Remove evaluation order dependence

In this code:

    self.user_attributes.retain(|_| (keep[i], i += 1).0);

it can be unclear to the reader that the increment of i actually
happens before keep is indexed. Especially so for people who've been
inflicted by C and its many surprising reasons for undefined behavior.
It seems better to write this using an iterator.

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

1 files changed, 6 insertions, 6 deletions

diff --git a/openpgp/src/cert.rs b/openpgp/src/cert.rs
index 1da3390e..a8a9f65a 100644
--- a/openpgp/src/cert.rs
+++ b/openpgp/src/cert.rs
@@ -2690,8 +2690,8 @@ impl Cert {
         }
         // Note: Vec::retain visits the elements in the original
         // order.
-        let mut i = 0;
-        self.userids.retain(|_| (keep[i], i += 1).0);
+        let mut keep = keep.iter();
+        self.userids.retain(|_| *keep.next().unwrap());
         self
     }
 
@@ -2729,8 +2729,8 @@ impl Cert {
         }
         // Note: Vec::retain visits the elements in the original
         // order.
-        let mut i = 0;
-        self.user_attributes.retain(|_| (keep[i], i += 1).0);
+        let mut keep = keep.iter();
+        self.user_attributes.retain(|_| *keep.next().unwrap());
         self
     }
 
@@ -2783,8 +2783,8 @@ impl Cert {
         }
         // Note: Vec::retain visits the elements in the original
         // order.
-        let mut i = 0;
-        self.subkeys.retain(|_| (keep[i], i += 1).0);
+        let mut keep = keep.iter();
+        self.subkeys.retain(|_| *keep.next().unwrap());
         self
     }