Replace most 'extern crate' directives with 'use'.

  - See #480.

23 files changed, 108 insertions, 111 deletions

diff --git a/openpgp/build.rs b/openpgp/build.rs
index 5c8a9ffb..f508b38e 100644
--- a/openpgp/build.rs
+++ b/openpgp/build.rs
@@ -2,7 +2,7 @@ use std::env;
 use std::fs;
 use std::io::{self, Write};
 use std::path::PathBuf;
-extern crate lalrpop;
+use lalrpop;
 
 fn main() {
     lalrpop::process_root().unwrap();
diff --git a/openpgp/src/armor.rs b/openpgp/src/armor.rs
index cfbbf4ae..54380acf 100644
--- a/openpgp/src/armor.rs
+++ b/openpgp/src/armor.rs
@@ -26,7 +26,7 @@
 //! let mut r = Reader::new(&mut file, ReaderMode::Tolerant(Some(Kind::File)));
 //! ```
 
-extern crate base64;
+use base64;
 use buffered_reader::BufferedReader;
 use std::io::{Cursor, Read, Write};
 use std::io::{Result, Error, ErrorKind};
@@ -637,7 +637,7 @@ impl<'a> Reader<'a> {
         // The range of the first 6 bits of a message is limited.
         // Save cpu cycles by only considering base64 data that starts
         // with one of those characters.
-        lazy_static!{
+        lazy_static::lazy_static!{
             static ref START_CHARS : Vec<u8> = {
                 let mut valid_start = Vec::new();
                 for &tag in &[ Tag::PKESK, Tag::SKESK,
diff --git a/openpgp/src/cert/amalgamation.rs b/openpgp/src/cert/amalgamation.rs
index 019b11b5..def67a4d 100644
--- a/openpgp/src/cert/amalgamation.rs
+++ b/openpgp/src/cert/amalgamation.rs
@@ -153,7 +153,7 @@
 //! code, which doesn't compile:
 //!
 //! ```compile_fail
-//! # extern crate sequoia_openpgp as openpgp;
+//! # use sequoia_openpgp as openpgp;
 //! use openpgp::cert::prelude::*;
 //! use openpgp::packet::prelude::*;
 //!
@@ -186,7 +186,7 @@
 //! below for the [`ComponentAmalgamation::component`] method:
 //!
 //! ```
-//! # extern crate sequoia_openpgp as openpgp;
+//! # use sequoia_openpgp as openpgp;
 //! use openpgp::cert::prelude::*;
 //! use openpgp::packet::prelude::*;
 //!
@@ -276,7 +276,7 @@ pub mod key;
 /// # Examples
 ///
 /// ```
-/// # extern crate sequoia_openpgp as openpgp;
+/// # use sequoia_openpgp as openpgp;
 /// use openpgp::cert::prelude::*;
 /// use openpgp::policy::{Policy, StandardPolicy};
 ///
@@ -386,7 +386,7 @@ pub trait ValidAmalgamation<'a, C: 'a>
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// # use openpgp::policy::StandardPolicy;
     /// #
@@ -415,7 +415,7 @@ pub trait ValidAmalgamation<'a, C: 'a>
     /// ```
     /// # use std::time::{SystemTime, Duration, UNIX_EPOCH};
     /// #
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// # use openpgp::policy::StandardPolicy;
     /// fn f(ua: &ValidUserIDAmalgamation) {
@@ -443,7 +443,7 @@ pub trait ValidAmalgamation<'a, C: 'a>
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// # use openpgp::policy::{Policy, StandardPolicy};
     /// #
@@ -470,7 +470,7 @@ pub trait ValidAmalgamation<'a, C: 'a>
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// # use openpgp::policy::{Policy, StandardPolicy};
     /// #
@@ -502,7 +502,7 @@ pub trait ValidAmalgamation<'a, C: 'a>
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// # use openpgp::policy::{Policy, StandardPolicy};
     /// #
@@ -546,7 +546,7 @@ pub trait ValidAmalgamation<'a, C: 'a>
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// use openpgp::cert::prelude::*;
     /// # use openpgp::policy::StandardPolicy;
     /// use openpgp::types::RevocationStatus;
@@ -595,7 +595,7 @@ pub trait ValidAmalgamation<'a, C: 'a>
 /// # Examples
 ///
 /// ```
-/// # extern crate sequoia_openpgp as openpgp;
+/// # use sequoia_openpgp as openpgp;
 /// # use openpgp::cert::prelude::*;
 /// # use openpgp::policy::StandardPolicy;
 /// #
@@ -686,7 +686,7 @@ impl<'a, C> ComponentAmalgamation<'a, C> {
     /// Returns the component's associated certificate.
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// #
     /// # fn main() -> openpgp::Result<()> {
@@ -730,7 +730,7 @@ impl<'a, C> ComponentAmalgamation<'a, C> {
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// use openpgp::cert::prelude::*;
     /// use openpgp::packet::prelude::*;
     ///
@@ -843,7 +843,7 @@ impl<'a, C> ComponentAmalgamation<'a, C> {
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::Result;
     /// use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
@@ -996,7 +996,7 @@ impl<'a> UserAttributeAmalgamation<'a> {
 /// Print out information about all non-revoked User IDs.
 ///
 /// ```
-/// # extern crate sequoia_openpgp as openpgp;
+/// # use sequoia_openpgp as openpgp;
 /// use openpgp::cert::prelude::*;
 /// use openpgp::packet::prelude::*;
 /// use openpgp::policy::StandardPolicy;
diff --git a/openpgp/src/cert/amalgamation/iter.rs b/openpgp/src/cert/amalgamation/iter.rs
index 44a36a14..b35bd48e 100644
--- a/openpgp/src/cert/amalgamation/iter.rs
+++ b/openpgp/src/cert/amalgamation/iter.rs
@@ -37,7 +37,7 @@ use crate::{
 /// Iterate over the User IDs in a certificate:
 ///
 /// ```
-/// # extern crate sequoia_openpgp as openpgp;
+/// # use sequoia_openpgp as openpgp;
 /// use openpgp::cert::prelude::*;
 ///
 /// #
@@ -57,7 +57,7 @@ use crate::{
 /// Only return valid User IDs.
 ///
 /// ```
-/// # extern crate sequoia_openpgp as openpgp;
+/// # use sequoia_openpgp as openpgp;
 /// use openpgp::cert::prelude::*;
 /// use openpgp::policy::StandardPolicy;
 /// #
@@ -154,7 +154,7 @@ impl<'a, C> ComponentAmalgamationIter<'a, C> {
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     /// #
@@ -209,7 +209,7 @@ impl<'a, C> ComponentAmalgamationIter<'a, C> {
 /// # Examples
 ///
 /// ```
-/// # extern crate sequoia_openpgp as openpgp;
+/// # use sequoia_openpgp as openpgp;
 /// use openpgp::cert::prelude::*;
 /// use openpgp::policy::StandardPolicy;
 /// #
@@ -333,7 +333,7 @@ impl<'a, C> ValidComponentAmalgamationIter<'a, C> {
     /// `revoked(false)`) is equivalent to:
     ///
     /// ```rust
-    /// extern crate sequoia_openpgp as openpgp;
+    /// use sequoia_openpgp as openpgp;
     /// # use openpgp::Result;
     /// use openpgp::cert::prelude::*;
     /// use openpgp::types::RevocationStatus;
diff --git a/openpgp/src/cert/amalgamation/key.rs b/openpgp/src/cert/amalgamation/key.rs
index 4fca9926..02106f2d 100644
--- a/openpgp/src/cert/amalgamation/key.rs
+++ b/openpgp/src/cert/amalgamation/key.rs
@@ -46,7 +46,7 @@
 //!
 //! ```
 //! # use std::convert::TryInto;
-//! # extern crate sequoia_openpgp as openpgp;
+//! # use sequoia_openpgp as openpgp;
 //! # use openpgp::cert::prelude::*;
 //! # use openpgp::packet::prelude::*;
 //! # let (cert, _) = CertBuilder::new()
@@ -81,7 +81,7 @@
 //! message:
 //!
 //! ```rust
-//! # extern crate sequoia_openpgp as openpgp;
+//! # use sequoia_openpgp as openpgp;
 //! # use openpgp::Result;
 //! # use openpgp::cert::prelude::*;
 //! use openpgp::types::RevocationStatus;
@@ -140,7 +140,7 @@
 //! is not valid, then forging the time stamp won't help an attacker.
 //!
 //! ```rust
-//! # extern crate sequoia_openpgp as openpgp;
+//! # use sequoia_openpgp as openpgp;
 //! # use openpgp::Result;
 //! # use openpgp::cert::prelude::*;
 //! use openpgp::types::RevocationStatus;
@@ -217,7 +217,7 @@
 //! approach.
 //!
 //! ```rust
-//! # extern crate sequoia_openpgp as openpgp;
+//! # use sequoia_openpgp as openpgp;
 //! # use openpgp::Result;
 //! # use openpgp::cert::prelude::*;
 //! use sequoia_openpgp::policy::StandardPolicy;
@@ -305,7 +305,7 @@ pub trait PrimaryKey<'a, P, R>
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// # use openpgp::policy::StandardPolicy;
     /// #
@@ -360,7 +360,7 @@ pub trait PrimaryKey<'a, P, R>
 /// Iterating over all keys:
 ///
 /// ```
-/// # extern crate sequoia_openpgp as openpgp;
+/// # use sequoia_openpgp as openpgp;
 /// # use openpgp::cert::prelude::*;
 /// # use openpgp::policy::StandardPolicy;
 /// #
@@ -380,7 +380,7 @@ pub trait PrimaryKey<'a, P, R>
 /// Getting the primary key:
 ///
 /// ```
-/// # extern crate sequoia_openpgp as openpgp;
+/// # use sequoia_openpgp as openpgp;
 /// # use openpgp::cert::prelude::*;
 /// # use openpgp::policy::StandardPolicy;
 /// #
@@ -398,7 +398,7 @@ pub trait PrimaryKey<'a, P, R>
 /// Iterating over just the subkeys:
 ///
 /// ```
-/// # extern crate sequoia_openpgp as openpgp;
+/// # use sequoia_openpgp as openpgp;
 /// # use openpgp::cert::prelude::*;
 /// # use openpgp::policy::StandardPolicy;
 /// #
@@ -841,7 +841,7 @@ impl<'a, P, R, R2> KeyAmalgamation<'a, P, R, R2>
 /// Find all non-revoked, live, signing-capable keys:
 ///
 /// ```
-/// # extern crate sequoia_openpgp as openpgp;
+/// # use sequoia_openpgp as openpgp;
 /// # use openpgp::cert::prelude::*;
 /// use openpgp::policy::StandardPolicy;
 /// use openpgp::types::RevocationStatus;
@@ -1262,7 +1262,7 @@ impl<'a, P, R, R2> ValidKeyAmalgamation<'a, P, R, R2>
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     ///
@@ -1310,7 +1310,7 @@ impl<'a, P, R, R2> ValidKeyAmalgamation<'a, P, R, R2>
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     ///
@@ -1380,7 +1380,7 @@ impl<'a, P> ValidPrimaryKeyAmalgamation<'a, P>
     ///
     /// ```
     /// use std::time;
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     ///
@@ -1462,7 +1462,7 @@ impl<'a, P> ValidSubordinateKeyAmalgamation<'a, P>
     ///
     /// ```
     /// use std::time;
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     ///
@@ -1701,7 +1701,7 @@ impl<'a, P> ValidErasedKeyAmalgamation<'a, P>
     ///
     /// ```
     /// use std::time;
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     ///
@@ -1825,7 +1825,7 @@ impl<'a, P, R, R2> ValidKeyAmalgamation<'a, P, R, R2>
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// # use openpgp::policy::{Policy, StandardPolicy};
     /// #
@@ -1856,7 +1856,7 @@ impl<'a, P, R, R2> ValidKeyAmalgamation<'a, P, R, R2>
     /// motion) *or* storage encryption (data at rest):
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     /// use openpgp::types::KeyFlags;
@@ -1912,7 +1912,7 @@ impl<'a, P, R, R2> ValidKeyAmalgamation<'a, P, R, R2>
     /// Finds keys that are certification capable:
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     ///
@@ -1946,7 +1946,7 @@ impl<'a, P, R, R2> ValidKeyAmalgamation<'a, P, R, R2>
     /// Finds keys that are signing capable:
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     ///
@@ -1979,7 +1979,7 @@ impl<'a, P, R, R2> ValidKeyAmalgamation<'a, P, R, R2>
     /// Finds keys that are authentication capable:
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     ///
@@ -2024,7 +2024,7 @@ impl<'a, P, R, R2> ValidKeyAmalgamation<'a, P, R, R2>
     /// Finds keys that are storage-encryption capable:
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     ///
@@ -2071,7 +2071,7 @@ impl<'a, P, R, R2> ValidKeyAmalgamation<'a, P, R, R2>
     /// Finds keys that are transport-encryption capable:
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     ///
@@ -2113,7 +2113,7 @@ impl<'a, P, R, R2> ValidKeyAmalgamation<'a, P, R, R2>
     /// ```
     /// use std::time;
     /// use std::convert::TryInto;
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     /// use openpgp::types::Timestamp;
@@ -2163,7 +2163,7 @@ impl<'a, P, R, R2> ValidKeyAmalgamation<'a, P, R, R2>
     /// ```
     /// use std::time;
     /// use std::convert::TryInto;
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     /// use openpgp::types::Timestamp;
diff --git a/openpgp/src/cert/amalgamation/key/iter.rs b/openpgp/src/cert/amalgamation/key/iter.rs
index f50a8118..98a9e808 100644
--- a/openpgp/src/cert/amalgamation/key/iter.rs
+++ b/openpgp/src/cert/amalgamation/key/iter.rs
@@ -233,7 +233,7 @@ impl<'a, P, R> KeyAmalgamationIter<'a, P, R>
     /// # Examples
     ///
     /// ```rust
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::Result;
     /// # use openpgp::cert::prelude::*;
     /// # fn main() { f().unwrap(); }
@@ -269,7 +269,7 @@ impl<'a, P, R> KeyAmalgamationIter<'a, P, R>
     /// # Examples
     ///
     /// ```rust
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::Result;
     /// # use openpgp::cert::prelude::*;
     /// # fn main() { f().unwrap(); }
@@ -312,7 +312,7 @@ impl<'a, P, R> KeyAmalgamationIter<'a, P, R>
     /// # Examples
     ///
     /// ```rust
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::Result;
     /// # use openpgp::cert::prelude::*;
     /// # fn main() { f().unwrap(); }
@@ -357,7 +357,7 @@ impl<'a, P, R> KeyAmalgamationIter<'a, P, R>
     /// # Examples
     ///
     /// ```rust
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::Result;
     /// # use openpgp::cert::prelude::*;
     /// # fn main() { f().unwrap(); }
@@ -399,7 +399,7 @@ impl<'a, P, R> KeyAmalgamationIter<'a, P, R>
     /// # Examples
     ///
     /// ```rust
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::Result;
     /// # use openpgp::cert::prelude::*;
     /// #
@@ -454,7 +454,7 @@ impl<'a, P, R> KeyAmalgamationIter<'a, P, R>
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     /// #
@@ -531,7 +531,7 @@ impl<'a, P, R> KeyAmalgamationIter<'a, P, R>
 /// Find a key that we can use to sign a document:
 ///
 /// ```
-/// # extern crate sequoia_openpgp as openpgp;
+/// # use sequoia_openpgp as openpgp;
 /// # use openpgp::cert::prelude::*;
 /// use openpgp::policy::StandardPolicy;
 /// use openpgp::types::RevocationStatus;
@@ -846,7 +846,7 @@ impl<'a, P, R> ValidKeyAmalgamationIter<'a, P, R>
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     /// use openpgp::types::KeyFlags;
@@ -917,7 +917,7 @@ impl<'a, P, R> ValidKeyAmalgamationIter<'a, P, R>
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     ///
@@ -962,7 +962,7 @@ impl<'a, P, R> ValidKeyAmalgamationIter<'a, P, R>
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     ///
@@ -1005,7 +1005,7 @@ impl<'a, P, R> ValidKeyAmalgamationIter<'a, P, R>
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     ///
@@ -1048,7 +1048,7 @@ impl<'a, P, R> ValidKeyAmalgamationIter<'a, P, R>
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     ///
@@ -1091,7 +1091,7 @@ impl<'a, P, R> ValidKeyAmalgamationIter<'a, P, R>
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     ///
@@ -1134,7 +1134,7 @@ impl<'a, P, R> ValidKeyAmalgamationIter<'a, P, R>
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     ///
@@ -1181,7 +1181,7 @@ impl<'a, P, R> ValidKeyAmalgamationIter<'a, P, R>
     /// # Examples
     ///
     /// ```
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
     ///
@@ -1210,7 +1210,7 @@ impl<'a, P, R> ValidKeyAmalgamationIter<'a, P, R>
     /// `ValidKeyAmalgamationIter::revoked(false)` is equivalent to:
     ///
     /// ```rust
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::Result;
     /// use openpgp::types::RevocationStatus;
     /// # use openpgp::cert::prelude::*;
@@ -1269,7 +1269,7 @@ impl<'a, P, R> ValidKeyAmalgamationIter<'a, P, R>
     /// # Examples
     ///
     /// ```rust
-    /// # extern crate sequoia_openpgp as openpgp;
+    /// # use sequoia_openpgp as openpgp;
     /// # use openpgp::Result;
     /// # use openpgp::cert::prelude::*;
     /// use openpgp::policy::StandardPolicy;
@@ -1315,7 +1315,7 @@ impl<'a, P, R> ValidKeyAmalgamationIter<'a, P, R>
     /// # Examples