diff --git a/compiler/rustc_lint/src/array_into_iter.rs b/compiler/rustc_lint/src/array_into_iter.rs
index 5ac42c50c724..1facd9737543 100644
--- a/compiler/rustc_lint/src/array_into_iter.rs
+++ b/compiler/rustc_lint/src/array_into_iter.rs
@@ -13,7 +13,7 @@ declare_lint! {
     ///
     /// ### Example
     ///
-    /// ```rust
+    /// ```rust,edition2018
     /// # #![allow(unused)]
     /// [1, 2, 3].into_iter().for_each(|n| { *n; });
     /// ```
diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
index 2850e7a6b44e..e1bcc3aa52bc 100644
--- a/compiler/rustc_lint/src/builtin.rs
+++ b/compiler/rustc_lint/src/builtin.rs
@@ -1686,7 +1686,7 @@ declare_lint! {
     ///
     /// ### Example
     ///
-    /// ```rust
+    /// ```rust,edition2018
     /// let x = 123;
     /// match x {
     ///     0...100 => {}
diff --git a/compiler/rustc_lint/src/non_fmt_panic.rs b/compiler/rustc_lint/src/non_fmt_panic.rs
index 33a6edafa264..ae9c5ce5c3c2 100644
--- a/compiler/rustc_lint/src/non_fmt_panic.rs
+++ b/compiler/rustc_lint/src/non_fmt_panic.rs
@@ -18,7 +18,7 @@ declare_lint! {
     ///
     /// ### Example
     ///
-    /// ```rust,no_run
+    /// ```rust,no_run,edition2018
     /// panic!("{}");
     /// panic!(123);
     /// ```
diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs
index a00561e52135..b14abb9e5db4 100644
--- a/compiler/rustc_lint_defs/src/builtin.rs
+++ b/compiler/rustc_lint_defs/src/builtin.rs
@@ -1584,7 +1584,7 @@ declare_lint! {
     ///
     /// ### Example
     ///
-    /// ```rust
+    /// ```rust,edition2018
     /// trait Trait { }
     ///
     /// fn takes_trait_object(_: Box<Trait>) {
@@ -3313,7 +3313,7 @@ declare_lint! {
     ///
     /// ### Example
     ///
-    /// ```rust,compile_fail
+    /// ```rust,edition2018,compile_fail
     /// #![deny(rust_2021_prefixes_incompatible_syntax)]
     ///
     /// macro_rules! m {
@@ -3333,6 +3333,8 @@ declare_lint! {
     ///
     /// This lint suggests to add whitespace between the `z` and `"hey"` tokens
     /// to keep them separated in Rust 2021.
+    // Allow this lint -- rustdoc doesn't yet support threading edition into this lint's parser.
+    #[allow(rustdoc::invalid_rust_codeblocks)]
     pub RUST_2021_PREFIXES_INCOMPATIBLE_SYNTAX,
     Allow,
     "identifiers that will be parsed as a prefix in Rust 2021",
diff --git a/compiler/rustc_metadata/src/dependency_format.rs b/compiler/rustc_metadata/src/dependency_format.rs
index b8d225606181..8c41fd9c4a23 100644
--- a/compiler/rustc_metadata/src/dependency_format.rs
+++ b/compiler/rustc_metadata/src/dependency_format.rs
@@ -11,10 +11,10 @@
 //! should be used when linking each output type requested in this session. This
 //! generally follows this set of rules:
 //!
-//!     1. Each library must appear exactly once in the output.
-//!     2. Each rlib contains only one library (it's just an object file)
-//!     3. Each dylib can contain more than one library (due to static linking),
-//!        and can also bring in many dynamic dependencies.
+//! 1. Each library must appear exactly once in the output.
+//! 2. Each rlib contains only one library (it's just an object file)
+//! 3. Each dylib can contain more than one library (due to static linking),
+//!    and can also bring in many dynamic dependencies.
 //!
 //! With these constraints in mind, it's generally a very difficult problem to
 //! find a solution that's not "all rlibs" or "all dylibs". I have suspicions
@@ -22,24 +22,24 @@
 //!
 //! The current selection algorithm below looks mostly similar to:
 //!
-//!     1. If static linking is required, then require all upstream dependencies
-//!        to be available as rlibs. If not, generate an error.
-//!     2. If static linking is requested (generating an executable), then
-//!        attempt to use all upstream dependencies as rlibs. If any are not
-//!        found, bail out and continue to step 3.
-//!     3. Static linking has failed, at least one library must be dynamically
-//!        linked. Apply a heuristic by greedily maximizing the number of
-//!        dynamically linked libraries.
-//!     4. Each upstream dependency available as a dynamic library is
-//!        registered. The dependencies all propagate, adding to a map. It is
-//!        possible for a dylib to add a static library as a dependency, but it
-//!        is illegal for two dylibs to add the same static library as a
-//!        dependency. The same dylib can be added twice. Additionally, it is
-//!        illegal to add a static dependency when it was previously found as a
-//!        dylib (and vice versa)
-//!     5. After all dynamic dependencies have been traversed, re-traverse the
-//!        remaining dependencies and add them statically (if they haven't been
-//!        added already).
+//! 1. If static linking is required, then require all upstream dependencies
+//!    to be available as rlibs. If not, generate an error.
+//! 2. If static linking is requested (generating an executable), then
+//!    attempt to use all upstream dependencies as rlibs. If any are not
+//!    found, bail out and continue to step 3.
+//! 3. Static linking has failed, at least one library must be dynamically
+//!    linked. Apply a heuristic by greedily maximizing the number of
+//!    dynamically linked libraries.
+//! 4. Each upstream dependency available as a dynamic library is
+//!    registered. The dependencies all propagate, adding to a map. It is
+//!    possible for a dylib to add a static library as a dependency, but it
+//!    is illegal for two dylibs to add the same static library as a
+//!    dependency. The same dylib can be added twice. Additionally, it is
+//!    illegal to add a static dependency when it was previously found as a
+//!    dylib (and vice versa)
+//! 5. After all dynamic dependencies have been traversed, re-traverse the
+//!    remaining dependencies and add them statically (if they haven't been
+//!    added already).
 //!
 //! While not perfect, this algorithm should help support use-cases such as leaf
 //! dependencies being static while the larger tree of inner dependencies are
diff --git a/compiler/rustc_middle/src/middle/region.rs b/compiler/rustc_middle/src/middle/region.rs
index bd4e83a42ef5..e271f59da879 100644
--- a/compiler/rustc_middle/src/middle/region.rs
+++ b/compiler/rustc_middle/src/middle/region.rs
@@ -257,7 +257,8 @@ pub struct ScopeTree {
     /// ```
     ///
     /// With the HIR tree (calls numbered for expository purposes)
-    /// ```
+    ///
+    /// ```text
     ///     Call#0(foo, [Call#1(f), Yield(y), Call#2(bar, Call#3(g))])
     /// ```
     ///
diff --git a/src/tools/lint-docs/src/lib.rs b/src/tools/lint-docs/src/lib.rs
index e5c7f1257123..fdc89a184da5 100644
--- a/src/tools/lint-docs/src/lib.rs
+++ b/src/tools/lint-docs/src/lib.rs
@@ -149,6 +149,10 @@ impl<'a> LintExtractor<'a> {
                         } else if line.starts_with("// ") {
                             // Ignore comments.
                             continue;
+                        } else if line.starts_with("#[allow") {
+                            // Ignore allow of lints (useful for
+                            // invalid_rust_codeblocks).
+                            continue;
                         } else {
                             let name = lint_name(line).map_err(|e| {
                                 format!(