diff --git a/compiler/rustc_error_codes/src/error_codes.rs b/compiler/rustc_error_codes/src/error_codes.rs
index 883a4bbe8e8..4e149fc2b99 100644
--- a/compiler/rustc_error_codes/src/error_codes.rs
+++ b/compiler/rustc_error_codes/src/error_codes.rs
@@ -184,6 +184,7 @@
 E0374: include_str!("./error_codes/E0374.md"),
 E0375: include_str!("./error_codes/E0375.md"),
 E0376: include_str!("./error_codes/E0376.md"),
+E0377: include_str!("./error_codes/E0377.md"),
 E0378: include_str!("./error_codes/E0378.md"),
 E0379: include_str!("./error_codes/E0379.md"),
 E0380: include_str!("./error_codes/E0380.md"),
@@ -579,8 +580,6 @@
 //  E0315, // cannot invoke closure outside of its lifetime
 //  E0319, // trait impls for defaulted traits allowed just for structs/enums
 //  E0372, // coherence not object safe
-    E0377, // the trait `CoerceUnsized` may only be implemented for a coercion
-           // between structures with the same definition
 //  E0385, // {} in an aliasable location
 //  E0402, // cannot use an outer type parameter in this context
 //  E0406, // merged into 420
diff --git a/compiler/rustc_error_codes/src/error_codes/E0377.md b/compiler/rustc_error_codes/src/error_codes/E0377.md
new file mode 100644
index 00000000000..b1d36406332
--- /dev/null
+++ b/compiler/rustc_error_codes/src/error_codes/E0377.md
@@ -0,0 +1,29 @@
+The trait `CoerceUnsized` may only be implemented for a coercion between
+structures with the same definition.
+
+Example of erroneous code:
+
+```compile_fail,E0377
+#![feature(coerce_unsized)]
+use std::ops::CoerceUnsized;
+
+pub struct Foo<T: ?Sized> {
+    field_with_unsized_type: T,
+}
+
+pub struct Bar<T: ?Sized> {
+    field_with_unsized_type: T,
+}
+
+// error: the trait `CoerceUnsized` may only be implemented for a coercion
+//        between structures with the same definition
+impl<T, U> CoerceUnsized<Bar<U>> for Foo<T> where T: CoerceUnsized<U> {}
+```
+
+When attempting to implement `CoerceUnsized`, the `impl` signature must look
+like: `impl CoerceUnsized<Type<U>> for Type<T> where T: CoerceUnsized<U>`;
+the *implementer* and *`CoerceUnsized` type parameter* must be the same
+type. In this example, `Bar` and `Foo` (even though structurally identical)
+are *not* the same type and are rejected. Learn more about the `CoerceUnsized`
+trait and DST coercion in
+[the `CoerceUnsized` docs](../std/ops/trait.CoerceUnsized.html).
diff --git a/src/bootstrap/install.rs b/src/bootstrap/install.rs
index c53d0d7e4cb..1815a097307 100644
--- a/src/bootstrap/install.rs
+++ b/src/bootstrap/install.rs
@@ -200,10 +200,14 @@ fn run($sel, $builder: &Builder<'_>) {
         install_sh(builder, "clippy", self.compiler.stage, Some(self.target), &tarball);
     };
     Miri, alias = "miri", Self::should_build(_config), only_hosts: true, {
-        let tarball = builder
-            .ensure(dist::Miri { compiler: self.compiler, target: self.target })
-            .expect("missing miri");
-        install_sh(builder, "miri", self.compiler.stage, Some(self.target), &tarball);
+        if let Some(tarball) = builder.ensure(dist::Miri { compiler: self.compiler, target: self.target }) {
+            install_sh(builder, "miri", self.compiler.stage, Some(self.target), &tarball);
+        } else {
+            // Miri is only available on nightly
+            builder.info(
+                &format!("skipping Install miri stage{} ({})", self.compiler.stage, self.target),
+            );
+        }
     };
     LlvmTools, alias = "llvm-tools", Self::should_build(_config), only_hosts: true, {
         let tarball = builder
diff --git a/src/librustdoc/clean/cfg.rs b/src/librustdoc/clean/cfg.rs
index 1843a21205c..f1853f3697d 100644
--- a/src/librustdoc/clean/cfg.rs
+++ b/src/librustdoc/clean/cfg.rs
@@ -507,7 +507,9 @@ fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
                         "openbsd" => "OpenBSD",
                         "redox" => "Redox",
                         "solaris" => "Solaris",
+                        "tvos" => "tvOS",
                         "wasi" => "WASI",
+                        "watchos" => "watchOS",
                         "windows" => "Windows",
                         _ => "",
                     },
diff --git a/src/librustdoc/html/static/css/rustdoc.css b/src/librustdoc/html/static/css/rustdoc.css
index efb19467c87..11e34a3fc7d 100644
--- a/src/librustdoc/html/static/css/rustdoc.css
+++ b/src/librustdoc/html/static/css/rustdoc.css
@@ -338,6 +338,7 @@ code, pre, a.test-arrow, .code-header {
 }
 pre {
 	padding: 14px;
+	line-height: 1.5; /* https://github.com/rust-lang/rust/issues/105906 */
 }
 .item-decl pre {
 	overflow-x: auto;
@@ -1972,10 +1973,7 @@ in storage.js
 }
 
 .scraped-example .code-wrapper .example-wrap {
-	display: grid;
-	grid-template-columns: max-content auto;
 	width: 100%;
-	overflow-x: auto;
 	overflow-y: hidden;
 	margin-bottom: 0;
 }
@@ -1984,13 +1982,6 @@ in storage.js
 	overflow-x: hidden;
 }
 
-.scraped-example .code-wrapper .example-wrap pre.rust {
-	overflow-x: inherit;
-	width: inherit;
-	overflow-y: hidden;
-}
-
-
 .more-examples-toggle {
 	max-width: calc(100% + 25px);
 	margin-top: 10px;
diff --git a/src/test/rustdoc-gui/codeblock-sub.goml b/src/test/rustdoc-gui/codeblock-sub.goml
new file mode 100644
index 00000000000..cbd314d2791
--- /dev/null
+++ b/src/test/rustdoc-gui/codeblock-sub.goml
@@ -0,0 +1,5 @@
+// Test that code blocks nested within <sub> do not have a line height of 0.
+goto: "file://" + |DOC_PATH| + "/test_docs/codeblock_sub/index.html"
+
+store-property: (codeblock_sub_1, "#codeblock-sub-1", "offsetHeight")
+assert-property-false: ("#codeblock-sub-3", { "offsetHeight": |codeblock_sub_1| })
diff --git a/src/test/rustdoc-gui/src/test_docs/lib.rs b/src/test/rustdoc-gui/src/test_docs/lib.rs
index f1b69d4dc1d..51250439694 100644
--- a/src/test/rustdoc-gui/src/test_docs/lib.rs
+++ b/src/test/rustdoc-gui/src/test_docs/lib.rs
@@ -455,3 +455,22 @@ impl TypeWithImplDoc {
     /// fn doc
     pub fn test_fn() {}
 }
+
+/// <sub id="codeblock-sub-1">
+///
+/// ```
+/// one
+/// ```
+///
+/// </sub>
+///
+/// <sub id="codeblock-sub-3">
+///
+/// ```
+/// one
+/// two
+/// three
+/// ```
+///
+/// </sub>
+pub mod codeblock_sub {}
diff --git a/src/test/ui/error-codes/E0377.rs b/src/test/ui/error-codes/E0377.rs
new file mode 100644
index 00000000000..6da2c20956a
--- /dev/null
+++ b/src/test/ui/error-codes/E0377.rs
@@ -0,0 +1,14 @@
+#![feature(coerce_unsized)]
+use std::ops::CoerceUnsized;
+
+pub struct Foo<T: ?Sized> {
+    field_with_unsized_type: T,
+}
+
+pub struct Bar<T: ?Sized> {
+    field_with_unsized_type: T,
+}
+
+impl<T, U> CoerceUnsized<Bar<U>> for Foo<T> where T: CoerceUnsized<U> {} //~ ERROR E0377
+
+fn main() {}
diff --git a/src/test/ui/error-codes/E0377.stderr b/src/test/ui/error-codes/E0377.stderr
new file mode 100644
index 00000000000..bf7d8c8d39d
--- /dev/null
+++ b/src/test/ui/error-codes/E0377.stderr
@@ -0,0 +1,9 @@
+error[E0377]: the trait `CoerceUnsized` may only be implemented for a coercion between structures with the same definition; expected `Foo`, found `Bar`
+  --> $DIR/E0377.rs:12:1
+   |
+LL | impl<T, U> CoerceUnsized<Bar<U>> for Foo<T> where T: CoerceUnsized<U> {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0377`.
diff --git a/src/tools/tidy/src/error_codes_check.rs b/src/tools/tidy/src/error_codes_check.rs
index 610e322e129..1b119e4113e 100644
--- a/src/tools/tidy/src/error_codes_check.rs
+++ b/src/tools/tidy/src/error_codes_check.rs
@@ -11,8 +11,8 @@
 
 // A few of those error codes can't be tested but all the others can and *should* be tested!
 const EXEMPTED_FROM_TEST: &[&str] = &[
-    "E0313", "E0377", "E0461", "E0462", "E0465", "E0476", "E0490", "E0514", "E0519", "E0523",
-    "E0554", "E0640", "E0717", "E0729", "E0789",
+    "E0313", "E0461", "E0462", "E0465", "E0476", "E0490", "E0514", "E0519", "E0523", "E0554",
+    "E0640", "E0717", "E0729", "E0789",
 ];
 
 // Some error codes don't have any tests apparently...