Use std::mem::take instead of std::mem::replace, for clarity.

  - Replace

        let bar = std::mem::replace(&foo, Default::Default());

    with

        let bar = std::mem::take(&foo);

    The new version seems a little clearer.

  - Found by clippy:
    https://rust-lang.github.io/rust-clippy/master/index.html#mem_replace_with_default

3 files changed, 11 insertions, 16 deletions

diff --git a/openpgp/src/cert.rs b/openpgp/src/cert.rs
index d9f7decd..2e0e33ee 100644
--- a/openpgp/src/cert.rs
+++ b/openpgp/src/cert.rs
@@ -1527,9 +1527,7 @@ impl Cert {
                 t!("check!({}, {}, {:?}, {}, ...)",
                    $desc, stringify!($binding), $binding.$sigs,
                    stringify!($verify_method));
-                for mut sig in mem::replace(&mut $binding.$sigs, Vec::new())
-                    .into_iter()
-                 {
+                for mut sig in mem::take(&mut $binding.$sigs).into_iter() {
                      match sig.$verify_method(self.primary.key(),
                                               self.primary.key(),
                                               $($verify_args),*) {
@@ -1567,9 +1565,7 @@ impl Cert {
                 t!("check_3rd_party!({}, {}, {:?}, {}, {}, ...)",
                    $desc, stringify!($binding), $binding.$sigs,
                    stringify!($verify_method), stringify!($hash_method));
-                for mut sig in mem::replace(&mut $binding.$sigs, Vec::new())
-                    .into_iter()
-                {
+                for mut sig in mem::take(&mut $binding.$sigs) {
                     // Use hash prefix as heuristic.
                     let key = self.primary.key();
                     match sig.hash_algo().context().and_then(|mut ctx| {
@@ -1709,7 +1705,7 @@ impl Cert {
         // See if the signatures that didn't validate are just out of
         // place.
         let mut bad_sigs: Vec<(Option<usize>, Signature)> =
-            mem::replace(&mut self.bad, Vec::new()).into_iter()
+            std::mem::take(&mut self.bad).into_iter()
             .map(|sig| {
                 t!("We're going to reconsider bad signature {:?}", sig);
                 (None, sig)
@@ -1720,15 +1716,15 @@ impl Cert {
         // remember where we took them from.
         for (i, c) in self.unknowns.iter_mut().enumerate() {
             for sig in
-                mem::replace(&mut c.self_signatures, Vec::new()).into_iter()
+                std::mem::take(&mut c.self_signatures).into_iter()
                 .chain(
-                    mem::replace(&mut c.certifications, Vec::new()).into_iter())
+                    std::mem::take(&mut c.certifications).into_iter())
                 .chain(
-                    mem::replace(&mut c.attestations, Vec::new()).into_iter())
+                    std::mem::take(&mut c.attestations).into_iter())
                 .chain(
-                    mem::replace(&mut c.self_revocations, Vec::new()).into_iter())
+                    std::mem::take(&mut c.self_revocations).into_iter())
                 .chain(
-                    mem::replace(&mut c.other_revocations, Vec::new()).into_iter())
+                    std::mem::take(&mut c.other_revocations).into_iter())
             {
                 t!("We're going to reconsider {:?} on unknown component #{}",
                    sig, i);
diff --git a/openpgp/src/parse/hashed_reader.rs b/openpgp/src/parse/hashed_reader.rs
index 0568829d..00f56427 100644
--- a/openpgp/src/parse/hashed_reader.rs
+++ b/openpgp/src/parse/hashed_reader.rs
@@ -427,8 +427,7 @@ mod test {
 
             let cookie = reader.cookie_mut();
 
-            let mut hashes = mem::replace(&mut cookie.sig_group_mut().hashes,
-                                          Default::default());
+            let mut hashes = std::mem::take(&mut cookie.sig_group_mut().hashes);
             for mode in hashes.iter_mut() {
                 let hash = mode.as_mut();
                 let algo = hash.algo();
diff --git a/openpgp/src/policy/cutofflist.rs b/openpgp/src/policy/cutofflist.rs
index 98d4af78..d21d83a5 100644
--- a/openpgp/src/policy/cutofflist.rs
+++ b/openpgp/src/policy/cutofflist.rs
@@ -1,5 +1,5 @@
 use std::fmt;
-use std::mem;
+
 use std::ops::{Index, IndexMut};
 
 use crate::{
@@ -51,7 +51,7 @@ impl<'a, T> VecOrSlice<'a, T> {
         where T: Clone
     {
         let mut v : Vec<T> = match self {
-            VecOrSlice::Vec(ref mut v) => mem::replace(v, Vec::new()),
+            VecOrSlice::Vec(ref mut v) => std::mem::take(v),
             VecOrSlice::Slice(s) => s.to_vec(),
             VecOrSlice::Empty() => Vec::with_capacity(size),
         };