diff --git a/tests/rustdoc-ui/invalid-toplevel-const.stderr b/tests/rustdoc-ui/invalid-toplevel-const.stderr
index 953e332a32c..ae19b728bfe 100644
--- a/tests/rustdoc-ui/invalid-toplevel-const.stderr
+++ b/tests/rustdoc-ui/invalid-toplevel-const.stderr
@@ -1,5 +1,5 @@
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for static items
-  --> $DIR/invalid-toplevel-const.rs:2:31
+  --> $DIR/invalid-toplevel-const.rs:1:31
    |
 LL | static CONST: Option<dyn Fn(& _)> = None;
    |                               ^ not allowed in type signatures
diff --git a/tests/rustdoc-ui/issue-105742.rs b/tests/rustdoc-ui/issue-105742.rs
index 9f36e5315ec..6d33e47a368 100644
--- a/tests/rustdoc-ui/issue-105742.rs
+++ b/tests/rustdoc-ui/issue-105742.rs
@@ -1,19 +1,37 @@
 // compile-flags: -Znormalize-docs
-
 use std::ops::Index;
 
 pub fn next<'a, T>(s: &'a mut dyn SVec<Item = T, Output = T>) {
+    //~^ERROR
+    //~|ERROR
+    //~|ERROR
     let _ = s;
 }
 
 pub trait SVec: Index<
     <Self as SVec>::Item,
+    //~^ERROR
+    //~|ERROR
+    //~|ERROR
+    //~|ERROR
     Output = <Index<<Self as SVec>::Item,
+    //~^ERROR
+    //~|ERROR
+    //~|ERROR
+    //~|ERROR
     Output = <Self as SVec>::Item> as SVec>::Item,
+    //~^ERROR
+    //~|ERROR
+    //~|ERROR
+    //~|ERROR
+    //~|ERROR
+    //~|ERROR
+    //~|ERROR
+    //~|ERROR
 > {
     type Item<'a, T>;
 
     fn len(&self) -> <Self as SVec>::Item;
-    //~^ ERROR
-    //~^^ ERROR
+    //~^ERROR
+    //~|ERROR
 }
diff --git a/tests/rustdoc-ui/issue-105742.stderr b/tests/rustdoc-ui/issue-105742.stderr
index 4d2ee972689..837e72852b4 100644
--- a/tests/rustdoc-ui/issue-105742.stderr
+++ b/tests/rustdoc-ui/issue-105742.stderr
@@ -1,11 +1,328 @@
 error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:16:38
+  --> $DIR/issue-105742.rs:12:21
+   |
+LL |     <Self as SVec>::Item,
+   |                     ^^^^ expected 1 lifetime argument
+   |
+note: associated type defined here, with 1 lifetime parameter: `'a`
+  --> $DIR/issue-105742.rs:32:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^ --
+help: add missing lifetime argument
+   |
+LL |     <Self as SVec>::Item<'a>,
+   |                         ++++
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:12:21
+   |
+LL |     <Self as SVec>::Item,
+   |                     ^^^^ expected 1 generic argument
+   |
+note: associated type defined here, with 1 generic parameter: `T`
+  --> $DIR/issue-105742.rs:32:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^     -
+help: add missing generic argument
+   |
+LL |     <Self as SVec>::Item<T>,
+   |                         +++
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:17:37
+   |
+LL |     Output = <Index<<Self as SVec>::Item,
+   |                                     ^^^^ expected 1 lifetime argument
+   |
+note: associated type defined here, with 1 lifetime parameter: `'a`
+  --> $DIR/issue-105742.rs:32:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^ --
+help: add missing lifetime argument
+   |
+LL |     Output = <Index<<Self as SVec>::Item<'a>,
+   |                                         ++++
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:17:37
+   |
+LL |     Output = <Index<<Self as SVec>::Item,
+   |                                     ^^^^ expected 1 generic argument
+   |
+note: associated type defined here, with 1 generic parameter: `T`
+  --> $DIR/issue-105742.rs:32:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^     -
+help: add missing generic argument
+   |
+LL |     Output = <Index<<Self as SVec>::Item<T>,
+   |                                         +++
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:22:30
+   |
+LL |     Output = <Self as SVec>::Item> as SVec>::Item,
+   |                              ^^^^ expected 1 lifetime argument
+   |
+note: associated type defined here, with 1 lifetime parameter: `'a`
+  --> $DIR/issue-105742.rs:32:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^ --
+help: add missing lifetime argument
+   |
+LL |     Output = <Self as SVec>::Item<'a>> as SVec>::Item,
+   |                                  ++++
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:22:30
+   |
+LL |     Output = <Self as SVec>::Item> as SVec>::Item,
+   |                              ^^^^ expected 1 generic argument
+   |
+note: associated type defined here, with 1 generic parameter: `T`
+  --> $DIR/issue-105742.rs:32:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^     -
+help: add missing generic argument
+   |
+LL |     Output = <Self as SVec>::Item<T>> as SVec>::Item,
+   |                                  +++
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:22:46
+   |
+LL |     Output = <Self as SVec>::Item> as SVec>::Item,
+   |                                              ^^^^ expected 1 lifetime argument
+   |
+note: associated type defined here, with 1 lifetime parameter: `'a`
+  --> $DIR/issue-105742.rs:32:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^ --
+help: add missing lifetime argument
+   |
+LL |     Output = <Self as SVec>::Item> as SVec>::Item<'a>,
+   |                                                  ++++
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:22:46
+   |
+LL |     Output = <Self as SVec>::Item> as SVec>::Item,
+   |                                              ^^^^ expected 1 generic argument
+   |
+note: associated type defined here, with 1 generic parameter: `T`
+  --> $DIR/issue-105742.rs:32:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^     -
+help: add missing generic argument
+   |
+LL |     Output = <Self as SVec>::Item> as SVec>::Item<T>,
+   |                                                  +++
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:4:40
+   |
+LL | pub fn next<'a, T>(s: &'a mut dyn SVec<Item = T, Output = T>) {
+   |                                        ^^^^ expected 1 lifetime argument
+   |
+note: associated type defined here, with 1 lifetime parameter: `'a`
+  --> $DIR/issue-105742.rs:32:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^ --
+help: add missing lifetime argument
+   |
+LL | pub fn next<'a, T>(s: &'a mut dyn SVec<Item<'_> = T, Output = T>) {
+   |                                            ++++
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:4:40
+   |
+LL | pub fn next<'a, T>(s: &'a mut dyn SVec<Item = T, Output = T>) {
+   |                                        ^^^^ expected 1 generic argument
+   |
+note: associated type defined here, with 1 generic parameter: `T`
+  --> $DIR/issue-105742.rs:32:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^     -
+help: add missing generic argument
+   |
+LL | pub fn next<'a, T>(s: &'a mut dyn SVec<Item<T> = T, Output = T>) {
+   |                                            +++
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:12:21
+   |
+LL |     <Self as SVec>::Item,
+   |                     ^^^^ expected 1 lifetime argument
+   |
+note: associated type defined here, with 1 lifetime parameter: `'a`
+  --> $DIR/issue-105742.rs:32:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^ --
+help: add missing lifetime argument
+   |
+LL |     <Self as SVec>::Item<'a>,
+   |                         ++++
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:12:21
+   |
+LL |     <Self as SVec>::Item,
+   |                     ^^^^ expected 1 generic argument
+   |
+note: associated type defined here, with 1 generic parameter: `T`
+  --> $DIR/issue-105742.rs:32:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^     -
+help: add missing generic argument
+   |
+LL |     <Self as SVec>::Item<T>,
+   |                         +++
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:17:37
+   |
+LL |     Output = <Index<<Self as SVec>::Item,
+   |                                     ^^^^ expected 1 lifetime argument
+   |
+note: associated type defined here, with 1 lifetime parameter: `'a`
+  --> $DIR/issue-105742.rs:32:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^ --
+help: add missing lifetime argument
+   |
+LL |     Output = <Index<<Self as SVec>::Item<'a>,
+   |                                         ++++
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:17:37
+   |
+LL |     Output = <Index<<Self as SVec>::Item,
+   |                                     ^^^^ expected 1 generic argument
+   |
+note: associated type defined here, with 1 generic parameter: `T`
+  --> $DIR/issue-105742.rs:32:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^     -
+help: add missing generic argument
+   |
+LL |     Output = <Index<<Self as SVec>::Item<T>,
+   |                                         +++
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:22:30
+   |
+LL |     Output = <Self as SVec>::Item> as SVec>::Item,
+   |                              ^^^^ expected 1 lifetime argument
+   |
+note: associated type defined here, with 1 lifetime parameter: `'a`
+  --> $DIR/issue-105742.rs:32:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^ --
+help: add missing lifetime argument
+   |
+LL |     Output = <Self as SVec>::Item<'a>> as SVec>::Item,
+   |                                  ++++
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:22:30
+   |
+LL |     Output = <Self as SVec>::Item> as SVec>::Item,
+   |                              ^^^^ expected 1 generic argument
+   |
+note: associated type defined here, with 1 generic parameter: `T`
+  --> $DIR/issue-105742.rs:32:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^     -
+help: add missing generic argument
+   |
+LL |     Output = <Self as SVec>::Item<T>> as SVec>::Item,
+   |                                  +++
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:22:46
+   |
+LL |     Output = <Self as SVec>::Item> as SVec>::Item,
+   |                                              ^^^^ expected 1 lifetime argument
+   |
+note: associated type defined here, with 1 lifetime parameter: `'a`
+  --> $DIR/issue-105742.rs:32:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^ --
+help: add missing lifetime argument
+   |
+LL |     Output = <Self as SVec>::Item> as SVec>::Item<'a>,
+   |                                                  ++++
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:22:46
+   |
+LL |     Output = <Self as SVec>::Item> as SVec>::Item,
+   |                                              ^^^^ expected 1 generic argument
+   |
+note: associated type defined here, with 1 generic parameter: `T`
+  --> $DIR/issue-105742.rs:32:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^     -
+help: add missing generic argument
+   |
+LL |     Output = <Self as SVec>::Item> as SVec>::Item<T>,
+   |                                                  +++
+
+error[E0038]: the trait `SVec` cannot be made into an object
+  --> $DIR/issue-105742.rs:4:31
+   |
+LL | pub fn next<'a, T>(s: &'a mut dyn SVec<Item = T, Output = T>) {
+   |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `SVec` cannot be made into an object
+   |
+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-105742.rs:11:17
+   |
+LL |    pub trait SVec: Index<
+   |  ____________----__^
+   | |            |
+   | |            this trait cannot be made into an object...
+LL | |      <Self as SVec>::Item,
+LL | |
+LL | |
+...  |
+LL | |/     Output = <Index<<Self as SVec>::Item,
+LL | ||
+LL | ||
+LL | ||
+LL | ||
+LL | ||     Output = <Self as SVec>::Item> as SVec>::Item,
+   | ||_________________________________________________^ ...because it uses `Self` as a type parameter
+...  |
+LL | |
+LL | |  > {
+   | |__^ ...because it uses `Self` as a type parameter
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:34:38
    |
 LL |     fn len(&self) -> <Self as SVec>::Item;
    |                                      ^^^^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-105742.rs:14:10
+  --> $DIR/issue-105742.rs:32:10
    |
 LL |     type Item<'a, T>;
    |          ^^^^ --
@@ -15,13 +332,13 @@ LL |     fn len(&self) -> <Self as SVec>::Item<'_>;
    |                                          ++++
 
 error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:16:38
+  --> $DIR/issue-105742.rs:34:38
    |
 LL |     fn len(&self) -> <Self as SVec>::Item;
    |                                      ^^^^ expected 1 generic argument
    |
 note: associated type defined here, with 1 generic parameter: `T`
-  --> $DIR/issue-105742.rs:14:10
+  --> $DIR/issue-105742.rs:32:10
    |
 LL |     type Item<'a, T>;
    |          ^^^^     -
@@ -30,6 +347,7 @@ help: add missing generic argument
 LL |     fn len(&self) -> <Self as SVec>::Item<T>;
    |                                          +++
 
-error: aborting due to 2 previous errors
+error: aborting due to 21 previous errors
 
-For more information about this error, try `rustc --explain E0107`.
+Some errors have detailed explanations: E0038, E0107.
+For more information about an error, try `rustc --explain E0038`.
diff --git a/tests/rustdoc-ui/issue-106226.stderr b/tests/rustdoc-ui/issue-106226.stderr
index 2beffbc125b..1c973dab61d 100644
--- a/tests/rustdoc-ui/issue-106226.stderr
+++ b/tests/rustdoc-ui/issue-106226.stderr
@@ -1,9 +1,9 @@
-error[E0308]: mismatched types
-  --> $DIR/issue-106226.rs:2:14
+error[E0121]: the placeholder `_` is not allowed within types on item signatures for type aliases
+  --> $DIR/issue-106226.rs:2:11
    |
 LL | type F = [_; ()];
-   |              ^^ expected `usize`, found `()`
+   |           ^ not allowed in type signatures
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0308`.
+For more information about this error, try `rustc --explain E0121`.
diff --git a/tests/rustdoc-ui/issue-79465.rs b/tests/rustdoc-ui/issue-79465.rs
index f1a77982fb5..e50f3995b83 100644
--- a/tests/rustdoc-ui/issue-79465.rs
+++ b/tests/rustdoc-ui/issue-79465.rs
@@ -1,3 +1,2 @@
 pub fn f1<T>(x: T::A) {}
 //~^ ERROR
-//~^^ ERROR
diff --git a/tests/rustdoc-ui/issue-79465.stderr b/tests/rustdoc-ui/issue-79465.stderr
index 489cc14420a..d187a2e664a 100644
--- a/tests/rustdoc-ui/issue-79465.stderr
+++ b/tests/rustdoc-ui/issue-79465.stderr
@@ -4,12 +4,6 @@ error[E0220]: associated type `A` not found for `T`
 LL | pub fn f1<T>(x: T::A) {}
    |                    ^ associated type `A` not found
 
-error[E0220]: associated type `A` not found for `T`
-  --> $DIR/issue-79465.rs:1:20
-   |
-LL | pub fn f1<T>(x: T::A) {}
-   |                    ^ associated type `A` not found
-
-error: aborting due to 2 previous errors
+error: aborting due to previous error
 
 For more information about this error, try `rustc --explain E0220`.
diff --git a/tests/rustdoc-ui/issue-96287.rs b/tests/rustdoc-ui/issue-96287.rs
index 8d8b4456e63..08cc7ef4c90 100644
--- a/tests/rustdoc-ui/issue-96287.rs
+++ b/tests/rustdoc-ui/issue-96287.rs
@@ -6,7 +6,6 @@ pub trait TraitWithAssoc {
 
 pub type Foo<V> = impl Trait<V::Assoc>;
 //~^ ERROR
-//~^^ ERROR
 
 pub trait Trait<U> {}
 
diff --git a/tests/rustdoc-ui/issue-96287.stderr b/tests/rustdoc-ui/issue-96287.stderr
index 0236b9fe647..7722eb96028 100644
--- a/tests/rustdoc-ui/issue-96287.stderr
+++ b/tests/rustdoc-ui/issue-96287.stderr
@@ -4,12 +4,6 @@ error[E0220]: associated type `Assoc` not found for `V`
 LL | pub type Foo<V> = impl Trait<V::Assoc>;
    |                                 ^^^^^ there is a similarly named associated type `Assoc` in the trait `TraitWithAssoc`
 
-error[E0220]: associated type `Assoc` not found for `V`
-  --> $DIR/issue-96287.rs:7:33
-   |
-LL | pub type Foo<V> = impl Trait<V::Assoc>;
-   |                                 ^^^^^ there is a similarly named associated type `Assoc` in the trait `TraitWithAssoc`
-
-error: aborting due to 2 previous errors
+error: aborting due to previous error
 
 For more information about this error, try `rustc --explain E0220`.