diff --git a/Cargo.lock b/Cargo.lock
index 9eba61f8d293b..73dc7f03236d1 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -606,12 +606,22 @@ dependencies = [
  "atty",
  "bitflags",
  "indexmap",
+ "lazy_static",
  "os_str_bytes",
  "strsim 0.10.0",
  "termcolor",
  "textwrap 0.14.2",
 ]
 
+[[package]]
+name = "clap_complete"
+version = "3.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df6f3613c0a3cddfd78b41b10203eb322cb29b600cbdf808a7d3db95691b8e25"
+dependencies = [
+ "clap 3.1.1",
+]
+
 [[package]]
 name = "clippy"
 version = "0.1.62"
@@ -2240,14 +2250,15 @@ dependencies = [
 
 [[package]]
 name = "mdbook"
-version = "0.4.15"
+version = "0.4.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "241f10687eb3b4e0634b3b4e423f97c5f1efbd69dc9522e24a8b94583eeec3c6"
+checksum = "74612ae81a3e5ee509854049dfa4c7975ae033c06f5fc4735c7dfbe60ee2a39d"
 dependencies = [
  "ammonia",
  "anyhow",
  "chrono",
- "clap 2.34.0",
+ "clap 3.1.1",
+ "clap_complete",
  "elasticlunr-rs",
  "env_logger 0.7.1",
  "handlebars",
@@ -2911,7 +2922,6 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "34f197a544b0c9ab3ae46c359a7ec9cbbb5c7bf97054266fecb7ead794a181d6"
 dependencies = [
  "bitflags",
- "getopts",
  "memchr",
  "unicase",
 ]
@@ -3129,9 +3139,9 @@ dependencies = [
 
 [[package]]
 name = "regex"
-version = "1.5.4"
+version = "1.5.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d07a8629359eb56f1e2fb1652bb04212c072a87ba68546a04065d525673ac461"
+checksum = "1a11647b6b25ff05a515cb92c365cec08801e83423a235b51e231e1808747286"
 dependencies = [
  "aho-corasick",
  "memchr",
diff --git a/src/tools/rustbook/Cargo.toml b/src/tools/rustbook/Cargo.toml
index b8c67de26230b..f074eb941dca2 100644
--- a/src/tools/rustbook/Cargo.toml
+++ b/src/tools/rustbook/Cargo.toml
@@ -9,6 +9,6 @@ clap = "2.25.0"
 env_logger = "0.7.1"
 
 [dependencies.mdbook]
-version = "0.4.14"
+version = "0.4.18"
 default-features = false
 features = ["search"]