diff --git a/compiler/rustc_codegen_llvm/src/intrinsic.rs b/compiler/rustc_codegen_llvm/src/intrinsic.rs
index 1060f911a9ed4..b309a124e8089 100644
--- a/compiler/rustc_codegen_llvm/src/intrinsic.rs
+++ b/compiler/rustc_codegen_llvm/src/intrinsic.rs
@@ -918,12 +918,29 @@ fn generic_simd_intrinsic(
     }
 
     if let Some(stripped) = name_str.strip_prefix("simd_shuffle") {
-        let n: u64 = stripped.parse().unwrap_or_else(|_| {
-            span_bug!(span, "bad `simd_shuffle` instruction only caught in codegen?")
-        });
+        // If this intrinsic is the older "simd_shuffleN" form, simply parse the integer.
+        // If there is no suffix, use the index array length.
+        let n: u64 = if stripped.is_empty() {
+            // Make sure this is actually an array, since typeck only checks the length-suffixed
+            // version of this intrinsic.
+            match args[2].layout.ty.kind() {
+                ty::Array(ty, len) if matches!(ty.kind(), ty::Uint(ty::UintTy::U32)) => {
+                    len.try_eval_usize(bx.cx.tcx, ty::ParamEnv::reveal_all()).unwrap_or_else(|| {
+                        span_bug!(span, "could not evaluate shuffle index array length")
+                    })
+                }
+                _ => return_error!(
+                    "simd_shuffle index must be an array of `u32`, got `{}`",
+                    args[2].layout.ty
+                ),
+            }
+        } else {
+            stripped.parse().unwrap_or_else(|_| {
+                span_bug!(span, "bad `simd_shuffle` instruction only caught in codegen?")
+            })
+        };
 
         require_simd!(ret_ty, "return");
-
         let (out_len, out_ty) = ret_ty.simd_size_and_type(bx.tcx());
         require!(
             out_len == n,
diff --git a/compiler/rustc_error_codes/src/error_codes/E0439.md b/compiler/rustc_error_codes/src/error_codes/E0439.md
index 3e663df866caa..24268aef2222a 100644
--- a/compiler/rustc_error_codes/src/error_codes/E0439.md
+++ b/compiler/rustc_error_codes/src/error_codes/E0439.md
@@ -1,8 +1,10 @@
+#### Note: this error code is no longer emitted by the compiler.
+
 The length of the platform-intrinsic function `simd_shuffle` wasn't specified.
 
 Erroneous code example:
 
-```compile_fail,E0439
+```ignore (no longer emitted)
 #![feature(platform_intrinsics)]
 
 extern "platform-intrinsic" {
diff --git a/compiler/rustc_infer/src/traits/error_reporting/mod.rs b/compiler/rustc_infer/src/traits/error_reporting/mod.rs
index d0bd508bc257f..0679519c68fd6 100644
--- a/compiler/rustc_infer/src/traits/error_reporting/mod.rs
+++ b/compiler/rustc_infer/src/traits/error_reporting/mod.rs
@@ -83,10 +83,6 @@ pub fn report_object_safety_error(
                     messages.push(msg.clone());
                 }
             }
-            if trait_span.is_some() {
-                // Only provide the help if its a local trait, otherwise it's not actionable.
-                violation.solution(&mut err);
-            }
         }
     }
     let has_multi_span = !multi_span.is_empty();
@@ -104,5 +100,11 @@ pub fn report_object_safety_error(
          to be resolvable dynamically; for more information visit \
          <https://doc.rust-lang.org/reference/items/traits.html#object-safety>",
     );
+    if trait_span.is_some() {
+        for violation in reported_violations {
+            // Only provide the help if its a local trait, otherwise it's not actionable.
+            violation.solution(&mut err);
+        }
+    }
     err
 }
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index 10c73fd64bc19..04a7948e8c96e 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -493,7 +493,20 @@ impl<'a> Parser<'a> {
         let ty_first = if self.token.is_keyword(kw::For) && self.look_ahead(1, |t| t != &token::Lt)
         {
             let span = self.prev_token.span.between(self.token.span);
-            self.struct_span_err(span, "missing trait in a trait impl").emit();
+            self.struct_span_err(span, "missing trait in a trait impl")
+                .span_suggestion(
+                    span,
+                    "add a trait here",
+                    " Trait ".into(),
+                    Applicability::HasPlaceholders,
+                )
+                .span_suggestion(
+                    span.to(self.token.span),
+                    "for an inherent impl, drop this `for`",
+                    "".into(),
+                    Applicability::MaybeIncorrect,
+                )
+                .emit();
             P(Ty {
                 kind: TyKind::Path(None, err_path(span)),
                 span,
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index c816d06045681..3eec1ae4c4da0 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -1211,6 +1211,7 @@ symbols! {
         simd_select_bitmask,
         simd_shl,
         simd_shr,
+        simd_shuffle,
         simd_sub,
         simd_trunc,
         simd_xor,
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index f5be8bf0949e6..8adf9015933c3 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -1487,10 +1487,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             ) => false,
 
             (ParamCandidate(other), ParamCandidate(victim)) => {
-                let value_same_except_bound_vars = other.value.skip_binder()
+                let same_except_bound_vars = other.value.skip_binder()
                     == victim.value.skip_binder()
+                    && other.constness == victim.constness
                     && !other.value.skip_binder().has_escaping_bound_vars();
-                if value_same_except_bound_vars {
+                if same_except_bound_vars {
                     // See issue #84398. In short, we can generate multiple ParamCandidates which are
                     // the same except for unused bound vars. Just pick the one with the fewest bound vars
                     // or the current one if tied (they should both evaluate to the same answer). This is
diff --git a/compiler/rustc_typeck/src/check/expr.rs b/compiler/rustc_typeck/src/check/expr.rs
index d578fac4cdb22..f4e3c8e0d9f7f 100644
--- a/compiler/rustc_typeck/src/check/expr.rs
+++ b/compiler/rustc_typeck/src/check/expr.rs
@@ -1842,7 +1842,28 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             expr_t
         );
         err.span_label(field.span, "method, not a field");
-        if !self.expr_in_place(expr.hir_id) {
+        let expr_is_call =
+            if let hir::Node::Expr(hir::Expr { kind: ExprKind::Call(callee, _args), .. }) =
+                self.tcx.hir().get(self.tcx.hir().get_parent_node(expr.hir_id))
+            {
+                expr.hir_id == callee.hir_id
+            } else {
+                false
+            };
+        let expr_snippet =
+            self.tcx.sess.source_map().span_to_snippet(expr.span).unwrap_or(String::new());
+        if expr_is_call && expr_snippet.starts_with("(") && expr_snippet.ends_with(")") {
+            let after_open = expr.span.lo() + rustc_span::BytePos(1);
+            let before_close = expr.span.hi() - rustc_span::BytePos(1);
+            err.multipart_suggestion(
+                "remove wrapping parentheses to call the method",
+                vec![
+                    (expr.span.with_hi(after_open), String::new()),
+                    (expr.span.with_lo(before_close), String::new()),
+                ],
+                Applicability::MachineApplicable,
+            );
+        } else if !self.expr_in_place(expr.hir_id) {
             self.suggest_method_call(
                 &mut err,
                 "use parentheses to call the method",
diff --git a/compiler/rustc_typeck/src/check/intrinsic.rs b/compiler/rustc_typeck/src/check/intrinsic.rs
index 664954b0eb7a2..ff7a26853b188 100644
--- a/compiler/rustc_typeck/src/check/intrinsic.rs
+++ b/compiler/rustc_typeck/src/check/intrinsic.rs
@@ -2,7 +2,7 @@
 //! intrinsics that the compiler exposes.
 
 use crate::errors::{
-    SimdShuffleMissingLength, UnrecognizedAtomicOperation, UnrecognizedIntrinsicFunction,
+    UnrecognizedAtomicOperation, UnrecognizedIntrinsicFunction,
     WrongNumberOfGenericArgumentsToIntrinsic,
 };
 use crate::require_same_types;
@@ -468,6 +468,7 @@ pub fn check_platform_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>)
         | sym::simd_reduce_max
         | sym::simd_reduce_min_nanless
         | sym::simd_reduce_max_nanless => (2, vec![param(0)], param(1)),
+        sym::simd_shuffle => (3, vec![param(0), param(0), param(1)], param(2)),
         name if name.as_str().starts_with("simd_shuffle") => {
             match name.as_str()["simd_shuffle".len()..].parse() {
                 Ok(n) => {
@@ -475,7 +476,9 @@ pub fn check_platform_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>)
                     (2, params, param(1))
                 }
                 Err(_) => {
-                    tcx.sess.emit_err(SimdShuffleMissingLength { span: it.span, name });
+                    let msg =
+                        format!("unrecognized platform-specific intrinsic function: `{}`", name);
+                    tcx.sess.struct_span_err(it.span, &msg).emit();
                     return;
                 }
             }
diff --git a/compiler/rustc_typeck/src/errors.rs b/compiler/rustc_typeck/src/errors.rs
index 1e6a240b2f86d..47077779616c0 100644
--- a/compiler/rustc_typeck/src/errors.rs
+++ b/compiler/rustc_typeck/src/errors.rs
@@ -121,14 +121,6 @@ pub struct AssocTypeBindingNotAllowed {
     pub span: Span,
 }
 
-#[derive(SessionDiagnostic)]
-#[error = "E0439"]
-pub struct SimdShuffleMissingLength {
-    #[message = "invalid `simd_shuffle`, needs length: `{name}`"]
-    pub span: Span,
-    pub name: Symbol,
-}
-
 #[derive(SessionDiagnostic)]
 #[error = "E0436"]
 pub struct FunctionalRecordUpdateOnNonStruct {
diff --git a/library/core/src/cell.rs b/library/core/src/cell.rs
index 2adf6a549e641..e56b631dbaf8d 100644
--- a/library/core/src/cell.rs
+++ b/library/core/src/cell.rs
@@ -1916,7 +1916,8 @@ impl<T: ?Sized> UnsafeCell<T> {
     /// ```
     #[inline(always)]
     #[stable(feature = "unsafe_cell_get_mut", since = "1.50.0")]
-    pub fn get_mut(&mut self) -> &mut T {
+    #[rustc_const_unstable(feature = "const_unsafecell_get_mut", issue = "88836")]
+    pub const fn get_mut(&mut self) -> &mut T {
         &mut self.value
     }
 
diff --git a/src/bootstrap/test.rs b/src/bootstrap/test.rs
index d12e86b7c1deb..386ffb384a81e 100644
--- a/src/bootstrap/test.rs
+++ b/src/bootstrap/test.rs
@@ -925,6 +925,11 @@ impl Step for RustdocGUI {
                     .env("RUSTDOC", builder.rustdoc(self.compiler))
                     .env("RUSTC", builder.rustc(self.compiler))
                     .current_dir(path);
+                // FIXME: implement a `// compile-flags` command or similar
+                //        instead of hard-coding this test
+                if entry.file_name() == "link_to_definition" {
+                    cargo.env("RUSTDOCFLAGS", "-Zunstable-options --generate-link-to-definition");
+                }
                 builder.run(&mut cargo);
             }
         }
diff --git a/src/librustdoc/html/static/css/themes/ayu.css b/src/librustdoc/html/static/css/themes/ayu.css
index f9ddef4120bbe..eada8f4a04dae 100644
--- a/src/librustdoc/html/static/css/themes/ayu.css
+++ b/src/librustdoc/html/static/css/themes/ayu.css
@@ -217,7 +217,7 @@ a {
 	color: #c5c5c5;
 }
 body.source .example-wrap pre.rust a {
-	background: #c5c5c5;
+	background: #333;
 }
 
 .docblock:not(.type-decl) a:not(.srclink):not(.test-arrow),
diff --git a/src/test/rustdoc-gui/code-sidebar-toggle.goml b/src/test/rustdoc-gui/code-sidebar-toggle.goml
index 00326e9bbc4cc..6fb92e196602e 100644
--- a/src/test/rustdoc-gui/code-sidebar-toggle.goml
+++ b/src/test/rustdoc-gui/code-sidebar-toggle.goml
@@ -1,5 +1,6 @@
 goto: file://|DOC_PATH|/test_docs/index.html
 click: ".srclink"
+wait-for: "#sidebar-toggle"
 click: "#sidebar-toggle"
 wait-for: 500
 fail: true
diff --git a/src/test/rustdoc-gui/jump-to-def-background.goml b/src/test/rustdoc-gui/jump-to-def-background.goml
new file mode 100644
index 0000000000000..3df899e0f2618
--- /dev/null
+++ b/src/test/rustdoc-gui/jump-to-def-background.goml
@@ -0,0 +1,23 @@
+// We check the background color on the jump to definition links in the source code page.
+goto: file://|DOC_PATH|/src/link_to_definition/lib.rs.html
+
+// Set the theme to dark.
+local-storage: {"rustdoc-theme": "dark", "rustdoc-preferred-dark-theme": "dark", "rustdoc-use-system-theme": "false"}
+// We reload the page so the local storage settings are being used.
+reload:
+
+assert-css: ("body.source .example-wrap pre.rust a", {"background-color": "rgb(51, 51, 51)"}, ALL)
+
+// Set the theme to ayu.
+local-storage: {"rustdoc-theme": "ayu", "rustdoc-preferred-dark-theme": "ayu", "rustdoc-use-system-theme": "false"}
+// We reload the page so the local storage settings are being used.
+reload:
+
+assert-css: ("body.source .example-wrap pre.rust a", {"background-color": "rgb(51, 51, 51)"}, ALL)
+
+// Set the theme to light.
+local-storage: {"rustdoc-theme": "light", "rustdoc-use-system-theme": "false"}
+// We reload the page so the local storage settings are being used.
+reload:
+
+assert-css: ("body.source .example-wrap pre.rust a", {"background-color": "rgb(238, 238, 238)"}, ALL)
diff --git a/src/test/rustdoc-gui/src/link_to_definition/Cargo.lock b/src/test/rustdoc-gui/src/link_to_definition/Cargo.lock
new file mode 100644
index 0000000000000..e4b4e52d028e5
--- /dev/null
+++ b/src/test/rustdoc-gui/src/link_to_definition/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "link_to_definition"
+version = "0.1.0"
diff --git a/src/test/rustdoc-gui/src/link_to_definition/Cargo.toml b/src/test/rustdoc-gui/src/link_to_definition/Cargo.toml
new file mode 100644
index 0000000000000..cdd294d74d3ae
--- /dev/null
+++ b/src/test/rustdoc-gui/src/link_to_definition/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "link_to_definition"
+version = "0.1.0"
+edition = "2018"
+
+[lib]
+path = "lib.rs"
diff --git a/src/test/rustdoc-gui/src/link_to_definition/lib.rs b/src/test/rustdoc-gui/src/link_to_definition/lib.rs
new file mode 100644
index 0000000000000..de9ee66a2bad0
--- /dev/null
+++ b/src/test/rustdoc-gui/src/link_to_definition/lib.rs
@@ -0,0 +1,6 @@
+pub struct Bar {
+    pub a: String,
+    pub b: u32,
+}
+
+pub fn foo(_b: &Bar) {}
diff --git a/src/test/ui/associated-consts/associated-const-in-trait.stderr b/src/test/ui/associated-consts/associated-const-in-trait.stderr
index 7b4594108246b..fc949f2494857 100644
--- a/src/test/ui/associated-consts/associated-const-in-trait.stderr
+++ b/src/test/ui/associated-consts/associated-const-in-trait.stderr
@@ -4,7 +4,6 @@ error[E0038]: the trait `Trait` cannot be made into an object
 LL | impl dyn Trait {
    |      ^^^^^^^^^ `Trait` cannot be made into an object
    |
-   = help: consider moving `N` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/associated-const-in-trait.rs:6:11
    |
@@ -12,6 +11,7 @@ LL | trait Trait {
    |       ----- this trait cannot be made into an object...
 LL |     const N: usize;
    |           ^ ...because it contains this associated `const`
+   = help: consider moving `N` to another trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/associated-item/issue-48027.stderr b/src/test/ui/associated-item/issue-48027.stderr
index 77915a80a79b0..7b158f1d75474 100644
--- a/src/test/ui/associated-item/issue-48027.stderr
+++ b/src/test/ui/associated-item/issue-48027.stderr
@@ -21,7 +21,6 @@ error[E0038]: the trait `Bar` cannot be made into an object
 LL | impl dyn Bar {}
    |      ^^^^^^^ `Bar` cannot be made into an object
    |
-   = help: consider moving `X` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/issue-48027.rs:2:11
    |
@@ -29,6 +28,7 @@ LL | trait Bar {
    |       --- this trait cannot be made into an object...
 LL |     const X: usize;
    |           ^ ...because it contains this associated `const`
+   = help: consider moving `X` to another trait
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/coherence/coherence-impl-trait-for-trait-object-safe.stderr b/src/test/ui/coherence/coherence-impl-trait-for-trait-object-safe.stderr
index a2b779e29540b..e9090c1b6bcfb 100644
--- a/src/test/ui/coherence/coherence-impl-trait-for-trait-object-safe.stderr
+++ b/src/test/ui/coherence/coherence-impl-trait-for-trait-object-safe.stderr
@@ -4,7 +4,6 @@ error[E0038]: the trait `NotObjectSafe` cannot be made into an object
 LL | impl NotObjectSafe for dyn NotObjectSafe { }
    |                        ^^^^^^^^^^^^^^^^^ `NotObjectSafe` cannot be made into an object
    |
-   = help: consider moving `eq` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/coherence-impl-trait-for-trait-object-safe.rs:6:43
    |
@@ -12,6 +11,7 @@ LL | trait NotObjectSafe { fn eq(&self, other: Self); }
    |       -------------                       ^^^^ ...because method `eq` references the `Self` type in this parameter
    |       |
    |       this trait cannot be made into an object...
+   = help: consider moving `eq` to another trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/const-generics/generic_const_exprs/object-safety-err-ret.stderr b/src/test/ui/const-generics/generic_const_exprs/object-safety-err-ret.stderr
index 319e6c2c032a0..4e1d71f154558 100644
--- a/src/test/ui/const-generics/generic_const_exprs/object-safety-err-ret.stderr
+++ b/src/test/ui/const-generics/generic_const_exprs/object-safety-err-ret.stderr
@@ -4,7 +4,6 @@ error[E0038]: the trait `Foo` cannot be made into an object
 LL | fn use_dyn(v: &dyn Foo) {
    |                ^^^^^^^ `Foo` cannot be made into an object
    |
-   = help: consider moving `test` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-err-ret.rs:8:23
    |
@@ -12,6 +11,7 @@ LL | trait Foo {
    |       --- this trait cannot be made into an object...
 LL |     fn test(&self) -> [u8; bar::<Self>()];
    |                       ^^^^^^^^^^^^^^^^^^^ ...because method `test` references the `Self` type in its return type
+   = help: consider moving `test` to another trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/error-codes/E0038.stderr b/src/test/ui/error-codes/E0038.stderr
index cead9776e4abb..3773d6f5234b0 100644
--- a/src/test/ui/error-codes/E0038.stderr
+++ b/src/test/ui/error-codes/E0038.stderr
@@ -4,7 +4,6 @@ error[E0038]: the trait `Trait` cannot be made into an object
 LL | fn call_foo(x: Box<dyn Trait>) {
    |                    ^^^^^^^^^ `Trait` cannot be made into an object
    |
-   = help: consider moving `foo` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/E0038.rs:2:22
    |
@@ -12,6 +11,7 @@ LL | trait Trait {
    |       ----- this trait cannot be made into an object...
 LL |     fn foo(&self) -> Self;
    |                      ^^^^ ...because method `foo` references the `Self` type in its return type
+   = help: consider moving `foo` to another trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/error-codes/E0439.rs b/src/test/ui/error-codes/E0439.rs
deleted file mode 100644
index 86e9cb55a9c86..0000000000000
--- a/src/test/ui/error-codes/E0439.rs
+++ /dev/null
@@ -1,8 +0,0 @@
-#![feature(platform_intrinsics)]
-
-extern "platform-intrinsic" {
-    fn simd_shuffle<A,B>(a: A, b: A, c: [u32; 8]) -> B; //~ ERROR E0439
-}
-
-fn main () {
-}
diff --git a/src/test/ui/error-codes/E0439.stderr b/src/test/ui/error-codes/E0439.stderr
deleted file mode 100644
index 8021f7d3951a8..0000000000000
--- a/src/test/ui/error-codes/E0439.stderr
+++ /dev/null
@@ -1,9 +0,0 @@
-error[E0439]: invalid `simd_shuffle`, needs length: `simd_shuffle`
-  --> $DIR/E0439.rs:4:5
-   |
-LL |     fn simd_shuffle<A,B>(a: A, b: A, c: [u32; 8]) -> B;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0439`.
diff --git a/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.stderr b/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.stderr
index a3bd65e518e4c..72cb4cc843cc4 100644
--- a/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.stderr
+++ b/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.stderr
@@ -40,7 +40,6 @@ error[E0038]: the trait `NonObjectSafe3` cannot be made into an object
 LL | fn takes_non_object_safe_box(obj: Box<dyn NonObjectSafe3>) {
    |                                       ^^^^^^^^^^^^^^^^^^ `NonObjectSafe3` cannot be made into an object
    |
-   = help: consider moving `foo` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/feature-gate-object_safe_for_dispatch.rs:11:8
    |
@@ -48,6 +47,7 @@ LL | trait NonObjectSafe3 {
    |       -------------- this trait cannot be made into an object...
 LL |     fn foo<T>(&self);
    |        ^^^ ...because method `foo` has generic type parameters
+   = help: consider moving `foo` to another trait
 
 error[E0038]: the trait `NonObjectSafe4` cannot be made into an object
   --> $DIR/feature-gate-object_safe_for_dispatch.rs:31:35
@@ -55,7 +55,6 @@ error[E0038]: the trait `NonObjectSafe4` cannot be made into an object
 LL | fn return_non_object_safe_rc() -> std::rc::Rc<dyn NonObjectSafe4> {
    |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `NonObjectSafe4` cannot be made into an object
    |
-   = help: consider moving `foo` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/feature-gate-object_safe_for_dispatch.rs:15:22
    |
@@ -63,6 +62,7 @@ LL | trait NonObjectSafe4 {
    |       -------------- this trait cannot be made into an object...
 LL |     fn foo(&self, s: &Self);
    |                      ^^^^^ ...because method `foo` references the `Self` type in this parameter
+   = help: consider moving `foo` to another trait
 
 error[E0038]: the trait `NonObjectSafe1` cannot be made into an object
   --> $DIR/feature-gate-object_safe_for_dispatch.rs:38:16
diff --git a/src/test/ui/generic-associated-types/gat-in-trait-path.stderr b/src/test/ui/generic-associated-types/gat-in-trait-path.stderr
index 8651789688eaa..a55642490f975 100644
--- a/src/test/ui/generic-associated-types/gat-in-trait-path.stderr
+++ b/src/test/ui/generic-associated-types/gat-in-trait-path.stderr
@@ -4,7 +4,6 @@ error[E0038]: the trait `Foo` cannot be made into an object
 LL | fn f(_arg : Box<dyn for<'a> Foo<A<'a> = &'a ()>>) {}
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `Foo` cannot be made into an object
    |
-   = help: consider moving `A` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/gat-in-trait-path.rs:5:10
    |
@@ -12,6 +11,7 @@ LL | trait Foo {
    |       --- this trait cannot be made into an object...
 LL |     type A<'a> where Self: 'a;
    |          ^ ...because it contains the generic associated type `A`
+   = help: consider moving `A` to another trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/generic-associated-types/issue-67510-pass.stderr b/src/test/ui/generic-associated-types/issue-67510-pass.stderr
index b4b89ab047363..7dd1bdf891eb5 100644
--- a/src/test/ui/generic-associated-types/issue-67510-pass.stderr
+++ b/src/test/ui/generic-associated-types/issue-67510-pass.stderr
@@ -4,7 +4,6 @@ error[E0038]: the trait `X` cannot be made into an object
 LL | fn _func1<'a>(_x: Box<dyn X<Y<'a>=&'a ()>>) {}
    |                       ^^^^^^^^^^^^^^^^^^^ `X` cannot be made into an object
    |
-   = help: consider moving `Y` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/issue-67510-pass.rs:4:10
    |
@@ -12,6 +11,7 @@ LL | trait X {
    |       - this trait cannot be made into an object...
 LL |     type Y<'a>;
    |          ^ ...because it contains the generic associated type `Y`
+   = help: consider moving `Y` to another trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/generic-associated-types/issue-76535.stderr b/src/test/ui/generic-associated-types/issue-76535.stderr
index 246454f0612db..0a7eb5dde6009 100644
--- a/src/test/ui/generic-associated-types/issue-76535.stderr
+++ b/src/test/ui/generic-associated-types/issue-76535.stderr
@@ -20,7 +20,6 @@ error[E0038]: the trait `SuperTrait` cannot be made into an object
 LL |     let sub: Box<dyn SuperTrait<SubType = SubStruct>> = Box::new(SuperStruct::new(0));
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `SuperTrait` cannot be made into an object
    |
-   = help: consider moving `SubType` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/issue-76535.rs:6:10
    |
@@ -28,6 +27,7 @@ LL | pub trait SuperTrait {
    |           ---------- this trait cannot be made into an object...
 LL |     type SubType<'a>: SubTrait;
    |          ^^^^^^^ ...because it contains the generic associated type `SubType`
+   = help: consider moving `SubType` to another trait
 
 error[E0038]: the trait `SuperTrait` cannot be made into an object
   --> $DIR/issue-76535.rs:36:57
@@ -35,7 +35,6 @@ error[E0038]: the trait `SuperTrait` cannot be made into an object
 LL |     let sub: Box<dyn SuperTrait<SubType = SubStruct>> = Box::new(SuperStruct::new(0));
    |                                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `SuperTrait` cannot be made into an object
    |
-   = help: consider moving `SubType` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/issue-76535.rs:6:10
    |
@@ -43,6 +42,7 @@ LL | pub trait SuperTrait {
    |           ---------- this trait cannot be made into an object...
 LL |     type SubType<'a>: SubTrait;
    |          ^^^^^^^ ...because it contains the generic associated type `SubType`
+   = help: consider moving `SubType` to another trait
    = note: required because of the requirements on the impl of `CoerceUnsized<Box<dyn SuperTrait<SubType = SubStruct<'_>>>>` for `Box<SuperStruct>`
    = note: required by cast to type `Box<dyn SuperTrait<SubType = SubStruct<'_>>>`
 
diff --git a/src/test/ui/generic-associated-types/issue-78671.stderr b/src/test/ui/generic-associated-types/issue-78671.stderr
index b92730839568d..17dd0ff4a0c94 100644
--- a/src/test/ui/generic-associated-types/issue-78671.stderr
+++ b/src/test/ui/generic-associated-types/issue-78671.stderr
@@ -20,7 +20,6 @@ error[E0038]: the trait `CollectionFamily` cannot be made into an object
 LL |     Box::new(Family) as &dyn CollectionFamily<Member=usize>
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `CollectionFamily` cannot be made into an object
    |
-   = help: consider moving `Member` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/issue-78671.rs:4:10
    |
@@ -28,6 +27,7 @@ LL | trait CollectionFamily {
    |       ---------------- this trait cannot be made into an object...
 LL |     type Member<T>;
    |          ^^^^^^ ...because it contains the generic associated type `Member`
+   = help: consider moving `Member` to another trait
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/generic-associated-types/issue-79422.stderr b/src/test/ui/generic-associated-types/issue-79422.stderr
index 8d8ef6bf83685..b6f856a97e725 100644
--- a/src/test/ui/generic-associated-types/issue-79422.stderr
+++ b/src/test/ui/generic-associated-types/issue-79422.stderr
@@ -20,7 +20,6 @@ error[E0038]: the trait `MapLike` cannot be made into an object
 LL |         as Box<dyn MapLike<u8, u8, VRefCont = dyn RefCont<'_, u8>>>;
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `MapLike` cannot be made into an object
    |
-   = help: consider moving `VRefCont` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/issue-79422.rs:20:10
    |
@@ -28,6 +27,7 @@ LL | trait MapLike<K, V> {
    |       ------- this trait cannot be made into an object...
 LL |     type VRefCont<'a>: RefCont<'a, V>;
    |          ^^^^^^^^ ...because it contains the generic associated type `VRefCont`
+   = help: consider moving `VRefCont` to another trait
 
 error[E0038]: the trait `MapLike` cannot be made into an object
   --> $DIR/issue-79422.rs:41:13
@@ -35,7 +35,6 @@ error[E0038]: the trait `MapLike` cannot be made into an object
 LL |     let m = Box::new(std::collections::BTreeMap::<u8, u8>::new())
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `MapLike` cannot be made into an object
    |
-   = help: consider moving `VRefCont` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/issue-79422.rs:20:10
    |
@@ -43,6 +42,7 @@ LL | trait MapLike<K, V> {
    |       ------- this trait cannot be made into an object...
 LL |     type VRefCont<'a>: RefCont<'a, V>;
    |          ^^^^^^^^ ...because it contains the generic associated type `VRefCont`
+   = help: consider moving `VRefCont` to another trait
    = note: required because of the requirements on the impl of `CoerceUnsized<Box<dyn MapLike<u8, u8, VRefCont = (dyn RefCont<'_, u8> + 'static)>>>` for `Box<BTreeMap<u8, u8>>`
    = note: required by cast to type `Box<dyn MapLike<u8, u8, VRefCont = (dyn RefCont<'_, u8> + 'static)>>`
 
diff --git a/src/test/ui/generic-associated-types/trait-objects.stderr b/src/test/ui/generic-associated-types/trait-objects.stderr
index 6429bb8159e1f..5ab37910207ca 100644
--- a/src/test/ui/generic-associated-types/trait-objects.stderr
+++ b/src/test/ui/generic-associated-types/trait-objects.stderr
@@ -4,7 +4,6 @@ error[E0038]: the trait `StreamingIterator` cannot be made into an object
 LL | fn min_size(x: &mut dyn for<'a> StreamingIterator<Item<'a> = &'a i32>) -> usize {
    |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `StreamingIterator` cannot be made into an object
    |
-   = help: consider moving `Item` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/trait-objects.rs:4:10
    |
@@ -12,6 +11,7 @@ LL | trait StreamingIterator {
    |       ----------------- this trait cannot be made into an object...
 LL |     type Item<'a> where Self: 'a;
    |          ^^^^ ...because it contains the generic associated type `Item`
+   = help: consider moving `Item` to another trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-18959.stderr b/src/test/ui/issues/issue-18959.stderr
index 2a5416ce85ba6..b9e27873636c3 100644
--- a/src/test/ui/issues/issue-18959.stderr
+++ b/src/test/ui/issues/issue-18959.stderr
@@ -4,7 +4,6 @@ error[E0038]: the trait `Bar` cannot be made into an object
 LL | fn foo(b: &dyn Bar) {
    |            ^^^^^^^ `Bar` cannot be made into an object
    |
-   = help: consider moving `foo` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/issue-18959.rs:1:20
    |
@@ -12,6 +11,7 @@ LL | pub trait Foo { fn foo<T>(&self, ext_thing: &T); }
    |                    ^^^ ...because method `foo` has generic type parameters
 LL | pub trait Bar: Foo { }
    |           --- this trait cannot be made into an object...
+   = help: consider moving `foo` to another trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-19538.stderr b/src/test/ui/issues/issue-19538.stderr
index 555d0ff0dc787..7b37e1f95dcc6 100644
--- a/src/test/ui/issues/issue-19538.stderr
+++ b/src/test/ui/issues/issue-19538.stderr
@@ -4,7 +4,6 @@ error[E0038]: the trait `Bar` cannot be made into an object
 LL |     let test: &mut dyn Bar = &mut thing;
    |               ^^^^^^^^^^^^ `Bar` cannot be made into an object
    |
-   = help: consider moving `foo` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/issue-19538.rs:2:8
    |
@@ -13,6 +12,7 @@ LL |     fn foo<T>(&self, val: T);
 ...
 LL | trait Bar: Foo { }
    |       --- this trait cannot be made into an object...
+   = help: consider moving `foo` to another trait
 
 error[E0038]: the trait `Bar` cannot be made into an object
   --> $DIR/issue-19538.rs:17:30
@@ -20,7 +20,6 @@ error[E0038]: the trait `Bar` cannot be made into an object
 LL |     let test: &mut dyn Bar = &mut thing;
    |                              ^^^^^^^^^^ `Bar` cannot be made into an object
    |
-   = help: consider moving `foo` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/issue-19538.rs:2:8
    |
@@ -29,6 +28,7 @@ LL |     fn foo<T>(&self, val: T);
 ...
 LL | trait Bar: Foo { }
    |       --- this trait cannot be made into an object...
+   = help: consider moving `foo` to another trait
    = note: required because of the requirements on the impl of `CoerceUnsized<&mut dyn Bar>` for `&mut Thing`
    = note: required by cast to type `&mut dyn Bar`
 
diff --git a/src/test/ui/issues/issue-56031.stderr b/src/test/ui/issues/issue-56031.stderr
index 3d7acee0a56eb..7ee5bc6ec6174 100644
--- a/src/test/ui/issues/issue-56031.stderr
+++ b/src/test/ui/issues/issue-56031.stderr
@@ -3,6 +3,16 @@ error: missing trait in a trait impl
    |
 LL | impl for T {}
    |     ^
+   |
+help: add a trait here
+   |
+LL | impl Trait for T {}
+   |      +++++
+help: for an inherent impl, drop this `for`
+   |
+LL - impl for T {}
+LL + impl T {}
+   | 
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/object-safety/object-safety-associated-consts.curr.stderr b/src/test/ui/object-safety/object-safety-associated-consts.curr.stderr
index 35ec586892c05..9dd144fee24a6 100644
--- a/src/test/ui/object-safety/object-safety-associated-consts.curr.stderr
+++ b/src/test/ui/object-safety/object-safety-associated-consts.curr.stderr
@@ -4,7 +4,6 @@ error[E0038]: the trait `Bar` cannot be made into an object
 LL | fn make_bar<T:Bar>(t: &T) -> &dyn Bar {
    |                              ^^^^^^^^ `Bar` cannot be made into an object
    |
-   = help: consider moving `X` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-associated-consts.rs:9:11
    |
@@ -12,6 +11,7 @@ LL | trait Bar {
    |       --- this trait cannot be made into an object...
 LL |     const X: usize;
    |           ^ ...because it contains this associated `const`
+   = help: consider moving `X` to another trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/object-safety/object-safety-associated-consts.object_safe_for_dispatch.stderr b/src/test/ui/object-safety/object-safety-associated-consts.object_safe_for_dispatch.stderr
index d51734ed2316b..9ba3b251e6603 100644
--- a/src/test/ui/object-safety/object-safety-associated-consts.object_safe_for_dispatch.stderr
+++ b/src/test/ui/object-safety/object-safety-associated-consts.object_safe_for_dispatch.stderr
@@ -4,7 +4,6 @@ error[E0038]: the trait `Bar` cannot be made into an object
 LL |     t
    |     ^ `Bar` cannot be made into an object
    |
-   = help: consider moving `X` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-associated-consts.rs:9:11
    |
@@ -12,6 +11,7 @@ LL | trait Bar {
    |       --- this trait cannot be made into an object...
 LL |     const X: usize;
    |           ^ ...because it contains this associated `const`
+   = help: consider moving `X` to another trait
    = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Bar>` for `&T`
    = note: required by cast to type `&dyn Bar`
 
diff --git a/src/test/ui/object-safety/object-safety-generics.curr.stderr b/src/test/ui/object-safety/object-safety-generics.curr.stderr
index 8d6094c514429..345950f1ae670 100644
--- a/src/test/ui/object-safety/object-safety-generics.curr.stderr
+++ b/src/test/ui/object-safety/object-safety-generics.curr.stderr
@@ -4,7 +4,6 @@ error[E0038]: the trait `Bar` cannot be made into an object
 LL | fn make_bar<T:Bar>(t: &T) -> &dyn Bar {
    |                              ^^^^^^^^ `Bar` cannot be made into an object
    |
-   = help: consider moving `bar` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-generics.rs:10:8
    |
@@ -12,6 +11,7 @@ LL | trait Bar {
    |       --- this trait cannot be made into an object...
 LL |     fn bar<T>(&self, t: T);
    |        ^^^ ...because method `bar` has generic type parameters
+   = help: consider moving `bar` to another trait
 
 error[E0038]: the trait `Bar` cannot be made into an object
   --> $DIR/object-safety-generics.rs:24:39
@@ -19,7 +19,6 @@ error[E0038]: the trait `Bar` cannot be made into an object
 LL | fn make_bar_explicit<T:Bar>(t: &T) -> &dyn Bar {
    |                                       ^^^^^^^^ `Bar` cannot be made into an object
    |
-   = help: consider moving `bar` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-generics.rs:10:8
    |
@@ -27,6 +26,7 @@ LL | trait Bar {
    |       --- this trait cannot be made into an object...
 LL |     fn bar<T>(&self, t: T);
    |        ^^^ ...because method `bar` has generic type parameters
+   = help: consider moving `bar` to another trait
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/object-safety/object-safety-generics.object_safe_for_dispatch.stderr b/src/test/ui/object-safety/object-safety-generics.object_safe_for_dispatch.stderr
index 3d2b2bb228cb5..86355627c796f 100644
--- a/src/test/ui/object-safety/object-safety-generics.object_safe_for_dispatch.stderr
+++ b/src/test/ui/object-safety/object-safety-generics.object_safe_for_dispatch.stderr
@@ -4,7 +4,6 @@ error[E0038]: the trait `Bar` cannot be made into an object
 LL |     t
    |     ^ `Bar` cannot be made into an object
    |
-   = help: consider moving `bar` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-generics.rs:10:8
    |
@@ -12,6 +11,7 @@ LL | trait Bar {
    |       --- this trait cannot be made into an object...
 LL |     fn bar<T>(&self, t: T);
    |        ^^^ ...because method `bar` has generic type parameters
+   = help: consider moving `bar` to another trait
    = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Bar>` for `&T`
    = note: required by cast to type `&dyn Bar`
 
@@ -21,7 +21,6 @@ error[E0038]: the trait `Bar` cannot be made into an object
 LL |     t as &dyn Bar
    |     ^ `Bar` cannot be made into an object
    |
-   = help: consider moving `bar` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-generics.rs:10:8
    |
@@ -29,6 +28,7 @@ LL | trait Bar {
    |       --- this trait cannot be made into an object...
 LL |     fn bar<T>(&self, t: T);
    |        ^^^ ...because method `bar` has generic type parameters
+   = help: consider moving `bar` to another trait
    = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Bar>` for `&T`
    = note: required by cast to type `&dyn Bar`
 
diff --git a/src/test/ui/object-safety/object-safety-mentions-Self.curr.stderr b/src/test/ui/object-safety/object-safety-mentions-Self.curr.stderr
index 336929702e6cd..f91c9b9856055 100644
--- a/src/test/ui/object-safety/object-safety-mentions-Self.curr.stderr
+++ b/src/test/ui/object-safety/object-safety-mentions-Self.curr.stderr
@@ -4,7 +4,6 @@ error[E0038]: the trait `Bar` cannot be made into an object
 LL | fn make_bar<T:Bar>(t: &T) -> &dyn Bar {
    |                              ^^^^^^^^ `Bar` cannot be made into an object
    |
-   = help: consider moving `bar` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-mentions-Self.rs:11:22
    |
@@ -12,6 +11,7 @@ LL | trait Bar {
    |       --- this trait cannot be made into an object...
 LL |     fn bar(&self, x: &Self);
    |                      ^^^^^ ...because method `bar` references the `Self` type in this parameter
+   = help: consider moving `bar` to another trait
 
 error[E0038]: the trait `Baz` cannot be made into an object
   --> $DIR/object-safety-mentions-Self.rs:28:30
@@ -19,7 +19,6 @@ error[E0038]: the trait `Baz` cannot be made into an object
 LL | fn make_baz<T:Baz>(t: &T) -> &dyn Baz {
    |                              ^^^^^^^^ `Baz` cannot be made into an object
    |
-   = help: consider moving `baz` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-mentions-Self.rs:15:22
    |
@@ -27,6 +26,7 @@ LL | trait Baz {
    |       --- this trait cannot be made into an object...
 LL |     fn baz(&self) -> Self;
    |                      ^^^^ ...because method `baz` references the `Self` type in its return type
+   = help: consider moving `baz` to another trait
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/object-safety/object-safety-mentions-Self.object_safe_for_dispatch.stderr b/src/test/ui/object-safety/object-safety-mentions-Self.object_safe_for_dispatch.stderr
index 6e7896e309cc6..f48628c9d1111 100644
--- a/src/test/ui/object-safety/object-safety-mentions-Self.object_safe_for_dispatch.stderr
+++ b/src/test/ui/object-safety/object-safety-mentions-Self.object_safe_for_dispatch.stderr
@@ -4,7 +4,6 @@ error[E0038]: the trait `Bar` cannot be made into an object
 LL |     t
    |     ^ `Bar` cannot be made into an object
    |
-   = help: consider moving `bar` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-mentions-Self.rs:11:22
    |
@@ -12,6 +11,7 @@ LL | trait Bar {
    |       --- this trait cannot be made into an object...
 LL |     fn bar(&self, x: &Self);
    |                      ^^^^^ ...because method `bar` references the `Self` type in this parameter
+   = help: consider moving `bar` to another trait
    = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Bar>` for `&T`
    = note: required by cast to type `&dyn Bar`
 
@@ -21,7 +21,6 @@ error[E0038]: the trait `Baz` cannot be made into an object
 LL |     t
    |     ^ `Baz` cannot be made into an object
    |
-   = help: consider moving `baz` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-mentions-Self.rs:15:22
    |
@@ -29,6 +28,7 @@ LL | trait Baz {
    |       --- this trait cannot be made into an object...
 LL |     fn baz(&self) -> Self;
    |                      ^^^^ ...because method `baz` references the `Self` type in its return type
+   = help: consider moving `baz` to another trait
    = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Baz>` for `&T`
    = note: required by cast to type `&dyn Baz`
 
diff --git a/src/test/ui/parser/issue-88818.rs b/src/test/ui/parser/issue-88818.rs
new file mode 100644
index 0000000000000..b9233ca8339e1
--- /dev/null
+++ b/src/test/ui/parser/issue-88818.rs
@@ -0,0 +1,10 @@
+// Regression test for #88818 (improve error message for missing trait
+// in `impl for X`).
+
+struct S { }
+impl for S { }
+//~^ ERROR: missing trait in a trait impl
+//~| HELP: add a trait here
+//~| HELP: for an inherent impl, drop this `for`
+
+fn main() {}
diff --git a/src/test/ui/parser/issue-88818.stderr b/src/test/ui/parser/issue-88818.stderr
new file mode 100644
index 0000000000000..d30990ae5820f
--- /dev/null
+++ b/src/test/ui/parser/issue-88818.stderr
@@ -0,0 +1,18 @@
+error: missing trait in a trait impl
+  --> $DIR/issue-88818.rs:5:5
+   |
+LL | impl for S { }
+   |     ^
+   |
+help: add a trait here
+   |
+LL | impl Trait for S { }
+   |      +++++
+help: for an inherent impl, drop this `for`
+   |
+LL - impl for S { }
+LL + impl S { }
+   | 
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/rfc-2632-const-trait-impl/call-generic-method-dup-bound.rs b/src/test/ui/rfc-2632-const-trait-impl/call-generic-method-dup-bound.rs
index 7185376b440c8..cc24dbd96d253 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/call-generic-method-dup-bound.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/call-generic-method-dup-bound.rs
@@ -16,12 +16,17 @@ impl const PartialEq for S {
 
 // This duplicate bound should not result in ambiguities. It should be equivalent to a single ~const
 // bound.
-// const fn equals_self<T: PartialEq + ~const PartialEq>(t: &T) -> bool {
-// FIXME(fee1-dead)^ why should the order matter here?
-const fn equals_self<T: ~const PartialEq + PartialEq>(t: &T) -> bool {
+const fn equals_self<T: PartialEq + ~const PartialEq>(t: &T) -> bool {
     *t == *t
 }
 
-pub const EQ: bool = equals_self(&S);
+trait A: PartialEq {}
+impl<T: PartialEq> A for T {}
+
+const fn equals_self2<T: A + ~const PartialEq>(t: &T) -> bool {
+    *t == *t
+}
+
+pub const EQ: bool = equals_self(&S) && equals_self2(&S);
 
 fn main() {}
diff --git a/src/test/ui/simd-intrinsic/simd-intrinsic-generic-shuffle.rs b/src/test/ui/simd-intrinsic/simd-intrinsic-generic-shuffle.rs
new file mode 100644
index 0000000000000..9611780ac079e
--- /dev/null
+++ b/src/test/ui/simd-intrinsic/simd-intrinsic-generic-shuffle.rs
@@ -0,0 +1,33 @@
+// build-fail
+
+// Test that the simd_shuffle intrinsic produces ok-ish error
+// messages when misused.
+
+#![feature(repr_simd, platform_intrinsics)]
+
+#[repr(simd)]
+#[derive(Copy, Clone)]
+pub struct Simd<T, const N: usize>([T; N]);
+
+extern "platform-intrinsic" {
+    fn simd_shuffle<T, I, U>(a: T, b: T, i: I) -> U;
+}
+
+fn main() {
+    const I: [u32; 2] = [0; 2];
+    const I2: [f32; 2] = [0.; 2];
+    let v = Simd::<u32, 4>([0; 4]);
+
+    unsafe {
+        let _: Simd<u32, 2> = simd_shuffle(v, v, I);
+
+        let _: Simd<u32, 4> = simd_shuffle(v, v, I);
+        //~^ ERROR invalid monomorphization of `simd_shuffle` intrinsic
+
+        let _: Simd<f32, 2> = simd_shuffle(v, v, I);
+        //~^ ERROR invalid monomorphization of `simd_shuffle` intrinsic
+
+        let _: Simd<u32, 2> = simd_shuffle(v, v, I2);
+        //~^ ERROR invalid monomorphization of `simd_shuffle` intrinsic
+    }
+}
diff --git a/src/test/ui/simd-intrinsic/simd-intrinsic-generic-shuffle.stderr b/src/test/ui/simd-intrinsic/simd-intrinsic-generic-shuffle.stderr
new file mode 100644
index 0000000000000..9eeb000fd261f
--- /dev/null
+++ b/src/test/ui/simd-intrinsic/simd-intrinsic-generic-shuffle.stderr
@@ -0,0 +1,21 @@
+error[E0511]: invalid monomorphization of `simd_shuffle` intrinsic: expected return type of length 2, found `Simd<u32, 4_usize>` with length 4
+  --> $DIR/simd-intrinsic-generic-shuffle.rs:24:31
+   |
+LL |         let _: Simd<u32, 4> = simd_shuffle(v, v, I);
+   |                               ^^^^^^^^^^^^^^^^^^^^^
+
+error[E0511]: invalid monomorphization of `simd_shuffle` intrinsic: expected return element type `u32` (element of input `Simd<u32, 4_usize>`), found `Simd<f32, 2_usize>` with element type `f32`
+  --> $DIR/simd-intrinsic-generic-shuffle.rs:27:31
+   |
+LL |         let _: Simd<f32, 2> = simd_shuffle(v, v, I);
+   |                               ^^^^^^^^^^^^^^^^^^^^^
+
+error[E0511]: invalid monomorphization of `simd_shuffle` intrinsic: simd_shuffle index must be an array of `u32`, got `[f32; 2]`
+  --> $DIR/simd-intrinsic-generic-shuffle.rs:30:31
+   |
+LL |         let _: Simd<u32, 2> = simd_shuffle(v, v, I2);
+   |                               ^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0511`.
diff --git a/src/test/ui/simd/shuffle-not-out-of-bounds.rs b/src/test/ui/simd/shuffle-not-out-of-bounds.rs
index 8a533453e75fd..aae6ce4663fba 100644
--- a/src/test/ui/simd/shuffle-not-out-of-bounds.rs
+++ b/src/test/ui/simd/shuffle-not-out-of-bounds.rs
@@ -188,4 +188,14 @@ fn main() {
          48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33,
          32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17,
          16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1));
+
+    extern "platform-intrinsic" {
+        fn simd_shuffle<T, I, U>(a: T, b: T, i: I) -> U;
+    }
+    let v = u8x2(0, 0);
+    const I: [u32; 2] = [4, 4];
+    unsafe {
+        let _: u8x2 = simd_shuffle(v, v, I);
+        //~^ ERROR invalid monomorphization of `simd_shuffle` intrinsic
+    }
 }
diff --git a/src/test/ui/simd/shuffle-not-out-of-bounds.stderr b/src/test/ui/simd/shuffle-not-out-of-bounds.stderr
index 07253a4ae46bc..737fb5e6e51e2 100644
--- a/src/test/ui/simd/shuffle-not-out-of-bounds.stderr
+++ b/src/test/ui/simd/shuffle-not-out-of-bounds.stderr
@@ -71,6 +71,12 @@ LL | |          16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1));
    |
    = note: this error originates in the macro `test_shuffle_lanes` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: aborting due to 6 previous errors
+error[E0511]: invalid monomorphization of `simd_shuffle` intrinsic: shuffle index #0 is out of bounds (limit 4)
+  --> $DIR/shuffle-not-out-of-bounds.rs:198:23
+   |
+LL |         let _: u8x2 = simd_shuffle(v, v, I);
+   |                       ^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 7 previous errors
 
 For more information about this error, try `rustc --explain E0511`.
diff --git a/src/test/ui/simd/shuffle.rs b/src/test/ui/simd/shuffle.rs
new file mode 100644
index 0000000000000..3592adfdc6ad1
--- /dev/null
+++ b/src/test/ui/simd/shuffle.rs
@@ -0,0 +1,24 @@
+//run-pass
+#![feature(repr_simd, platform_intrinsics)]
+
+extern "platform-intrinsic" {
+    fn simd_shuffle<T, I, U>(a: T, b: T, i: I) -> U;
+}
+
+#[derive(Copy, Clone)]
+#[repr(simd)]
+struct Simd<T, const N: usize>([T; N]);
+
+fn main() {
+    const I1: [u32; 4] = [0, 2, 4, 6];
+    const I2: [u32; 2] = [1, 5];
+    let a = Simd::<u8, 4>([0, 1, 2, 3]);
+    let b = Simd::<u8, 4>([4, 5, 6, 7]);
+    unsafe {
+        let x: Simd<u8, 4> = simd_shuffle(a, b, I1);
+        assert_eq!(x.0, [0, 2, 4, 6]);
+
+        let y: Simd<u8, 2> = simd_shuffle(a, b, I2);
+        assert_eq!(y.0, [1, 5]);
+    }
+}
diff --git a/src/test/ui/suggestions/object-unsafe-trait-references-self.stderr b/src/test/ui/suggestions/object-unsafe-trait-references-self.stderr
index f332b7213d8bc..54f19fe9da445 100644
--- a/src/test/ui/suggestions/object-unsafe-trait-references-self.stderr
+++ b/src/test/ui/suggestions/object-unsafe-trait-references-self.stderr
@@ -4,8 +4,6 @@ error[E0038]: the trait `Trait` cannot be made into an object
 LL | fn bar(x: &dyn Trait) {}
    |            ^^^^^^^^^ `Trait` cannot be made into an object
    |
-   = help: consider moving `baz` to another trait
-   = help: consider moving `bat` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-unsafe-trait-references-self.rs:2:22
    |
@@ -15,6 +13,8 @@ LL |     fn baz(&self, _: Self) {}
    |                      ^^^^ ...because method `baz` references the `Self` type in this parameter
 LL |     fn bat(&self) -> Self {}
    |                      ^^^^ ...because method `bat` references the `Self` type in its return type
+   = help: consider moving `baz` to another trait
+   = help: consider moving `bat` to another trait
 
 error[E0038]: the trait `Other` cannot be made into an object
   --> $DIR/object-unsafe-trait-references-self.rs:10:12
diff --git a/src/test/ui/suggestions/object-unsafe-trait-should-use-where-sized.stderr b/src/test/ui/suggestions/object-unsafe-trait-should-use-where-sized.stderr
index 74237e6e6c638..03381415e7dc2 100644
--- a/src/test/ui/suggestions/object-unsafe-trait-should-use-where-sized.stderr
+++ b/src/test/ui/suggestions/object-unsafe-trait-should-use-where-sized.stderr
@@ -22,6 +22,10 @@ LL |     fn foo() where Self: Other, { }
    |        ^^^ ...because associated function `foo` has no `self` parameter
 LL |     fn bar(self: ()) {}
    |                  ^^ ...because method `bar`'s `self` parameter cannot be dispatched on
+help: consider changing method `bar`'s `self` parameter to be `&self`
+   |
+LL |     fn bar(self: &Self) {}
+   |                  ~~~~~
 help: consider turning `foo` into a method by giving it a `&self` argument
    |
 LL |     fn foo(&self) where Self: Other, { }
@@ -30,10 +34,6 @@ help: alternatively, consider constraining `foo` so it does not apply to trait o
    |
 LL |     fn foo() where Self: Other, Self: Sized, { }
    |                               +++++++++++++
-help: consider changing method `bar`'s `self` parameter to be `&self`
-   |
-LL |     fn bar(self: &Self) {}
-   |                  ~~~~~
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/traits/item-privacy.stderr b/src/test/ui/traits/item-privacy.stderr
index 2260dcfc70ea3..81982363b2b85 100644
--- a/src/test/ui/traits/item-privacy.stderr
+++ b/src/test/ui/traits/item-privacy.stderr
@@ -127,9 +127,6 @@ error[E0038]: the trait `assoc_const::C` cannot be made into an object
 LL |     <dyn C>::A;
    |      ^^^^^ `assoc_const::C` cannot be made into an object
    |
-   = help: consider moving `C` to another trait
-   = help: consider moving `B` to another trait
-   = help: consider moving `A` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/item-privacy.rs:25:15
    |
@@ -143,6 +140,9 @@ LL |     pub trait C: A + B {
    |               - this trait cannot be made into an object...
 LL |         const C: u8 = 0;
    |               ^ ...because it contains this associated `const`
+   = help: consider moving `B` to another trait
+   = help: consider moving `A` to another trait
+   = help: consider moving `C` to another trait
 
 error[E0223]: ambiguous associated type
   --> $DIR/item-privacy.rs:115:12
diff --git a/src/test/ui/traits/test-2.stderr b/src/test/ui/traits/test-2.stderr
index 0289424510f97..d943b48fd0082 100644
--- a/src/test/ui/traits/test-2.stderr
+++ b/src/test/ui/traits/test-2.stderr
@@ -32,8 +32,6 @@ error[E0038]: the trait `bar` cannot be made into an object
 LL |     (box 10 as Box<dyn bar>).dup();
    |                ^^^^^^^^^^^^ `bar` cannot be made into an object
    |
-   = help: consider moving `dup` to another trait
-   = help: consider moving `blah` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/test-2.rs:4:30
    |
@@ -42,6 +40,8 @@ LL | trait bar { fn dup(&self) -> Self; fn blah<X>(&self); }
    |       |                      |
    |       |                      ...because method `dup` references the `Self` type in its return type
    |       this trait cannot be made into an object...
+   = help: consider moving `dup` to another trait
+   = help: consider moving `blah` to another trait
 
 error[E0038]: the trait `bar` cannot be made into an object
   --> $DIR/test-2.rs:13:6
@@ -49,8 +49,6 @@ error[E0038]: the trait `bar` cannot be made into an object
 LL |     (box 10 as Box<dyn bar>).dup();
    |      ^^^^^^ `bar` cannot be made into an object
    |
-   = help: consider moving `dup` to another trait
-   = help: consider moving `blah` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/test-2.rs:4:30
    |
@@ -59,6 +57,8 @@ LL | trait bar { fn dup(&self) -> Self; fn blah<X>(&self); }
    |       |                      |
    |       |                      ...because method `dup` references the `Self` type in its return type
    |       this trait cannot be made into an object...
+   = help: consider moving `dup` to another trait
+   = help: consider moving `blah` to another trait
    = note: required because of the requirements on the impl of `CoerceUnsized<Box<dyn bar>>` for `Box<{integer}>`
    = note: required by cast to type `Box<dyn bar>`
 
diff --git a/src/test/ui/type/type-parameter-defaults-referencing-Self-ppaux.stderr b/src/test/ui/type/type-parameter-defaults-referencing-Self-ppaux.stderr
index 2de5f6eb0f03a..8a296dc7ee6e1 100644
--- a/src/test/ui/type/type-parameter-defaults-referencing-Self-ppaux.stderr
+++ b/src/test/ui/type/type-parameter-defaults-referencing-Self-ppaux.stderr
@@ -16,7 +16,6 @@ error[E0038]: the trait `MyAdd` cannot be made into an object
 LL |     let y = x as dyn MyAdd<i32>;
    |                  ^^^^^^^^^^^^^^ `MyAdd` cannot be made into an object
    |
-   = help: consider moving `add` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/type-parameter-defaults-referencing-Self-ppaux.rs:6:55
    |
@@ -24,6 +23,7 @@ LL | trait MyAdd<Rhs=Self> { fn add(&self, other: &Rhs) -> Self; }
    |       -----                                           ^^^^ ...because method `add` references the `Self` type in its return type
    |       |
    |       this trait cannot be made into an object...
+   = help: consider moving `add` to another trait
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/typeck/issue-88803-call-expr-method.fixed b/src/test/ui/typeck/issue-88803-call-expr-method.fixed
new file mode 100644
index 0000000000000..19b96ecf3fc3a
--- /dev/null
+++ b/src/test/ui/typeck/issue-88803-call-expr-method.fixed
@@ -0,0 +1,9 @@
+// run-rustfix
+
+fn main() {
+    let a = Some(42);
+    println!(
+        "The value is {}.",
+        a.unwrap() //~ERROR [E0615]
+    );
+}
diff --git a/src/test/ui/typeck/issue-88803-call-expr-method.rs b/src/test/ui/typeck/issue-88803-call-expr-method.rs
new file mode 100644
index 0000000000000..a061994663749
--- /dev/null
+++ b/src/test/ui/typeck/issue-88803-call-expr-method.rs
@@ -0,0 +1,9 @@
+// run-rustfix
+
+fn main() {
+    let a = Some(42);
+    println!(
+        "The value is {}.",
+        (a.unwrap)() //~ERROR [E0615]
+    );
+}
diff --git a/src/test/ui/typeck/issue-88803-call-expr-method.stderr b/src/test/ui/typeck/issue-88803-call-expr-method.stderr
new file mode 100644
index 0000000000000..dd717ed9416d3
--- /dev/null
+++ b/src/test/ui/typeck/issue-88803-call-expr-method.stderr
@@ -0,0 +1,15 @@
+error[E0615]: attempted to take value of method `unwrap` on type `Option<{integer}>`
+  --> $DIR/issue-88803-call-expr-method.rs:7:12
+   |
+LL |         (a.unwrap)()
+   |            ^^^^^^ method, not a field
+   |
+help: remove wrapping parentheses to call the method
+   |
+LL -         (a.unwrap)()
+LL +         a.unwrap()
+   | 
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0615`.
diff --git a/src/test/ui/wf/issue-87495.stderr b/src/test/ui/wf/issue-87495.stderr
index 010200b5ded1f..c924cd87997e1 100644
--- a/src/test/ui/wf/issue-87495.stderr
+++ b/src/test/ui/wf/issue-87495.stderr
@@ -4,7 +4,6 @@ error[E0038]: the trait `T` cannot be made into an object
 LL |     const CONST: (bool, dyn T);
    |                         ^^^^^ `T` cannot be made into an object
    |
-   = help: consider moving `CONST` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/issue-87495.rs:4:11
    |
@@ -12,6 +11,7 @@ LL | trait T {
    |       - this trait cannot be made into an object...
 LL |     const CONST: (bool, dyn T);
    |           ^^^^^ ...because it contains this associated `const`
+   = help: consider moving `CONST` to another trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/wf/wf-object-safe.stderr b/src/test/ui/wf/wf-object-safe.stderr
index 9b749f88fb810..64969fbe3203e 100644
--- a/src/test/ui/wf/wf-object-safe.stderr
+++ b/src/test/ui/wf/wf-object-safe.stderr
@@ -4,7 +4,6 @@ error[E0038]: the trait `A` cannot be made into an object
 LL |     let _x: &dyn A;
    |             ^^^^^^ `A` cannot be made into an object
    |
-   = help: consider moving `foo` to another trait
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/wf-object-safe.rs:5:23
    |
@@ -12,6 +11,7 @@ LL | trait A {
    |       - this trait cannot be made into an object...
 LL |     fn foo(&self, _x: &Self);
    |                       ^^^^^ ...because method `foo` references the `Self` type in this parameter
+   = help: consider moving `foo` to another trait
 
 error: aborting due to previous error