Merge commit '0e87918536b9833bbc6c683d1f9d51ee2bf03ef1' into clippyup

61 files changed, 1756 insertions, 194 deletions

diff --git a/src/tools/clippy/tests/ui-toml/upper_case_acronyms_aggressive/upper_case_acronyms.rs b/src/tools/clippy/tests/ui-toml/upper_case_acronyms_aggressive/upper_case_acronyms.rs
index 735909887ac..c6659edacc3 100644
--- a/src/tools/clippy/tests/ui-toml/upper_case_acronyms_aggressive/upper_case_acronyms.rs
+++ b/src/tools/clippy/tests/ui-toml/upper_case_acronyms_aggressive/upper_case_acronyms.rs
@@ -20,4 +20,9 @@ enum Flags {
 // `GccLlvmSomething`
 struct GCCLLVMSomething;
 
+// don't warn on public items
+pub struct MIXEDCapital;
+
+pub struct FULLCAPITAL;
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/def_id_nocore.stderr b/src/tools/clippy/tests/ui/def_id_nocore.stderr
index ed87a50547d..702684f6b43 100644
--- a/src/tools/clippy/tests/ui/def_id_nocore.stderr
+++ b/src/tools/clippy/tests/ui/def_id_nocore.stderr
@@ -1,10 +1,11 @@
-error: methods called `as_*` usually take self by reference or self by mutable reference; consider choosing a less ambiguous name
+error: methods called `as_*` usually take `self` by reference or `self` by mutable reference
   --> $DIR/def_id_nocore.rs:26:19
    |
 LL |     pub fn as_ref(self) -> &'static str {
    |                   ^^^^
    |
    = note: `-D clippy::wrong-self-convention` implied by `-D warnings`
+   = help: consider choosing a less ambiguous name
 
 error: aborting due to previous error
 
diff --git a/src/tools/clippy/tests/ui/dereference.stderr b/src/tools/clippy/tests/ui/dereference.stderr
deleted file mode 100644
index d26b462a433..00000000000
--- a/src/tools/clippy/tests/ui/dereference.stderr
+++ /dev/null
@@ -1,70 +0,0 @@
-error: explicit deref method call
-  --> $DIR/dereference.rs:30:19
-   |
-LL |     let b: &str = a.deref();
-   |                   ^^^^^^^^^ help: try this: `&*a`
-   |
-   = note: `-D clippy::explicit-deref-methods` implied by `-D warnings`
-
-error: explicit deref_mut method call
-  --> $DIR/dereference.rs:32:23
-   |
-LL |     let b: &mut str = a.deref_mut();
-   |                       ^^^^^^^^^^^^^ help: try this: `&mut *a`
-
-error: explicit deref method call
-  --> $DIR/dereference.rs:35:39
-   |
-LL |     let b: String = format!("{}, {}", a.deref(), a.deref());
-   |                                       ^^^^^^^^^ help: try this: `&*a`
-
-error: explicit deref method call
-  --> $DIR/dereference.rs:35:50
-   |
-LL |     let b: String = format!("{}, {}", a.deref(), a.deref());
-   |                                                  ^^^^^^^^^ help: try this: `&*a`
-
-error: explicit deref method call
-  --> $DIR/dereference.rs:37:20
-   |
-LL |     println!("{}", a.deref());
-   |                    ^^^^^^^^^ help: try this: `&*a`
-
-error: explicit deref method call
-  --> $DIR/dereference.rs:40:11
-   |
-LL |     match a.deref() {
-   |           ^^^^^^^^^ help: try this: `&*a`
-
-error: explicit deref method call
-  --> $DIR/dereference.rs:44:28
-   |
-LL |     let b: String = concat(a.deref());
-   |                            ^^^^^^^^^ help: try this: `&*a`
-
-error: explicit deref method call
-  --> $DIR/dereference.rs:46:13
-   |
-LL |     let b = just_return(a).deref();
-   |             ^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&*just_return(a)`
-
-error: explicit deref method call
-  --> $DIR/dereference.rs:48:28
-   |
-LL |     let b: String = concat(just_return(a).deref());
-   |                            ^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&*just_return(a)`
-
-error: explicit deref method call
-  --> $DIR/dereference.rs:50:19
-   |
-LL |     let b: &str = a.deref().deref();
-   |                   ^^^^^^^^^^^^^^^^^ help: try this: `&*a.deref()`
-
-error: explicit deref method call
-  --> $DIR/dereference.rs:53:13
-   |
-LL |     let b = opt_a.unwrap().deref();
-   |             ^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&*opt_a.unwrap()`
-
-error: aborting due to 11 previous errors
-
diff --git a/src/tools/clippy/tests/ui/dereference.fixed b/src/tools/clippy/tests/ui/explicit_deref_methods.fixed
index 459ca91b93b..51d0468e47c 100644
--- a/src/tools/clippy/tests/ui/dereference.fixed
+++ b/src/tools/clippy/tests/ui/explicit_deref_methods.fixed
@@ -29,7 +29,7 @@ fn main() {
 
     let b: &str = &*a;
 
-    let b: &mut str = &mut *a;
+    let b: &mut str = &mut **a;
 
     // both derefs should get linted here
     let b: String = format!("{}, {}", &*a, &*a);
@@ -43,11 +43,11 @@ fn main() {
 
     let b: String = concat(&*a);
 
-    let b = &*just_return(a);
+    let b = just_return(a);
 
-    let b: String = concat(&*just_return(a));
+    let b: String = concat(just_return(a));
 
-    let b: &str = &*a.deref();
+    let b: &str = &**a;
 
     let opt_a = Some(a.clone());
     let b = &*opt_a.unwrap();
@@ -76,6 +76,8 @@ fn main() {
     }
     let b: &str = expr_deref!(a);
 
+    let b: &str = expr_deref!(&*a);
+
     // The struct does not implement Deref trait
     #[derive(Copy, Clone)]
     struct NoLint(u32);
diff --git a/src/tools/clippy/tests/ui/dereference.rs b/src/tools/clippy/tests/ui/explicit_deref_methods.rs
index 8dc5272e67f..680664bd4f6 100644
--- a/src/tools/clippy/tests/ui/dereference.rs
+++ b/src/tools/clippy/tests/ui/explicit_deref_methods.rs
@@ -76,6 +76,8 @@ fn main() {
     }
     let b: &str = expr_deref!(a);
 
+    let b: &str = expr_deref!(a.deref());
+
     // The struct does not implement Deref trait
     #[derive(Copy, Clone)]
     struct NoLint(u32);
diff --git a/src/tools/clippy/tests/ui/explicit_deref_methods.stderr b/src/tools/clippy/tests/ui/explicit_deref_methods.stderr
new file mode 100644
index 00000000000..8035d77d18d
--- /dev/null
+++ b/src/tools/clippy/tests/ui/explicit_deref_methods.stderr
@@ -0,0 +1,76 @@
+error: explicit `deref` method call
+  --> $DIR/explicit_deref_methods.rs:30:19
+   |
+LL |     let b: &str = a.deref();
+   |                   ^^^^^^^^^ help: try this: `&*a`
+   |
+   = note: `-D clippy::explicit-deref-methods` implied by `-D warnings`
+
+error: explicit `deref_mut` method call
+  --> $DIR/explicit_deref_methods.rs:32:23
+   |
+LL |     let b: &mut str = a.deref_mut();
+   |                       ^^^^^^^^^^^^^ help: try this: `&mut **a`
+
+error: explicit `deref` method call
+  --> $DIR/explicit_deref_methods.rs:35:39
+   |
+LL |     let b: String = format!("{}, {}", a.deref(), a.deref());
+   |                                       ^^^^^^^^^ help: try this: `&*a`
+
+error: explicit `deref` method call
+  --> $DIR/explicit_deref_methods.rs:35:50
+   |
+LL |     let b: String = format!("{}, {}", a.deref(), a.deref());
+   |                                                  ^^^^^^^^^ help: try this: `&*a`
+
+error: explicit `deref` method call
+  --> $DIR/explicit_deref_methods.rs:37:20
+   |
+LL |     println!("{}", a.deref());
+   |                    ^^^^^^^^^ help: try this: `&*a`
+
+error: explicit `deref` method call
+  --> $DIR/explicit_deref_methods.rs:40:11
+   |
+LL |     match a.deref() {
+   |           ^^^^^^^^^ help: try this: `&*a`
+
+error: explicit `deref` method call
+  --> $DIR/explicit_deref_methods.rs:44:28
+   |
+LL |     let b: String = concat(a.deref());
+   |                            ^^^^^^^^^ help: try this: `&*a`
+
+error: explicit `deref` method call
+  --> $DIR/explicit_deref_methods.rs:46:13
+   |
+LL |     let b = just_return(a).deref();
+   |             ^^^^^^^^^^^^^^^^^^^^^^ help: try this: `just_return(a)`
+
+error: explicit `deref` method call
+  --> $DIR/explicit_deref_methods.rs:48:28
+   |
+LL |     let b: String = concat(just_return(a).deref());
+   |                            ^^^^^^^^^^^^^^^^^^^^^^ help: try this: `just_return(a)`
+
+error: explicit `deref` method call
+  --> $DIR/explicit_deref_methods.rs:50:19
+   |
+LL |     let b: &str = a.deref().deref();
+   |                   ^^^^^^^^^^^^^^^^^ help: try this: `&**a`
+
+error: explicit `deref` method call
+  --> $DIR/explicit_deref_methods.rs:53:13
+   |
+LL |     let b = opt_a.unwrap().deref();
+   |             ^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&*opt_a.unwrap()`
+
+error: explicit `deref` method call
+  --> $DIR/explicit_deref_methods.rs:79:31
+   |
+LL |     let b: &str = expr_deref!(a.deref());
+   |                               ^^^^^^^^^ help: try this: `&*a`
+
+error: aborting due to 12 previous errors
+
diff --git a/src/tools/clippy/tests/ui/field_reassign_with_default.rs b/src/tools/clippy/tests/ui/field_reassign_with_default.rs
index 9fc208f5332..1368c5d7984 100644
--- a/src/tools/clippy/tests/ui/field_reassign_with_default.rs
+++ b/src/tools/clippy/tests/ui/field_reassign_with_default.rs
@@ -136,6 +136,13 @@ fn main() {
 
     // Don't lint in external macros
     field_reassign_with_default!();
+
+    // be sure suggestion is correct with generics
+    let mut a: Wrapper<bool> = Default::default();
+    a.i = true;
+
+    let mut a: WrapperMulti<i32, i64> = Default::default();
+    a.i = 42;
 }
 
 mod m {
@@ -145,3 +152,14 @@ mod m {
         b: u64,
     }
 }
+
+#[derive(Default)]
+struct Wrapper<T> {
+    i: T,
+}
+
+#[derive(Default)]
+struct WrapperMulti<T, U> {
+    i: T,
+    j: U,
+}
diff --git a/src/tools/clippy/tests/ui/field_reassign_with_default.stderr b/src/tools/clippy/tests/ui/field_reassign_with_default.stderr
index 2f0f28f7bb7..dd7c0360bb1 100644
--- a/src/tools/clippy/tests/ui/field_reassign_with_default.stderr
+++ b/src/tools/clippy/tests/ui/field_reassign_with_default.stderr
@@ -83,5 +83,29 @@ note: consider initializing the variable with `C { i: vec![1], ..Default::defaul
 LL |     let mut a: C = C::default();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 7 previous errors
+error: field assignment outside of initializer for an instance created with Default::default()
+  --> $DIR/field_reassign_with_default.rs:142:5
+   |
+LL |     a.i = true;
+   |     ^^^^^^^^^^^
+   |
+note: consider initializing the variable with `Wrapper::<bool> { i: true }` and removing relevant reassignments
+  --> $DIR/field_reassign_with_default.rs:141:5
+   |
+LL |     let mut a: Wrapper<bool> = Default::default();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: field assignment outside of initializer for an instance created with Default::default()
+  --> $DIR/field_reassign_with_default.rs:145:5
+   |
+LL |     a.i = 42;
+   |     ^^^^^^^^^
+   |
+note: consider initializing the variable with `WrapperMulti::<i32, i64> { i: 42, ..Default::default() }` and removing relevant reassignments
+  --> $DIR/field_reassign_with_default.rs:144:5
+   |
+LL |     let mut a: WrapperMulti<i32, i64> = Default::default();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 9 previous errors
 
diff --git a/src/tools/clippy/tests/ui/if_then_some_else_none.rs b/src/tools/clippy/tests/ui/if_then_some_else_none.rs
new file mode 100644
index 00000000000..54789bf9320
--- /dev/null
+++ b/src/tools/clippy/tests/ui/if_then_some_else_none.rs
@@ -0,0 +1,104 @@
+#![warn(clippy::if_then_some_else_none)]
+#![feature(custom_inner_attributes)]
+
+fn main() {
+    // Should issue an error.
+    let _ = if foo() {
+        println!("true!");
+        Some("foo")
+    } else {
+        None
+    };
+
+    // Should issue an error when macros are used.
+    let _ = if matches!(true, true) {
+        println!("true!");
+        Some(matches!(true, false))
+    } else {
+        None
+    };
+
+    // Should issue an error. Binary expression `o < 32` should be parenthesized.
+    let x = Some(5);
+    let _ = x.and_then(|o| if o < 32 { Some(o) } else { None });
+
+    // Should issue an error. Unary expression `!x` should be parenthesized.
+    let x = true;
+    let _ = if !x { Some(0) } else { None };
+
+    // Should not issue an error since the `else` block has a statement besides `None`.
+    let _ = if foo() {
+        println!("true!");
+        Some("foo")
+    } else {
+        eprintln!("false...");
+        None
+    };
+
+    // Should not issue an error since there are more than 2 blocks in the if-else chain.
+    let _ = if foo() {
+        println!("foo true!");
+        Some("foo")
+    } else if bar() {
+        println!("bar true!");
+        Some("bar")
+    } else {
+        None
+    };
+
+    let _ = if foo() {
+        println!("foo true!");
+        Some("foo")
+    } else {
+        bar().then(|| {
+            println!("bar true!");
+            "bar"
+        })
+    };
+
+    // Should not issue an error since the `then` block has `None`, not `Some`.
+    let _ = if foo() { None } else { Some("foo is false") };
+
+    // Should not issue an error since the `else` block doesn't use `None` directly.
+    let _ = if foo() { Some("foo is true") } else { into_none() };
+
+    // Should not issue an error since the `then` block doesn't use `Some` directly.
+    let _ = if foo() { into_some("foo") } else { None };
+}
+
+fn _msrv_1_49() {
+    #![clippy::msrv = "1.49"]
+    // `bool::then` was stabilized in 1.50. Do not lint this
+    let _ = if foo() {
+        println!("true!");
+        Some(149)
+    } else {
+        None
+    };
+}
+
+fn _msrv_1_50() {
+    #![clippy::msrv = "1.50"]
+    let _ = if foo() {
+        println!("true!");
+        Some(150)
+    } else {
+        None
+    };
+}
+
+fn foo() -> bool {
+    unimplemented!()
+}
+
+fn bar() -> bool {
+    unimplemented!()
+}
+
+fn into_some<T>(v: T) -> Option<T> {
+    Some(v)
+}
+
+fn into_none<T>() -> Option<T> {
+    None
+}
diff --git a/src/tools/clippy/tests/ui/if_then_some_else_none.stderr b/src/tools/clippy/tests/ui/if_then_some_else_none.stderr
new file mode 100644
index 00000000000..8cb22d569f4
--- /dev/null
+++ b/src/tools/clippy/tests/ui/if_then_some_else_none.stderr
@@ -0,0 +1,61 @@
+error: this could be simplified with `bool::then`
+  --> $DIR/if_then_some_else_none.rs:6:13
+   |
+LL |       let _ = if foo() {
+   |  _____________^
+LL | |         println!("true!");
+LL | |         Some("foo")
+LL | |     } else {
+LL | |         None
+LL | |     };
+   | |_____^
+   |
+   = note: `-D clippy::if-then-some-else-none` implied by `-D warnings`
+   = help: consider using `bool::then` like: `foo().then(|| { /* snippet */ "foo" })`
+
+error: this could be simplified with `bool::then`
+  --> $DIR/if_then_some_else_none.rs:14:13
+   |
+LL |       let _ = if matches!(true, true) {
+   |  _____________^
+LL | |         println!("true!");
+LL | |         Some(matches!(true, false))
+LL | |     } else {
+LL | |         None
+LL | |     };
+   | |_____^
+   |
+   = help: consider using `bool::then` like: `matches!(true, true).then(|| { /* snippet */ matches!(true, false) })`
+
+error: this could be simplified with `bool::then`
+  --> $DIR/if_then_some_else_none.rs:23:28
+   |
+LL |     let _ = x.and_then(|o| if o < 32 { Some(o) } else { None });
+   |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: consider using `bool::then` like: `(o < 32).then(|| o)`
+
+error: this could be simplified with `bool::then`
+  --> $DIR/if_then_some_else_none.rs:27:13
+   |
+LL |     let _ = if !x { Some(0) } else { None };
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: consider using `bool::then` like: `(!x).then(|| 0)`
+
+error: this could be simplified with `bool::then`
+  --> $DIR/if_then_some_else_none.rs:82:13
+   |
+LL |       let _ = if foo() {
+   |  _____________^
+LL | |         println!("true!");
+LL | |         Some(150)
+LL | |     } else {
+LL | |         None
+LL | |     };
+   | |_____^
+   |
+   = help: consider using `bool::then` like: `foo().then(|| { /* snippet */ 150 })`
+
+error: aborting due to 5 previous errors
+
diff --git a/src/tools/clippy/tests/ui/inconsistent_struct_constructor.stderr b/src/tools/clippy/tests/ui/inconsistent_struct_constructor.stderr
index d7abe44f254..d021bb19579 100644
--- a/src/tools/clippy/tests/ui/inconsistent_struct_constructor.stderr
+++ b/src/tools/clippy/tests/ui/inconsistent_struct_constructor.stderr
@@ -1,4 +1,4 @@
-error: inconsistent struct constructor
+error: struct constructor field order is inconsistent with struct definition field order
   --> $DIR/inconsistent_struct_constructor.rs:25:9
    |
 LL |         Foo { y, x, z };
@@ -6,7 +6,7 @@ LL |         Foo { y, x, z };
    |
    = note: `-D clippy::inconsistent-struct-constructor` implied by `-D warnings`
 
-error: inconsistent struct constructor
+error: struct constructor field order is inconsistent with struct definition field order
   --> $DIR/inconsistent_struct_constructor.rs:43:9
    |
 LL | /         Foo {
diff --git a/src/tools/clippy/tests/ui/manual_flatten.rs b/src/tools/clippy/tests/ui/manual_flatten.rs
index cff68eca933..b5bd35a6878 100644
--- a/src/tools/clippy/tests/ui/manual_flatten.rs
+++ b/src/tools/clippy/tests/ui/manual_flatten.rs
@@ -1,4 +1,5 @@
 #![warn(clippy::manual_flatten)]
+#![allow(clippy::useless_vec)]
 
 fn main() {
     // Test for loop over implicitly adjusted `Iterator` with `if let` expression
@@ -69,6 +70,27 @@ fn main() {
         }
     }
 
+    let vec_of_ref = vec![&Some(1)];
+    for n in &vec_of_ref {
+        if let Some(n) = n {
+            println!("{:?}", n);
+        }
+    }
+
+    let vec_of_ref = &vec_of_ref;
+    for n in vec_of_ref {
+        if let Some(n) = n {
+            println!("{:?}", n);
+        }
+    }
+
+    let slice_of_ref = &[&Some(1)];
+    for n in slice_of_ref {
+        if let Some(n) = n {
+            println!("{:?}", n);
+        }
+    }
+
     // Using manual flatten should not trigger the lint
     for n in vec![Some(1), Some(2), Some(3)].iter().flatten() {
         println!("{}", n);
diff --git a/src/tools/clippy/tests/ui/manual_flatten.stderr b/src/tools/clippy/tests/ui/manual_flatten.stderr
index 855dd9130e2..be5f8a1d818 100644
--- a/src/tools/clippy/tests/ui/manual_flatten.stderr
+++ b/src/tools/clippy/tests/ui/manual_flatten.stderr
@@ -1,5 +1,5 @@
 error: unnecessary `if let` since only the `Some` variant of the iterator element is used
-  --> $DIR/manual_flatten.rs:6:5
+  --> $DIR/manual_flatten.rs:7:5
    |
 LL |       for n in x {
    |       ^        - help: try: `x.into_iter().flatten()`
@@ -13,7 +13,7 @@ LL | |     }
    |
    = note: `-D clippy::manual-flatten` implied by `-D warnings`
 help: ...and remove the `if let` statement in the for loop
-  --> $DIR/manual_flatten.rs:7:9
+  --> $DIR/manual_flatten.rs:8:9
    |
 LL | /         if let Some(y) = n {
 LL | |             println!("{}", y);
@@ -21,7 +21,7 @@ LL | |         }
    | |_________^
 
 error: unnecessary `if let` since only the `Ok` variant of the iterator element is used
-  --> $DIR/manual_flatten.rs:14:5
+  --> $DIR/manual_flatten.rs:15:5
    |
 LL |       for n in y.clone() {
    |       ^        --------- help: try: `y.clone().into_iter().flatten()`
@@ -34,7 +34,7 @@ LL | |     }
    | |_____^
    |
 help: ...and remove the `if let` statement in the for loop
-  --> $DIR/manual_flatten.rs:15:9
+  --> $DIR/manual_flatten.rs:16:9
    |
 LL | /         if let Ok(n) = n {
 LL | |             println!("{}", n);
@@ -42,7 +42,7 @@ LL | |         };
    | |_________^
 
 error: unnecessary `if let` since only the `Ok` variant of the iterator element is used
-  --> $DIR/manual_flatten.rs:21:5
+  --> $DIR/manual_flatten.rs:22:5
    |
 LL |       for n in &y {
    |       ^        -- help: try: `y.iter().flatten()`
@@ -55,7 +55,7 @@ LL | |     }
    | |_____^
    |
 help: ...and remove the `if let` statement in the for loop
-  --> $DIR/manual_flatten.rs:22:9
+  --> $DIR/manual_flatten.rs:23:9
    |
 LL | /         if let Ok(n) = n {
 LL | |             println!("{}", n);
@@ -63,7 +63,7 @@ LL | |         }
    | |_________^
 
 error: unnecessary `if let` since only the `Ok` variant of the iterator element is used
-  --> $DIR/manual_flatten.rs:31:5
+  --> $DIR/manual_flatten.rs:32:5
    |
 LL |       for n in z {
    |       ^        - help: try: `z.into_iter().flatten()`
@@ -76,7 +76,7 @@ LL | |     }
    | |_____^
    |
 help: ...and remove the `if let` statement in the for loop
-  --> $DIR/manual_flatten.rs:32:9
+  --> $DIR/manual_flatten.rs:33:9
    |
 LL | /         if let Ok(n) = n {
 LL | |             println!("{}", n);
@@ -84,7 +84,7 @@ LL | |         }
    | |_________^
 
 error: unnecessary `if let` since only the `Some` variant of the iterator element is used
-  --> $DIR/manual_flatten.rs:40:5
+  --> $DIR/manual_flatten.rs:41:5
    |
 LL |       for n in z {
    |       ^        - help: try: `z.flatten()`
@@ -97,12 +97,75 @@ LL | |     }
    | |_____^
    |
 help: ...and remove the `if let` statement in the for loop
-  --> $DIR/manual_flatten.rs:41:9
+  --> $DIR/manual_flatten.rs:42:9
    |
 LL | /         if let Some(m) = n {
 LL | |             println!("{}", m);
 LL | |         }
    | |_________^
 
-error: aborting due to 5 previous errors
+error: unnecessary `if let` since only the `Some` variant of the iterator element is used
+  --> $DIR/manual_flatten.rs:74:5
+   |
+LL |       for n in &vec_of_ref {
+   |       ^        ----------- help: try: `vec_of_ref.iter().copied().flatten()`
+   |  _____|
+   | |
+LL | |         if let Some(n) = n {
+LL | |             println!("{:?}", n);
+LL | |         }
+LL | |     }
+   | |_____^
+   |
+help: ...and remove the `if let` statement in the for loop
+  --> $DIR/manual_flatten.rs:75:9
+   |
+LL | /         if let Some(n) = n {
+LL | |             println!("{:?}", n);
+LL | |         }
+   | |_________^
+
+error: unnecessary `if let` since only the `Some` variant of the iterator element is used
+  --> $DIR/manual_flatten.rs:81:5
+   |
+LL |       for n in vec_of_ref {
+   |       ^        ---------- help: try: `vec_of_ref.into_iter().copied().flatten()`
+   |  _____|
+   | |
+LL | |         if let Some(n) = n {
+LL | |             println!("{:?}", n);
+LL | |         }
+LL | |     }
+   | |_____^
+   |
+help: ...and remove the `if let` statement in the for loop
+  --> $DIR/manual_flatten.rs:82:9
+   |
+LL | /         if let Some(n) = n {
+LL | |             println!("{:?}", n);
+LL | |         }
+   | |_________^
+
+error: unnecessary `if let` since only the `Some` variant of the iterator element is used
+  --> $DIR/manual_flatten.rs:88:5
+   |
+LL |       for n in slice_of_ref {
+   |       ^        ------------ help: try: `slice_of_ref.into_iter().copied().flatten()`
+   |  _____|
+   | |
+LL | |         if let Some(n) = n {
+LL | |             println!("{:?}", n);
+LL | |         }
+LL | |     }
+   | |_____^
+   |
+help: ...and remove the `if let` statement in the for loop
+  --> $DIR/manual_flatten.rs:89:9
+   |
+LL | /         if let Some(n) = n {
+LL | |             println!("{:?}", n);
+LL | |         }
+   | |_________^
+
+error: aborting due to 8 previous errors
 
diff --git a/src/tools/clippy/tests/ui/manual_map_option.fixed b/src/tools/clippy/tests/ui/manual_map_option.fixed
index 9222aaf6c78..acb6a580ceb 100644
--- a/src/tools/clippy/tests/ui/manual_map_option.fixed
+++ b/src/tools/clippy/tests/ui/manual_map_option.fixed
@@ -128,4 +128,9 @@ fn main() {
             None => None,
         };
     }
+
+    // #6847
+    if Some(0).is_some() {
+        Some(0)
+    } else { Some(0).map(|x| x + 1) };
 }
diff --git a/src/tools/clippy/tests/ui/manual_map_option.rs b/src/tools/clippy/tests/ui/manual_map_option.rs
index 1ccb450619c..3299e617707 100644
--- a/src/tools/clippy/tests/ui/manual_map_option.rs
+++ b/src/tools/clippy/tests/ui/manual_map_option.rs
@@ -186,4 +186,13 @@ fn main() {
             None => None,
         };
     }
+
+    // #6847
+    if let Some(_) = Some(0) {
+        Some(0)
+    } else if let Some(x) = Some(0) {
+        Some(x + 1)
+    } else {
+        None
+    };
 }
diff --git a/src/tools/clippy/tests/ui/manual_map_option.stderr b/src/tools/clippy/tests/ui/manual_map_option.stderr
index d9f86eecd93..048ccfb9582 100644
--- a/src/tools/clippy/tests/ui/manual_map_option.stderr
+++ b/src/tools/clippy/tests/ui/manual_map_option.stderr
@@ -172,5 +172,24 @@ LL | |         None => None,
 LL | |     };
    | |_____^ help: try this: `option_env!("").map(String::from)`
 
-error: aborting due to 19 previous errors
+error: redundant pattern matching, consider using `is_some()`
+  --> $DIR/manual_map_option.rs:191:12
+   |
+LL |     if let Some(_) = Some(0) {
+   |     -------^^^^^^^---------- help: try this: `if Some(0).is_some()`
+   |
+   = note: `-D clippy::redundant-pattern-matching` implied by `-D warnings`
+
+error: manual implementation of `Option::map`
+  --> $DIR/manual_map_option.rs:193:12
+   |
+LL |       } else if let Some(x) = Some(0) {
+   |  ____________^
+LL | |         Some(x + 1)
+LL | |     } else {
+LL | |         None
+LL | |     };
+   | |_____^ help: try this: `{ Some(0).map(|x| x + 1) }`
+
+error: aborting due to 21 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 81d903c15d3..f1d3252230b 100644
--- a/src/tools/clippy/tests/ui/manual_unwrap_or.fixed
+++ b/src/tools/clippy/tests/ui/manual_unwrap_or.fixed
@@ -136,4 +136,19 @@ fn result_unwrap_or() {
     };
 }
 
+// don't lint in const fn
+const fn const_fn_option_unwrap_or() {
+    match Some(1) {
+        Some(s) => s,
+        None => 0,
+    };
+}
+
+const fn const_fn_result_unwrap_or() {
+    match Ok::<&str, &str>("Alice") {
+        Ok(s) => s,
+        Err(_) => "Bob",
+    };
+}
+
 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 16105d379c3..c9eee25a5b1 100644
--- a/src/tools/clippy/tests/ui/manual_unwrap_or.rs
+++ b/src/tools/clippy/tests/ui/manual_unwrap_or.rs
@@ -175,4 +175,19 @@ fn result_unwrap_or() {
     };
 }
 
+// don't lint in const fn
+const fn const_fn_option_unwrap_or() {
+    match Some(1) {
+        Some(s) => s,
+        None => 0,
+    };
+}
+
+const fn const_fn_result_unwrap_or() {
+    match Ok::<&str, &str>("Alice") {
+        Ok(s) => s,
+        Err(_) => "Bob",
+    };
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/match_single_binding2.fixed b/src/tools/clippy/tests/ui/match_single_binding2.fixed
new file mode 100644
index 00000000000..e73a85b73d7
--- /dev/null
+++ b/src/tools/clippy/tests/ui/match_single_binding2.fixed
@@ -0,0 +1,37 @@
+// run-rustfix
+
+#![warn(clippy::match_single_binding)]
+#![allow(unused_variables)]
+
+fn main() {
+    // Lint (additional curly braces needed, see #6572)
+    struct AppendIter<I>
+    where
+        I: Iterator,
+    {
+        inner: Option<(I, <I as Iterator>::Item)>,
+    }
+
+    #[allow(dead_code)]
+    fn size_hint<I: Iterator>(iter: &AppendIter<I>) -> (usize, Option<usize>) {
+        match &iter.inner {
+            Some((iter, _item)) => {
+                let (min, max) = iter.size_hint();
+                (min.saturating_add(1), max.and_then(|max| max.checked_add(1)))
+            },
+            None => (0, Some(0)),
+        }
+    }
+
+    // Lint (no additional curly braces needed)
+    let opt = Some((5, 2));
+    let get_tup = || -> (i32, i32) { (1, 2) };
+    match opt {
+        #[rustfmt::skip]
+        Some((first, _second)) => {
+            let (a, b) = get_tup();
+            println!("a {:?} and b {:?}", a, b);
+        },
+        None => println!("nothing"),
+    }
+}
diff --git a/src/tools/clippy/tests/ui/match_single_binding2.rs b/src/tools/clippy/tests/ui/match_single_binding2.rs
new file mode 100644
index 00000000000..7362cb390e5
--- /dev/null
+++ b/src/tools/clippy/tests/ui/match_single_binding2.rs
@@ -0,0 +1,37 @@
+// run-rustfix
+
+#![warn(clippy::match_single_binding)]
+#![allow(unused_variables)]
+
+fn main() {
+    // Lint (additional curly braces needed, see #6572)
+    struct AppendIter<I>
+    where
+        I: Iterator,
+    {
+        inner: Option<(I, <I as Iterator>::Item)>,
+    }
+
+    #[allow(dead_code)]
+    fn size_hint<I: Iterator>(iter: &AppendIter<I>) -> (usize, Option<usize>) {
+        match &iter.inner {
+            Some((iter, _item)) => match iter.size_hint() {
+                (min, max) => (min.saturating_add(1), max.and_then(|max| max.checked_add(1))),
+            },
+            None => (0, Some(0)),
+        }
+    }
+
+    // Lint (no additional curly braces needed)
+    let opt = Some((5, 2));
+    let get_tup = || -> (i32, i32) { (1, 2) };
+    match opt {
+        #[rustfmt::skip]
+        Some((first, _second)) => {
+            match get_tup() {
+                (a, b) => println!("a {:?} and b {:?}", a, b),
+            }
+        },
+        None => println!("nothing"),
+    }
+}
diff --git a/src/tools/clippy/tests/ui/match_single_binding2.stderr b/src/tools/clippy/tests/ui/match_single_binding2.stderr
new file mode 100644
index 00000000000..bc18d191aa3
--- /dev/null
+++ b/src/tools/clippy/tests/ui/match_single_binding2.stderr
@@ -0,0 +1,34 @@
+error: this match could be written as a `let` statement
+  --> $DIR/match_single_binding2.rs:18:36
+   |
+LL |               Some((iter, _item)) => match iter.size_hint() {
+   |  ____________________________________^
+LL | |                 (min, max) => (min.saturating_add(1), max.and_then(|max| max.checked_add(1))),
+LL | |             },
+   | |_____________^
+   |
+   = note: `-D clippy::match-single-binding` implied by `-D warnings`
+help: consider using `let` statement
+   |
+LL |             Some((iter, _item)) => {
+LL |                 let (min, max) = iter.size_hint();
+LL |                 (min.saturating_add(1), max.and_then(|max| max.checked_add(1)))
+LL |             },
+   |
+
+error: this match could be written as a `let` statement
+  --> $DIR/match_single_binding2.rs:31:13
+   |
+LL | /             match get_tup() {
+LL | |                 (a, b) => println!("a {:?} and b {:?}", a, b),
+LL | |             }
+   | |_____________^
+   |
+help: consider using `let` statement
+   |
+LL |             let (a, b) = get_tup();
+LL |             println!("a {:?} and b {:?}", a, b);
+   |
+
+error: aborting due to 2 previous errors
+
diff --git a/src/tools/clippy/tests/ui/match_wildcard_for_single_variants.fixed b/src/tools/clippy/tests/ui/match_wildcard_for_single_variants.fixed
index 519200977a7..d99f9af3faf 100644
--- a/src/tools/clippy/tests/ui/match_wildcard_for_single_variants.fixed
+++ b/src/tools/clippy/tests/ui/match_wildcard_for_single_variants.fixed
@@ -15,6 +15,16 @@ enum Color {
     Blue,
     Rgb(u8, u8, u8),
 }
+impl Color {
+    fn f(self) {
+        match self {
+            Self::Red => (),
+            Self::Green => (),
+            Self::Blue => (),
+            Self::Rgb(..) => (),
+        };
+    }
+}
 
 fn main() {
     let f = Foo::A;
@@ -56,4 +66,46 @@ fn main() {
         Color::Rgb(255, _, _) => {},
         _ => {},
     }
+
+    // References shouldn't change anything
+    match &color {
+        &Color::Red => (),
+        Color::Green => (),
+        &Color::Rgb(..) => (),
+        Color::Blue => (),
+    }
+
+    use self::Color as C;
+
+    match color {
+        C::Red => (),
+        C::Green => (),
+        C::Rgb(..) => (),
+        C::Blue => (),
+    }
+
+    match color {
+        C::Red => (),
+        Color::Green => (),
+        Color::Rgb(..) => (),
+        Color::Blue => (),
+    }
+
+    match Some(0) {
+        Some(0) => 0,
+        Some(_) => 1,
+        _ => 2,
+    };
+
+    #[non_exhaustive]
+    enum Bar {
+        A,
+        B,
+        C,
+    }
+    match Bar::A {
+        Bar::A => (),
+        Bar::B => (),
+        _ => (),
+    };
 }
diff --git a/src/tools/clippy/tests/ui/match_wildcard_for_single_variants.rs b/src/tools/clippy/tests/ui/match_wildcard_for_single_variants.rs
index 1df917e085c..1752a95de4b 100644
--- a/src/tools/clippy/tests/ui/match_wildcard_for_single_variants.rs
+++ b/src/tools/clippy/tests/ui/match_wildcard_for_single_variants.rs
@@ -15,6 +15,16 @@ enum Color {
     Blue,
     Rgb(u8, u8, u8),
 }
+impl Color {
+    fn f(self) {
+        match self {
+            Self::Red => (),
+            Self::Green => (),
+            Self::Blue => (),
+            _ => (),
+        };
+    }
+}
 
 fn main() {
     let f = Foo::A;
@@ -56,4 +66,46 @@ fn main() {
         Color::Rgb(255, _, _) => {},
         _ => {},
     }
+
+    // References shouldn't change anything
+    match &color {
+        &Color::Red => (),
+        Color::Green => (),
+        &Color::Rgb(..) => (),
+        &_ => (),
+    }
+
+    use self::Color as C;
+
+    match color {
+        C::Red => (),
+        C::Green => (),
+        C::Rgb(..) => (),
+        _ => (),
+    }
+
+    match color {
+        C::Red => (),
+        Color::Green => (),
+        Color::Rgb(..) => (),
+        _ => (),
+    }
+
+    match Some(0) {
+        Some(0) => 0,
+        Some(_) => 1,
+        _ => 2,
+    };
+
+    #[non_exhaustive]
+    enum Bar {
+        A,
+        B,
+        C,
+    }
+    match Bar::A {
+        Bar::A => (),
+        Bar::B => (),
+        _ => (),
+    };
 }
diff --git a/src/tools/clippy/tests/ui/match_wildcard_for_single_variants.stderr b/src/tools/clippy/tests/ui/match_wildcard_for_single_variants.stderr
index 82790aa9e80..34538dea8e5 100644
--- a/src/tools/clippy/tests/ui/match_wildcard_for_single_variants.stderr
+++ b/src/tools/clippy/tests/ui/match_wildcard_for_single_variants.stderr
@@ -1,28 +1,52 @@
-error: wildcard match will miss any future added variants
-  --> $DIR/match_wildcard_for_single_variants.rs:24:9
+error: wildcard matches only a single variant and will also match any future added variants
+  --> $DIR/match_wildcard_for_single_variants.rs:24:13
    |
-LL |         _ => {},
-   |         ^ help: try this: `Foo::C`
+LL |             _ => (),
+   |             ^ help: try this: `Self::Rgb(..)`
    |
    = note: `-D clippy::match-wildcard-for-single-variants` implied by `-D warnings`
 
-error: wildcard match will miss any future added variants
+error: wildcard matches only a single variant and will also match any future added variants
   --> $DIR/match_wildcard_for_single_variants.rs:34:9
    |
 LL |         _ => {},
+   |         ^ help: try this: `Foo::C`
+
+error: wildcard matches only a single variant and will also match any future added variants
+  --> $DIR/match_wildcard_for_single_variants.rs:44:9
+   |
+LL |         _ => {},
    |         ^ help: try this: `Color::Blue`
 
-error: wildcard match will miss any future added variants
-  --> $DIR/match_wildcard_for_single_variants.rs:42:9
+error: wildcard matches only a single variant and will also match any future added variants
+  --> $DIR/match_wildcard_for_single_variants.rs:52:9
    |
 LL |         _ => {},
    |         ^ help: try this: `Color::Blue`
 
-error: wildcard match will miss any future added variants
-  --> $DIR/match_wildcard_for_single_variants.rs:48:9
+error: wildcard matches only a single variant and will also match any future added variants
+  --> $DIR/match_wildcard_for_single_variants.rs:58:9
    |
 LL |         _ => {},
    |         ^ help: try this: `Color::Blue`
 
-error: aborting due to 4 previous errors
+error: wildcard matches only a single variant and will also match any future added variants
+  --> $DIR/match_wildcard_for_single_variants.rs:75:9
+   |
+LL |         &_ => (),
+   |         ^^ help: try this: `Color::Blue`
+
+error: wildcard matches only a single variant and will also match any future added variants
+  --> $DIR/match_wildcard_for_single_variants.rs:84:9
+   |
+LL |         _ => (),
+   |         ^ help: try this: `C::Blue`
+
+error: wildcard matches only a single variant and will also match any future added variants
+  --> $DIR/match_wildcard_for_single_variants.rs:91:9
+   |
+LL |         _ => (),
+   |         ^ help: try this: `Color::Blue`
+
+error: aborting due to 8 previous errors
 
diff --git a/src/tools/clippy/tests/ui/mem_replace.fixed b/src/tools/clippy/tests/ui/mem_replace.fixed
index 54e962e7116..3b6224254a0 100644
--- a/src/tools/clippy/tests/ui/mem_replace.fixed
+++ b/src/tools/clippy/tests/ui/mem_replace.fixed
@@ -7,6 +7,7 @@
     clippy::mem_replace_with_default
 )]
 
+use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, LinkedList, VecDeque};
 use std::mem;
 
 fn replace_option_with_none() {
@@ -19,9 +20,37 @@ fn replace_option_with_none() {
 fn replace_with_default() {
     let mut s = String::from("foo");
     let _ = std::mem::take(&mut s);
+
     let s = &mut String::from("foo");
     let _ = std::mem::take(s);
     let _ = std::mem::take(s);
+
+    let mut v = vec![123];
+    let _ = std::mem::take(&mut v);
+    let _ = std::mem::take(&mut v);
+    let _ = std::mem::take(&mut v);
+    let _ = std::mem::take(&mut v);
+
+    let mut hash_map: HashMap<i32, i32> = HashMap::new();
+    let _ = std::mem::take(&mut hash_map);
+
+    let mut btree_map: BTreeMap<i32, i32> = BTreeMap::new();
+    let _ = std::mem::take(&mut btree_map);
+
+    let mut vd: VecDeque<i32> = VecDeque::new();
+    let _ = std::mem::take(&mut vd);
+
+    let mut hash_set: HashSet<&str> = HashSet::new();
+    let _ = std::mem::take(&mut hash_set);
+
+    let mut btree_set: BTreeSet<&str> = BTreeSet::new();
+    let _ = std::mem::take(&mut btree_set);
+
+    let mut list: LinkedList<i32> = LinkedList::new();
+    let _ = std::mem::take(&mut list);
+
+    let mut binary_heap: BinaryHeap<i32> = BinaryHeap::new();
+    let _ = std::mem::take(&mut binary_heap);
 }
 
 fn main() {
diff --git a/src/tools/clippy/tests/ui/mem_replace.rs b/src/tools/clippy/tests/ui/mem_replace.rs
index 60f52781071..0a36db9e921 100644
--- a/src/tools/clippy/tests/ui/mem_replace.rs
+++ b/src/tools/clippy/tests/ui/mem_replace.rs
@@ -7,6 +7,7 @@
     clippy::mem_replace_with_default
 )]
 
+use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, LinkedList, VecDeque};
 use std::mem;
 
 fn replace_option_with_none() {
@@ -19,9 +20,37 @@ fn replace_option_with_none() {
 fn replace_with_default() {
     let mut s = String::from("foo");
     let _ = std::mem::replace(&mut s, String::default());
+
     let s = &mut String::from("foo");
     let _ = std::mem::replace(s, String::default());
     let _ = std::mem::replace(s, Default::default());
+
+    let mut v = vec![123];
+    let _ = std::mem::replace(&mut v, Vec::default());
+    let _ = std::mem::replace(&mut v, Default::default());
+    let _ = std::mem::replace(&mut v, Vec::new());
+    let _ = std::mem::replace(&mut v, vec![]);
+
+    let mut hash_map: HashMap<i32, i32> = HashMap::new();
+    let _ = std::mem::replace(&mut hash_map, HashMap::new());
+
+    let mut btree_map: BTreeMap<i32, i32> = BTreeMap::new();
+    let _ = std::mem::replace(&mut btree_map, BTreeMap::new());
+
+    let mut vd: VecDeque<i32> = VecDeque::new();
+    let _ = std::mem::replace(&mut vd, VecDeque::new());
+
+    let mut hash_set: HashSet<&str> = HashSet::new();
+    let _ = std::mem::replace(&mut hash_set, HashSet::new());
+
+    let mut btree_set: BTreeSet<&str> = BTreeSet::new();
+    let _ = std::mem::replace(&mut btree_set, BTreeSet::new());
+
+    let mut list: LinkedList<i32> = LinkedList::new();
+    let _ = std::mem::replace(&mut list, LinkedList::new());
+
+    let mut binary_heap: BinaryHeap<i32> = BinaryHeap::new();
+    let _ = std::mem::replace(&mut binary_heap, BinaryHeap::new());
 }
 
 fn main() {
diff --git a/src/tools/clippy/tests/ui/mem_replace.stderr b/src/tools/clippy/tests/ui/mem_replace.stderr
index 245d33aa4f2..f8aa1538bff 100644
--- a/src/tools/clippy/tests/ui/mem_replace.stderr
+++ b/src/tools/clippy/tests/ui/mem_replace.stderr
@@ -1,5 +1,5 @@
 error: replacing an `Option` with `None`
-  --> $DIR/mem_replace.rs:14:13
+  --> $DIR/mem_replace.rs:15:13
    |
 LL |     let _ = mem::replace(&mut an_option, None);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider `Option::take()` instead: `an_option.take()`
@@ -7,13 +7,13 @@ LL |     let _ = mem::replace(&mut an_option, None);
    = note: `-D clippy::mem-replace-option-with-none` implied by `-D warnings`
 
 error: replacing an `Option` with `None`
-  --> $DIR/mem_replace.rs:16:13
+  --> $DIR/mem_replace.rs:17:13
    |
 LL |     let _ = mem::replace(an_option, None);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider `Option::take()` instead: `an_option.take()`
 
 error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
-  --> $DIR/mem_replace.rs:21:13
+  --> $DIR/mem_replace.rs:22:13
    |
 LL |     let _ = std::mem::replace(&mut s, String::default());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut s)`
@@ -21,16 +21,82 @@ LL |     let _ = std::mem::replace(&mut s, String::default());
    = note: `-D clippy::mem-replace-with-default` implied by `-D warnings`
 
 error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
-  --> $DIR/mem_replace.rs:23:13
+  --> $DIR/mem_replace.rs:25:13
    |
 LL |     let _ = std::mem::replace(s, String::default());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(s)`
 
 error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
-  --> $DIR/mem_replace.rs:24:13
+  --> $DIR/mem_replace.rs:26:13
    |
 LL |     let _ = std::mem::replace(s, Default::default());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(s)`
 
-error: aborting due to 5 previous errors
+error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
+  --> $DIR/mem_replace.rs:29:13
+   |
+LL |     let _ = std::mem::replace(&mut v, Vec::default());
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut v)`
+
+error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
+  --> $DIR/mem_replace.rs:30:13
+   |
+LL |     let _ = std::mem::replace(&mut v, Default::default());
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut v)`
+
+error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
+  --> $DIR/mem_replace.rs:31:13
+   |
+LL |     let _ = std::mem::replace(&mut v, Vec::new());
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut v)`
+
+error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
+  --> $DIR/mem_replace.rs:32:13
+   |
+LL |     let _ = std::mem::replace(&mut v, vec![]);
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut v)`
+
+error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
+  --> $DIR/mem_replace.rs:35:13
+   |
+LL |     let _ = std::mem::replace(&mut hash_map, HashMap::new());
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut hash_map)`
+
+error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
+  --> $DIR/mem_replace.rs:38:13
+   |
+LL |     let _ = std::mem::replace(&mut btree_map, BTreeMap::new());
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut btree_map)`
+
+error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
+  --> $DIR/mem_replace.rs:41:13
+   |
+LL |     let _ = std::mem::replace(&mut vd, VecDeque::new());
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut vd)`
+
+error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
+  --> $DIR/mem_replace.rs:44:13
+   |
+LL |     let _ = std::mem::replace(&mut hash_set, HashSet::new());
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut hash_set)`
+
+error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
+  --> $DIR/mem_replace.rs:47:13
+   |
+LL |     let _ = std::mem::replace(&mut btree_set, BTreeSet::new());
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut btree_set)`
+
+error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
+  --> $DIR/mem_replace.rs:50:13
+   |
+LL |     let _ = std::mem::replace(&mut list, LinkedList::new());
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut list)`
+
+error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
+  --> $DIR/mem_replace.rs:53:13
+   |
+LL |     let _ = std::mem::replace(&mut binary_heap, BinaryHeap::new());
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut binary_heap)`
+
+error: aborting due to 16 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 71fb3565224..fd8433870bb 100644
--- a/src/tools/clippy/tests/ui/needless_question_mark.fixed
+++ b/src/tools/clippy/tests/ui/needless_question_mark.fixed
@@ -167,3 +167,28 @@ mod question_mark_both {
         needless_question_mark_result();
     }
 }
+
+// #6921 if a macro wraps an expr in Some(  ) and the ? is in the macro use,
+// the suggestion fails to apply; do not lint
+macro_rules! some_in_macro {
+    ($expr:expr) => {
+        || -> _ { Some($expr) }()
+    };
+}
+
+pub fn test1() {
+    let x = Some(3);
+    let _x = some_in_macro!(x?);
+}
+
+// this one is ok because both the ? and the Some are both inside the macro def
+macro_rules! some_and_qmark_in_macro {
+    ($expr:expr) => {
+        || -> Option<_> { Some($expr) }()
+    };
+}
+
+pub fn test2() {
+    let x = Some(3);
+    let _x = some_and_qmark_in_macro!(x?);
+}
diff --git a/src/tools/clippy/tests/ui/needless_question_mark.rs b/src/tools/clippy/tests/ui/needless_question_mark.rs
index e31f6f48fa7..36d45ac7e03 100644
--- a/src/tools/clippy/tests/ui/needless_question_mark.rs
+++ b/src/tools/clippy/tests/ui/needless_question_mark.rs
@@ -167,3 +167,28 @@ mod question_mark_both {
         needless_question_mark_result();
     }
 }
+
+// #6921 if a macro wraps an expr in Some(  ) and the ? is in the macro use,
+// the suggestion fails to apply; do not lint
+macro_rules! some_in_macro {
+    ($expr:expr) => {
+        || -> _ { Some($expr) }()
+    };
+}
+
+pub fn test1() {
+    let x = Some(3);
+    let _x = some_in_macro!(x?);
+}
+
+// this one is ok because both the ? and the Some are both inside the macro def
+macro_rules! some_and_qmark_in_macro {
+    ($expr:expr) => {
+        || -> Option<_> { Some(Some($expr)?) }()
+    };
+}
+
+pub fn test2() {
+    let x = Some(3);
+    let _x = some_and_qmark_in_macro!(x?);
+}
diff --git a/src/tools/clippy/tests/ui/needless_question_mark.stderr b/src/tools/clippy/tests/ui/needless_question_mark.stderr
index 983c56031d8..7cbf1e505ad 100644
--- a/src/tools/clippy/tests/ui/needless_question_mark.stderr
+++ b/src/tools/clippy/tests/ui/needless_question_mark.stderr
@@ -84,5 +84,16 @@ error: question mark operator is useless here
 LL |         Ok(to.magic?) // should be triggered
    |         ^^^^^^^^^^^^^ help: try: `to.magic`
 
-error: aborting due to 14 previous errors
+error: question mark operator is useless here
+  --> $DIR/needless_question_mark.rs:187:27
+   |
+LL |         || -> Option<_> { Some(Some($expr)?) }()
+   |                           ^^^^^^^^^^^^^^^^^^ help: try: `Some($expr)`
+...
+LL |     let _x = some_and_qmark_in_macro!(x?);
+   |              ---------------------------- in this macro invocation
+   |
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 15 previous errors
 
diff --git a/src/tools/clippy/tests/ui/new_ret_no_self.rs b/src/tools/clippy/tests/ui/new_ret_no_self.rs
index e82873629a5..2f315ffe298 100644
--- a/src/tools/clippy/tests/ui/new_ret_no_self.rs
+++ b/src/tools/clippy/tests/ui/new_ret_no_self.rs
@@ -340,3 +340,13 @@ mod issue5435 {
         }
     }
 }
+
+// issue #1724
+struct RetOtherSelf<T>(T);
+struct RetOtherSelfWrapper<T>(T);
+
+impl RetOtherSelf<T> {
+    fn new(t: T) -> RetOtherSelf<RetOtherSelfWrapper<T>> {
+        RetOtherSelf(RetOtherSelfWrapper(t))
+    }
+}
diff --git a/src/tools/clippy/tests/ui/new_without_default.rs b/src/tools/clippy/tests/ui/new_without_default.rs
index 3b6041823d8..64659b63f46 100644
--- a/src/tools/clippy/tests/ui/new_without_default.rs
+++ b/src/tools/clippy/tests/ui/new_without_default.rs
@@ -159,4 +159,19 @@ impl NewNotEqualToDerive {
     }
 }
 
+// see #6933
+pub struct FooGenerics<T>(std::marker::PhantomData<T>);
+impl<T> FooGenerics<T> {
+    pub fn new() -> Self {
+        Self(Default::default())
+    }
+}
+
+pub struct BarGenerics<T>(std::marker::PhantomData<T>);
+impl<T: Copy> BarGenerics<T> {
+    pub fn new() -> Self {
+        Self(Default::default())
+    }
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/new_without_default.stderr b/src/tools/clippy/tests/ui/new_without_default.stderr
index e529e441eb7..973836f75a9 100644
--- a/src/tools/clippy/tests/ui/new_without_default.stderr
+++ b/src/tools/clippy/tests/ui/new_without_default.stderr
@@ -43,7 +43,7 @@ LL | |     }
    |
 help: try this
    |
-LL | impl Default for LtKo<'c> {
+LL | impl<'c> Default for LtKo<'c> {
 LL |     fn default() -> Self {
 LL |         Self::new()
 LL |     }
@@ -67,5 +67,39 @@ LL |     }
 LL | }
    |
 
-error: aborting due to 4 previous errors
+error: you should consider adding a `Default` implementation for `FooGenerics<T>`
+  --> $DIR/new_without_default.rs:165:5
+   |
+LL | /     pub fn new() -> Self {
+LL | |         Self(Default::default())
+LL | |     }
+   | |_____^
+   |
+help: try this
+   |
+LL | impl<T> Default for FooGenerics<T> {
+LL |     fn default() -> Self {
+LL |         Self::new()
+LL |     }
+LL | }
+   |
+
+error: you should consider adding a `Default` implementation for `BarGenerics<T>`
+  --> $DIR/new_without_default.rs:172:5
+   |
+LL | /     pub fn new() -> Self {
+LL | |         Self(Default::default())
+LL | |     }
+   | |_____^
+   |
+help: try this
+   |
+LL | impl<T: Copy> Default for BarGenerics<T> {
+LL |     fn default() -> Self {
+LL |         Self::new()
+LL |     }
+LL | }
+   |
+
+error: aborting due to 6 previous errors
 
diff --git a/src/tools/clippy/tests/ui/or_fun_call.fixed b/src/tools/clippy/tests/ui/or_fun_call.fixed
index 64347cae5da..4390ff7dc30 100644
--- a/src/tools/clippy/tests/ui/or_fun_call.fixed
+++ b/src/tools/clippy/tests/ui/or_fun_call.fixed
@@ -120,6 +120,9 @@ fn test_or_with_ctors() {
 
     let slice = &["foo"][..];
     let _ = opt.ok_or(slice.len());
+
+    let string = "foo";
+    let _ = opt.ok_or(string.len());
 }
 
 // Issue 4514 - early return
@@ -132,4 +135,18 @@ fn f() -> Option<()> {
     Some(())
 }
 
+mod issue6675 {
+    unsafe fn foo() {
+        let mut s = "test".to_owned();
+        None.unwrap_or_else(|| s.as_mut_vec());
+    }
+
+    fn bar() {
+        let mut s = "test".to_owned();
+        None.unwrap_or_else(|| unsafe { s.as_mut_vec() });
+        #[rustfmt::skip]
+        None.unwrap_or_else(|| unsafe { s.as_mut_vec() });
+    }
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/or_fun_call.rs b/src/tools/clippy/tests/ui/or_fun_call.rs
index 7faab0017b2..75908c974cc 100644
--- a/src/tools/clippy/tests/ui/or_fun_call.rs
+++ b/src/tools/clippy/tests/ui/or_fun_call.rs
@@ -120,6 +120,9 @@ fn test_or_with_ctors() {
 
     let slice = &["foo"][..];
     let _ = opt.ok_or(slice.len());
+
+    let string = "foo";
+    let _ = opt.ok_or(string.len());
 }
 
 // Issue 4514 - early return
@@ -132,4 +135,18 @@ fn f() -> Option<()> {
     Some(())
 }
 
+mod issue6675 {
+    unsafe fn foo() {
+        let mut s = "test".to_owned();
+        None.unwrap_or(s.as_mut_vec());
+    }
+
+    fn bar() {
+        let mut s = "test".to_owned();
+        None.unwrap_or(unsafe { s.as_mut_vec() });
+        #[rustfmt::skip]
+        None.unwrap_or( unsafe { s.as_mut_vec() }    );
+    }
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/or_fun_call.stderr b/src/tools/clippy/tests/ui/or_fun_call.stderr
index 1e2bfd490e0..9905029ce91 100644
--- a/src/tools/clippy/tests/ui/or_fun_call.stderr
+++ b/src/tools/clippy/tests/ui/or_fun_call.stderr
@@ -114,5 +114,23 @@ error: use of `or` followed by a function call
 LL |         .or(Some(Bar(b, Duration::from_secs(2))));
    |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `or_else(|| Some(Bar(b, Duration::from_secs(2))))`
 
-error: aborting due to 19 previous errors
+error: use of `unwrap_or` followed by a function call
+  --> $DIR/or_fun_call.rs:141:14
+   |
+LL |         None.unwrap_or(s.as_mut_vec());
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| s.as_mut_vec())`
+
+error: use of `unwrap_or` followed by a function call
+  --> $DIR/or_fun_call.rs:146:14
+   |
+LL |         None.unwrap_or(unsafe { s.as_mut_vec() });
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| unsafe { s.as_mut_vec() })`
+
+error: use of `unwrap_or` followed by a function call
+  --> $DIR/or_fun_call.rs:148:14
+   |
+LL |         None.unwrap_or( unsafe { s.as_mut_vec() }    );
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| unsafe { s.as_mut_vec() })`
+
+error: aborting due to 22 previous errors
 
diff --git a/src/tools/clippy/tests/ui/print.stderr b/src/tools/clippy/tests/ui/print.stderr
index 208d9532628..1754c418381 100644
--- a/src/tools/clippy/tests/ui/print.stderr
+++ b/src/tools/clippy/tests/ui/print.stderr
@@ -1,8 +1,8 @@
 error: use of `Debug`-based formatting
-  --> $DIR/print.rs:11:19
+  --> $DIR/print.rs:11:20
    |
 LL |         write!(f, "{:?}", 43.1415)
-   |                   ^^^^^^
+   |                    ^^^^
    |
    = note: `-D clippy::use-debug` implied by `-D warnings`
 
@@ -33,10 +33,10 @@ LL |     print!("Hello {:?}", "World");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: use of `Debug`-based formatting
-  --> $DIR/print.rs:28:12
+  --> $DIR/print.rs:28:19
    |
 LL |     print!("Hello {:?}", "World");
-   |            ^^^^^^^^^^^^
+   |                   ^^^^
 
 error: use of `print!`
   --> $DIR/print.rs:30:5
@@ -45,10 +45,10 @@ LL |     print!("Hello {:#?}", "#orld");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: use of `Debug`-based formatting
-  --> $DIR/print.rs:30:12
+  --> $DIR/print.rs:30:19
    |
 LL |     print!("Hello {:#?}", "#orld");
-   |            ^^^^^^^^^^^^^
+   |                   ^^^^^
 
 error: aborting due to 8 previous errors
 
diff --git a/src/tools/clippy/tests/ui/print_literal.stderr b/src/tools/clippy/tests/ui/print_literal.stderr
index e284aece236..54a4084c89e 100644
--- a/src/tools/clippy/tests/ui/print_literal.stderr
+++ b/src/tools/clippy/tests/ui/print_literal.stderr
@@ -5,66 +5,120 @@ LL |     print!("Hello {}", "world");
    |                        ^^^^^^^
    |
    = note: `-D clippy::print-literal` implied by `-D warnings`
+help: try this
+   |
+LL |     print!("Hello world");
+   |                   ^^^^^--
 
 error: literal with an empty format string
   --> $DIR/print_literal.rs:26:36
    |
 LL |     println!("Hello {} {}", world, "world");
    |                                    ^^^^^^^
+   |
+help: try this
+   |
+LL |     println!("Hello {} world", world);
+   |                        ^^^^^       --
 
 error: literal with an empty format string
   --> $DIR/print_literal.rs:27:26
    |
 LL |     println!("Hello {}", "world");
    |                          ^^^^^^^
+   |
+help: try this
+   |
+LL |     println!("Hello world");
+   |                     ^^^^^--
 
 error: literal with an empty format string
   --> $DIR/print_literal.rs:32:25
    |
 LL |     println!("{0} {1}", "hello", "world");
    |                         ^^^^^^^
+   |
+help: try this
+   |
+LL |     println!("hello {1}", "world");
+   |               ^^^^^    --
 
 error: literal with an empty format string
   --> $DIR/print_literal.rs:32:34
    |
 LL |     println!("{0} {1}", "hello", "world");
    |                                  ^^^^^^^
+   |
+help: try this
+   |
+LL |     println!("{0} world", "hello");
+   |                   ^^^^^         --
 
 error: literal with an empty format string
   --> $DIR/print_literal.rs:33:25
    |
 LL |     println!("{1} {0}", "hello", "world");
    |                         ^^^^^^^
+   |
+help: try this
+   |
+LL |     println!("{1} hello", "world");
+   |                   ^^^^^--
 
 error: literal with an empty format string
   --> $DIR/print_literal.rs:33:34
    |
 LL |     println!("{1} {0}", "hello", "world");
    |                                  ^^^^^^^
+   |
+help: try this
+   |
+LL |     println!("world {0}", "hello");
+   |               ^^^^^             --
 
 error: literal with an empty format string
-  --> $DIR/print_literal.rs:36:35
+  --> $DIR/print_literal.rs:36:29
    |
 LL |     println!("{foo} {bar}", foo = "hello", bar = "world");
-   |                                   ^^^^^^^
+   |                             ^^^^^^^^^^^^^
+   |
+help: try this
+   |
+LL |     println!("hello {bar}", bar = "world");
+   |               ^^^^^      --
 
 error: literal with an empty format string
-  --> $DIR/print_literal.rs:36:50
+  --> $DIR/print_literal.rs:36:44
    |
 LL |     println!("{foo} {bar}", foo = "hello", bar = "world");
-   |                                                  ^^^^^^^
+   |                                            ^^^^^^^^^^^^^
+   |
+help: try this
+   |
+LL |     println!("{foo} world", foo = "hello");
+   |                     ^^^^^               --
 
 error: literal with an empty format string
-  --> $DIR/print_literal.rs:37:35
+  --> $DIR/print_literal.rs:37:29
    |
 LL |     println!("{bar} {foo}", foo = "hello", bar = "world");
-   |                                   ^^^^^^^
+   |                             ^^^^^^^^^^^^^
+   |
+help: try this
+   |
+LL |     println!("{bar} hello", bar = "world");
+   |                     ^^^^^--
 
 error: literal with an empty format string
-  --> $DIR/print_literal.rs:37:50
+  --> $DIR/print_literal.rs:37:44
    |
 LL |     println!("{bar} {foo}", foo = "hello", bar = "world");
-   |                                                  ^^^^^^^
+   |                                            ^^^^^^^^^^^^^
+   |
+help: try this
+   |
+LL |     println!("world {foo}", foo = "hello");
+   |               ^^^^^                     --
 
 error: aborting due to 11 previous errors
 
diff --git a/src/tools/clippy/tests/ui/search_is_some.rs b/src/tools/clippy/tests/ui/search_is_some.rs
index f0dc3b3d06b..72bc6ef35d3 100644
--- a/src/tools/clippy/tests/ui/search_is_some.rs
+++ b/src/tools/clippy/tests/ui/search_is_some.rs
@@ -1,8 +1,9 @@
 // aux-build:option_helpers.rs
+#![warn(clippy::search_is_some)]
+#![allow(dead_code)]
 extern crate option_helpers;
 use option_helpers::IteratorFalsePositives;
 
-#[warn(clippy::search_is_some)]
 #[rustfmt::skip]
 fn main() {
     let v = vec![3, 2, 1, 0, -1, -2, -3];
@@ -36,3 +37,37 @@ fn main() {
     // `Pattern` that is not a string
     let _ = "hello world".find(|c: char| c == 'o' || c == 'l').is_some();
 }
+
+#[rustfmt::skip]
+fn is_none() {
+    let v = vec![3, 2, 1, 0, -1, -2, -3];
+    let y = &&42;
+
+
+    // Check `find().is_none()`, multi-line case.
+    let _ = v.iter().find(|&x| {
+                              *x < 0
+                          }
+                   ).is_none();
+
+    // Check `position().is_none()`, multi-line case.
+    let _ = v.iter().position(|&x| {
+                                  x < 0
+                              }
+                   ).is_none();
+
+    // Check `rposition().is_none()`, multi-line case.
+    let _ = v.iter().rposition(|&x| {
+                                   x < 0
+                               }
+                   ).is_none();
+
+    // Check that we don't lint if the caller is not an `Iterator` or string
+    let falsepos = IteratorFalsePositives { foo: 0 };
+    let _ = falsepos.find().is_none();
+    let _ = falsepos.position().is_none();
+    let _ = falsepos.rposition().is_none();
+    // check that we don't lint if `find()` is called with
+    // `Pattern` that is not a string
+    let _ = "hello world".find(|c: char| c == 'o' || c == 'l').is_none();
+}
diff --git a/src/tools/clippy/tests/ui/search_is_some.stderr b/src/tools/clippy/tests/ui/search_is_some.stderr
index c601f568c60..f3c758e451e 100644
--- a/src/tools/clippy/tests/ui/search_is_some.stderr
+++ b/src/tools/clippy/tests/ui/search_is_some.stderr
@@ -1,5 +1,5 @@
 error: called `is_some()` after searching an `Iterator` with `find`
-  --> $DIR/search_is_some.rs:13:13
+  --> $DIR/search_is_some.rs:14:13
    |
 LL |       let _ = v.iter().find(|&x| {
    |  _____________^
@@ -12,7 +12,7 @@ LL | |                    ).is_some();
    = help: this is more succinctly expressed by calling `any()`
 
 error: called `is_some()` after searching an `Iterator` with `position`
-  --> $DIR/search_is_some.rs:19:13
+  --> $DIR/search_is_some.rs:20:13
    |
 LL |       let _ = v.iter().position(|&x| {
    |  _____________^
@@ -24,7 +24,7 @@ LL | |                    ).is_some();
    = help: this is more succinctly expressed by calling `any()`
 
 error: called `is_some()` after searching an `Iterator` with `rposition`
-  --> $DIR/search_is_some.rs:25:13
+  --> $DIR/search_is_some.rs:26:13
    |
 LL |       let _ = v.iter().rposition(|&x| {
    |  _____________^
@@ -35,5 +35,41 @@ LL | |                    ).is_some();
    |
    = help: this is more succinctly expressed by calling `any()`
 
-error: aborting due to 3 previous errors
+error: called `is_none()` after searching an `Iterator` with `find`
+  --> $DIR/search_is_some.rs:48:13
+   |
+LL |       let _ = v.iter().find(|&x| {
+   |  _____________^
+LL | |                               *x < 0
+LL | |                           }
+LL | |                    ).is_none();
+   | |______________________________^
+   |
+   = help: this is more succinctly expressed by calling `any()` with negation
+
+error: called `is_none()` after searching an `Iterator` with `position`
+  --> $DIR/search_is_some.rs:54:13
+   |
+LL |       let _ = v.iter().position(|&x| {
+   |  _____________^
+LL | |                                   x < 0
+LL | |                               }
+LL | |                    ).is_none();
+   | |______________________________^
+   |
+   = help: this is more succinctly expressed by calling `any()` with negation
+
+error: called `is_none()` after searching an `Iterator` with `rposition`
+  --> $DIR/search_is_some.rs:60:13
+   |
+LL |       let _ = v.iter().rposition(|&x| {
+   |  _____________^
+LL | |                                    x < 0
+LL | |                                }
+LL | |                    ).is_none();
+   | |______________________________^
+   |
+   = help: this is more succinctly expressed by calling `any()` with negation
+
+error: aborting due to 6 previous errors
 
diff --git a/src/tools/clippy/tests/ui/search_is_some_fixable.fixed b/src/tools/clippy/tests/ui/search_is_some_fixable.fixed
index dc3f290e562..62ff16f67f4 100644
--- a/src/tools/clippy/tests/ui/search_is_some_fixable.fixed
+++ b/src/tools/clippy/tests/ui/search_is_some_fixable.fixed
@@ -1,5 +1,5 @@
 // run-rustfix
-
+#![allow(dead_code)]
 #![warn(clippy::search_is_some)]
 
 fn main() {
@@ -33,3 +33,36 @@ fn main() {
     let _ = s1[2..].contains(&s2);
     let _ = s1[2..].contains(&s2[2..]);
 }
+
+fn is_none() {
+    let v = vec![3, 2, 1, 0, -1, -2, -3];
+    let y = &&42;
+
+    // Check `find().is_none()`, single-line case.
+    let _ = !v.iter().any(|x| *x < 0);
+    let _ = !(0..1).any(|x| **y == x); // one dereference less
+    let _ = !(0..1).any(|x| x == 0);
+    let _ = !v.iter().any(|x| *x == 0);
+
+    // Check `position().is_none()`, single-line case.
+    let _ = !v.iter().any(|&x| x < 0);
+
+    // Check `rposition().is_none()`, single-line case.
+    let _ = !v.iter().any(|&x| x < 0);
+
+    let s1 = String::from("hello world");
+    let s2 = String::from("world");
+
+    // caller of `find()` is a `&`static str`
+    let _ = !"hello world".contains("world");
+    let _ = !"hello world".contains(&s2);
+    let _ = !"hello world".contains(&s2[2..]);
+    // caller of `find()` is a `String`
+    let _ = !s1.contains("world");
+    let _ = !s1.contains(&s2);
+    let _ = !s1.contains(&s2[2..]);
+    // caller of `find()` is slice of `String`
+    let _ = !s1[2..].contains("world");
+    let _ = !s1[2..].contains(&s2);
+    let _ = !s1[2..].contains(&s2[2..]);
+}
diff --git a/src/tools/clippy/tests/ui/search_is_some_fixable.rs b/src/tools/clippy/tests/ui/search_is_some_fixable.rs
index 146cf5adf1b..8407f716647 100644
--- a/src/tools/clippy/tests/ui/search_is_some_fixable.rs
+++ b/src/tools/clippy/tests/ui/search_is_some_fixable.rs
@@ -1,5 +1,5 @@
 // run-rustfix
-
+#![allow(dead_code)]
 #![warn(clippy::search_is_some)]
 
 fn main() {
@@ -33,3 +33,36 @@ fn main() {
     let _ = s1[2..].find(&s2).is_some();
     let _ = s1[2..].find(&s2[2..]).is_some();
 }
+
+fn is_none() {
+    let v = vec![3, 2, 1, 0, -1, -2, -3];
+    let y = &&42;
+
+    // Check `find().is_none()`, single-line case.
+    let _ = v.iter().find(|&x| *x < 0).is_none();
+    let _ = (0..1).find(|x| **y == *x).is_none(); // one dereference less
+    let _ = (0..1).find(|x| *x == 0).is_none();
+    let _ = v.iter().find(|x| **x == 0).is_none();
+
+    // Check `position().is_none()`, single-line case.
+    let _ = v.iter().position(|&x| x < 0).is_none();
+
+    // Check `rposition().is_none()`, single-line case.
+    let _ = v.iter().rposition(|&x| x < 0).is_none();
+
+    let s1 = String::from("hello world");
+    let s2 = String::from("world");
+
+    // caller of `find()` is a `&`static str`
+    let _ = "hello world".find("world").is_none();
+    let _ = "hello world".find(&s2).is_none();
+    let _ = "hello world".find(&s2[2..]).is_none();
+    // caller of `find()` is a `String`
+    let _ = s1.find("world").is_none();
+    let _ = s1.find(&s2).is_none();
+    let _ = s1.find(&s2[2..]).is_none();
+    // caller of `find()` is slice of `String`
+    let _ = s1[2..].find("world").is_none();
+    let _ = s1[2..].find(&s2).is_none();
+    let _ = s1[2..].find(&s2[2..]).is_none();
+}
diff --git a/src/tools/clippy/tests/ui/search_is_some_fixable.stderr b/src/tools/clippy/tests/ui/search_is_some_fixable.stderr
index 23c1d9a901b..bd1b6955a97 100644
--- a/src/tools/clippy/tests/ui/search_is_some_fixable.stderr
+++ b/src/tools/clippy/tests/ui/search_is_some_fixable.stderr
@@ -90,5 +90,95 @@ error: called `is_some()` after calling `find()` on a string
 LL |     let _ = s1[2..].find(&s2[2..]).is_some();
    |                     ^^^^^^^^^^^^^^^^^^^^^^^^ help: use `contains()` instead: `contains(&s2[2..])`
 
-error: aborting due to 15 previous errors
+error: called `is_none()` after searching an `Iterator` with `find`
+  --> $DIR/search_is_some_fixable.rs:42:13
+   |
+LL |     let _ = v.iter().find(|&x| *x < 0).is_none();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `!_.any()` instead: `!v.iter().any(|x| *x < 0)`
+
+error: called `is_none()` after searching an `Iterator` with `find`
+  --> $DIR/search_is_some_fixable.rs:43:13
+   |
+LL |     let _ = (0..1).find(|x| **y == *x).is_none(); // one dereference less
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `!_.any()` instead: `!(0..1).any(|x| **y == x)`
+
+error: called `is_none()` after searching an `Iterator` with `find`
+  --> $DIR/search_is_some_fixable.rs:44:13
+   |
+LL |     let _ = (0..1).find(|x| *x == 0).is_none();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `!_.any()` instead: `!(0..1).any(|x| x == 0)`
+
+error: called `is_none()` after searching an `Iterator` with `find`
+  --> $DIR/search_is_some_fixable.rs:45:13
+   |
+LL |     let _ = v.iter().find(|x| **x == 0).is_none();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `!_.any()` instead: `!v.iter().any(|x| *x == 0)`
+
+error: called `is_none()` after searching an `Iterator` with `position`
+  --> $DIR/search_is_some_fixable.rs:48:13
+   |
+LL |     let _ = v.iter().position(|&x| x < 0).is_none();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `!_.any()` instead: `!v.iter().any(|&x| x < 0)`
+
+error: called `is_none()` after searching an `Iterator` with `rposition`
+  --> $DIR/search_is_some_fixable.rs:51:13
+   |
+LL |     let _ = v.iter().rposition(|&x| x < 0).is_none();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `!_.any()` instead: `!v.iter().any(|&x| x < 0)`
+
+error: called `is_none()` after calling `find()` on a string
+  --> $DIR/search_is_some_fixable.rs:57:13
+   |
+LL |     let _ = "hello world".find("world").is_none();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `!_.contains()` instead: `!"hello world".contains("world")`
+
+error: called `is_none()` after calling `find()` on a string
+  --> $DIR/search_is_some_fixable.rs:58:13
+   |
+LL |     let _ = "hello world".find(&s2).is_none();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `!_.contains()` instead: `!"hello world".contains(&s2)`
+
+error: called `is_none()` after calling `find()` on a string
+  --> $DIR/search_is_some_fixable.rs:59:13
+   |
+LL |     let _ = "hello world".find(&s2[2..]).is_none();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `!_.contains()` instead: `!"hello world".contains(&s2[2..])`
+
+error: called `is_none()` after calling `find()` on a string
+  --> $DIR/search_is_some_fixable.rs:61:13
+   |
+LL |     let _ = s1.find("world").is_none();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `!_.contains()` instead: `!s1.contains("world")`
+
+error: called `is_none()` after calling `find()` on a string
+  --> $DIR/search_is_some_fixable.rs:62:13
+   |
+LL |     let _ = s1.find(&s2).is_none();
+   |             ^^^^^^^^^^^^^^^^^^^^^^ help: use `!_.contains()` instead: `!s1.contains(&s2)`
+
+error: called `is_none()` after calling `find()` on a string
+  --> $DIR/search_is_some_fixable.rs:63:13
+   |
+LL |     let _ = s1.find(&s2[2..]).is_none();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `!_.contains()` instead: `!s1.contains(&s2[2..])`
+
+error: called `is_none()` after calling `find()` on a string
+  --> $DIR/search_is_some_fixable.rs:65:13
+   |
+LL |     let _ = s1[2..].find("world").is_none();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `!_.contains()` instead: `!s1[2..].contains("world")`
+
+error: called `is_none()` after calling `find()` on a string
+  --> $DIR/search_is_some_fixable.rs:66:13
+   |
+LL |     let _ = s1[2..].find(&s2).is_none();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `!_.contains()` instead: `!s1[2..].contains(&s2)`
+
+error: called `is_none()` after calling `find()` on a string
+  --> $DIR/search_is_some_fixable.rs:67:13
+   |
+LL |     let _ = s1[2..].find(&s2[2..]).is_none();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `!_.contains()` instead: `!s1[2..].contains(&s2[2..])`
+
+error: aborting due to 30 previous errors
 
diff --git a/src/tools/clippy/tests/ui/string_lit_as_bytes.fixed b/src/tools/clippy/tests/ui/string_lit_as_bytes.fixed
index ccf8f61c4a9..dd22bfa5c53 100644
--- a/src/tools/clippy/tests/ui/string_lit_as_bytes.fixed
+++ b/src/tools/clippy/tests/ui/string_lit_as_bytes.fixed
@@ -8,10 +8,16 @@ fn str_lit_as_bytes() {
 
     let bs = br###"raw string with 3# plus " ""###;
 
+    let bs = b"lit to string".to_vec();
+    let bs = b"lit to owned".to_vec();
+
     // no warning, because these cannot be written as byte string literals:
     let ubs = "☃".as_bytes();
     let ubs = "hello there! this is a very long string".as_bytes();
 
+    let ubs = "☃".to_string().into_bytes();
+    let ubs = "this is also too long and shouldn't be fixed".to_string().into_bytes();
+
     let strify = stringify!(foobar).as_bytes();
 
     let current_version = env!("CARGO_PKG_VERSION").as_bytes();
diff --git a/src/tools/clippy/tests/ui/string_lit_as_bytes.rs b/src/tools/clippy/tests/ui/string_lit_as_bytes.rs
index 178df08e249..d2a710ed6b8 100644
--- a/src/tools/clippy/tests/ui/string_lit_as_bytes.rs
+++ b/src/tools/clippy/tests/ui/string_lit_as_bytes.rs
@@ -8,10 +8,16 @@ fn str_lit_as_bytes() {
 
     let bs = r###"raw string with 3# plus " ""###.as_bytes();
 
+    let bs = "lit to string".to_string().into_bytes();
+    let bs = "lit to owned".to_owned().into_bytes();
+
     // no warning, because these cannot be written as byte string literals:
     let ubs = "☃".as_bytes();
     let ubs = "hello there! this is a very long string".as_bytes();
 
+    let ubs = "☃".to_string().into_bytes();
+    let ubs = "this is also too long and shouldn't be fixed".to_string().into_bytes();
+
     let strify = stringify!(foobar).as_bytes();
 
     let current_version = env!("CARGO_PKG_VERSION").as_bytes();
diff --git a/src/tools/clippy/tests/ui/string_lit_as_bytes.stderr b/src/tools/clippy/tests/ui/string_lit_as_bytes.stderr
index 99c512354d5..e0ddb070b50 100644
--- a/src/tools/clippy/tests/ui/string_lit_as_bytes.stderr
+++ b/src/tools/clippy/tests/ui/string_lit_as_bytes.stderr
@@ -12,17 +12,29 @@ error: calling `as_bytes()` on a string literal
 LL |     let bs = r###"raw string with 3# plus " ""###.as_bytes();
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using a byte string literal instead: `br###"raw string with 3# plus " ""###`
 
+error: calling `into_bytes()` on a string literal
+  --> $DIR/string_lit_as_bytes.rs:11:14
+   |
+LL |     let bs = "lit to string".to_string().into_bytes();
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using a byte string literal instead: `b"lit to string".to_vec()`
+
+error: calling `into_bytes()` on a string literal
+  --> $DIR/string_lit_as_bytes.rs:12:14
+   |
+LL |     let bs = "lit to owned".to_owned().into_bytes();
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using a byte string literal instead: `b"lit to owned".to_vec()`
+
 error: calling `as_bytes()` on `include_str!(..)`
-  --> $DIR/string_lit_as_bytes.rs:19:22
+  --> $DIR/string_lit_as_bytes.rs:25:22
    |
 LL |     let includestr = include_str!("entry_unfixable.rs").as_bytes();
    |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `include_bytes!(..)` instead: `include_bytes!("entry_unfixable.rs")`
 
 error: calling `as_bytes()` on a string literal
-  --> $DIR/string_lit_as_bytes.rs:21:13
+  --> $DIR/string_lit_as_bytes.rs:27:13
    |
 LL |     let _ = "string with newline/t/n".as_bytes();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using a byte string literal instead: `b"string with newline/t/n"`
 
-error: aborting due to 4 previous errors
+error: aborting due to 6 previous errors
 
diff --git a/src/tools/clippy/tests/ui/suspicious_map.rs b/src/tools/clippy/tests/ui/suspicious_map.rs
index d838d8fde21..3a2a10cf09e 100644
--- a/src/tools/clippy/tests/ui/suspicious_map.rs
+++ b/src/tools/clippy/tests/ui/suspicious_map.rs
@@ -2,4 +2,31 @@
 
 fn main() {
     let _ = (0..3).map(|x| x + 2).count();
+
+    let f = |x| x + 1;
+    let _ = (0..3).map(f).count();
+}
+
+fn negative() {
+    // closure with side effects
+    let mut sum = 0;
+    let _ = (0..3).map(|x| sum += x).count();
+
+    // closure variable with side effects
+    let ext_closure = |x| sum += x;
+    let _ = (0..3).map(ext_closure).count();
+
+    // closure that returns unit
+    let _ = (0..3)
+        .map(|x| {
+            // do nothing
+        })
+        .count();
+
+    // external function
+    let _ = (0..3).map(do_something).count();
+}
+
+fn do_something<T>(t: T) -> String {
+    unimplemented!()
 }
diff --git a/src/tools/clippy/tests/ui/suspicious_map.stderr b/src/tools/clippy/tests/ui/suspicious_map.stderr
index e1b4ba40376..8c3f36584a5 100644
--- a/src/tools/clippy/tests/ui/suspicious_map.stderr
+++ b/src/tools/clippy/tests/ui/suspicious_map.stderr
@@ -7,5 +7,13 @@ LL |     let _ = (0..3).map(|x| x + 2).count();
    = note: `-D clippy::suspicious-map` implied by `-D warnings`
    = help: make sure you did not confuse `map` with `filter` or `for_each`
 
-error: aborting due to previous error
+error: this call to `map()` won't have an effect on the call to `count()`
+  --> $DIR/suspicious_map.rs:7:13
+   |
+LL |     let _ = (0..3).map(f).count();
+   |             ^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: make sure you did not confuse `map` with `filter` or `for_each`
+
+error: aborting due to 2 previous errors
 
diff --git a/src/tools/clippy/tests/ui/unnecessary_cast.stderr b/src/tools/clippy/tests/ui/unnecessary_cast.stderr
index 8981d13e8ea..70aa448af68 100644
--- a/src/tools/clippy/tests/ui/unnecessary_cast.stderr
+++ b/src/tools/clippy/tests/ui/unnecessary_cast.stderr
@@ -1,22 +1,22 @@
-error: casting to the same type is unnecessary (`i32` -> `i32`)
+error: casting integer literal to `i32` is unnecessary
   --> $DIR/unnecessary_cast.rs:6:5
    |
 LL |     1i32 as i32;
-   |     ^^^^^^^^^^^
+   |     ^^^^^^^^^^^ help: try: `1_i32`
    |
    = note: `-D clippy::unnecessary-cast` implied by `-D warnings`
 
-error: casting to the same type is unnecessary (`f32` -> `f32`)
+error: casting float literal to `f32` is unnecessary
   --> $DIR/unnecessary_cast.rs:7:5
    |
 LL |     1f32 as f32;
-   |     ^^^^^^^^^^^
+   |     ^^^^^^^^^^^ help: try: `1_f32`
 
 error: casting to the same type is unnecessary (`bool` -> `bool`)
   --> $DIR/unnecessary_cast.rs:8:5
    |
 LL |     false as bool;
-   |     ^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^ help: try: `false`
 
 error: aborting due to 3 previous errors
 
diff --git a/src/tools/clippy/tests/ui/upper_case_acronyms.rs b/src/tools/clippy/tests/ui/upper_case_acronyms.rs
index 735909887ac..8c09c6f5b23 100644
--- a/src/tools/clippy/tests/ui/upper_case_acronyms.rs
+++ b/src/tools/clippy/tests/ui/upper_case_acronyms.rs
@@ -20,4 +20,8 @@ enum Flags {
 // `GccLlvmSomething`
 struct GCCLLVMSomething;
 
+// public items must not be linted
+pub struct NOWARNINGHERE;
+pub struct ALSONoWarningHERE;
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/use_self.fixed b/src/tools/clippy/tests/ui/use_self.fixed
index b94d5448d92..1282befdfb3 100644
--- a/src/tools/clippy/tests/ui/use_self.fixed
+++ b/src/tools/clippy/tests/ui/use_self.fixed
@@ -75,13 +75,13 @@ mod lifetimes {
 
 mod issue2894 {
     trait IntoBytes {
-        fn to_bytes(&self) -> Vec<u8>;
+        fn to_bytes(self) -> Vec<u8>;
     }
 
     // This should not be linted
     impl IntoBytes for u8 {
-        fn to_bytes(&self) -> Vec<u8> {
-            vec![*self]
+        fn to_bytes(self) -> Vec<u8> {
+            vec![self]
         }
     }
 }
diff --git a/src/tools/clippy/tests/ui/use_self.rs b/src/tools/clippy/tests/ui/use_self.rs
index ac99c6d9d7b..7aaac7b2414 100644
--- a/src/tools/clippy/tests/ui/use_self.rs
+++ b/src/tools/clippy/tests/ui/use_self.rs
@@ -75,13 +75,13 @@ mod lifetimes {
 
 mod issue2894 {
     trait IntoBytes {
-        fn to_bytes(&self) -> Vec<u8>;
+        fn to_bytes(self) -> Vec<u8>;
     }
 
     // This should not be linted
     impl IntoBytes for u8 {
-        fn to_bytes(&self) -> Vec<u8> {
-            vec![*self]
+        fn to_bytes(self) -> Vec<u8> {
+            vec![self]
         }
     }
 }
diff --git a/src/tools/clippy/tests/ui/wildcard_enum_match_arm.fixed b/src/tools/clippy/tests/ui/wildcard_enum_match_arm.fixed
index c266f684a36..fd754e4c794 100644
--- a/src/tools/clippy/tests/ui/wildcard_enum_match_arm.fixed
+++ b/src/tools/clippy/tests/ui/wildcard_enum_match_arm.fixed
@@ -77,7 +77,7 @@ fn main() {
     let error_kind = ErrorKind::NotFound;
     match error_kind {
         ErrorKind::NotFound => {},
-        std::io::ErrorKind::PermissionDenied | std::io::ErrorKind::ConnectionRefused | std::io::ErrorKind::ConnectionReset | std::io::ErrorKind::ConnectionAborted | std::io::ErrorKind::NotConnected | std::io::ErrorKind::AddrInUse | std::io::ErrorKind::AddrNotAvailable | std::io::ErrorKind::BrokenPipe | std::io::ErrorKind::AlreadyExists | std::io::ErrorKind::WouldBlock | std::io::ErrorKind::InvalidInput | std::io::ErrorKind::InvalidData | std::io::ErrorKind::TimedOut | std::io::ErrorKind::WriteZero | std::io::ErrorKind::Interrupted | std::io::ErrorKind::Other | std::io::ErrorKind::UnexpectedEof | _ => {},
+        ErrorKind::PermissionDenied | ErrorKind::ConnectionRefused | ErrorKind::ConnectionReset | ErrorKind::ConnectionAborted | ErrorKind::NotConnected | ErrorKind::AddrInUse | ErrorKind::AddrNotAvailable | ErrorKind::BrokenPipe | ErrorKind::AlreadyExists | ErrorKind::WouldBlock | ErrorKind::InvalidInput | ErrorKind::InvalidData | ErrorKind::TimedOut | ErrorKind::WriteZero | ErrorKind::Interrupted | ErrorKind::Other | ErrorKind::UnexpectedEof | _ => {},
     }
     match error_kind {
         ErrorKind::NotFound => {},
diff --git a/src/tools/clippy/tests/ui/wildcard_enum_match_arm.stderr b/src/tools/clippy/tests/ui/wildcard_enum_match_arm.stderr
index 0da2b68ba0b..a513a62c748 100644
--- a/src/tools/clippy/tests/ui/wildcard_enum_match_arm.stderr
+++ b/src/tools/clippy/tests/ui/wildcard_enum_match_arm.stderr
@@ -1,4 +1,4 @@
-error: wildcard match will miss any future added variants
+error: wildcard match will also match any future added variants
   --> $DIR/wildcard_enum_match_arm.rs:39:9
    |
 LL |         _ => eprintln!("Not red"),
@@ -10,29 +10,29 @@ note: the lint level is defined here
 LL | #![deny(clippy::wildcard_enum_match_arm)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: wildcard match will miss any future added variants
+error: wildcard match will also match any future added variants
   --> $DIR/wildcard_enum_match_arm.rs:43:9
    |
 LL |         _not_red => eprintln!("Not red"),
    |         ^^^^^^^^ help: try this: `_not_red @ Color::Green | _not_red @ Color::Blue | _not_red @ Color::Rgb(..) | _not_red @ Color::Cyan`
 
-error: wildcard match will miss any future added variants
+error: wildcard match will also match any future added variants
   --> $DIR/wildcard_enum_match_arm.rs:47:9
    |
 LL |         not_red => format!("{:?}", not_red),
    |         ^^^^^^^ help: try this: `not_red @ Color::Green | not_red @ Color::Blue | not_red @ Color::Rgb(..) | not_red @ Color::Cyan`
 
-error: wildcard match will miss any future added variants
+error: wildcard match will also match any future added variants
   --> $DIR/wildcard_enum_match_arm.rs:63:9
    |
 LL |         _ => "No red",
    |         ^ help: try this: `Color::Red | Color::Green | Color::Blue | Color::Rgb(..) | Color::Cyan`
 
-error: match on non-exhaustive enum doesn't explicitly match all known variants
+error: wildcard matches known variants and will also match future added variants
   --> $DIR/wildcard_enum_match_arm.rs:80:9
    |
 LL |         _ => {},
-   |         ^ help: try this: `std::io::ErrorKind::PermissionDenied | std::io::ErrorKind::ConnectionRefused | std::io::ErrorKind::ConnectionReset | std::io::ErrorKind::ConnectionAborted | std::io::ErrorKind::NotConnected | std::io::ErrorKind::AddrInUse | std::io::ErrorKind::AddrNotAvailable | std::io::ErrorKind::BrokenPipe | std::io::ErrorKind::AlreadyExists | std::io::ErrorKind::WouldBlock | std::io::ErrorKind::InvalidInput | std::io::ErrorKind::InvalidData | std::io::ErrorKind::TimedOut | std::io::ErrorKind::WriteZero | std::io::ErrorKind::Interrupted | std::io::ErrorKind::Other | std::io::ErrorKind::UnexpectedEof | _`
+   |         ^ help: try this: `ErrorKind::PermissionDenied | ErrorKind::ConnectionRefused | ErrorKind::ConnectionReset | ErrorKind::ConnectionAborted | ErrorKind::NotConnected | ErrorKind::AddrInUse | ErrorKind::AddrNotAvailable | ErrorKind::BrokenPipe | ErrorKind::AlreadyExists | ErrorKind::WouldBlock | ErrorKind::InvalidInput | ErrorKind::InvalidData | ErrorKind::TimedOut | ErrorKind::WriteZero | ErrorKind::Interrupted | ErrorKind::Other | ErrorKind::UnexpectedEof | _`
 
 error: aborting due to 5 previous errors
 
diff --git a/src/tools/clippy/tests/ui/write_literal.stderr b/src/tools/clippy/tests/ui/write_literal.stderr
index e54d89ecf29..507a78e8280 100644
--- a/src/tools/clippy/tests/ui/write_literal.stderr
+++ b/src/tools/clippy/tests/ui/write_literal.stderr
@@ -5,66 +5,120 @@ LL |     write!(&mut v, "Hello {}", "world");
    |                                ^^^^^^^
    |
    = note: `-D clippy::write-literal` implied by `-D warnings`
+help: try this
+   |
+LL |     write!(&mut v, "Hello world");
+   |                           ^^^^^--
 
 error: literal with an empty format string
   --> $DIR/write_literal.rs:31:44
    |
 LL |     writeln!(&mut v, "Hello {} {}", world, "world");
    |                                            ^^^^^^^
+   |
+help: try this
+   |
+LL |     writeln!(&mut v, "Hello {} world", world);
+   |                                ^^^^^       --
 
 error: literal with an empty format string
   --> $DIR/write_literal.rs:32:34
    |
 LL |     writeln!(&mut v, "Hello {}", "world");
    |                                  ^^^^^^^
+   |
+help: try this
+   |
+LL |     writeln!(&mut v, "Hello world");
+   |                             ^^^^^--
 
 error: literal with an empty format string
   --> $DIR/write_literal.rs:37:33
    |
 LL |     writeln!(&mut v, "{0} {1}", "hello", "world");
    |                                 ^^^^^^^
+   |
+help: try this
+   |
+LL |     writeln!(&mut v, "hello {1}", "world");
+   |                       ^^^^^    --
 
 error: literal with an empty format string
   --> $DIR/write_literal.rs:37:42
    |
 LL |     writeln!(&mut v, "{0} {1}", "hello", "world");
    |                                          ^^^^^^^
+   |
+help: try this
+   |
+LL |     writeln!(&mut v, "{0} world", "hello");
+   |                           ^^^^^         --
 
 error: literal with an empty format string
   --> $DIR/write_literal.rs:38:33
    |
 LL |     writeln!(&mut v, "{1} {0}", "hello", "world");
    |                                 ^^^^^^^
+   |
+help: try this
+   |
+LL |     writeln!(&mut v, "{1} hello", "world");
+   |                           ^^^^^--
 
 error: literal with an empty format string
   --> $DIR/write_literal.rs:38:42
    |
 LL |     writeln!(&mut v, "{1} {0}", "hello", "world");
    |                                          ^^^^^^^
+   |
+help: try this
+   |
+LL |     writeln!(&mut v, "world {0}", "hello");
+   |                       ^^^^^             --
 
 error: literal with an empty format string
-  --> $DIR/write_literal.rs:41:43
+  --> $DIR/write_literal.rs:41:37
    |
 LL |     writeln!(&mut v, "{foo} {bar}", foo = "hello", bar = "world");
-   |                                           ^^^^^^^
+   |                                     ^^^^^^^^^^^^^
+   |
+help: try this
+   |
+LL |     writeln!(&mut v, "hello {bar}", bar = "world");
+   |                       ^^^^^      --
 
 error: literal with an empty format string
-  --> $DIR/write_literal.rs:41:58
+  --> $DIR/write_literal.rs:41:52
    |
 LL |     writeln!(&mut v, "{foo} {bar}", foo = "hello", bar = "world");
-   |                                                          ^^^^^^^
+   |                                                    ^^^^^^^^^^^^^
+   |
+help: try this
+   |
+LL |     writeln!(&mut v, "{foo} world", foo = "hello");
+   |                             ^^^^^               --
 
 error: literal with an empty format string
-  --> $DIR/write_literal.rs:42:43
+  --> $DIR/write_literal.rs:42:37
    |
 LL |     writeln!(&mut v, "{bar} {foo}", foo = "hello", bar = "world");
-   |                                           ^^^^^^^
+   |                                     ^^^^^^^^^^^^^
+   |
+help: try this
+   |
+LL |     writeln!(&mut v, "{bar} hello", bar = "world");
+   |                             ^^^^^--
 
 error: literal with an empty format string
-  --> $DIR/write_literal.rs:42:58
+  --> $DIR/write_literal.rs:42:52
    |
 LL |     writeln!(&mut v, "{bar} {foo}", foo = "hello", bar = "world");
-   |                                                          ^^^^^^^
+   |                                                    ^^^^^^^^^^^^^
+   |
+help: try this
+   |
+LL |     writeln!(&mut v, "world {foo}", foo = "hello");
+   |                       ^^^^^                     --
 
 error: aborting due to 11 previous errors
 
diff --git a/src/tools/clippy/tests/ui/write_literal_2.rs b/src/tools/clippy/tests/ui/write_literal_2.rs
new file mode 100644
index 00000000000..f341e8215e1
--- /dev/null
+++ b/src/tools/clippy/tests/ui/write_literal_2.rs
@@ -0,0 +1,27 @@
+#![allow(unused_must_use)]
+#![warn(clippy::write_literal)]
+
+use std::io::Write;
+
+fn main() {
+    let mut v = Vec::new();
+
+    writeln!(&mut v, "{}", "{hello}");
+    writeln!(&mut v, r"{}", r"{hello}");
+    writeln!(&mut v, "{}", '\'');
+    writeln!(&mut v, "{}", '"');
+    writeln!(&mut v, r"{}", '"'); // don't lint
+    writeln!(&mut v, r"{}", '\'');
+    writeln!(
+        &mut v,
+        "some {}",
+        "hello \
+        world!"
+    );
+    writeln!(
+        &mut v,
+        "some {}\
+        {} \\ {}",
+        "1", "2", "3",
+    );
+}
diff --git a/src/tools/clippy/tests/ui/write_literal_2.stderr b/src/tools/clippy/tests/ui/write_literal_2.stderr
new file mode 100644
index 00000000000..5b488358011
--- /dev/null
+++ b/src/tools/clippy/tests/ui/write_literal_2.stderr
@@ -0,0 +1,106 @@
+error: literal with an empty format string
+  --> $DIR/write_literal_2.rs:9:28
+   |
+LL |     writeln!(&mut v, "{}", "{hello}");
+   |                            ^^^^^^^^^
+   |
+   = note: `-D clippy::write-literal` implied by `-D warnings`
+help: try this
+   |
+LL |     writeln!(&mut v, "{{hello}}");
+   |                       ^^^^^^^^^--
+
+error: literal with an empty format string
+  --> $DIR/write_literal_2.rs:10:29
+   |
+LL |     writeln!(&mut v, r"{}", r"{hello}");
+   |                             ^^^^^^^^^^
+   |
+help: try this
+   |
+LL |     writeln!(&mut v, r"{{hello}}");
+   |                        ^^^^^^^^^--
+
+error: literal with an empty format string
+  --> $DIR/write_literal_2.rs:11:28
+   |
+LL |     writeln!(&mut v, "{}", '/'');
+   |                            ^^^^
+   |
+help: try this
+   |
+LL |     writeln!(&mut v, "'");
+   |                       ^--
+
+error: literal with an empty format string
+  --> $DIR/write_literal_2.rs:12:28
+   |
+LL |     writeln!(&mut v, "{}", '"');
+   |                            ^^^
+   |
+help: try this
+   |
+LL |     writeln!(&mut v, "/"");
+   |                       ^^--
+
+error: literal with an empty format string
+  --> $DIR/write_literal_2.rs:14:29
+   |
+LL |     writeln!(&mut v, r"{}", '/'');
+   |                             ^^^^
+   |
+help: try this
+   |
+LL |     writeln!(&mut v, r"'");
+   |                        ^--
+
+error: literal with an empty format string
+  --> $DIR/write_literal_2.rs:18:9
+   |
+LL | /         "hello /
+LL | |         world!"
+   | |_______________^
+   |
+help: try this
+   |
+LL |         "some hello /
+LL |         world!"
+   |
+
+error: literal with an empty format string
+  --> $DIR/write_literal_2.rs:25:9
+   |
+LL |         "1", "2", "3",
+   |         ^^^
+   |
+help: try this
+   |
+LL |         "some 1{} / {}", "2", "3",
+   |               ^        --
+
+error: literal with an empty format string
+  --> $DIR/write_literal_2.rs:25:14
+   |
+LL |         "1", "2", "3",
+   |              ^^^
+   |
+help: try this
+   |
+LL |         2 / {}",
+LL |         "1", "3",
+   |
+
+error: literal with an empty format string
+  --> $DIR/write_literal_2.rs:25:19
+   |
+LL |         "1", "2", "3",
+   |                   ^^^
+   |
+help: try this
+   |
+LL |         {} / 3",
+LL |         "1", "2",
+   |
+
+error: aborting due to 9 previous errors
+
diff --git a/src/tools/clippy/tests/ui/wrong_self_convention.rs b/src/tools/clippy/tests/ui/wrong_self_convention.rs
index 6cfc0fcb4ca..ba9e19a1722 100644
--- a/src/tools/clippy/tests/ui/wrong_self_convention.rs
+++ b/src/tools/clippy/tests/ui/wrong_self_convention.rs
@@ -163,3 +163,35 @@ mod issue6307 {
         fn to_mut(&mut self);
     }
 }
+
+mod issue6727 {
+    trait ToU64 {
+        fn to_u64(self) -> u64;
+        fn to_u64_v2(&self) -> u64;
+    }
+
+    #[derive(Clone, Copy)]
+    struct FooCopy;
+
+    impl ToU64 for FooCopy {
+        fn to_u64(self) -> u64 {
+            1
+        }
+        // trigger lint
+        fn to_u64_v2(&self) -> u64 {
+            1
+        }
+    }
+
+    struct FooNoCopy;
+
+    impl ToU64 for FooNoCopy {
+        // trigger lint
+        fn to_u64(self) -> u64 {
+            2
+        }
+        fn to_u64_v2(&self) -> u64 {
+            2
+        }
+    }
+}
diff --git a/src/tools/clippy/tests/ui/wrong_self_convention.stderr b/src/tools/clippy/tests/ui/wrong_self_convention.stderr
index 32bd9075bd5..1d58a12ac79 100644
--- a/src/tools/clippy/tests/ui/wrong_self_convention.stderr
+++ b/src/tools/clippy/tests/ui/wrong_self_convention.stderr
@@ -1,148 +1,195 @@
-error: methods called `from_*` usually take no self; consider choosing a less ambiguous name
+error: methods called `from_*` usually take no `self`
   --> $DIR/wrong_self_convention.rs:18:17
    |
 LL |     fn from_i32(self) {}
    |                 ^^^^
    |
    = note: `-D clippy::wrong-self-convention` implied by `-D warnings`
+   = help: consider choosing a less ambiguous name
 
-error: methods called `from_*` usually take no self; consider choosing a less ambiguous name
+error: methods called `from_*` usually take no `self`
   --> $DIR/wrong_self_convention.rs:24:21
    |
 LL |     pub fn from_i64(self) {}
    |                     ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `as_*` usually take self by reference or self by mutable reference; consider choosing a less ambiguous name
+error: methods called `as_*` usually take `self` by reference or `self` by mutable reference
   --> $DIR/wrong_self_convention.rs:36:15
    |
 LL |     fn as_i32(self) {}
    |               ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `into_*` usually take self by value; consider choosing a less ambiguous name
+error: methods called `into_*` usually take `self` by value
   --> $DIR/wrong_self_convention.rs:38:17
    |
 LL |     fn into_i32(&self) {}
    |                 ^^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `is_*` usually take self by reference or no self; consider choosing a less ambiguous name
+error: methods called `is_*` usually take `self` by reference or no `self`
   --> $DIR/wrong_self_convention.rs:40:15
    |
 LL |     fn is_i32(self) {}
    |               ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `to_*` usually take self by reference; consider choosing a less ambiguous name
+error: methods with the following characteristics: (`to_*` and `self` type is not `Copy`) usually take `self` by reference
   --> $DIR/wrong_self_convention.rs:42:15
    |
 LL |     fn to_i32(self) {}
    |               ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `from_*` usually take no self; consider choosing a less ambiguous name
+error: methods called `from_*` usually take no `self`
   --> $DIR/wrong_self_convention.rs:44:17
    |
 LL |     fn from_i32(self) {}
    |                 ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `as_*` usually take self by reference or self by mutable reference; consider choosing a less ambiguous name
+error: methods called `as_*` usually take `self` by reference or `self` by mutable reference
   --> $DIR/wrong_self_convention.rs:46:19
    |
 LL |     pub fn as_i64(self) {}
    |                   ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `into_*` usually take self by value; consider choosing a less ambiguous name
+error: methods called `into_*` usually take `self` by value
   --> $DIR/wrong_self_convention.rs:47:21
    |
 LL |     pub fn into_i64(&self) {}
    |                     ^^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `is_*` usually take self by reference or no self; consider choosing a less ambiguous name
+error: methods called `is_*` usually take `self` by reference or no `self`
   --> $DIR/wrong_self_convention.rs:48:19
    |
 LL |     pub fn is_i64(self) {}
    |                   ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `to_*` usually take self by reference; consider choosing a less ambiguous name
+error: methods with the following characteristics: (`to_*` and `self` type is not `Copy`) usually take `self` by reference
   --> $DIR/wrong_self_convention.rs:49:19
    |
 LL |     pub fn to_i64(self) {}
    |                   ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `from_*` usually take no self; consider choosing a less ambiguous name
+error: methods called `from_*` usually take no `self`
   --> $DIR/wrong_self_convention.rs:50:21
    |
 LL |     pub fn from_i64(self) {}
    |                     ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `as_*` usually take self by reference or self by mutable reference; consider choosing a less ambiguous name
+error: methods called `as_*` usually take `self` by reference or `self` by mutable reference
   --> $DIR/wrong_self_convention.rs:95:19
    |
 LL |         fn as_i32(self) {}
    |                   ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `into_*` usually take self by value; consider choosing a less ambiguous name
+error: methods called `into_*` usually take `self` by value
   --> $DIR/wrong_self_convention.rs:98:25
    |
 LL |         fn into_i32_ref(&self) {}
    |                         ^^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `is_*` usually take self by reference or no self; consider choosing a less ambiguous name
+error: methods called `is_*` usually take `self` by reference or no `self`
   --> $DIR/wrong_self_convention.rs:100:19
    |
 LL |         fn is_i32(self) {}
    |                   ^^^^
-
-error: methods called `to_*` usually take self by reference; consider choosing a less ambiguous name
-  --> $DIR/wrong_self_convention.rs:102:19
    |
-LL |         fn to_i32(self) {}
-   |                   ^^^^
+   = help: consider choosing a less ambiguous name
 
-error: methods called `from_*` usually take no self; consider choosing a less ambiguous name
+error: methods called `from_*` usually take no `self`
   --> $DIR/wrong_self_convention.rs:104:21
    |
 LL |         fn from_i32(self) {}
    |                     ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `as_*` usually take self by reference or self by mutable reference; consider choosing a less ambiguous name
+error: methods called `as_*` usually take `self` by reference or `self` by mutable reference
   --> $DIR/wrong_self_convention.rs:119:19
    |
 LL |         fn as_i32(self);
    |                   ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `into_*` usually take self by value; consider choosing a less ambiguous name
+error: methods called `into_*` usually take `self` by value
   --> $DIR/wrong_self_convention.rs:122:25
    |
 LL |         fn into_i32_ref(&self);
    |                         ^^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `is_*` usually take self by reference or no self; consider choosing a less ambiguous name
+error: methods called `is_*` usually take `self` by reference or no `self`
   --> $DIR/wrong_self_convention.rs:124:19
    |
 LL |         fn is_i32(self);
    |                   ^^^^
-
-error: methods called `to_*` usually take self by reference; consider choosing a less ambiguous name
-  --> $DIR/wrong_self_convention.rs:126:19
    |
-LL |         fn to_i32(self);
-   |                   ^^^^
+   = help: consider choosing a less ambiguous name
 
-error: methods called `from_*` usually take no self; consider choosing a less ambiguous name
+error: methods called `from_*` usually take no `self`
   --> $DIR/wrong_self_convention.rs:128:21
    |
 LL |         fn from_i32(self);
    |                     ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `into_*` usually take self by value; consider choosing a less ambiguous name
+error: methods called `into_*` usually take `self` by value
   --> $DIR/wrong_self_convention.rs:146:25
    |
 LL |         fn into_i32_ref(&self);
    |                         ^^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
-error: methods called `from_*` usually take no self; consider choosing a less ambiguous name
+error: methods called `from_*` usually take no `self`
   --> $DIR/wrong_self_convention.rs:152:21
    |
 LL |         fn from_i32(self);
    |                     ^^^^
+   |
+   = help: consider choosing a less ambiguous name
+
+error: methods with the following characteristics: (`to_*` and `self` type is `Copy`) usually take `self` by value
+  --> $DIR/wrong_self_convention.rs:181:22
+   |
+LL |         fn to_u64_v2(&self) -> u64 {
+   |                      ^^^^^
+   |
+   = help: consider choosing a less ambiguous name
+
+error: methods with the following characteristics: (`to_*` and `self` type is not `Copy`) usually take `self` by reference
+  --> $DIR/wrong_self_convention.rs:190:19
+   |
+LL |         fn to_u64(self) -> u64 {
+   |                   ^^^^
+   |
+   = help: consider choosing a less ambiguous name
 
 error: aborting due to 24 previous errors
 
diff --git a/src/tools/clippy/tests/ui/wrong_self_conventions_mut.rs b/src/tools/clippy/tests/ui/wrong_self_conventions_mut.rs
new file mode 100644
index 00000000000..486a0d77235
--- /dev/null
+++ b/src/tools/clippy/tests/ui/wrong_self_conventions_mut.rs
@@ -0,0 +1,30 @@
+// edition:2018
+#![warn(clippy::wrong_self_convention)]
+#![allow(dead_code)]
+
+fn main() {}
+
+mod issue6758 {
+    pub enum Test<T> {
+        One(T),
+        Many(Vec<T>),
+    }
+
+    impl<T> Test<T> {
+        // If a method starts with `to_` and not ends with `_mut` it should expect `&self`
+        pub fn to_many(&mut self) -> Option<&mut [T]> {
+            match self {
+                Self::Many(data) => Some(data),
+                _ => None,
+            }
+        }
+
+        // If a method starts with `to_` and ends with `_mut` it should expect `&mut self`
+        pub fn to_many_mut(&self) -> Option<&[T]> {
+            match self {
+                Self::Many(data) => Some(data),
+                _ => None,
+            }
+        }
+    }
+}
diff --git a/src/tools/clippy/tests/ui/wrong_self_conventions_mut.stderr b/src/tools/clippy/tests/ui/wrong_self_conventions_mut.stderr
new file mode 100644
index 00000000000..6ce37c59491
--- /dev/null
+++ b/src/tools/clippy/tests/ui/wrong_self_conventions_mut.stderr
@@ -0,0 +1,19 @@
+error: methods with the following characteristics: (`to_*` and `self` type is not `Copy`) usually take `self` by reference
+  --> $DIR/wrong_self_conventions_mut.rs:15:24
+   |
+LL |         pub fn to_many(&mut self) -> Option<&mut [T]> {
+   |                        ^^^^^^^^^
+   |
+   = note: `-D clippy::wrong-self-convention` implied by `-D warnings`
+   = help: consider choosing a less ambiguous name
+
+error: methods with the following characteristics: (`to_*` and `*_mut`) usually take `self` by mutable reference
+  --> $DIR/wrong_self_conventions_mut.rs:23:28
+   |
+LL |         pub fn to_many_mut(&self) -> Option<&[T]> {
+   |                            ^^^^^
+   |
+   = help: consider choosing a less ambiguous name
+
+error: aborting due to 2 previous errors
+