Auto merge of #98152 - JohnTitor:rollup-osr17j6, r=JohnTitor

Rollup of 7 pull requests

Successful merges:

 - #97202 (os str capacity documentation)
 - #97964 (Fix suggestions for `&a: T` parameters)
 - #98053 (Fix generic impl rustdoc json output)
 - #98059 (Inline `const_eval_select`)
 - #98092 (Fix sidebar items expand collapse)
 - #98119 (Refactor path segment parameter error)
 - #98135 (Add regression test for #93775)

Failed merges:

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

22 files changed, 607 insertions, 94 deletions

diff --git a/src/librustdoc/html/static/js/source-script.js b/src/librustdoc/html/static/js/source-script.js
index 58c036e0b3c..14d8a942977 100644
--- a/src/librustdoc/html/static/js/source-script.js
+++ b/src/librustdoc/html/static/js/source-script.js
@@ -32,10 +32,10 @@ function createDirEntry(elem, parent, fullPath, currentFile, hasFoundFile) {
     fullPath += elem["name"] + "/";
 
     name.onclick = () => {
-        if (hasClass(this, "expand")) {
-            removeClass(this, "expand");
+        if (hasClass(name, "expand")) {
+            removeClass(name, "expand");
         } else {
-            addClass(this, "expand");
+            addClass(name, "expand");
         }
     };
     name.innerText = elem["name"];
diff --git a/src/librustdoc/json/mod.rs b/src/librustdoc/json/mod.rs
index f338050bee0..0964b757e74 100644
--- a/src/librustdoc/json/mod.rs
+++ b/src/librustdoc/json/mod.rs
@@ -181,15 +181,44 @@ impl<'tcx> FormatRenderer<'tcx> for JsonRenderer<'tcx> {
         let name = item.name;
         let item_id = item.item_id;
         if let Some(mut new_item) = self.convert_item(item) {
-            if let types::ItemEnum::Trait(ref mut t) = new_item.inner {
-                t.implementations = self.get_trait_implementors(item_id.expect_def_id())
-            } else if let types::ItemEnum::Struct(ref mut s) = new_item.inner {
-                s.impls = self.get_impls(item_id.expect_def_id())
-            } else if let types::ItemEnum::Enum(ref mut e) = new_item.inner {
-                e.impls = self.get_impls(item_id.expect_def_id())
-            } else if let types::ItemEnum::Union(ref mut u) = new_item.inner {
-                u.impls = self.get_impls(item_id.expect_def_id())
-            }
+            let can_be_ignored = match new_item.inner {
+                types::ItemEnum::Trait(ref mut t) => {
+                    t.implementations = self.get_trait_implementors(item_id.expect_def_id());
+                    false
+                }
+                types::ItemEnum::Struct(ref mut s) => {
+                    s.impls = self.get_impls(item_id.expect_def_id());
+                    false
+                }
+                types::ItemEnum::Enum(ref mut e) => {
+                    e.impls = self.get_impls(item_id.expect_def_id());
+                    false
+                }
+                types::ItemEnum::Union(ref mut u) => {
+                    u.impls = self.get_impls(item_id.expect_def_id());
+                    false
+                }
+
+                types::ItemEnum::Method(_)
+                | types::ItemEnum::AssocConst { .. }
+                | types::ItemEnum::AssocType { .. } => true,
+                types::ItemEnum::Module(_)
+                | types::ItemEnum::ExternCrate { .. }
+                | types::ItemEnum::Import(_)
+                | types::ItemEnum::StructField(_)
+                | types::ItemEnum::Variant(_)
+                | types::ItemEnum::Function(_)
+                | types::ItemEnum::TraitAlias(_)
+                | types::ItemEnum::Impl(_)
+                | types::ItemEnum::Typedef(_)
+                | types::ItemEnum::OpaqueTy(_)
+                | types::ItemEnum::Constant(_)
+                | types::ItemEnum::Static(_)
+                | types::ItemEnum::ForeignType
+                | types::ItemEnum::Macro(_)
+                | types::ItemEnum::ProcMacro(_)
+                | types::ItemEnum::PrimitiveType(_) => false,
+            };
             let removed = self
                 .index
                 .borrow_mut()
@@ -199,7 +228,11 @@ impl<'tcx> FormatRenderer<'tcx> for JsonRenderer<'tcx> {
             // to make sure the items are unique. The main place this happens is when an item, is
             // reexported in more than one place. See `rustdoc-json/reexport/in_root_and_mod`
             if let Some(old_item) = removed {
-                assert_eq!(old_item, new_item);
+                // In case of generic implementations (like `impl<T> Trait for T {}`), all the
+                // inner items will be duplicated so we can ignore if they are slightly different.
+                if !can_be_ignored {
+                    assert_eq!(old_item, new_item);
+                }
             }
         }
 
diff --git a/src/test/rustdoc-gui/source-code-page.goml b/src/test/rustdoc-gui/source-code-page.goml
index 509739c9f29..188b2605f0f 100644
--- a/src/test/rustdoc-gui/source-code-page.goml
+++ b/src/test/rustdoc-gui/source-code-page.goml
@@ -1,4 +1,4 @@
-// Checks that the interactions with the source code pages are workined as expected.
+// Checks that the interactions with the source code pages are working as expected.
 goto: file://|DOC_PATH|/src/test_docs/lib.rs.html
 // Check that we can click on the line number.
 click: ".line-numbers > span:nth-child(4)" // This is the span for line 4.
@@ -27,3 +27,26 @@ assert-position: ("//*[@id='1']", {"x": 104, "y": 103})
 // We click on the left of the "1" span but still in the "line-number" `<pre>`.
 click: (103, 103)
 assert-document-property: ({"URL": "/lib.rs.html"}, ENDS_WITH)
+
+// Checking the source code sidebar.
+
+// First we "open" it.
+click: "#sidebar-toggle"
+assert: ".sidebar.expanded"
+
+// We check that the first entry of the sidebar is collapsed (which, for whatever reason,
+// is number 2 and not 1...).
+assert-attribute: ("#source-sidebar .name:nth-child(2)", {"class": "name"})
+assert-text: ("#source-sidebar .name:nth-child(2)", "implementors")
+// We also check its children are hidden too.
+assert-css: ("#source-sidebar .name:nth-child(2) + .children", {"display": "none"})
+// We now click on it.
+click: "#source-sidebar .name:nth-child(2)"
+assert-attribute: ("#source-sidebar .name:nth-child(2)", {"class": "name expand"})
+// Checking that its children are displayed as well.
+assert-css: ("#source-sidebar .name:nth-child(2) + .children", {"display": "block"})
+
+// And now we collapse it again.
+click: "#source-sidebar .name:nth-child(2)"
+assert-attribute: ("#source-sidebar .name:nth-child(2)", {"class": "name"})
+assert-css: ("#source-sidebar .name:nth-child(2) + .children", {"display": "none"})
diff --git a/src/test/rustdoc-json/generic_impl.rs b/src/test/rustdoc-json/generic_impl.rs
new file mode 100644
index 00000000000..ac68ba578b6
--- /dev/null
+++ b/src/test/rustdoc-json/generic_impl.rs
@@ -0,0 +1,24 @@
+// Regression test for <https://github.com/rust-lang/rust/issues/97986>.
+
+// @has generic_impl.json
+// @has - "$.index[*][?(@.name=='f')]"
+// @has - "$.index[*][?(@.name=='AssocTy')]"
+// @has - "$.index[*][?(@.name=='AssocConst')]"
+
+pub mod m {
+    pub struct S;
+}
+
+pub trait F {
+    type AssocTy;
+    const AssocConst: usize;
+    fn f() -> m::S;
+}
+
+impl<T> F for T {
+    type AssocTy = u32;
+    const AssocConst: usize = 0;
+    fn f() -> m::S {
+        m::S
+    }
+}
diff --git a/src/test/ui/associated-consts/issue-93775.rs b/src/test/ui/associated-consts/issue-93775.rs
new file mode 100644
index 00000000000..7a007b732de
--- /dev/null
+++ b/src/test/ui/associated-consts/issue-93775.rs
@@ -0,0 +1,29 @@
+// build-pass
+// ignore-tidy-linelength
+
+// Regression for #93775, needs build-pass to test it.
+
+#![recursion_limit = "1000"]
+
+use std::marker::PhantomData;
+
+struct Z;
+struct S<T>(PhantomData<T>);
+
+type Nested = S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<S<Z>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>;
+
+trait AsNum {
+    const NUM: u32;
+}
+
+impl AsNum for Z {
+    const NUM: u32 = 0;
+}
+
+impl<T: AsNum> AsNum for S<T> {
+    const NUM: u32 = T::NUM + 1;
+}
+
+fn main() {
+    let _ = Nested::NUM;
+}
diff --git a/src/test/ui/destructure-trait-ref.stderr b/src/test/ui/destructure-trait-ref.stderr
index 302917ca02e..1291517928e 100644
--- a/src/test/ui/destructure-trait-ref.stderr
+++ b/src/test/ui/destructure-trait-ref.stderr
@@ -23,10 +23,14 @@ LL |     let &&x = &1isize as &dyn T;
    |          ^^   ----------------- this expression has type `&dyn T`
    |          |
    |          expected trait object `dyn T`, found reference
-   |          help: you can probably remove the explicit borrow: `x`
    |
    = note: expected trait object `dyn T`
                  found reference `&_`
+help: consider removing `&` from the pattern
+   |
+LL -     let &&x = &1isize as &dyn T;
+LL +     let &x = &1isize as &dyn T;
+   | 
 
 error[E0308]: mismatched types
   --> $DIR/destructure-trait-ref.rs:36:11
@@ -35,10 +39,14 @@ LL |     let &&&x = &(&1isize as &dyn T);
    |           ^^   -------------------- this expression has type `&&dyn T`
    |           |
    |           expected trait object `dyn T`, found reference
-   |           help: you can probably remove the explicit borrow: `x`
    |
    = note: expected trait object `dyn T`
                  found reference `&_`
+help: consider removing `&` from the pattern
+   |
+LL -     let &&&x = &(&1isize as &dyn T);
+LL +     let &&x = &(&1isize as &dyn T);
+   | 
 
 error[E0308]: mismatched types
   --> $DIR/destructure-trait-ref.rs:40:13
diff --git a/src/test/ui/error-codes/E0214.stderr b/src/test/ui/error-codes/E0214.stderr
index bcbd3a91cb9..e0179aac27f 100644
--- a/src/test/ui/error-codes/E0214.stderr
+++ b/src/test/ui/error-codes/E0214.stderr
@@ -2,10 +2,12 @@ error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
   --> $DIR/E0214.rs:2:12
    |
 LL |     let v: Vec(&str) = vec!["foo"];
-   |            ^^^^^^^^^
-   |            |
-   |            only `Fn` traits may use parentheses
-   |            help: use angle brackets instead: `Vec<&str>`
+   |            ^^^^^^^^^ only `Fn` traits may use parentheses
+   |
+help: use angle brackets instead
+   |
+LL |     let v: Vec<&str> = vec!["foo"];
+   |               ~    ~
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-23589.stderr b/src/test/ui/issues/issue-23589.stderr
index e065e17c280..1a91f5e04db 100644
--- a/src/test/ui/issues/issue-23589.stderr
+++ b/src/test/ui/issues/issue-23589.stderr
@@ -2,10 +2,12 @@ error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
   --> $DIR/issue-23589.rs:2:12
    |
 LL |     let v: Vec(&str) = vec!['1', '2'];
-   |            ^^^^^^^^^
-   |            |
-   |            only `Fn` traits may use parentheses
-   |            help: use angle brackets instead: `Vec<&str>`
+   |            ^^^^^^^^^ only `Fn` traits may use parentheses
+   |
+help: use angle brackets instead
+   |
+LL |     let v: Vec<&str> = vec!['1', '2'];
+   |               ~    ~
 
 error[E0308]: mismatched types
   --> $DIR/issue-23589.rs:2:29
diff --git a/src/test/ui/mismatched_types/issue-38371-unfixable.rs b/src/test/ui/mismatched_types/issue-38371-unfixable.rs
new file mode 100644
index 00000000000..c4316bfdd18
--- /dev/null
+++ b/src/test/ui/mismatched_types/issue-38371-unfixable.rs
@@ -0,0 +1,5 @@
+fn ugh(&[bar]: &u32) {} //~ ERROR expected an array or slice
+
+fn bgh(&&bar: u32) {} //~ ERROR mismatched types
+
+fn main() {}
diff --git a/src/test/ui/mismatched_types/issue-38371-unfixable.stderr b/src/test/ui/mismatched_types/issue-38371-unfixable.stderr
new file mode 100644
index 00000000000..3c5e765abfb
--- /dev/null
+++ b/src/test/ui/mismatched_types/issue-38371-unfixable.stderr
@@ -0,0 +1,21 @@
+error[E0529]: expected an array or slice, found `u32`
+  --> $DIR/issue-38371-unfixable.rs:1:9
+   |
+LL | fn ugh(&[bar]: &u32) {}
+   |         ^^^^^ pattern cannot match with input type `u32`
+
+error[E0308]: mismatched types
+  --> $DIR/issue-38371-unfixable.rs:3:8
+   |
+LL | fn bgh(&&bar: u32) {}
+   |        ^^^^^  --- expected due to this
+   |        |
+   |        expected `u32`, found reference
+   |
+   = note:   expected type `u32`
+           found reference `&_`
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0308, E0529.
+For more information about an error, try `rustc --explain E0308`.
diff --git a/src/test/ui/mismatched_types/issue-38371.fixed b/src/test/ui/mismatched_types/issue-38371.fixed
new file mode 100644
index 00000000000..0e20835bef0
--- /dev/null
+++ b/src/test/ui/mismatched_types/issue-38371.fixed
@@ -0,0 +1,18 @@
+// run-rustfix
+// see also issue-38371-unfixable.rs
+#![allow(dead_code)]
+
+#[derive(Copy, Clone)]
+struct Foo {}
+
+fn foo(_a: &Foo) {} //~ ERROR mismatched types
+
+fn bar(_a: Foo) {}
+
+fn qux(_a: &Foo) {}
+
+fn zar(&_a: &Foo) {}
+
+fn agh(&_a: &u32) {} //~ ERROR mismatched types
+
+fn main() {}
diff --git a/src/test/ui/mismatched_types/issue-38371.rs b/src/test/ui/mismatched_types/issue-38371.rs
index d2cd2b88ab7..fb9e4c173e7 100644
--- a/src/test/ui/mismatched_types/issue-38371.rs
+++ b/src/test/ui/mismatched_types/issue-38371.rs
@@ -1,27 +1,18 @@
-struct Foo {
-}
+// run-rustfix
+// see also issue-38371-unfixable.rs
+#![allow(dead_code)]
 
-fn foo(&foo: Foo) { //~ ERROR mismatched types
-}
+#[derive(Copy, Clone)]
+struct Foo {}
 
-fn bar(foo: Foo) {
-}
+fn foo(&_a: Foo) {} //~ ERROR mismatched types
 
-fn qux(foo: &Foo) {
-}
+fn bar(_a: Foo) {}
 
-fn zar(&foo: &Foo) {
-}
+fn qux(_a: &Foo) {}
 
-// The somewhat unexpected help message in this case is courtesy of
-// match_default_bindings.
-fn agh(&&bar: &u32) { //~ ERROR mismatched types
-}
+fn zar(&_a: &Foo) {}
 
-fn bgh(&&bar: u32) { //~ ERROR mismatched types
-}
-
-fn ugh(&[bar]: &u32) { //~ ERROR expected an array or slice
-}
+fn agh(&&_a: &u32) {} //~ ERROR mismatched types
 
 fn main() {}
diff --git a/src/test/ui/mismatched_types/issue-38371.stderr b/src/test/ui/mismatched_types/issue-38371.stderr
index 5d2ce9302ec..003f17cda15 100644
--- a/src/test/ui/mismatched_types/issue-38371.stderr
+++ b/src/test/ui/mismatched_types/issue-38371.stderr
@@ -1,46 +1,35 @@
 error[E0308]: mismatched types
-  --> $DIR/issue-38371.rs:4:8
+  --> $DIR/issue-38371.rs:8:8
    |
-LL | fn foo(&foo: Foo) {
-   |        ^^^^-----
-   |        |     |
-   |        |     expected due to this
+LL | fn foo(&_a: Foo) {}
+   |        ^^^  --- expected due to this
+   |        |
    |        expected struct `Foo`, found reference
-   |        help: did you mean `foo`: `&Foo`
    |
    = note: expected struct `Foo`
            found reference `&_`
+help: to take parameter `_a` by reference, move `&` to the type
+   |
+LL - fn foo(&_a: Foo) {}
+LL + fn foo(_a: &Foo) {}
+   | 
 
 error[E0308]: mismatched types
-  --> $DIR/issue-38371.rs:18:9
+  --> $DIR/issue-38371.rs:16:9
    |
-LL | fn agh(&&bar: &u32) {
-   |         ^^^^  ---- expected due to this
+LL | fn agh(&&_a: &u32) {}
+   |         ^^^  ---- expected due to this
    |         |
    |         expected `u32`, found reference
-   |         help: you can probably remove the explicit borrow: `bar`
-   |
-   = note:   expected type `u32`
-           found reference `&_`
-
-error[E0308]: mismatched types
-  --> $DIR/issue-38371.rs:21:8
-   |
-LL | fn bgh(&&bar: u32) {
-   |        ^^^^^  --- expected due to this
-   |        |
-   |        expected `u32`, found reference
    |
    = note:   expected type `u32`
            found reference `&_`
-
-error[E0529]: expected an array or slice, found `u32`
-  --> $DIR/issue-38371.rs:24:9
+help: consider removing `&` from the pattern
    |
-LL | fn ugh(&[bar]: &u32) {
-   |         ^^^^^ pattern cannot match with input type `u32`
+LL - fn agh(&&_a: &u32) {}
+LL + fn agh(&_a: &u32) {}
+   | 
 
-error: aborting due to 4 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0308, E0529.
-For more information about an error, try `rustc --explain E0308`.
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/mismatched_types/ref-pat-suggestions.fixed b/src/test/ui/mismatched_types/ref-pat-suggestions.fixed
new file mode 100644
index 00000000000..ab8483eef49
--- /dev/null
+++ b/src/test/ui/mismatched_types/ref-pat-suggestions.fixed
@@ -0,0 +1,24 @@
+// run-rustfix
+
+fn _f0(_a: &u32) {} //~ ERROR mismatched types
+fn _f1(_a: &mut u32) {} //~ ERROR mismatched types
+fn _f2(&_a: &u32) {} //~ ERROR mismatched types
+fn _f3(&mut _a: &mut u32) {} //~ ERROR mismatched types
+fn _f4(&_a: &u32) {} //~ ERROR mismatched types
+fn _f5(&mut _a: &mut u32) {} //~ ERROR mismatched types
+
+fn main() {
+    let _: fn(u32) = |_a| (); //~ ERROR mismatched types
+    let _: fn(u32) = |_a| (); //~ ERROR mismatched types
+    let _: fn(&u32) = |&_a| (); //~ ERROR mismatched types
+    let _: fn(&mut u32) = |&mut _a| (); //~ ERROR mismatched types
+    let _: fn(&u32) = |&_a| (); //~ ERROR mismatched types
+    let _: fn(&mut u32) = |&mut _a| (); //~ ERROR mismatched types
+
+    let _ = |_a: &u32| (); //~ ERROR mismatched types
+    let _ = |_a: &mut u32| (); //~ ERROR mismatched types
+    let _ = |&_a: &u32| (); //~ ERROR mismatched types
+    let _ = |&mut _a: &mut u32| (); //~ ERROR mismatched types
+    let _ = |&_a: &u32| (); //~ ERROR mismatched types
+    let _ = |&mut _a: &mut u32| (); //~ ERROR mismatched types
+}
diff --git a/src/test/ui/mismatched_types/ref-pat-suggestions.rs b/src/test/ui/mismatched_types/ref-pat-suggestions.rs
new file mode 100644
index 00000000000..7e55539aa3d
--- /dev/null
+++ b/src/test/ui/mismatched_types/ref-pat-suggestions.rs
@@ -0,0 +1,24 @@
+// run-rustfix
+
+fn _f0(&_a: u32) {} //~ ERROR mismatched types
+fn _f1(&mut _a: u32) {} //~ ERROR mismatched types
+fn _f2(&&_a: &u32) {} //~ ERROR mismatched types
+fn _f3(&mut &_a: &mut u32) {} //~ ERROR mismatched types
+fn _f4(&&mut _a: &u32) {} //~ ERROR mismatched types
+fn _f5(&mut &mut _a: &mut u32) {} //~ ERROR mismatched types
+
+fn main() {
+    let _: fn(u32) = |&_a| (); //~ ERROR mismatched types
+    let _: fn(u32) = |&mut _a| (); //~ ERROR mismatched types
+    let _: fn(&u32) = |&&_a| (); //~ ERROR mismatched types
+    let _: fn(&mut u32) = |&mut &_a| (); //~ ERROR mismatched types
+    let _: fn(&u32) = |&&mut _a| (); //~ ERROR mismatched types
+    let _: fn(&mut u32) = |&mut &mut _a| (); //~ ERROR mismatched types
+
+    let _ = |&_a: u32| (); //~ ERROR mismatched types
+    let _ = |&mut _a: u32| (); //~ ERROR mismatched types
+    let _ = |&&_a: &u32| (); //~ ERROR mismatched types
+    let _ = |&mut &_a: &mut u32| (); //~ ERROR mismatched types
+    let _ = |&&mut _a: &u32| (); //~ ERROR mismatched types
+    let _ = |&mut &mut _a: &mut u32| (); //~ ERROR mismatched types
+}
diff --git a/src/test/ui/mismatched_types/ref-pat-suggestions.stderr b/src/test/ui/mismatched_types/ref-pat-suggestions.stderr
new file mode 100644
index 00000000000..0516bad49ab
--- /dev/null
+++ b/src/test/ui/mismatched_types/ref-pat-suggestions.stderr
@@ -0,0 +1,297 @@
+error[E0308]: mismatched types
+  --> $DIR/ref-pat-suggestions.rs:3:8
+   |
+LL | fn _f0(&_a: u32) {}
+   |        ^^^  --- expected due to this
+   |        |
+   |        expected `u32`, found reference
+   |
+   = note:   expected type `u32`
+           found reference `&_`
+help: to take parameter `_a` by reference, move `&` to the type
+   |
+LL - fn _f0(&_a: u32) {}
+LL + fn _f0(_a: &u32) {}
+   | 
+
+error[E0308]: mismatched types
+  --> $DIR/ref-pat-suggestions.rs:4:8
+   |
+LL | fn _f1(&mut _a: u32) {}
+   |        ^^^^^^^  --- expected due to this
+   |        |
+   |        expected `u32`, found `&mut _`
+   |
+   = note:           expected type `u32`
+           found mutable reference `&mut _`
+help: to take parameter `_a` by reference, move `&mut` to the type
+   |
+LL - fn _f1(&mut _a: u32) {}
+LL + fn _f1(_a: &mut u32) {}
+   | 
+
+error[E0308]: mismatched types
+  --> $DIR/ref-pat-suggestions.rs:5:9
+   |
+LL | fn _f2(&&_a: &u32) {}
+   |         ^^^  ---- expected due to this
+   |         |
+   |         expected `u32`, found reference
+   |
+   = note:   expected type `u32`
+           found reference `&_`
+help: consider removing `&` from the pattern
+   |
+LL - fn _f2(&&_a: &u32) {}
+LL + fn _f2(&_a: &u32) {}
+   | 
+
+error[E0308]: mismatched types
+  --> $DIR/ref-pat-suggestions.rs:6:13
+   |
+LL | fn _f3(&mut &_a: &mut u32) {}
+   |             ^^^  -------- expected due to this
+   |             |
+   |             expected `u32`, found reference
+   |
+   = note:   expected type `u32`
+           found reference `&_`
+help: consider removing `&` from the pattern
+   |
+LL - fn _f3(&mut &_a: &mut u32) {}
+LL + fn _f3(&mut _a: &mut u32) {}
+   | 
+
+error[E0308]: mismatched types
+  --> $DIR/ref-pat-suggestions.rs:7:9
+   |
+LL | fn _f4(&&mut _a: &u32) {}
+   |         ^^^^^^^  ---- expected due to this
+   |         |
+   |         expected `u32`, found `&mut _`
+   |
+   = note:           expected type `u32`
+           found mutable reference `&mut _`
+help: consider removing `&mut` from the pattern
+   |
+LL - fn _f4(&&mut _a: &u32) {}
+LL + fn _f4(&_a: &u32) {}
+   | 
+
+error[E0308]: mismatched types
+  --> $DIR/ref-pat-suggestions.rs:8:13
+   |
+LL | fn _f5(&mut &mut _a: &mut u32) {}
+   |             ^^^^^^^  -------- expected due to this
+   |             |
+   |             expected `u32`, found `&mut _`
+   |
+   = note:           expected type `u32`
+           found mutable reference `&mut _`
+help: consider removing `&mut` from the pattern
+   |
+LL - fn _f5(&mut &mut _a: &mut u32) {}
+LL + fn _f5(&mut _a: &mut u32) {}
+   | 
+
+error[E0308]: mismatched types
+  --> $DIR/ref-pat-suggestions.rs:11:23
+   |
+LL |     let _: fn(u32) = |&_a| ();
+   |                       ^--
+   |                       ||
+   |                       |expected due to this
+   |                       expected `u32`, found reference
+   |
+   = note:   expected type `u32`
+           found reference `&_`
+help: consider removing `&` from the pattern
+   |
+LL -     let _: fn(u32) = |&_a| ();
+LL +     let _: fn(u32) = |_a| ();
+   | 
+
+error[E0308]: mismatched types
+  --> $DIR/ref-pat-suggestions.rs:12:23
+   |
+LL |     let _: fn(u32) = |&mut _a| ();
+   |                       ^^^^^--
+   |                       |    |
+   |                       |    expected due to this
+   |                       expected `u32`, found `&mut _`
+   |
+   = note:           expected type `u32`
+           found mutable reference `&mut _`
+help: consider removing `&mut` from the pattern
+   |
+LL -     let _: fn(u32) = |&mut _a| ();
+LL +     let _: fn(u32) = |_a| ();
+   | 
+
+error[E0308]: mismatched types
+  --> $DIR/ref-pat-suggestions.rs:13:25
+   |
+LL |     let _: fn(&u32) = |&&_a| ();
+   |                         ^--
+   |                         ||
+   |                         |expected due to this
+   |                         expected `u32`, found reference
+   |
+   = note:   expected type `u32`
+           found reference `&_`
+help: consider removing `&` from the pattern
+   |
+LL -     let _: fn(&u32) = |&&_a| ();
+LL +     let _: fn(&u32) = |&_a| ();
+   | 
+
+error[E0308]: mismatched types
+  --> $DIR/ref-pat-suggestions.rs:14:33
+   |
+LL |     let _: fn(&mut u32) = |&mut &_a| ();
+   |                                 ^--
+   |                                 ||
+   |                                 |expected due to this
+   |                                 expected `u32`, found reference
+   |
+   = note:   expected type `u32`
+           found reference `&_`
+help: consider removing `&` from the pattern
+   |
+LL -     let _: fn(&mut u32) = |&mut &_a| ();
+LL +     let _: fn(&mut u32) = |&mut _a| ();
+   | 
+
+error[E0308]: mismatched types
+  --> $DIR/ref-pat-suggestions.rs:15:25
+   |
+LL |     let _: fn(&u32) = |&&mut _a| ();
+   |                         ^^^^^--
+   |                         |    |
+   |                         |    expected due to this
+   |                         expected `u32`, found `&mut _`
+   |
+   = note:           expected type `u32`
+           found mutable reference `&mut _`
+help: consider removing `&mut` from the pattern
+   |
+LL -     let _: fn(&u32) = |&&mut _a| ();
+LL +     let _: fn(&u32) = |&_a| ();
+   | 
+
+error[E0308]: mismatched types
+  --> $DIR/ref-pat-suggestions.rs:16:33
+   |
+LL |     let _: fn(&mut u32) = |&mut &mut _a| ();
+   |                                 ^^^^^--
+   |                                 |    |
+   |                                 |    expected due to this
+   |                                 expected `u32`, found `&mut _`
+   |
+   = note:           expected type `u32`
+           found mutable reference `&mut _`
+help: consider removing `&mut` from the pattern
+   |
+LL -     let _: fn(&mut u32) = |&mut &mut _a| ();
+LL +     let _: fn(&mut u32) = |&mut _a| ();
+   | 
+
+error[E0308]: mismatched types
+  --> $DIR/ref-pat-suggestions.rs:18:14
+   |
+LL |     let _ = |&_a: u32| ();
+   |              ^^^  --- expected due to this
+   |              |
+   |              expected `u32`, found reference
+   |
+   = note:   expected type `u32`
+           found reference `&_`
+help: to take parameter `_a` by reference, move `&` to the type
+   |
+LL -     let _ = |&_a: u32| ();
+LL +     let _ = |_a: &u32| ();
+   | 
+
+error[E0308]: mismatched types
+  --> $DIR/ref-pat-suggestions.rs:19:14
+   |
+LL |     let _ = |&mut _a: u32| ();
+   |              ^^^^^^^  --- expected due to this
+   |              |
+   |              expected `u32`, found `&mut _`
+   |
+   = note:           expected type `u32`
+           found mutable reference `&mut _`
+help: to take parameter `_a` by reference, move `&mut` to the type
+   |
+LL -     let _ = |&mut _a: u32| ();
+LL +     let _ = |_a: &mut u32| ();
+   | 
+
+error[E0308]: mismatched types
+  --> $DIR/ref-pat-suggestions.rs:20:15
+   |
+LL |     let _ = |&&_a: &u32| ();
+   |               ^^^  ---- expected due to this
+   |               |
+   |               expected `u32`, found reference
+   |
+   = note:   expected type `u32`
+           found reference `&_`
+help: consider removing `&` from the pattern
+   |
+LL -     let _ = |&&_a: &u32| ();
+LL +     let _ = |&_a: &u32| ();
+   | 
+
+error[E0308]: mismatched types
+  --> $DIR/ref-pat-suggestions.rs:21:19
+   |
+LL |     let _ = |&mut &_a: &mut u32| ();
+   |                   ^^^  -------- expected due to this
+   |                   |
+   |                   expected `u32`, found reference
+   |
+   = note:   expected type `u32`
+           found reference `&_`
+help: consider removing `&` from the pattern
+   |
+LL -     let _ = |&mut &_a: &mut u32| ();
+LL +     let _ = |&mut _a: &mut u32| ();
+   | 
+
+error[E0308]: mismatched types
+  --> $DIR/ref-pat-suggestions.rs:22:15
+   |
+LL |     let _ = |&&mut _a: &u32| ();
+   |               ^^^^^^^  ---- expected due to this
+   |               |
+   |               expected `u32`, found `&mut _`
+   |
+   = note:           expected type `u32`
+           found mutable reference `&mut _`
+help: consider removing `&mut` from the pattern
+   |
+LL -     let _ = |&&mut _a: &u32| ();
+LL +     let _ = |&_a: &u32| ();
+   | 
+
+error[E0308]: mismatched types
+  --> $DIR/ref-pat-suggestions.rs:23:19
+   |
+LL |     let _ = |&mut &mut _a: &mut u32| ();
+   |                   ^^^^^^^  -------- expected due to this
+   |                   |
+   |                   expected `u32`, found `&mut _`
+   |
+   = note:           expected type `u32`
+           found mutable reference `&mut _`
+help: consider removing `&mut` from the pattern
+   |
+LL -     let _ = |&mut &mut _a: &mut u32| ();
+LL +     let _ = |&mut _a: &mut u32| ();
+   | 
+
+error: aborting due to 18 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/pattern/for-loop-bad-item.stderr b/src/test/ui/pattern/for-loop-bad-item.stderr
index 9410e4da8d2..886d815d70b 100644
--- a/src/test/ui/pattern/for-loop-bad-item.stderr
+++ b/src/test/ui/pattern/for-loop-bad-item.stderr
@@ -5,10 +5,14 @@ LL |     for ((_, _), (&mut c, _)) in &mut map {
    |                   ^^^^^^         -------- this is an iterator with items of type `(&(char, char), &mut (char, char))`
    |                   |
    |                   expected `char`, found `&mut _`
-   |                   help: you can probably remove the explicit borrow: `c`
    |
    = note:           expected type `char`
            found mutable reference `&mut _`
+help: consider removing `&mut` from the pattern
+   |
+LL -     for ((_, _), (&mut c, _)) in &mut map {
+LL +     for ((_, _), (c, _)) in &mut map {
+   | 
 
 error[E0308]: mismatched types
   --> $DIR/for-loop-bad-item.rs:14:14
diff --git a/src/test/ui/proc-macro/issue-66286.stderr b/src/test/ui/proc-macro/issue-66286.stderr
index 2854dd7d59c..fe2464b3b81 100644
--- a/src/test/ui/proc-macro/issue-66286.stderr
+++ b/src/test/ui/proc-macro/issue-66286.stderr
@@ -2,10 +2,12 @@ error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
   --> $DIR/issue-66286.rs:8:22
    |
 LL | pub extern fn foo(_: Vec(u32)) -> u32 {
-   |                      ^^^^^^^^
-   |                      |
-   |                      only `Fn` traits may use parentheses
-   |                      help: use angle brackets instead: `Vec<u32>`
+   |                      ^^^^^^^^ only `Fn` traits may use parentheses
+   |
+help: use angle brackets instead
+   |
+LL | pub extern fn foo(_: Vec<u32>) -> u32 {
+   |                         ~   ~
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/suggestions/let-binding-init-expr-as-ty.stderr b/src/test/ui/suggestions/let-binding-init-expr-as-ty.stderr
index 63ba7893f04..2bf072ef521 100644
--- a/src/test/ui/suggestions/let-binding-init-expr-as-ty.stderr
+++ b/src/test/ui/suggestions/let-binding-init-expr-as-ty.stderr
@@ -10,10 +10,12 @@ error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
   --> $DIR/let-binding-init-expr-as-ty.rs:2:19
    |
 LL |     let foo: i32::from_be(num);
-   |                   ^^^^^^^^^^^^
-   |                   |
-   |                   only `Fn` traits may use parentheses
-   |                   help: use angle brackets instead: `from_be<num>`
+   |                   ^^^^^^^^^^^^ only `Fn` traits may use parentheses
+   |
+help: use angle brackets instead
+   |
+LL |     let foo: i32::from_be<num>;
+   |                          ~   ~
 
 error[E0223]: ambiguous associated type
   --> $DIR/let-binding-init-expr-as-ty.rs:2:14
diff --git a/src/test/ui/suggestions/match-ergonomics.stderr b/src/test/ui/suggestions/match-ergonomics.stderr
index 4eab2df3080..a9342f9fc30 100644
--- a/src/test/ui/suggestions/match-ergonomics.stderr
+++ b/src/test/ui/suggestions/match-ergonomics.stderr
@@ -4,13 +4,15 @@ error[E0308]: mismatched types
 LL |     match &x[..] {
    |           ------ this expression has type `&[i32]`
 LL |         [&v] => {},
-   |          ^^
-   |          |
-   |          expected `i32`, found reference
-   |          help: you can probably remove the explicit borrow: `v`
+   |          ^^ expected `i32`, found reference
    |
    = note:   expected type `i32`
            found reference `&_`
+help: consider removing `&` from the pattern
+   |
+LL -         [&v] => {},
+LL +         [v] => {},
+   | 
 
 error[E0529]: expected an array or slice, found `Vec<i32>`
   --> $DIR/match-ergonomics.rs:8:9
@@ -34,13 +36,15 @@ error[E0308]: mismatched types
 LL |     match y {
    |           - this expression has type `i32`
 LL |         &v => {},
-   |         ^^
-   |         |
-   |         expected `i32`, found reference
-   |         help: you can probably remove the explicit borrow: `v`
+   |         ^^ expected `i32`, found reference
    |
    = note:   expected type `i32`
            found reference `&_`
+help: consider removing `&` from the pattern
+   |
+LL -         &v => {},
+LL +         v => {},
+   | 
 
 error[E0308]: mismatched types
   --> $DIR/match-ergonomics.rs:40:13
@@ -49,10 +53,14 @@ LL |     if let [&v] = &x[..] {}
    |             ^^    ------ this expression has type `&[i32]`
    |             |
    |             expected `i32`, found reference
-   |             help: you can probably remove the explicit borrow: `v`
    |
    = note:   expected type `i32`
            found reference `&_`
+help: consider removing `&` from the pattern
+   |
+LL -     if let [&v] = &x[..] {}
+LL +     if let [v] = &x[..] {}
+   | 
 
 error: aborting due to 5 previous errors
 
diff --git a/src/test/ui/type/issue-91268.stderr b/src/test/ui/type/issue-91268.stderr
index 199fd6a23f7..71c357865fe 100644
--- a/src/test/ui/type/issue-91268.stderr
+++ b/src/test/ui/type/issue-91268.stderr
@@ -29,6 +29,11 @@ error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
    |
 LL |     0: u8(ţ
    |        ^^^^ only `Fn` traits may use parentheses
+   |
+help: use angle brackets instead
+   |
+LL |     0: u8<ţ>
+   |          ~ +
 
 error[E0109]: type arguments are not allowed on this type
   --> $DIR/issue-91268.rs:9:11
diff --git a/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-3.stderr b/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-3.stderr
index f5cf6db30f9..4df404e8198 100644
--- a/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-3.stderr
+++ b/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-3.stderr
@@ -2,10 +2,12 @@ error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
   --> $DIR/unboxed-closure-sugar-used-on-struct-3.rs:14:13
    |
 LL |     let b = Bar::(isize, usize)::new(); // OK too (for the parser)
-   |             ^^^^^^^^^^^^^^^^^^^
-   |             |
-   |             only `Fn` traits may use parentheses
-   |             help: use angle brackets instead: `Bar::<isize, usize>`
+   |             ^^^^^^^^^^^^^^^^^^^ only `Fn` traits may use parentheses
+   |
+help: use angle brackets instead
+   |
+LL |     let b = Bar::<isize, usize>::new(); // OK too (for the parser)
+   |                  ~            ~
 
 error: aborting due to previous error