openpgp: Use non_exhaustive attribute.

  - Fixes #563
  - With an MSRV >= 1.40.0, we can use #[non_exhaustive], as mentioned
    in #406.
  - This is also a clippy lint:
    https://rust-lang.github.io/rust-clippy/master/index.html#manual_non_exhaustive

3 files changed, 1 insertions, 7 deletions

diff --git a/openpgp/src/crypto/backend/nettle/ecdh.rs b/openpgp/src/crypto/backend/nettle/ecdh.rs
index 29e3d448..93d22a07 100644
--- a/openpgp/src/crypto/backend/nettle/ecdh.rs
+++ b/openpgp/src/crypto/backend/nettle/ecdh.rs
@@ -109,8 +109,6 @@ pub fn encrypt<R>(recipient: &Key<key::PublicParts, R>,
             // N/A
             Curve::Unknown(_) | Curve::Ed25519 =>
                 Err(Error::UnsupportedEllipticCurve(curve.clone()).into()),
-
-            Curve::__Nonexhaustive => unreachable!(),
         }
     } else {
         Err(Error::InvalidArgument("Expected an ECDHPublicKey".into()).into())
diff --git a/openpgp/src/crypto/backend/nettle/hash.rs b/openpgp/src/crypto/backend/nettle/hash.rs
index b4600b14..bf1d9cb5 100644
--- a/openpgp/src/crypto/backend/nettle/hash.rs
+++ b/openpgp/src/crypto/backend/nettle/hash.rs
@@ -29,7 +29,6 @@ impl HashAlgorithm {
             HashAlgorithm::MD5 => true,
             HashAlgorithm::Private(_) => false,
             HashAlgorithm::Unknown(_) => false,
-            HashAlgorithm::__Nonexhaustive => unreachable!(),
         }
     }
 
@@ -60,7 +59,6 @@ impl HashAlgorithm {
             HashAlgorithm::RipeMD => Ok(Box::new(Ripemd160::default())),
             HashAlgorithm::Private(_) | HashAlgorithm::Unknown(_) =>
                 Err(Error::UnsupportedHashAlgorithm(self).into()),
-            HashAlgorithm::__Nonexhaustive => unreachable!(),
         }
     }
 
@@ -78,7 +76,6 @@ impl HashAlgorithm {
             HashAlgorithm::RipeMD => Ok(rsa::ASN1_OID_RIPEMD160),
             HashAlgorithm::Private(_) | HashAlgorithm::Unknown(_) =>
                 Err(Error::UnsupportedHashAlgorithm(self).into()),
-            HashAlgorithm::__Nonexhaustive => unreachable!(),
         }
     }
 }
diff --git a/openpgp/src/crypto/backend/nettle/symmetric.rs b/openpgp/src/crypto/backend/nettle/symmetric.rs
index 4883a5a1..f25bcd7e 100644
--- a/openpgp/src/crypto/backend/nettle/symmetric.rs
+++ b/openpgp/src/crypto/backend/nettle/symmetric.rs
@@ -58,7 +58,6 @@ impl SymmetricAlgorithm {
                 => true,
             Unencrypted | IDEA | Private(_) | Unknown(_)
                 => false,
-            __Nonexhaustive => unreachable!(),
         }
     }
 
@@ -246,4 +245,4 @@ impl SymmetricAlgorithm {
             _ => Err(Error::UnsupportedSymmetricAlgorithm(self).into()),
         }
     }
-}
\ No newline at end of file
+}