: i32) -> Option<i32> {
+    Some(n)
+}
diff --git a/src/tools/clippy/tests/ui/return_and_then.rs b/src/tools/clippy/tests/ui/return_and_then.rs
new file mode 100644
index 00000000000..8bcbdfc3a63
--- /dev/null
+++ b/src/tools/clippy/tests/ui/return_and_then.rs
@@ -0,0 +1,63 @@
+#![warn(clippy::return_and_then)]
+
+fn main() {
+    fn test_opt_block(opt: Option<i32>) -> Option<i32> {
+        opt.and_then(|n| {
+            let mut ret = n + 1;
+            ret += n;
+            if n > 1 { Some(ret) } else { None }
+        })
+    }
+
+    fn test_opt_func(opt: Option<i32>) -> Option<i32> {
+        opt.and_then(|n| test_opt_block(Some(n)))
+    }
+
+    fn test_call_chain() -> Option<i32> {
+        gen_option(1).and_then(|n| test_opt_block(Some(n)))
+    }
+
+    fn test_res_block(opt: Result<i32, i32>) -> Result<i32, i32> {
+        opt.and_then(|n| if n > 1 { Ok(n + 1) } else { Err(n) })
+    }
+
+    fn test_res_func(opt: Result<i32, i32>) -> Result<i32, i32> {
+        opt.and_then(|n| test_res_block(Ok(n)))
+    }
+
+    fn test_ref_only() -> Option<i32> {
+        // ref: empty string
+        Some("").and_then(|x| if x.len() > 2 { Some(3) } else { None })
+    }
+
+    fn test_tmp_only() -> Option<i32> {
+        // unused temporary: vec![1, 2, 4]
+        Some(match (vec![1, 2, 3], vec![1, 2, 4]) {
+            (a, _) if a.len() > 1 => a,
+            (_, b) => b,
+        })
+        .and_then(|x| if x.len() > 2 { Some(3) } else { None })
+    }
+
+    // should not lint
+    fn test_tmp_ref() -> Option<String> {
+        String::from("<BOOM>")
+            .strip_prefix("<")
+            .and_then(|s| s.strip_suffix(">").map(String::from))
+    }
+
+    // should not lint
+    fn test_unconsumed_tmp() -> Option<i32> {
+        [1, 2, 3]
+            .iter()
+            .map(|x| x + 1)
+            .collect::<Vec<_>>() // temporary Vec created here
+            .as_slice() // creates temporary slice
+            .first() // creates temporary reference
+            .and_then(|x| test_opt_block(Some(*x)))
+    }
+}
+
+fn gen_option(n: i32) -> Option<i32> {
+    Some(n)
+}
diff --git a/src/tools/clippy/tests/ui/return_and_then.stderr b/src/tools/clippy/tests/ui/return_and_then.stderr
new file mode 100644
index 00000000000..b2e8bf2ca45
--- /dev/null
+++ b/src/tools/clippy/tests/ui/return_and_then.stderr
@@ -0,0 +1,101 @@
+error: use the question mark operator instead of an `and_then` call
+  --> tests/ui/return_and_then.rs:5:9
+   |
+LL | /         opt.and_then(|n| {
+LL | |             let mut ret = n + 1;
+LL | |             ret += n;
+LL | |             if n > 1 { Some(ret) } else { None }
+LL | |         })
+   | |__________^
+   |
+   = note: `-D clippy::return-and-then` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::return_and_then)]`
+help: try
+   |
+LL ~         let n = opt?;
+LL +         let mut ret = n + 1;
+LL +         ret += n;
+LL +         if n > 1 { Some(ret) } else { None }
+   |
+
+error: use the question mark operator instead of an `and_then` call
+  --> tests/ui/return_and_then.rs:13:9
+   |
+LL |         opt.and_then(|n| test_opt_block(Some(n)))
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: try
+   |
+LL ~         let n = opt?;
+LL +         test_opt_block(Some(n))
+   |
+
+error: use the question mark operator instead of an `and_then` call
+  --> tests/ui/return_and_then.rs:17:9
+   |
+LL |         gen_option(1).and_then(|n| test_opt_block(Some(n)))
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: try
+   |
+LL ~         let n = gen_option(1)?;
+LL +         test_opt_block(Some(n))
+   |
+
+error: use the question mark operator instead of an `and_then` call
+  --> tests/ui/return_and_then.rs:21:9
+   |
+LL |         opt.and_then(|n| if n > 1 { Ok(n + 1) } else { Err(n) })
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: try
+   |
+LL ~         let n = opt?;
+LL +         if n > 1 { Ok(n + 1) } else { Err(n) }
+   |
+
+error: use the question mark operator instead of an `and_then` call
+  --> tests/ui/return_and_then.rs:25:9
+   |
+LL |         opt.and_then(|n| test_res_block(Ok(n)))
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: try
+   |
+LL ~         let n = opt?;
+LL +         test_res_block(Ok(n))
+   |
+
+error: use the question mark operator instead of an `and_then` call
+  --> tests/ui/return_and_then.rs:30:9
+   |
+LL |         Some("").and_then(|x| if x.len() > 2 { Some(3) } else { None })
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: try
+   |
+LL ~         let x = Some("")?;
+LL +         if x.len() > 2 { Some(3) } else { None }
+   |
+
+error: use the question mark operator instead of an `and_then` call
+  --> tests/ui/return_and_then.rs:35:9
+   |
+LL | /         Some(match (vec![1, 2, 3], vec![1, 2, 4]) {
+LL | |             (a, _) if a.len() > 1 => a,
+LL | |             (_, b) => b,
+LL | |         })
+LL | |         .and_then(|x| if x.len() > 2 { Some(3) } else { None })
+   | |_______________________________________________________________^
+   |
+help: try
+   |
+LL ~         let x = Some(match (vec![1, 2, 3], vec![1, 2, 4]) {
+LL +             (a, _) if a.len() > 1 => a,
+LL +             (_, b) => b,
+LL +         })?;
+LL +         if x.len() > 2 { Some(3) } else { None }
+   |
+
+error: aborting due to 7 previous errors
+
diff --git a/src/tools/clippy/tests/ui/size_of_in_element_count/expressions.rs b/src/tools/clippy/tests/ui/size_of_in_element_count/expressions.rs
index 91b7ea3922c..f405ba200ac 100644
--- a/src/tools/clippy/tests/ui/size_of_in_element_count/expressions.rs
+++ b/src/tools/clippy/tests/ui/size_of_in_element_count/expressions.rs
@@ -8,11 +8,11 @@ fn main() {
     const SIZE: usize = 128;
     const HALF_SIZE: usize = SIZE / 2;
     const DOUBLE_SIZE: usize = SIZE * 2;
-    let mut x = [2u8; SIZE];
-    let mut y = [2u8; SIZE];
+    let mut x = [2u16; SIZE];
+    let mut y = [2u16; SIZE];
 
     // Count expression involving multiplication of size_of (Should trigger the lint)
-    unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>() * SIZE) };
+    unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of::<u16>() * SIZE) };
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
 
     // Count expression involving nested multiplications of size_of (Should trigger the lint)
@@ -20,22 +20,19 @@ fn main() {
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
 
     // Count expression involving divisions of size_of (Should trigger the lint)
-    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE * size_of::<u8>() / 2) };
+    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE * size_of::<u16>() / 2) };
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
 
     // Count expression involving divisions by size_of (Should not trigger the lint)
-    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE / size_of::<u8>()) };
+    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE / size_of::<u16>()) };
 
     // Count expression involving divisions by multiple size_of (Should not trigger the lint)
-    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE / (2 * size_of::<u8>())) };
+    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE / (2 * size_of::<u16>())) };
 
     // Count expression involving recursive divisions by size_of (Should trigger the lint)
-    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE / (2 / size_of::<u8>())) };
+    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE / (2 / size_of::<u16>())) };
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
 
     // No size_of calls (Should not trigger the lint)
     unsafe { copy(x.as_ptr(), y.as_mut_ptr(), SIZE) };
-
-    // Different types for pointee and size_of (Should not trigger the lint)
-    unsafe { y.as_mut_ptr().write_bytes(0u8, size_of::<u16>() / 2 * SIZE) };
 }
diff --git a/src/tools/clippy/tests/ui/size_of_in_element_count/expressions.stderr b/src/tools/clippy/tests/ui/size_of_in_element_count/expressions.stderr
index 6396afd7f39..74be0d7773d 100644
--- a/src/tools/clippy/tests/ui/size_of_in_element_count/expressions.stderr
+++ b/src/tools/clippy/tests/ui/size_of_in_element_count/expressions.stderr
@@ -1,8 +1,8 @@
 error: found a count of bytes instead of a count of elements of `T`
   --> tests/ui/size_of_in_element_count/expressions.rs:15:62
    |
-LL |     unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>() * SIZE) };
-   |                                                              ^^^^^^^^^^^^^^^^^^^^^^
+LL |     unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of::<u16>() * SIZE) };
+   |                                                              ^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
    = note: `-D clippy::size-of-in-element-count` implied by `-D warnings`
@@ -19,16 +19,16 @@ LL |     unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), HALF_SIZE * si
 error: found a count of bytes instead of a count of elements of `T`
   --> tests/ui/size_of_in_element_count/expressions.rs:23:47
    |
-LL |     unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE * size_of::<u8>() / 2) };
-   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE * size_of::<u16>() / 2) };
+   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
 error: found a count of bytes instead of a count of elements of `T`
   --> tests/ui/size_of_in_element_count/expressions.rs:33:47
    |
-LL |     unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE / (2 / size_of::<u8>())) };
-   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE / (2 / size_of::<u16>())) };
+   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
diff --git a/src/tools/clippy/tests/ui/size_of_in_element_count/functions.rs b/src/tools/clippy/tests/ui/size_of_in_element_count/functions.rs
index 3501cbdf81c..af18136a1db 100644
--- a/src/tools/clippy/tests/ui/size_of_in_element_count/functions.rs
+++ b/src/tools/clippy/tests/ui/size_of_in_element_count/functions.rs
@@ -11,57 +11,52 @@ fn main() {
     const SIZE: usize = 128;
     const HALF_SIZE: usize = SIZE / 2;
     const DOUBLE_SIZE: usize = SIZE * 2;
-    let mut x = [2u8; SIZE];
-    let mut y = [2u8; SIZE];
+    let mut x = [2u16; SIZE];
+    let mut y = [2u16; SIZE];
 
     // Count is size_of (Should trigger the lint)
-    unsafe { copy_nonoverlapping::<u8>(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>()) };
+    unsafe { copy_nonoverlapping::<u16>(x.as_ptr(), y.as_mut_ptr(), size_of::<u16>()) };
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
     unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x[0])) };
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
 
-    unsafe { x.as_ptr().copy_to(y.as_mut_ptr(), size_of::<u8>()) };
+    unsafe { x.as_ptr().copy_to(y.as_mut_ptr(), size_of::<u16>()) };
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
-    unsafe { x.as_ptr().copy_to_nonoverlapping(y.as_mut_ptr(), size_of::<u8>()) };
+    unsafe { x.as_ptr().copy_to_nonoverlapping(y.as_mut_ptr(), size_of::<u16>()) };
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
-    unsafe { y.as_mut_ptr().copy_from(x.as_ptr(), size_of::<u8>()) };
+    unsafe { y.as_mut_ptr().copy_from(x.as_ptr(), size_of::<u16>()) };
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
-    unsafe { y.as_mut_ptr().copy_from_nonoverlapping(x.as_ptr(), size_of::<u8>()) };
+    unsafe { y.as_mut_ptr().copy_from_nonoverlapping(x.as_ptr(), size_of::<u16>()) };
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
 
-    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>()) };
+    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of::<u16>()) };
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
     unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x[0])) };
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
 
-    unsafe { y.as_mut_ptr().write_bytes(0u8, size_of::<u8>() * SIZE) };
-    //~^ ERROR: found a count of bytes instead of a count of elements of `T`
-    unsafe { write_bytes(y.as_mut_ptr(), 0u8, size_of::<u8>() * SIZE) };
-    //~^ ERROR: found a count of bytes instead of a count of elements of `T`
-
-    unsafe { swap_nonoverlapping(y.as_mut_ptr(), x.as_mut_ptr(), size_of::<u8>() * SIZE) };
+    unsafe { swap_nonoverlapping(y.as_mut_ptr(), x.as_mut_ptr(), size_of::<u16>() * SIZE) };
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
 
-    slice_from_raw_parts_mut(y.as_mut_ptr(), size_of::<u8>() * SIZE);
+    slice_from_raw_parts_mut(y.as_mut_ptr(), size_of::<u16>() * SIZE);
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
-    slice_from_raw_parts(y.as_ptr(), size_of::<u8>() * SIZE);
+    slice_from_raw_parts(y.as_ptr(), size_of::<u16>() * SIZE);
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
 
-    unsafe { from_raw_parts_mut(y.as_mut_ptr(), size_of::<u8>() * SIZE) };
+    unsafe { from_raw_parts_mut(y.as_mut_ptr(), size_of::<u16>() * SIZE) };
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
-    unsafe { from_raw_parts(y.as_ptr(), size_of::<u8>() * SIZE) };
+    unsafe { from_raw_parts(y.as_ptr(), size_of::<u16>() * SIZE) };
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
 
-    unsafe { y.as_mut_ptr().sub(size_of::<u8>()) };
+    unsafe { y.as_mut_ptr().sub(size_of::<u16>()) };
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
-    y.as_ptr().wrapping_sub(size_of::<u8>());
+    y.as_ptr().wrapping_sub(size_of::<u16>());
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
-    unsafe { y.as_ptr().add(size_of::<u8>()) };
+    unsafe { y.as_ptr().add(size_of::<u16>()) };
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
-    y.as_mut_ptr().wrapping_add(size_of::<u8>());
+    y.as_mut_ptr().wrapping_add(size_of::<u16>());
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
-    unsafe { y.as_ptr().offset(size_of::<u8>() as isize) };
+    unsafe { y.as_ptr().offset(size_of::<u16>() as isize) };
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
-    y.as_mut_ptr().wrapping_offset(size_of::<u8>() as isize);
+    y.as_mut_ptr().wrapping_offset(size_of::<u16>() as isize);
     //~^ ERROR: found a count of bytes instead of a count of elements of `T`
 }
diff --git a/src/tools/clippy/tests/ui/size_of_in_element_count/functions.stderr b/src/tools/clippy/tests/ui/size_of_in_element_count/functions.stderr
index abde7dc7cd2..de54789b225 100644
--- a/src/tools/clippy/tests/ui/size_of_in_element_count/functions.stderr
+++ b/src/tools/clippy/tests/ui/size_of_in_element_count/functions.stderr
@@ -1,8 +1,8 @@
 error: found a count of bytes instead of a count of elements of `T`
-  --> tests/ui/size_of_in_element_count/functions.rs:18:68
+  --> tests/ui/size_of_in_element_count/functions.rs:18:69
    |
-LL |     unsafe { copy_nonoverlapping::<u8>(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>()) };
-   |                                                                    ^^^^^^^^^^^^^^^
+LL |     unsafe { copy_nonoverlapping::<u16>(x.as_ptr(), y.as_mut_ptr(), size_of::<u16>()) };
+   |                                                                     ^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
    = note: `-D clippy::size-of-in-element-count` implied by `-D warnings`
@@ -19,40 +19,40 @@ LL |     unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x
 error: found a count of bytes instead of a count of elements of `T`
   --> tests/ui/size_of_in_element_count/functions.rs:23:49
    |
-LL |     unsafe { x.as_ptr().copy_to(y.as_mut_ptr(), size_of::<u8>()) };
-   |                                                 ^^^^^^^^^^^^^^^
+LL |     unsafe { x.as_ptr().copy_to(y.as_mut_ptr(), size_of::<u16>()) };
+   |                                                 ^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
 error: found a count of bytes instead of a count of elements of `T`
   --> tests/ui/size_of_in_element_count/functions.rs:25:64
    |
-LL |     unsafe { x.as_ptr().copy_to_nonoverlapping(y.as_mut_ptr(), size_of::<u8>()) };
-   |                                                                ^^^^^^^^^^^^^^^
+LL |     unsafe { x.as_ptr().copy_to_nonoverlapping(y.as_mut_ptr(), size_of::<u16>()) };
+   |                                                                ^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
 error: found a count of bytes instead of a count of elements of `T`
   --> tests/ui/size_of_in_element_count/functions.rs:27:51
    |
-LL |     unsafe { y.as_mut_ptr().copy_from(x.as_ptr(), size_of::<u8>()) };
-   |                                                   ^^^^^^^^^^^^^^^
+LL |     unsafe { y.as_mut_ptr().copy_from(x.as_ptr(), size_of::<u16>()) };
+   |                                                   ^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
 error: found a count of bytes instead of a count of elements of `T`
   --> tests/ui/size_of_in_element_count/functions.rs:29:66
    |
-LL |     unsafe { y.as_mut_ptr().copy_from_nonoverlapping(x.as_ptr(), size_of::<u8>()) };
-   |                                                                  ^^^^^^^^^^^^^^^
+LL |     unsafe { y.as_mut_ptr().copy_from_nonoverlapping(x.as_ptr(), size_of::<u16>()) };
+   |                                                                  ^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
 error: found a count of bytes instead of a count of elements of `T`
   --> tests/ui/size_of_in_element_count/functions.rs:32:47
    |
-LL |     unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>()) };
-   |                                               ^^^^^^^^^^^^^^^
+LL |     unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of::<u16>()) };
+   |                                               ^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
@@ -65,108 +65,92 @@ LL |     unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x[0])) };
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
 error: found a count of bytes instead of a count of elements of `T`
-  --> tests/ui/size_of_in_element_count/functions.rs:37:46
+  --> tests/ui/size_of_in_element_count/functions.rs:37:66
    |
-LL |     unsafe { y.as_mut_ptr().write_bytes(0u8, size_of::<u8>() * SIZE) };
-   |                                              ^^^^^^^^^^^^^^^^^^^^^^
+LL |     unsafe { swap_nonoverlapping(y.as_mut_ptr(), x.as_mut_ptr(), size_of::<u16>() * SIZE) };
+   |                                                                  ^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
 error: found a count of bytes instead of a count of elements of `T`
-  --> tests/ui/size_of_in_element_count/functions.rs:39:47
+  --> tests/ui/size_of_in_element_count/functions.rs:40:46
    |
-LL |     unsafe { write_bytes(y.as_mut_ptr(), 0u8, size_of::<u8>() * SIZE) };
-   |                                               ^^^^^^^^^^^^^^^^^^^^^^
+LL |     slice_from_raw_parts_mut(y.as_mut_ptr(), size_of::<u16>() * SIZE);
+   |                                              ^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
 error: found a count of bytes instead of a count of elements of `T`
-  --> tests/ui/size_of_in_element_count/functions.rs:42:66
+  --> tests/ui/size_of_in_element_count/functions.rs:42:38
    |
-LL |     unsafe { swap_nonoverlapping(y.as_mut_ptr(), x.as_mut_ptr(), size_of::<u8>() * SIZE) };
-   |                                                                  ^^^^^^^^^^^^^^^^^^^^^^
+LL |     slice_from_raw_parts(y.as_ptr(), size_of::<u16>() * SIZE);
+   |                                      ^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
 error: found a count of bytes instead of a count of elements of `T`
-  --> tests/ui/size_of_in_element_count/functions.rs:45:46
+  --> tests/ui/size_of_in_element_count/functions.rs:45:49
    |
-LL |     slice_from_raw_parts_mut(y.as_mut_ptr(), size_of::<u8>() * SIZE);
-   |                                              ^^^^^^^^^^^^^^^^^^^^^^
+LL |     unsafe { from_raw_parts_mut(y.as_mut_ptr(), size_of::<u16>() * SIZE) };
+   |                                                 ^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
 error: found a count of bytes instead of a count of elements of `T`
-  --> tests/ui/size_of_in_element_count/functions.rs:47:38
+  --> tests/ui/size_of_in_element_count/functions.rs:47:41
    |
-LL |     slice_from_raw_parts(y.as_ptr(), size_of::<u8>() * SIZE);
-   |                                      ^^^^^^^^^^^^^^^^^^^^^^
+LL |     unsafe { from_raw_parts(y.as_ptr(), size_of::<u16>() * SIZE) };
+   |                                         ^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
 error: found a count of bytes instead of a count of elements of `T`
-  --> tests/ui/size_of_in_element_count/functions.rs:50:49
+  --> tests/ui/size_of_in_element_count/functions.rs:50:33
    |
-LL |     unsafe { from_raw_parts_mut(y.as_mut_ptr(), size_of::<u8>() * SIZE) };
-   |                                                 ^^^^^^^^^^^^^^^^^^^^^^
+LL |     unsafe { y.as_mut_ptr().sub(size_of::<u16>()) };
+   |                                 ^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
 error: found a count of bytes instead of a count of elements of `T`
-  --> tests/ui/size_of_in_element_count/functions.rs:52:41
+  --> tests/ui/size_of_in_element_count/functions.rs:52:29
    |
-LL |     unsafe { from_raw_parts(y.as_ptr(), size_of::<u8>() * SIZE) };
-   |                                         ^^^^^^^^^^^^^^^^^^^^^^
+LL |     y.as_ptr().wrapping_sub(size_of::<u16>());
+   |                             ^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
 error: found a count of bytes instead of a count of elements of `T`
-  --> tests/ui/size_of_in_element_count/functions.rs:55:33
+  --> tests/ui/size_of_in_element_count/functions.rs:54:29
    |
-LL |     unsafe { y.as_mut_ptr().sub(size_of::<u8>()) };
-   |                                 ^^^^^^^^^^^^^^^
+LL |     unsafe { y.as_ptr().add(size_of::<u16>()) };
+   |                             ^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
 error: found a count of bytes instead of a count of elements of `T`
-  --> tests/ui/size_of_in_element_count/functions.rs:57:29
+  --> tests/ui/size_of_in_element_count/functions.rs:56:33
    |
-LL |     y.as_ptr().wrapping_sub(size_of::<u8>());
-   |                             ^^^^^^^^^^^^^^^
+LL |     y.as_mut_ptr().wrapping_add(size_of::<u16>());
+   |                                 ^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
 error: found a count of bytes instead of a count of elements of `T`
-  --> tests/ui/size_of_in_element_count/functions.rs:59:29
+  --> tests/ui/size_of_in_element_count/functions.rs:58:32
    |
-LL |     unsafe { y.as_ptr().add(size_of::<u8>()) };
-   |                             ^^^^^^^^^^^^^^^
+LL |     unsafe { y.as_ptr().offset(size_of::<u16>() as isize) };
+   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
 error: found a count of bytes instead of a count of elements of `T`
-  --> tests/ui/size_of_in_element_count/functions.rs:61:33
+  --> tests/ui/size_of_in_element_count/functions.rs:60:36
    |
-LL |     y.as_mut_ptr().wrapping_add(size_of::<u8>());
-   |                                 ^^^^^^^^^^^^^^^
+LL |     y.as_mut_ptr().wrapping_offset(size_of::<u16>() as isize);
+   |                                    ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
 
-error: found a count of bytes instead of a count of elements of `T`
-  --> tests/ui/size_of_in_element_count/functions.rs:63:32
-   |
-LL |     unsafe { y.as_ptr().offset(size_of::<u8>() as isize) };
-   |                                ^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
-
-error: found a count of bytes instead of a count of elements of `T`
-  --> tests/ui/size_of_in_element_count/functions.rs:65:36
-   |
-LL |     y.as_mut_ptr().wrapping_offset(size_of::<u8>() as isize);
-   |                                    ^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type
-
-error: aborting due to 21 previous errors
+error: aborting due to 19 previous errors
 
diff --git a/src/tools/clippy/tests/ui/toplevel_ref_arg_non_rustfix.stderr b/src/tools/clippy/tests/ui/toplevel_ref_arg_non_rustfix.stderr
index fb8fb1a0090..26166e2fc8d 100644
--- a/src/tools/clippy/tests/ui/toplevel_ref_arg_non_rustfix.stderr
+++ b/src/tools/clippy/tests/ui/toplevel_ref_arg_non_rustfix.stderr
@@ -1,4 +1,4 @@
-error: `ref` directly on a function argument is ignored. Consider using a reference type instead
+error: `ref` directly on a function parameter does not prevent taking ownership of the passed argument. Consider using a reference type instead
   --> tests/ui/toplevel_ref_arg_non_rustfix.rs:9:15
    |
 LL | fn the_answer(ref mut x: u8) {
@@ -7,7 +7,7 @@ LL | fn the_answer(ref mut x: u8) {
    = note: `-D clippy::toplevel-ref-arg` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::toplevel_ref_arg)]`
 
-error: `ref` directly on a function argument is ignored. Consider using a reference type instead
+error: `ref` directly on a function parameter does not prevent taking ownership of the passed argument. Consider using a reference type instead
   --> tests/ui/toplevel_ref_arg_non_rustfix.rs:20:24
    |
 LL |         fn fun_example(ref _x: usize) {}
diff --git a/src/tools/clippy/tests/ui/unnecessary_semicolon.edition2021.fixed b/src/tools/clippy/tests/ui/unnecessary_semicolon.edition2021.fixed
index 7a3b79553de..343c88b9815 100644
--- a/src/tools/clippy/tests/ui/unnecessary_semicolon.edition2021.fixed
+++ b/src/tools/clippy/tests/ui/unnecessary_semicolon.edition2021.fixed
@@ -55,3 +55,9 @@ fn no_borrow_issue(a: u32, b: u32) {
         None => {},
     }
 }
+
+fn issue14100() -> bool {
+    // Removing the `;` would make the block type be `()` instead of `!`, and this could no longer be
+    // cast into the `bool` function return type.
+    if return true {};
+}
diff --git a/src/tools/clippy/tests/ui/unnecessary_semicolon.edition2024.fixed b/src/tools/clippy/tests/ui/unnecessary_semicolon.edition2024.fixed
index d186d5e7ebc..1cba5760eb0 100644
--- a/src/tools/clippy/tests/ui/unnecessary_semicolon.edition2024.fixed
+++ b/src/tools/clippy/tests/ui/unnecessary_semicolon.edition2024.fixed
@@ -55,3 +55,9 @@ fn no_borrow_issue(a: u32, b: u32) {
         None => {},
     }
 }
+
+fn issue14100() -> bool {
+    // Removing the `;` would make the block type be `()` instead of `!`, and this could no longer be
+    // cast into the `bool` function return type.
+    if return true {};
+}
diff --git a/src/tools/clippy/tests/ui/unnecessary_semicolon.rs b/src/tools/clippy/tests/ui/unnecessary_semicolon.rs
index 3028c5b27b3..6abbbd79aaf 100644
--- a/src/tools/clippy/tests/ui/unnecessary_semicolon.rs
+++ b/src/tools/clippy/tests/ui/unnecessary_semicolon.rs
@@ -55,3 +55,9 @@ fn no_borrow_issue(a: u32, b: u32) {
         None => {},
     };
 }
+
+fn issue14100() -> bool {
+    // Removing the `;` would make the block type be `()` instead of `!`, and this could no longer be
+    // cast into the `bool` function return type.
+    if return true {};
+}
diff --git a/src/tools/clippy/tests/ui/write_literal.fixed b/src/tools/clippy/tests/ui/write_literal.fixed
index 3d216b76cbf..f1def776e1b 100644
--- a/src/tools/clippy/tests/ui/write_literal.fixed
+++ b/src/tools/clippy/tests/ui/write_literal.fixed
@@ -62,3 +62,19 @@ fn main() {
     writeln!(v, "hello {0} {1}, world {2}", 2, 3, 4);
     //~^ ERROR: literal with an empty format string
 }
+
+fn issue_13959() {
+    let mut v = Vec::new();
+    writeln!(v, "\"");
+    writeln!(
+        v,
+        "
+        foo
+        \\
+        \\\\
+        \"
+        \\\"
+        bar
+"
+    );
+}
diff --git a/src/tools/clippy/tests/ui/write_literal.rs b/src/tools/clippy/tests/ui/write_literal.rs
index 79d6daa2e3b..1b7df91b47e 100644
--- a/src/tools/clippy/tests/ui/write_literal.rs
+++ b/src/tools/clippy/tests/ui/write_literal.rs
@@ -62,3 +62,20 @@ fn main() {
     writeln!(v, "{0} {1} {2}, {3} {4}", "hello", 2, 3, "world", 4);
     //~^ ERROR: literal with an empty format string
 }
+
+fn issue_13959() {
+    let mut v = Vec::new();
+    writeln!(v, "{}", r#"""#);
+    writeln!(
+        v,
+        "{}",
+        r#"
+        foo
+        \
+        \\
+        "
+        \"
+        bar
+"#
+    );
+}
diff --git a/src/tools/clippy/tests/ui/write_literal.stderr b/src/tools/clippy/tests/ui/write_literal.stderr
index 9f4cdfd91e8..35c93d567cd 100644
--- a/src/tools/clippy/tests/ui/write_literal.stderr
+++ b/src/tools/clippy/tests/ui/write_literal.stderr
@@ -144,5 +144,41 @@ LL -     writeln!(v, "{0} {1} {2}, {3} {4}", "hello", 2, 3, "world", 4);
 LL +     writeln!(v, "hello {0} {1}, world {2}", 2, 3, 4);
    |
 
-error: aborting due to 12 previous errors
+error: literal with an empty format string
+  --> tests/ui/write_literal.rs:68:23
+   |
+LL |     writeln!(v, "{}", r#"""#);
+   |                       ^^^^^^
+   |
+help: try
+   |
+LL -     writeln!(v, "{}", r#"""#);
+LL +     writeln!(v, "\"");
+   |
+
+error: literal with an empty format string
+  --> tests/ui/write_literal.rs:72:9
+   |
+LL | /         r#"
+LL | |         foo
+LL | |         \
+LL | |         \\
+...  |
+LL | |         bar
+LL | | "#
+   | |__^
+   |
+help: try
+   |
+LL ~         "
+LL +         foo
+LL +         \\
+LL +         \\\\
+LL +         \"
+LL +         \\\"
+LL +         bar
+LL ~ "
+   |
+
+error: aborting due to 14 previous errors