diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 8f4099653562e..3253c3ae87c72 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -1853,7 +1853,7 @@ pub(crate) fn clean_middle_ty<'tcx>(
         ty::Placeholder(..) => panic!("Placeholder"),
         ty::GeneratorWitness(..) => panic!("GeneratorWitness"),
         ty::Infer(..) => panic!("Infer"),
-        ty::Error(_) => panic!("Error"),
+        ty::Error(_) => rustc_errors::FatalError.raise(),
     }
 }
 
diff --git a/src/test/rustdoc-ui/issue-105334.rs b/src/test/rustdoc-ui/issue-105334.rs
new file mode 100644
index 0000000000000..ee1adc6a02914
--- /dev/null
+++ b/src/test/rustdoc-ui/issue-105334.rs
@@ -0,0 +1,2 @@
+impl Vec< br##"*.."## > {}
+//~^ ERROR
diff --git a/src/test/rustdoc-ui/issue-105334.stderr b/src/test/rustdoc-ui/issue-105334.stderr
new file mode 100644
index 0000000000000..e163bb4db9ee6
--- /dev/null
+++ b/src/test/rustdoc-ui/issue-105334.stderr
@@ -0,0 +1,9 @@
+error[E0747]: constant provided when a type was expected
+  --> $DIR/issue-105334.rs:1:11
+   |
+LL | impl Vec< br##"*.."## > {}
+   |           ^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0747`.
diff --git a/src/test/rustdoc-ui/issue-105737.rs b/src/test/rustdoc-ui/issue-105737.rs
new file mode 100644
index 0000000000000..154f069d8ffac
--- /dev/null
+++ b/src/test/rustdoc-ui/issue-105737.rs
@@ -0,0 +1,4 @@
+impl Vec<lol> {}
+//~^ ERROR
+
+pub fn lol() {}
diff --git a/src/test/rustdoc-ui/issue-105737.stderr b/src/test/rustdoc-ui/issue-105737.stderr
new file mode 100644
index 0000000000000..2dd9beb17da9b
--- /dev/null
+++ b/src/test/rustdoc-ui/issue-105737.stderr
@@ -0,0 +1,12 @@
+error[E0747]: constant provided when a type was expected
+  --> $DIR/issue-105737.rs:1:10
+   |
+LL | impl Vec<lol> {}
+   |          ^^^
+   |
+   = help: `lol` is a function item, not a type
+   = help: function item types cannot be named directly
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0747`.
diff --git a/src/test/rustdoc-ui/issue-105742.rs b/src/test/rustdoc-ui/issue-105742.rs
new file mode 100644
index 0000000000000..cb1de7433cfaa
--- /dev/null
+++ b/src/test/rustdoc-ui/issue-105742.rs
@@ -0,0 +1,40 @@
+// 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/src/test/rustdoc-ui/issue-105742.stderr b/src/test/rustdoc-ui/issue-105742.stderr
new file mode 100644
index 0000000000000..cc101b7ff3757
--- /dev/null
+++ b/src/test/rustdoc-ui/issue-105742.stderr
@@ -0,0 +1,385 @@
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:13:21
+   |
+LL |     <Self as SVec>::Item,
+   |                     ^^^^ expected 1 lifetime argument
+   |
+note: associated type defined here, with 1 lifetime parameter: `'a`
+  --> $DIR/issue-105742.rs:33:10
+   |
+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:13:21
+   |
+LL |     <Self as SVec>::Item,
+   |                     ^^^^ expected 1 generic argument
+   |
+note: associated type defined here, with 1 generic parameter: `T`
+  --> $DIR/issue-105742.rs:33:10
+   |
+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:18:37
+   |
+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:33:10
+   |
+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:18:37
+   |
+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:33:10
+   |
+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:23:30
+   |
+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:33:10
+   |
+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:23:30
+   |
+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:33:10
+   |
+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:23:46
+   |
+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:33:10
+   |
+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:23:46
+   |
+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:33:10
+   |
+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:5:40
+   |
+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:33:10
+   |
+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:5:40
+   |
+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:33:10
+   |
+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:13:21
+   |
+LL |     <Self as SVec>::Item,
+   |                     ^^^^ expected 1 lifetime argument
+   |
+note: associated type defined here, with 1 lifetime parameter: `'a`
+  --> $DIR/issue-105742.rs:33:10
+   |
+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:13:21
+   |
+LL |     <Self as SVec>::Item,
+   |                     ^^^^ expected 1 generic argument
+   |
+note: associated type defined here, with 1 generic parameter: `T`
+  --> $DIR/issue-105742.rs:33:10
+   |
+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:18:37
+   |
+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:33:10
+   |
+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:18:37
+   |
+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:33:10
+   |
+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:23:30
+   |
+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:33:10
+   |
+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:23:30
+   |
+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:33:10
+   |
+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:23:46
+   |
+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:33:10
+   |
+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:23:46
+   |
+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:33:10
+   |
+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:5:31
+   |
+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:12:17
+   |
+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:35:38
+   |
+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:33:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^ --
+help: add missing lifetime argument
+   |
+LL |     fn len(&self) -> <Self as SVec>::Item<'_>;
+   |                                      ~~~~~~~~
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:35:38
+   |
+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:33:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^     -
+help: add missing generic argument
+   |
+LL |     fn len(&self) -> <Self as SVec>::Item<T>;
+   |                                      ~~~~~~~
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:35:38
+   |
+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:33:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^ --
+help: add missing lifetime argument
+   |
+LL |     fn len(&self) -> <Self as SVec>::Item<'_>;
+   |                                      ~~~~~~~~
+
+error[E0107]: missing generics for associated type `SVec::Item`
+  --> $DIR/issue-105742.rs:35:38
+   |
+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:33:10
+   |
+LL |     type Item<'a, T>;
+   |          ^^^^     -
+help: add missing generic argument
+   |
+LL |     fn len(&self) -> <Self as SVec>::Item<T>;
+   |                                      ~~~~~~~
+
+error: aborting due to 23 previous errors
+
+Some errors have detailed explanations: E0038, E0107.
+For more information about an error, try `rustc --explain E0038`.
diff --git a/src/test/rustdoc-ui/issue-106226.rs b/src/test/rustdoc-ui/issue-106226.rs
new file mode 100644
index 0000000000000..71b497a9adc73
--- /dev/null
+++ b/src/test/rustdoc-ui/issue-106226.rs
@@ -0,0 +1,3 @@
+// This is a regression test for <https://github.com/rust-lang/rust/issues/106226>.
+type F = [_; ()];
+//~^ ERROR
diff --git a/src/test/rustdoc-ui/issue-106226.stderr b/src/test/rustdoc-ui/issue-106226.stderr
new file mode 100644
index 0000000000000..2beffbc125bd4
--- /dev/null
+++ b/src/test/rustdoc-ui/issue-106226.stderr
@@ -0,0 +1,9 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-106226.rs:2:14
+   |
+LL | type F = [_; ()];
+   |              ^^ expected `usize`, found `()`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/rustdoc-ui/issue-96287.rs b/src/test/rustdoc-ui/issue-96287.rs
new file mode 100644
index 0000000000000..8d8b4456e6335
--- /dev/null
+++ b/src/test/rustdoc-ui/issue-96287.rs
@@ -0,0 +1,17 @@
+#![feature(type_alias_impl_trait)]
+
+pub trait TraitWithAssoc {
+    type Assoc;
+}
+
+pub type Foo<V> = impl Trait<V::Assoc>;
+//~^ ERROR
+//~^^ ERROR
+
+pub trait Trait<U> {}
+
+impl<W> Trait<W> for () {}
+
+pub fn foo_desugared<T: TraitWithAssoc>(_: T) -> Foo<T> {
+    ()
+}
diff --git a/src/test/rustdoc-ui/issue-96287.stderr b/src/test/rustdoc-ui/issue-96287.stderr
new file mode 100644
index 0000000000000..0236b9fe64775
--- /dev/null
+++ b/src/test/rustdoc-ui/issue-96287.stderr
@@ -0,0 +1,15 @@
+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[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
+
+For more information about this error, try `rustc --explain E0220`.