Merge commit '9e3cd88718cd1912a515d26dbd9c4019fd5a9577' into clippyup

39 files changed, 929 insertions, 154 deletions

diff --git a/src/tools/clippy/tests/ui/crashes/ice-7231.rs b/src/tools/clippy/tests/ui/crashes/ice-7231.rs
new file mode 100644
index 00000000000..5595d8d1d62
--- /dev/null
+++ b/src/tools/clippy/tests/ui/crashes/ice-7231.rs
@@ -0,0 +1,10 @@
+// edition:2018
+#![allow(clippy::never_loop)]
+
+async fn f() {
+    loop {
+        break;
+    }
+}
+
+fn main() {}
diff --git a/src/tools/clippy/tests/ui/floating_point_powi.fixed b/src/tools/clippy/tests/ui/floating_point_powi.fixed
index 56762400593..85f7c531e39 100644
--- a/src/tools/clippy/tests/ui/floating_point_powi.fixed
+++ b/src/tools/clippy/tests/ui/floating_point_powi.fixed
@@ -4,8 +4,6 @@
 fn main() {
     let one = 1;
     let x = 3f32;
-    let _ = x * x;
-    let _ = x * x;
 
     let y = 4f32;
     let _ = x.mul_add(x, y);
@@ -13,7 +11,10 @@ fn main() {
     let _ = x.mul_add(x, y).sqrt();
     let _ = y.mul_add(y, x).sqrt();
     // Cases where the lint shouldn't be applied
+    let _ = x.powi(2);
+    let _ = x.powi(1 + 1);
     let _ = x.powi(3);
+    let _ = x.powi(4) + y;
     let _ = x.powi(one + 1);
     let _ = (x.powi(2) + y.powi(2)).sqrt();
 }
diff --git a/src/tools/clippy/tests/ui/floating_point_powi.rs b/src/tools/clippy/tests/ui/floating_point_powi.rs
index 1f800e4628d..ece61d1bec4 100644
--- a/src/tools/clippy/tests/ui/floating_point_powi.rs
+++ b/src/tools/clippy/tests/ui/floating_point_powi.rs
@@ -4,8 +4,6 @@
 fn main() {
     let one = 1;
     let x = 3f32;
-    let _ = x.powi(2);
-    let _ = x.powi(1 + 1);
 
     let y = 4f32;
     let _ = x.powi(2) + y;
@@ -13,7 +11,10 @@ fn main() {
     let _ = (x.powi(2) + y).sqrt();
     let _ = (x + y.powi(2)).sqrt();
     // Cases where the lint shouldn't be applied
+    let _ = x.powi(2);
+    let _ = x.powi(1 + 1);
     let _ = x.powi(3);
+    let _ = x.powi(4) + y;
     let _ = x.powi(one + 1);
     let _ = (x.powi(2) + y.powi(2)).sqrt();
 }
diff --git a/src/tools/clippy/tests/ui/floating_point_powi.stderr b/src/tools/clippy/tests/ui/floating_point_powi.stderr
index d5a5f1bcca1..37d840988bb 100644
--- a/src/tools/clippy/tests/ui/floating_point_powi.stderr
+++ b/src/tools/clippy/tests/ui/floating_point_powi.stderr
@@ -1,40 +1,28 @@
-error: square can be computed more efficiently
-  --> $DIR/floating_point_powi.rs:7:13
-   |
-LL |     let _ = x.powi(2);
-   |             ^^^^^^^^^ help: consider using: `x * x`
-   |
-   = note: `-D clippy::suboptimal-flops` implied by `-D warnings`
-
-error: square can be computed more efficiently
-  --> $DIR/floating_point_powi.rs:8:13
-   |
-LL |     let _ = x.powi(1 + 1);
-   |             ^^^^^^^^^^^^^ help: consider using: `x * x`
-
-error: square can be computed more efficiently
-  --> $DIR/floating_point_powi.rs:11:13
+error: multiply and add expressions can be calculated more efficiently and accurately
+  --> $DIR/floating_point_powi.rs:9:13
    |
 LL |     let _ = x.powi(2) + y;
    |             ^^^^^^^^^^^^^ help: consider using: `x.mul_add(x, y)`
+   |
+   = note: `-D clippy::suboptimal-flops` implied by `-D warnings`
 
-error: square can be computed more efficiently
-  --> $DIR/floating_point_powi.rs:12:13
+error: multiply and add expressions can be calculated more efficiently and accurately
+  --> $DIR/floating_point_powi.rs:10:13
    |
 LL |     let _ = x + y.powi(2);
    |             ^^^^^^^^^^^^^ help: consider using: `y.mul_add(y, x)`
 
-error: square can be computed more efficiently
-  --> $DIR/floating_point_powi.rs:13:13
+error: multiply and add expressions can be calculated more efficiently and accurately
+  --> $DIR/floating_point_powi.rs:11:13
    |
 LL |     let _ = (x.powi(2) + y).sqrt();
    |             ^^^^^^^^^^^^^^^ help: consider using: `x.mul_add(x, y)`
 
-error: square can be computed more efficiently
-  --> $DIR/floating_point_powi.rs:14:13
+error: multiply and add expressions can be calculated more efficiently and accurately
+  --> $DIR/floating_point_powi.rs:12:13
    |
 LL |     let _ = (x + y.powi(2)).sqrt();
    |             ^^^^^^^^^^^^^^^ help: consider using: `y.mul_add(y, x)`
 
-error: aborting due to 6 previous errors
+error: aborting due to 4 previous errors
 
diff --git a/src/tools/clippy/tests/ui/impl.rs b/src/tools/clippy/tests/ui/impl.rs
index 1c46e3a5337..39443775015 100644
--- a/src/tools/clippy/tests/ui/impl.rs
+++ b/src/tools/clippy/tests/ui/impl.rs
@@ -33,4 +33,35 @@ impl fmt::Debug for MyStruct {
     }
 }
 
+// issue #5772
+struct WithArgs<T>(T);
+impl WithArgs<u32> {
+    fn f1() {}
+}
+impl WithArgs<u64> {
+    fn f2() {}
+}
+impl WithArgs<u64> {
+    fn f3() {}
+}
+
+// Ok, the struct is allowed to have multiple impls.
+#[allow(clippy::multiple_inherent_impl)]
+struct Allowed;
+impl Allowed {}
+impl Allowed {}
+impl Allowed {}
+
+struct AllowedImpl;
+#[allow(clippy::multiple_inherent_impl)]
+impl AllowedImpl {}
+// Ok, the first block is skipped by this lint.
+impl AllowedImpl {}
+
+struct OneAllowedImpl;
+impl OneAllowedImpl {}
+#[allow(clippy::multiple_inherent_impl)]
+impl OneAllowedImpl {}
+impl OneAllowedImpl {} // Lint, only one of the three blocks is allowed.
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/impl.stderr b/src/tools/clippy/tests/ui/impl.stderr
index aab688cc2d8..8703ecac93e 100644
--- a/src/tools/clippy/tests/ui/impl.stderr
+++ b/src/tools/clippy/tests/ui/impl.stderr
@@ -31,5 +31,33 @@ LL | |     fn first() {}
 LL | | }
    | |_^
 
-error: aborting due to 2 previous errors
+error: multiple implementations of this structure
+  --> $DIR/impl.rs:44:1
+   |
+LL | / impl WithArgs<u64> {
+LL | |     fn f3() {}
+LL | | }
+   | |_^
+   |
+note: first implementation here
+  --> $DIR/impl.rs:41:1
+   |
+LL | / impl WithArgs<u64> {
+LL | |     fn f2() {}
+LL | | }
+   | |_^
+
+error: multiple implementations of this structure
+  --> $DIR/impl.rs:65:1
+   |
+LL | impl OneAllowedImpl {} // Lint, only one of the three blocks is allowed.
+   | ^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: first implementation here
+  --> $DIR/impl.rs:62:1
+   |
+LL | impl OneAllowedImpl {}
+   | ^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 4 previous errors
 
diff --git a/src/tools/clippy/tests/ui/manual_unwrap_or.fixed b/src/tools/clippy/tests/ui/manual_unwrap_or.fixed
index e7a29596b73..3717f962745 100644
--- a/src/tools/clippy/tests/ui/manual_unwrap_or.fixed
+++ b/src/tools/clippy/tests/ui/manual_unwrap_or.fixed
@@ -163,4 +163,19 @@ mod issue6965 {
     }
 }
 
+use std::rc::Rc;
+fn format_name(name: Option<&Rc<str>>) -> &str {
+    match name {
+        None => "<anon>",
+        Some(name) => name,
+    }
+}
+
+fn implicit_deref_ref() {
+    let _: &str = match Some(&"bye") {
+        None => "hi",
+        Some(s) => s,
+    };
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/manual_unwrap_or.rs b/src/tools/clippy/tests/ui/manual_unwrap_or.rs
index 66006b6c616..989adde1f5b 100644
--- a/src/tools/clippy/tests/ui/manual_unwrap_or.rs
+++ b/src/tools/clippy/tests/ui/manual_unwrap_or.rs
@@ -205,4 +205,19 @@ mod issue6965 {
     }
 }
 
+use std::rc::Rc;
+fn format_name(name: Option<&Rc<str>>) -> &str {
+    match name {
+        None => "<anon>",
+        Some(name) => name,
+    }
+}
+
+fn implicit_deref_ref() {
+    let _: &str = match Some(&"bye") {
+        None => "hi",
+        Some(s) => s,
+    };
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/match_single_binding.fixed b/src/tools/clippy/tests/ui/match_single_binding.fixed
index 526e94b10bd..30bf6402253 100644
--- a/src/tools/clippy/tests/ui/match_single_binding.fixed
+++ b/src/tools/clippy/tests/ui/match_single_binding.fixed
@@ -94,10 +94,7 @@ fn main() {
         0 => println!("Disabled branch"),
         _ => println!("Enabled branch"),
     }
-    // Lint
-    let x = 1;
-    let y = 1;
-    println!("Single branch");
+
     // Ok
     let x = 1;
     let y = 1;
diff --git a/src/tools/clippy/tests/ui/match_single_binding.rs b/src/tools/clippy/tests/ui/match_single_binding.rs
index 6a2ca7c5e93..d8bb80d8b96 100644
--- a/src/tools/clippy/tests/ui/match_single_binding.rs
+++ b/src/tools/clippy/tests/ui/match_single_binding.rs
@@ -106,15 +106,7 @@ fn main() {
         0 => println!("Disabled branch"),
         _ => println!("Enabled branch"),
     }
-    // Lint
-    let x = 1;
-    let y = 1;
-    match match y {
-        0 => 1,
-        _ => 2,
-    } {
-        _ => println!("Single branch"),
-    }
+
     // Ok
     let x = 1;
     let y = 1;
diff --git a/src/tools/clippy/tests/ui/match_single_binding.stderr b/src/tools/clippy/tests/ui/match_single_binding.stderr
index cbbf5d29c02..795c8c3e24d 100644
--- a/src/tools/clippy/tests/ui/match_single_binding.stderr
+++ b/src/tools/clippy/tests/ui/match_single_binding.stderr
@@ -167,16 +167,5 @@ LL |             unwrapped
 LL |         })
    |
 
-error: this match could be replaced by its body itself
-  --> $DIR/match_single_binding.rs:112:5
-   |
-LL | /     match match y {
-LL | |         0 => 1,
-LL | |         _ => 2,
-LL | |     } {
-LL | |         _ => println!("Single branch"),
-LL | |     }
-   | |_____^ help: consider using the match body instead: `println!("Single branch");`
-
-error: aborting due to 12 previous errors
+error: aborting due to 11 previous errors
 
diff --git a/src/tools/clippy/tests/ui/match_single_binding2.fixed b/src/tools/clippy/tests/ui/match_single_binding2.fixed
index e73a85b73d7..a91fcc2125d 100644
--- a/src/tools/clippy/tests/ui/match_single_binding2.fixed
+++ b/src/tools/clippy/tests/ui/match_single_binding2.fixed
@@ -34,4 +34,20 @@ fn main() {
         },
         None => println!("nothing"),
     }
+
+    fn side_effects() {}
+
+    // Lint (scrutinee has side effects)
+    // issue #7094
+    side_effects();
+    println!("Side effects");
+
+    // Lint (scrutinee has side effects)
+    // issue #7094
+    let x = 1;
+    match x {
+        0 => 1,
+        _ => 2,
+    };
+    println!("Single branch");
 }
diff --git a/src/tools/clippy/tests/ui/match_single_binding2.rs b/src/tools/clippy/tests/ui/match_single_binding2.rs
index 7362cb390e5..476386ebabe 100644
--- a/src/tools/clippy/tests/ui/match_single_binding2.rs
+++ b/src/tools/clippy/tests/ui/match_single_binding2.rs
@@ -34,4 +34,22 @@ fn main() {
         },
         None => println!("nothing"),
     }
+
+    fn side_effects() {}
+
+    // Lint (scrutinee has side effects)
+    // issue #7094
+    match side_effects() {
+        _ => println!("Side effects"),
+    }
+
+    // Lint (scrutinee has side effects)
+    // issue #7094
+    let x = 1;
+    match match x {
+        0 => 1,
+        _ => 2,
+    } {
+        _ => println!("Single branch"),
+    }
 }
diff --git a/src/tools/clippy/tests/ui/match_single_binding2.stderr b/src/tools/clippy/tests/ui/match_single_binding2.stderr
index bc18d191aa3..4372f55af87 100644
--- a/src/tools/clippy/tests/ui/match_single_binding2.stderr
+++ b/src/tools/clippy/tests/ui/match_single_binding2.stderr
@@ -30,5 +30,39 @@ LL |             let (a, b) = get_tup();
 LL |             println!("a {:?} and b {:?}", a, b);
    |
 
-error: aborting due to 2 previous errors
+error: this match could be replaced by its scrutinee and body
+  --> $DIR/match_single_binding2.rs:42:5
+   |
+LL | /     match side_effects() {
+LL | |         _ => println!("Side effects"),
+LL | |     }
+   | |_____^
+   |
+help: consider using the scrutinee and body instead
+   |
+LL |     side_effects();
+LL |     println!("Side effects");
+   |
+
+error: this match could be replaced by its scrutinee and body
+  --> $DIR/match_single_binding2.rs:49:5
+   |
+LL | /     match match x {
+LL | |         0 => 1,
+LL | |         _ => 2,
+LL | |     } {
+LL | |         _ => println!("Single branch"),
+LL | |     }
+   | |_____^
+   |
+help: consider using the scrutinee and body instead
+   |
+LL |     match x {
+LL |         0 => 1,
+LL |         _ => 2,
+LL |     };
+LL |     println!("Single branch");
+   |
+
+error: aborting due to 4 previous errors
 
diff --git a/src/tools/clippy/tests/ui/needless_bitwise_bool.fixed b/src/tools/clippy/tests/ui/needless_bitwise_bool.fixed
new file mode 100644
index 00000000000..5e1ea663a10
--- /dev/null
+++ b/src/tools/clippy/tests/ui/needless_bitwise_bool.fixed
@@ -0,0 +1,40 @@
+// run-rustfix
+
+#![warn(clippy::needless_bitwise_bool)]
+
+fn returns_bool() -> bool {
+    true
+}
+
+const fn const_returns_bool() -> bool {
+    false
+}
+
+fn main() {
+    let (x, y) = (false, true);
+    if x & y {
+        println!("true")
+    }
+    if returns_bool() & x {
+        println!("true")
+    }
+    if !returns_bool() & returns_bool() {
+        println!("true")
+    }
+    if y && !x {
+        println!("true")
+    }
+
+    // BELOW: lints we hope to catch as `Expr::can_have_side_effects` improves.
+    if y & !const_returns_bool() {
+        println!("true") // This is a const function, in an UnOp
+    }
+
+    if y & "abcD".is_empty() {
+        println!("true") // This is a const method call
+    }
+
+    if y & (0 < 1) {
+        println!("true") // This is a BinOp with no side effects
+    }
+}
diff --git a/src/tools/clippy/tests/ui/needless_bitwise_bool.rs b/src/tools/clippy/tests/ui/needless_bitwise_bool.rs
new file mode 100644
index 00000000000..f3075fba0a2
--- /dev/null
+++ b/src/tools/clippy/tests/ui/needless_bitwise_bool.rs
@@ -0,0 +1,40 @@
+// run-rustfix
+
+#![warn(clippy::needless_bitwise_bool)]
+
+fn returns_bool() -> bool {
+    true
+}
+
+const fn const_returns_bool() -> bool {
+    false
+}
+
+fn main() {
+    let (x, y) = (false, true);
+    if x & y {
+        println!("true")
+    }
+    if returns_bool() & x {
+        println!("true")
+    }
+    if !returns_bool() & returns_bool() {
+        println!("true")
+    }
+    if y & !x {
+        println!("true")
+    }
+
+    // BELOW: lints we hope to catch as `Expr::can_have_side_effects` improves.
+    if y & !const_returns_bool() {
+        println!("true") // This is a const function, in an UnOp
+    }
+
+    if y & "abcD".is_empty() {
+        println!("true") // This is a const method call
+    }
+
+    if y & (0 < 1) {
+        println!("true") // This is a BinOp with no side effects
+    }
+}
diff --git a/src/tools/clippy/tests/ui/needless_bitwise_bool.stderr b/src/tools/clippy/tests/ui/needless_bitwise_bool.stderr
new file mode 100644
index 00000000000..63c88ef63f5
--- /dev/null
+++ b/src/tools/clippy/tests/ui/needless_bitwise_bool.stderr
@@ -0,0 +1,10 @@
+error: use of bitwise operator instead of lazy operator between booleans
+  --> $DIR/needless_bitwise_bool.rs:24:8
+   |
+LL |     if y & !x {
+   |        ^^^^^^ help: try: `y && !x`
+   |
+   = note: `-D clippy::needless-bitwise-bool` implied by `-D warnings`
+
+error: aborting due to previous error
+
diff --git a/src/tools/clippy/tests/ui/needless_collect.fixed b/src/tools/clippy/tests/ui/needless_collect.fixed
index af6c7bf15ea..6ecbbcb6249 100644
--- a/src/tools/clippy/tests/ui/needless_collect.fixed
+++ b/src/tools/clippy/tests/ui/needless_collect.fixed
@@ -2,7 +2,7 @@
 
 #![allow(unused, clippy::suspicious_map, clippy::iter_count)]
 
-use std::collections::{BTreeSet, HashMap, HashSet};
+use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, LinkedList};
 
 #[warn(clippy::needless_collect)]
 #[allow(unused_variables, clippy::iter_cloned_collect, clippy::iter_next_slice)]
@@ -13,9 +13,24 @@ fn main() {
         // Empty
     }
     sample.iter().cloned().any(|x| x == 1);
-    sample.iter().map(|x| (x, x)).count();
+    // #7164 HashMap's and BTreeMap's `len` usage should not be linted
+    sample.iter().map(|x| (x, x)).collect::<HashMap<_, _>>().len();
+    sample.iter().map(|x| (x, x)).collect::<BTreeMap<_, _>>().len();
+
+    sample.iter().map(|x| (x, x)).next().is_none();
+    sample.iter().map(|x| (x, x)).next().is_none();
+
     // Notice the `HashSet`--this should not be linted
     sample.iter().collect::<HashSet<_>>().len();
     // Neither should this
     sample.iter().collect::<BTreeSet<_>>().len();
+
+    sample.iter().count();
+    sample.iter().next().is_none();
+    sample.iter().cloned().any(|x| x == 1);
+    sample.iter().any(|x| x == &1);
+
+    // `BinaryHeap` doesn't have `contains` method
+    sample.iter().count();
+    sample.iter().next().is_none();
 }
diff --git a/src/tools/clippy/tests/ui/needless_collect.rs b/src/tools/clippy/tests/ui/needless_collect.rs
index 6ae14f370b1..8dc69bcf5b3 100644
--- a/src/tools/clippy/tests/ui/needless_collect.rs
+++ b/src/tools/clippy/tests/ui/needless_collect.rs
@@ -2,7 +2,7 @@
 
 #![allow(unused, clippy::suspicious_map, clippy::iter_count)]
 
-use std::collections::{BTreeSet, HashMap, HashSet};
+use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, LinkedList};
 
 #[warn(clippy::needless_collect)]
 #[allow(unused_variables, clippy::iter_cloned_collect, clippy::iter_next_slice)]
@@ -13,9 +13,24 @@ fn main() {
         // Empty
     }
     sample.iter().cloned().collect::<Vec<_>>().contains(&1);
+    // #7164 HashMap's and BTreeMap's `len` usage should not be linted
     sample.iter().map(|x| (x, x)).collect::<HashMap<_, _>>().len();
+    sample.iter().map(|x| (x, x)).collect::<BTreeMap<_, _>>().len();
+
+    sample.iter().map(|x| (x, x)).collect::<HashMap<_, _>>().is_empty();
+    sample.iter().map(|x| (x, x)).collect::<BTreeMap<_, _>>().is_empty();
+
     // Notice the `HashSet`--this should not be linted
     sample.iter().collect::<HashSet<_>>().len();
     // Neither should this
     sample.iter().collect::<BTreeSet<_>>().len();
+
+    sample.iter().collect::<LinkedList<_>>().len();
+    sample.iter().collect::<LinkedList<_>>().is_empty();
+    sample.iter().cloned().collect::<LinkedList<_>>().contains(&1);
+    sample.iter().collect::<LinkedList<_>>().contains(&&1);
+
+    // `BinaryHeap` doesn't have `contains` method
+    sample.iter().collect::<BinaryHeap<_>>().len();
+    sample.iter().collect::<BinaryHeap<_>>().is_empty();
 }
diff --git a/src/tools/clippy/tests/ui/needless_collect.stderr b/src/tools/clippy/tests/ui/needless_collect.stderr
index 2a9539d5975..039091627a8 100644
--- a/src/tools/clippy/tests/ui/needless_collect.stderr
+++ b/src/tools/clippy/tests/ui/needless_collect.stderr
@@ -19,10 +19,52 @@ LL |     sample.iter().cloned().collect::<Vec<_>>().contains(&1);
    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `any(|x| x == 1)`
 
 error: avoid using `collect()` when not needed
-  --> $DIR/needless_collect.rs:16:35
+  --> $DIR/needless_collect.rs:20:35
    |
-LL |     sample.iter().map(|x| (x, x)).collect::<HashMap<_, _>>().len();
-   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `count()`
+LL |     sample.iter().map(|x| (x, x)).collect::<HashMap<_, _>>().is_empty();
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `next().is_none()`
 
-error: aborting due to 4 previous errors
+error: avoid using `collect()` when not needed
+  --> $DIR/needless_collect.rs:21:35
+   |
+LL |     sample.iter().map(|x| (x, x)).collect::<BTreeMap<_, _>>().is_empty();
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `next().is_none()`
+
+error: avoid using `collect()` when not needed
+  --> $DIR/needless_collect.rs:28:19
+   |
+LL |     sample.iter().collect::<LinkedList<_>>().len();
+   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `count()`
+
+error: avoid using `collect()` when not needed
+  --> $DIR/needless_collect.rs:29:19
+   |
+LL |     sample.iter().collect::<LinkedList<_>>().is_empty();
+   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `next().is_none()`
+
+error: avoid using `collect()` when not needed
+  --> $DIR/needless_collect.rs:30:28
+   |
+LL |     sample.iter().cloned().collect::<LinkedList<_>>().contains(&1);
+   |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `any(|x| x == 1)`
+
+error: avoid using `collect()` when not needed
+  --> $DIR/needless_collect.rs:31:19
+   |
+LL |     sample.iter().collect::<LinkedList<_>>().contains(&&1);
+   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `any(|x| x == &1)`
+
+error: avoid using `collect()` when not needed
+  --> $DIR/needless_collect.rs:34:19
+   |
+LL |     sample.iter().collect::<BinaryHeap<_>>().len();
+   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `count()`
+
+error: avoid using `collect()` when not needed
+  --> $DIR/needless_collect.rs:35:19
+   |
+LL |     sample.iter().collect::<BinaryHeap<_>>().is_empty();
+   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `next().is_none()`
+
+error: aborting due to 11 previous errors
 
diff --git a/src/tools/clippy/tests/ui/needless_question_mark.fixed b/src/tools/clippy/tests/ui/needless_question_mark.fixed
index 52ddd9d2dc8..f1fc81aa12b 100644
--- a/src/tools/clippy/tests/ui/needless_question_mark.fixed
+++ b/src/tools/clippy/tests/ui/needless_question_mark.fixed
@@ -94,6 +94,11 @@ where
     Ok(x?)
 }
 
+// not quite needless
+fn deref_ref(s: Option<&String>) -> Option<&str> {
+    Some(s?)
+}
+
 fn main() {}
 
 // #6921 if a macro wraps an expr in Some(  ) and the ? is in the macro use,
diff --git a/src/tools/clippy/tests/ui/needless_question_mark.rs b/src/tools/clippy/tests/ui/needless_question_mark.rs
index 1ea4ba0d83f..44a0c5f61b5 100644
--- a/src/tools/clippy/tests/ui/needless_question_mark.rs
+++ b/src/tools/clippy/tests/ui/needless_question_mark.rs
@@ -94,6 +94,11 @@ where
     Ok(x?)
 }
 
+// not quite needless
+fn deref_ref(s: Option<&String>) -> Option<&str> {
+    Some(s?)
+}
+
 fn main() {}
 
 // #6921 if a macro wraps an expr in Some(  ) and the ? is in the macro use,
diff --git a/src/tools/clippy/tests/ui/needless_question_mark.stderr b/src/tools/clippy/tests/ui/needless_question_mark.stderr
index f1f05d1af3a..02bf50d077a 100644
--- a/src/tools/clippy/tests/ui/needless_question_mark.stderr
+++ b/src/tools/clippy/tests/ui/needless_question_mark.stderr
@@ -67,7 +67,7 @@ LL |         return Ok(t.magic?);
    |                ^^^^^^^^^^^^ help: try: `t.magic`
 
 error: question mark operator is useless here
-  --> $DIR/needless_question_mark.rs:115:27
+  --> $DIR/needless_question_mark.rs:120:27
    |
 LL |         || -> Option<_> { Some(Some($expr)?) }()
    |                           ^^^^^^^^^^^^^^^^^^ help: try: `Some($expr)`
diff --git a/src/tools/clippy/tests/ui/option_if_let_else.fixed b/src/tools/clippy/tests/ui/option_if_let_else.fixed
index 47e7460fa7a..769ccc14bc1 100644
--- a/src/tools/clippy/tests/ui/option_if_let_else.fixed
+++ b/src/tools/clippy/tests/ui/option_if_let_else.fixed
@@ -10,7 +10,11 @@ fn bad1(string: Option<&str>) -> (bool, &str) {
 fn else_if_option(string: Option<&str>) -> Option<(bool, &str)> {
     if string.is_none() {
         None
-    } else { string.map_or(Some((false, "")), |x| Some((true, x))) }
+    } else if let Some(x) = string {
+        Some((true, x))
+    } else {
+        Some((false, ""))
+    }
 }
 
 fn unop_bad(string: &Option<&str>, mut num: Option<i32>) {
diff --git a/src/tools/clippy/tests/ui/option_if_let_else.stderr b/src/tools/clippy/tests/ui/option_if_let_else.stderr
index 7aab068800a..4ebb068d22e 100644
--- a/src/tools/clippy/tests/ui/option_if_let_else.stderr
+++ b/src/tools/clippy/tests/ui/option_if_let_else.stderr
@@ -11,17 +11,6 @@ LL | |     }
    = note: `-D clippy::option-if-let-else` implied by `-D warnings`
 
 error: use Option::map_or instead of an if let/else
-  --> $DIR/option_if_let_else.rs:17:12
-   |
-LL |       } else if let Some(x) = string {
-   |  ____________^
-LL | |         Some((true, x))
-LL | |     } else {
-LL | |         Some((false, ""))
-LL | |     }
-   | |_____^ help: try: `{ string.map_or(Some((false, "")), |x| Some((true, x))) }`
-
-error: use Option::map_or instead of an if let/else
   --> $DIR/option_if_let_else.rs:25:13
    |
 LL |     let _ = if let Some(s) = *string { s.len() } else { 0 };
@@ -159,5 +148,5 @@ error: use Option::map_or instead of an if let/else
 LL |     let _ = if let Some(x) = optional { x + 2 } else { 5 };
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `optional.map_or(5, |x| x + 2)`
 
-error: aborting due to 12 previous errors
+error: aborting due to 11 previous errors
 
diff --git a/src/tools/clippy/tests/ui/unused_async.rs b/src/tools/clippy/tests/ui/unused_async.rs
new file mode 100644
index 00000000000..4f4203f5fdb
--- /dev/null
+++ b/src/tools/clippy/tests/ui/unused_async.rs
@@ -0,0 +1,15 @@
+// edition:2018
+#![warn(clippy::unused_async)]
+
+async fn foo() -> i32 {
+    4
+}
+
+async fn bar() -> i32 {
+    foo().await
+}
+
+fn main() {
+    foo();
+    bar();
+}
diff --git a/src/tools/clippy/tests/ui/unused_async.stderr b/src/tools/clippy/tests/ui/unused_async.stderr
new file mode 100644
index 00000000000..8b834d205b1
--- /dev/null
+++ b/src/tools/clippy/tests/ui/unused_async.stderr
@@ -0,0 +1,13 @@
+error: unused `async` for function with no await statements
+  --> $DIR/unused_async.rs:4:1
+   |
+LL | / async fn foo() -> i32 {
+LL | |     4
+LL | | }
+   | |_^
+   |
+   = note: `-D clippy::unused-async` implied by `-D warnings`
+   = help: consider removing the `async` from this function
+
+error: aborting due to previous error
+
diff --git a/src/tools/clippy/tests/ui/use_self.fixed b/src/tools/clippy/tests/ui/use_self.fixed
index 1282befdfb3..631da6fe066 100644
--- a/src/tools/clippy/tests/ui/use_self.fixed
+++ b/src/tools/clippy/tests/ui/use_self.fixed
@@ -462,3 +462,33 @@ mod issue6818 {
         a: i32,
     }
 }
+
+mod issue7206 {
+    struct MyStruct<const C: char>;
+    impl From<MyStruct<'a'>> for MyStruct<'b'> {
+        fn from(_s: MyStruct<'a'>) -> Self {
+            Self
+        }
+    }
+
+    // keep linting non-`Const` generic args
+    struct S<'a> {
+        inner: &'a str,
+    }
+
+    struct S2<T> {
+        inner: T,
+    }
+
+    impl<T> S2<T> {
+        fn new() -> Self {
+            unimplemented!();
+        }
+    }
+
+    impl<'a> S2<S<'a>> {
+        fn new_again() -> Self {
+            Self::new()
+        }
+    }
+}
diff --git a/src/tools/clippy/tests/ui/use_self.rs b/src/tools/clippy/tests/ui/use_self.rs
index 7aaac7b2414..7a10d755faa 100644
--- a/src/tools/clippy/tests/ui/use_self.rs
+++ b/src/tools/clippy/tests/ui/use_self.rs
@@ -462,3 +462,33 @@ mod issue6818 {
         a: i32,
     }
 }
+
+mod issue7206 {
+    struct MyStruct<const C: char>;
+    impl From<MyStruct<'a'>> for MyStruct<'b'> {
+        fn from(_s: MyStruct<'a'>) -> Self {
+            Self
+        }
+    }
+
+    // keep linting non-`Const` generic args
+    struct S<'a> {
+        inner: &'a str,
+    }
+
+    struct S2<T> {
+        inner: T,
+    }
+
+    impl<T> S2<T> {
+        fn new() -> Self {
+            unimplemented!();
+        }
+    }
+
+    impl<'a> S2<S<'a>> {
+        fn new_again() -> Self {
+            S2::new()
+        }
+    }
+}
diff --git a/src/tools/clippy/tests/ui/use_self.stderr b/src/tools/clippy/tests/ui/use_self.stderr
index a32a9b9157d..cf6222c9b45 100644
--- a/src/tools/clippy/tests/ui/use_self.stderr
+++ b/src/tools/clippy/tests/ui/use_self.stderr
@@ -162,5 +162,11 @@ error: unnecessary structure name repetition
 LL |             A::new::<submod::B>(submod::B {})
    |             ^ help: use the applicable keyword: `Self`
 
-error: aborting due to 27 previous errors
+error: unnecessary structure name repetition
+  --> $DIR/use_self.rs:491:13
+   |
+LL |             S2::new()
+   |             ^^ help: use the applicable keyword: `Self`
+
+error: aborting due to 28 previous errors
 
diff --git a/src/tools/clippy/tests/ui/useless_conversion.fixed b/src/tools/clippy/tests/ui/useless_conversion.fixed
index 03977de9455..76aa82068d6 100644
--- a/src/tools/clippy/tests/ui/useless_conversion.fixed
+++ b/src/tools/clippy/tests/ui/useless_conversion.fixed
@@ -70,4 +70,23 @@ fn main() {
     let a: i32 = 1;
     let b: i32 = 1;
     let _ = (a + b) * 3;
+
+    // see #7205
+    let s: Foo<'a'> = Foo;
+    let _: Foo<'b'> = s.into();
+    let s2: Foo<'a'> = Foo;
+    let _: Foo<'a'> = s2;
+    let s3: Foo<'a'> = Foo;
+    let _ = s3;
+    let s4: Foo<'a'> = Foo;
+    let _ = vec![s4, s4, s4].into_iter();
+}
+
+#[derive(Copy, Clone)]
+struct Foo<const C: char>;
+
+impl From<Foo<'a'>> for Foo<'b'> {
+    fn from(_s: Foo<'a'>) -> Self {
+        Foo
+    }
 }
diff --git a/src/tools/clippy/tests/ui/useless_conversion.rs b/src/tools/clippy/tests/ui/useless_conversion.rs
index f6e094c1661..ccee7abb404 100644
--- a/src/tools/clippy/tests/ui/useless_conversion.rs
+++ b/src/tools/clippy/tests/ui/useless_conversion.rs
@@ -70,4 +70,23 @@ fn main() {
     let a: i32 = 1;
     let b: i32 = 1;
     let _ = i32::from(a + b) * 3;
+
+    // see #7205
+    let s: Foo<'a'> = Foo;
+    let _: Foo<'b'> = s.into();
+    let s2: Foo<'a'> = Foo;
+    let _: Foo<'a'> = s2.into();
+    let s3: Foo<'a'> = Foo;
+    let _ = Foo::<'a'>::from(s3);
+    let s4: Foo<'a'> = Foo;
+    let _ = vec![s4, s4, s4].into_iter().into_iter();
+}
+
+#[derive(Copy, Clone)]
+struct Foo<const C: char>;
+
+impl From<Foo<'a'>> for Foo<'b'> {
+    fn from(_s: Foo<'a'>) -> Self {
+        Foo
+    }
 }
diff --git a/src/tools/clippy/tests/ui/useless_conversion.stderr b/src/tools/clippy/tests/ui/useless_conversion.stderr
index 26a33595031..e6760f700f3 100644
--- a/src/tools/clippy/tests/ui/useless_conversion.stderr
+++ b/src/tools/clippy/tests/ui/useless_conversion.stderr
@@ -70,5 +70,23 @@ error: useless conversion to the same type: `i32`
 LL |     let _ = i32::from(a + b) * 3;
    |             ^^^^^^^^^^^^^^^^ help: consider removing `i32::from()`: `(a + b)`
 
-error: aborting due to 11 previous errors
+error: useless conversion to the same type: `Foo<'a'>`
+  --> $DIR/useless_conversion.rs:78:23
+   |
+LL |     let _: Foo<'a'> = s2.into();
+   |                       ^^^^^^^^^ help: consider removing `.into()`: `s2`
+
+error: useless conversion to the same type: `Foo<'a'>`
+  --> $DIR/useless_conversion.rs:80:13
+   |
+LL |     let _ = Foo::<'a'>::from(s3);
+   |             ^^^^^^^^^^^^^^^^^^^^ help: consider removing `Foo::<'a'>::from()`: `s3`
+
+error: useless conversion to the same type: `std::vec::IntoIter<Foo<'a'>>`
+  --> $DIR/useless_conversion.rs:82:13
+   |
+LL |     let _ = vec![s4, s4, s4].into_iter().into_iter();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider removing `.into_iter()`: `vec![s4, s4, s4].into_iter()`
+
+error: aborting due to 14 previous errors
 
diff --git a/src/tools/clippy/tests/ui/while_let_on_iterator.fixed b/src/tools/clippy/tests/ui/while_let_on_iterator.fixed
index 749393db124..c3e2cf0c4a4 100644
--- a/src/tools/clippy/tests/ui/while_let_on_iterator.fixed
+++ b/src/tools/clippy/tests/ui/while_let_on_iterator.fixed
@@ -1,7 +1,7 @@
 // run-rustfix
 
 #![warn(clippy::while_let_on_iterator)]
-#![allow(clippy::never_loop, unreachable_code, unused_mut)]
+#![allow(clippy::never_loop, unreachable_code, unused_mut, dead_code)]
 
 fn base() {
     let mut iter = 1..20;
@@ -41,13 +41,6 @@ fn base() {
     // or this
     let mut iter = 1u32..20;
     while let Some(_) = iter.next() {
-        break;
-    }
-    println!("Remaining iter {:?}", iter);
-
-    // or this
-    let mut iter = 1u32..20;
-    while let Some(_) = iter.next() {
         iter = 1..20;
     }
 }
@@ -135,18 +128,6 @@ fn refutable2() {
 
 fn nested_loops() {
     let a = [42, 1337];
-    let mut y = a.iter();
-    loop {
-        // x is reused, so don't lint here
-        while let Some(_) = y.next() {}
-    }
-
-    let mut y = a.iter();
-    for _ in 0..2 {
-        while let Some(_) = y.next() {
-            // y is reused, don't lint
-        }
-    }
 
     loop {
         let mut y = a.iter();
@@ -167,10 +148,8 @@ fn issue1121() {
 }
 
 fn issue2965() {
-    // This should not cause an ICE and suggest:
-    //
-    // for _ in values.iter() {}
-    //
+    // This should not cause an ICE
+
     use std::collections::HashSet;
     let mut values = HashSet::new();
     values.insert(1);
@@ -205,13 +184,145 @@ fn issue1654() {
     }
 }
 
+fn issue6491() {
+    // Used in outer loop, needs &mut
+    let mut it = 1..40;
+    while let Some(n) = it.next() {
+        for m in &mut it {
+            if m % 10 == 0 {
+                break;
+            }
+            println!("doing something with m: {}", m);
+        }
+        println!("n still is {}", n);
+    }
+
+    // This is fine, inner loop uses a new iterator.
+    let mut it = 1..40;
+    for n in it {
+        let mut it = 1..40;
+        for m in it {
+            if m % 10 == 0 {
+                break;
+            }
+            println!("doing something with m: {}", m);
+        }
+
+        // Weird binding shouldn't change anything.
+        let (mut it, _) = (1..40, 0);
+        for m in it {
+            if m % 10 == 0 {
+                break;
+            }
+            println!("doing something with m: {}", m);
+        }
+
+        // Used after the loop, needs &mut.
+        let mut it = 1..40;
+        for m in &mut it {
+            if m % 10 == 0 {
+                break;
+            }
+            println!("doing something with m: {}", m);
+        }
+        println!("next item {}", it.next().unwrap());
+
+        println!("n still is {}", n);
+    }
+}
+
+fn issue6231() {
+    // Closure in the outer loop, needs &mut
+    let mut it = 1..40;
+    let mut opt = Some(0);
+    while let Some(n) = opt.take().or_else(|| it.next()) {
+        for m in &mut it {
+            if n % 10 == 0 {
+                break;
+            }
+            println!("doing something with m: {}", m);
+        }
+        println!("n still is {}", n);
+    }
+}
+
+fn issue1924() {
+    struct S<T>(T);
+    impl<T: Iterator<Item = u32>> S<T> {
+        fn f(&mut self) -> Option<u32> {
+            // Used as a field.
+            for i in &mut self.0 {
+                if !(3..=7).contains(&i) {
+                    return Some(i);
+                }
+            }
+            None
+        }
+
+        fn f2(&mut self) -> Option<u32> {
+            // Don't lint, self borrowed inside the loop
+            while let Some(i) = self.0.next() {
+                if i == 1 {
+                    return self.f();
+                }
+            }
+            None
+        }
+    }
+    impl<T: Iterator<Item = u32>> S<(S<T>, Option<u32>)> {
+        fn f3(&mut self) -> Option<u32> {
+            // Don't lint, self borrowed inside the loop
+            while let Some(i) = self.0.0.0.next() {
+                if i == 1 {
+                    return self.0.0.f();
+                }
+            }
+            while let Some(i) = self.0.0.0.next() {
+                if i == 1 {
+                    return self.f3();
+                }
+            }
+            // This one is fine, a different field is borrowed
+            for i in &mut self.0.0.0 {
+                if i == 1 {
+                    return self.0.1.take();
+                } else {
+                    self.0.1 = Some(i);
+                }
+            }
+            None
+        }
+    }
+
+    struct S2<T>(T, u32);
+    impl<T: Iterator<Item = u32>> Iterator for S2<T> {
+        type Item = u32;
+        fn next(&mut self) -> Option<u32> {
+            self.0.next()
+        }
+    }
+
+    // Don't lint, field of the iterator is accessed in the loop
+    let mut it = S2(1..40, 0);
+    while let Some(n) = it.next() {
+        if n == it.1 {
+            break;
+        }
+    }
+
+    // Needs &mut, field of the iterator is accessed after the loop
+    let mut it = S2(1..40, 0);
+    for n in &mut it {
+        if n == 0 {
+            break;
+        }
+    }
+    println!("iterator field {}", it.1);
+}
+
 fn main() {
-    base();
-    refutable();
-    refutable2();
-    nested_loops();
-    issue1121();
-    issue2965();
-    issue3670();
-    issue1654();
+    let mut it = 0..20;
+    for _ in it {
+        println!("test");
+    }
 }
diff --git a/src/tools/clippy/tests/ui/while_let_on_iterator.rs b/src/tools/clippy/tests/ui/while_let_on_iterator.rs
index 30e3b82a7cc..1717006a449 100644
--- a/src/tools/clippy/tests/ui/while_let_on_iterator.rs
+++ b/src/tools/clippy/tests/ui/while_let_on_iterator.rs
@@ -1,7 +1,7 @@
 // run-rustfix
 
 #![warn(clippy::while_let_on_iterator)]
-#![allow(clippy::never_loop, unreachable_code, unused_mut)]
+#![allow(clippy::never_loop, unreachable_code, unused_mut, dead_code)]
 
 fn base() {
     let mut iter = 1..20;
@@ -41,13 +41,6 @@ fn base() {
     // or this
     let mut iter = 1u32..20;
     while let Some(_) = iter.next() {
-        break;
-    }
-    println!("Remaining iter {:?}", iter);
-
-    // or this
-    let mut iter = 1u32..20;
-    while let Some(_) = iter.next() {
         iter = 1..20;
     }
 }
@@ -135,18 +128,6 @@ fn refutable2() {
 
 fn nested_loops() {
     let a = [42, 1337];
-    let mut y = a.iter();
-    loop {
-        // x is reused, so don't lint here
-        while let Some(_) = y.next() {}
-    }
-
-    let mut y = a.iter();
-    for _ in 0..2 {
-        while let Some(_) = y.next() {
-            // y is reused, don't lint
-        }
-    }
 
     loop {
         let mut y = a.iter();
@@ -167,10 +148,8 @@ fn issue1121() {
 }
 
 fn issue2965() {
-    // This should not cause an ICE and suggest:
-    //
-    // for _ in values.iter() {}
-    //
+    // This should not cause an ICE
+
     use std::collections::HashSet;
     let mut values = HashSet::new();
     values.insert(1);
@@ -205,13 +184,145 @@ fn issue1654() {
     }
 }
 
+fn issue6491() {
+    // Used in outer loop, needs &mut
+    let mut it = 1..40;
+    while let Some(n) = it.next() {
+        while let Some(m) = it.next() {
+            if m % 10 == 0 {
+                break;
+            }
+            println!("doing something with m: {}", m);
+        }
+        println!("n still is {}", n);
+    }
+
+    // This is fine, inner loop uses a new iterator.
+    let mut it = 1..40;
+    while let Some(n) = it.next() {
+        let mut it = 1..40;
+        while let Some(m) = it.next() {
+            if m % 10 == 0 {
+                break;
+            }
+            println!("doing something with m: {}", m);
+        }
+
+        // Weird binding shouldn't change anything.
+        let (mut it, _) = (1..40, 0);
+        while let Some(m) = it.next() {
+            if m % 10 == 0 {
+                break;
+            }
+            println!("doing something with m: {}", m);
+        }
+
+        // Used after the loop, needs &mut.
+        let mut it = 1..40;
+        while let Some(m) = it.next() {
+            if m % 10 == 0 {
+                break;
+            }
+            println!("doing something with m: {}", m);
+        }
+        println!("next item {}", it.next().unwrap());
+
+        println!("n still is {}", n);
+    }
+}
+
+fn issue6231() {
+    // Closure in the outer loop, needs &mut
+    let mut it = 1..40;
+    let mut opt = Some(0);
+    while let Some(n) = opt.take().or_else(|| it.next()) {
+        while let Some(m) = it.next() {
+            if n % 10 == 0 {
+                break;
+            }
+            println!("doing something with m: {}", m);
+        }
+        println!("n still is {}", n);
+    }
+}
+
+fn issue1924() {
+    struct S<T>(T);
+    impl<T: Iterator<Item = u32>> S<T> {
+        fn f(&mut self) -> Option<u32> {
+            // Used as a field.
+            while let Some(i) = self.0.next() {
+                if i < 3 || i > 7 {
+                    return Some(i);
+                }
+            }
+            None
+        }
+
+        fn f2(&mut self) -> Option<u32> {
+            // Don't lint, self borrowed inside the loop
+            while let Some(i) = self.0.next() {
+                if i == 1 {
+                    return self.f();
+                }
+            }
+            None
+        }
+    }
+    impl<T: Iterator<Item = u32>> S<(S<T>, Option<u32>)> {
+        fn f3(&mut self) -> Option<u32> {
+            // Don't lint, self borrowed inside the loop
+            while let Some(i) = self.0.0.0.next() {
+                if i == 1 {
+                    return self.0.0.f();
+                }
+            }
+            while let Some(i) = self.0.0.0.next() {
+                if i == 1 {
+                    return self.f3();
+                }
+            }
+            // This one is fine, a different field is borrowed
+            while let Some(i) = self.0.0.0.next() {
+                if i == 1 {
+                    return self.0.1.take();
+                } else {
+                    self.0.1 = Some(i);
+                }
+            }
+            None
+        }
+    }
+
+    struct S2<T>(T, u32);
+    impl<T: Iterator<Item = u32>> Iterator for S2<T> {
+        type Item = u32;
+        fn next(&mut self) -> Option<u32> {
+            self.0.next()
+        }
+    }
+
+    // Don't lint, field of the iterator is accessed in the loop
+    let mut it = S2(1..40, 0);
+    while let Some(n) = it.next() {
+        if n == it.1 {
+            break;
+        }
+    }
+
+    // Needs &mut, field of the iterator is accessed after the loop
+    let mut it = S2(1..40, 0);
+    while let Some(n) = it.next() {
+        if n == 0 {
+            break;
+        }
+    }
+    println!("iterator field {}", it.1);
+}
+
 fn main() {
-    base();
-    refutable();
-    refutable2();
-    nested_loops();
-    issue1121();
-    issue2965();
-    issue3670();
-    issue1654();
+    let mut it = 0..20;
+    while let Some(..) = it.next() {
+        println!("test");
+    }
 }
diff --git a/src/tools/clippy/tests/ui/while_let_on_iterator.stderr b/src/tools/clippy/tests/ui/while_let_on_iterator.stderr
index 6554977c798..eff559bef7e 100644
--- a/src/tools/clippy/tests/ui/while_let_on_iterator.stderr
+++ b/src/tools/clippy/tests/ui/while_let_on_iterator.stderr
@@ -19,28 +19,96 @@ LL |     while let Some(_) = iter.next() {}
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `for _ in iter`
 
 error: this loop could be written as a `for` loop
-  --> $DIR/while_let_on_iterator.rs:101:9
+  --> $DIR/while_let_on_iterator.rs:94:9
    |
 LL |         while let Some([..]) = it.next() {}
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `for [..] in it`
 
 error: this loop could be written as a `for` loop
-  --> $DIR/while_let_on_iterator.rs:108:9
+  --> $DIR/while_let_on_iterator.rs:101:9
    |
 LL |         while let Some([_x]) = it.next() {}
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `for [_x] in it`
 
 error: this loop could be written as a `for` loop
-  --> $DIR/while_let_on_iterator.rs:121:9
+  --> $DIR/while_let_on_iterator.rs:114:9
    |
 LL |         while let Some(x @ [_]) = it.next() {
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `for x @ [_] in it`
 
 error: this loop could be written as a `for` loop
-  --> $DIR/while_let_on_iterator.rs:153:9
+  --> $DIR/while_let_on_iterator.rs:134:9
    |
 LL |         while let Some(_) = y.next() {
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `for _ in y`
 
-error: aborting due to 7 previous errors
+error: this loop could be written as a `for` loop
+  --> $DIR/while_let_on_iterator.rs:191:9
+   |
+LL |         while let Some(m) = it.next() {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `for m in &mut it`
+
+error: this loop could be written as a `for` loop
+  --> $DIR/while_let_on_iterator.rs:202:5
+   |
+LL |     while let Some(n) = it.next() {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `for n in it`
+
+error: this loop could be written as a `for` loop
+  --> $DIR/while_let_on_iterator.rs:204:9
+   |
+LL |         while let Some(m) = it.next() {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `for m in it`
+
+error: this loop could be written as a `for` loop
+  --> $DIR/while_let_on_iterator.rs:213:9
+   |
+LL |         while let Some(m) = it.next() {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `for m in it`
+
+error: this loop could be written as a `for` loop
+  --> $DIR/while_let_on_iterator.rs:222:9
+   |
+LL |         while let Some(m) = it.next() {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `for m in &mut it`
+
+error: this loop could be written as a `for` loop
+  --> $DIR/while_let_on_iterator.rs:239:9
+   |
+LL |         while let Some(m) = it.next() {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `for m in &mut it`
+
+error: this loop could be written as a `for` loop
+  --> $DIR/while_let_on_iterator.rs:254:13
+   |
+LL |             while let Some(i) = self.0.next() {
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `for i in &mut self.0`
+
+error: manual `!RangeInclusive::contains` implementation
+  --> $DIR/while_let_on_iterator.rs:255:20
+   |
+LL |                 if i < 3 || i > 7 {
+   |                    ^^^^^^^^^^^^^^ help: use: `!(3..=7).contains(&i)`
+   |
+   = note: `-D clippy::manual-range-contains` implied by `-D warnings`
+
+error: this loop could be written as a `for` loop
+  --> $DIR/while_let_on_iterator.rs:286:13
+   |
+LL |             while let Some(i) = self.0.0.0.next() {
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `for i in &mut self.0.0.0`
+
+error: this loop could be written as a `for` loop
+  --> $DIR/while_let_on_iterator.rs:315:5
+   |
+LL |     while let Some(n) = it.next() {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `for n in &mut it`
+
+error: this loop could be written as a `for` loop
+  --> $DIR/while_let_on_iterator.rs:325:5
+   |
+LL |     while let Some(..) = it.next() {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `for _ in it`
+
+error: aborting due to 18 previous errors
 
diff --git a/src/tools/clippy/tests/ui/write_with_newline.stderr b/src/tools/clippy/tests/ui/write_with_newline.stderr
index a14e86122ee..cecc2ea9406 100644
--- a/src/tools/clippy/tests/ui/write_with_newline.stderr
+++ b/src/tools/clippy/tests/ui/write_with_newline.stderr
@@ -51,8 +51,8 @@ LL |     write!(&mut v, "/n");
    |
 help: use `writeln!()` instead
    |
-LL |     writeln!(&mut v, );
-   |     ^^^^^^^         --
+LL |     writeln!(&mut v);
+   |     ^^^^^^^       --
 
 error: using `write!()` with a format string that ends in a single newline
   --> $DIR/write_with_newline.rs:36:5
diff --git a/src/tools/clippy/tests/ui/wrong_self_convention2.rs b/src/tools/clippy/tests/ui/wrong_self_convention2.rs
index ae3a740d405..3a72174d03d 100644
--- a/src/tools/clippy/tests/ui/wrong_self_convention2.rs
+++ b/src/tools/clippy/tests/ui/wrong_self_convention2.rs
@@ -23,7 +23,7 @@ mod issue6983 {
     }
 
     struct FooNoCopy;
-    // trigger lint
+    // don't trigger
     impl ToU64 for FooNoCopy {
         fn to_u64(self) -> u64 {
             2
@@ -42,3 +42,30 @@ mod issue7032 {
         }
     }
 }
+
+mod issue7179 {
+    pub struct S(i32);
+
+    impl S {
+        // don't trigger (`s` is not `self`)
+        pub fn from_be(s: Self) -> Self {
+            S(i32::from_be(s.0))
+        }
+
+        // lint
+        pub fn from_be_self(self) -> Self {
+            S(i32::from_be(self.0))
+        }
+    }
+
+    trait T {
+        // don't trigger (`s` is not `self`)
+        fn from_be(s: Self) -> Self;
+        // lint
+        fn from_be_self(self) -> Self;
+    }
+
+    trait Foo: Sized {
+        fn as_byte_slice(slice: &[Self]) -> &[u8];
+    }
+}
diff --git a/src/tools/clippy/tests/ui/wrong_self_convention2.stderr b/src/tools/clippy/tests/ui/wrong_self_convention2.stderr
index 0ca1a390974..d2d74ce099e 100644
--- a/src/tools/clippy/tests/ui/wrong_self_convention2.stderr
+++ b/src/tools/clippy/tests/ui/wrong_self_convention2.stderr
@@ -1,11 +1,19 @@
-error: methods with the following characteristics: (`to_*` and `self` type is not `Copy`) usually take `self` by reference
-  --> $DIR/wrong_self_convention2.rs:28:19
+error: methods called `from_*` usually take no `self`
+  --> $DIR/wrong_self_convention2.rs:56:29
    |
-LL |         fn to_u64(self) -> u64 {
-   |                   ^^^^
+LL |         pub fn from_be_self(self) -> Self {
+   |                             ^^^^
    |
    = note: `-D clippy::wrong-self-convention` implied by `-D warnings`
    = help: consider choosing a less ambiguous name
 
-error: aborting due to previous error
+error: methods called `from_*` usually take no `self`
+  --> $DIR/wrong_self_convention2.rs:65:25
+   |
+LL |         fn from_be_self(self) -> Self;
+   |                         ^^^^
+   |
+   = help: consider choosing a less ambiguous name
+
+error: aborting due to 2 previous errors