diff --git a/src/bootstrap/src/core/build_steps/tool.rs b/src/bootstrap/src/core/build_steps/tool.rs
index d0058eeb43d3c..9ae03ac7fe075 100644
--- a/src/bootstrap/src/core/build_steps/tool.rs
+++ b/src/bootstrap/src/core/build_steps/tool.rs
@@ -334,7 +334,11 @@ macro_rules! bootstrap_tool {
 }
 
 bootstrap_tool!(
-    Rustbook, "src/tools/rustbook", "rustbook", submodules = SUBMODULES_FOR_RUSTBOOK;
+    // This is marked as an external tool because it includes dependencies
+    // from submodules. Trying to keep the lints in sync between all the repos
+    // is a bit of a pain. Unfortunately it means the rustbook source itself
+    // doesn't deny warnings, but it is a relatively small piece of code.
+    Rustbook, "src/tools/rustbook", "rustbook", is_external_tool = true, submodules = SUBMODULES_FOR_RUSTBOOK;
     UnstableBookGen, "src/tools/unstable-book-gen", "unstable-book-gen";
     Tidy, "src/tools/tidy", "tidy";
     Linkchecker, "src/tools/linkchecker", "linkchecker";
diff --git a/src/doc/book b/src/doc/book
index 04d06dfe54160..5a65e2af063ff 160000
--- a/src/doc/book
+++ b/src/doc/book
@@ -1 +1 @@
-Subproject commit 04d06dfe541607e6419f3d028c3f9b245f3be4d9
+Subproject commit 5a65e2af063ff701ae858f1f7536ee347b3cfe63
diff --git a/src/doc/nomicon b/src/doc/nomicon
index 7ef05b9777c94..625b200e5b33a 160000
--- a/src/doc/nomicon
+++ b/src/doc/nomicon
@@ -1 +1 @@
-Subproject commit 7ef05b9777c94836bc92f50f23e6e00981521a89
+Subproject commit 625b200e5b33a5af35589db0bc454203a3d46d20
diff --git a/src/doc/reference b/src/doc/reference
index acd6794e712d5..293af99100377 160000
--- a/src/doc/reference
+++ b/src/doc/reference
@@ -1 +1 @@
-Subproject commit acd6794e712d5e2ef6f5c84fb95688d32a69b816
+Subproject commit 293af991003772bdccf2d6b980182d84dd055942
diff --git a/src/doc/rust-by-example b/src/doc/rust-by-example
index 093397535b48a..054259ed1bf01 160000
--- a/src/doc/rust-by-example
+++ b/src/doc/rust-by-example
@@ -1 +1 @@
-Subproject commit 093397535b48ae13ec76bc526b7e6eb8c096a85c
+Subproject commit 054259ed1bf01cdee4309ee764c7e103f6df3de5