1 files changed, 31 insertions, 26 deletions

diff --git a/src/error.rs b/src/error.rs
index 7bea3f2..f1e91c3 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -11,6 +11,7 @@ use crate::device;
 
 /// An error returned by the nitrokey crate.
 #[derive(Debug)]
+#[non_exhaustive]
 pub enum Error {
     /// An error reported by the Nitrokey device in the response packet.
     CommandError(CommandError),
@@ -21,9 +22,7 @@ pub enum Error {
     /// A library usage error.
     LibraryError(LibraryError),
     /// An error that occurred due to a poisoned lock.
-    PoisonError(sync::PoisonError<sync::MutexGuard<'static, crate::Manager>>),
-    /// An error that occurred during random number generation.
-    RandError(Box<dyn error::Error>),
+    PoisonError,
     /// An error that is caused by an unexpected value returned by libnitrokey.
     UnexpectedError(String),
     /// An unknown error returned by libnitrokey.
@@ -72,14 +71,14 @@ impl From<str::Utf8Error> for Error {
     }
 }
 
-impl From<sync::PoisonError<sync::MutexGuard<'static, crate::Manager>>> for Error {
-    fn from(error: sync::PoisonError<sync::MutexGuard<'static, crate::Manager>>) -> Self {
-        Error::PoisonError(error)
+impl<T> From<sync::PoisonError<T>> for Error {
+    fn from(_error: sync::PoisonError<T>) -> Self {
+        Error::PoisonError
     }
 }
 
-impl From<sync::TryLockError<sync::MutexGuard<'static, crate::Manager>>> for Error {
-    fn from(error: sync::TryLockError<sync::MutexGuard<'static, crate::Manager>>) -> Self {
+impl<T> From<sync::TryLockError<T>> for Error {
+    fn from(error: sync::TryLockError<T>) -> Self {
         match error {
             sync::TryLockError::Poisoned(err) => err.into(),
             sync::TryLockError::WouldBlock => Error::ConcurrentAccessError,
@@ -93,22 +92,7 @@ impl<'a, T: device::Device<'a>> From<(T, Error)> for Error {
     }
 }
 
-impl error::Error for Error {
-    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
-        match *self {
-            Error::CommandError(ref err) => Some(err),
-            Error::CommunicationError(ref err) => Some(err),
-            Error::ConcurrentAccessError => None,
-            Error::LibraryError(ref err) => Some(err),
-            Error::PoisonError(ref err) => Some(err),
-            Error::RandError(ref err) => Some(err.as_ref()),
-            Error::UnexpectedError(_) => None,
-            Error::UnknownError(_) => None,
-            Error::UnsupportedModelError => None,
-            Error::Utf8Error(ref err) => Some(err),
-        }
-    }
-}
+impl error::Error for Error {}
 
 impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
@@ -117,8 +101,7 @@ impl fmt::Display for Error {
             Error::CommunicationError(ref err) => write!(f, "Communication error: {}", err),
             Error::ConcurrentAccessError => write!(f, "Internal error: concurrent access"),
             Error::LibraryError(ref err) => write!(f, "Library error: {}", err),
-            Error::PoisonError(_) => write!(f, "Internal error: poisoned lock"),
-            Error::RandError(ref err) => write!(f, "RNG error: {}", err),
+            Error::PoisonError => write!(f, "Internal error: poisoned lock"),
             Error::UnexpectedError(ref s) => write!(f, "An unexpected error occurred: {}", s),
             Error::UnknownError(ref err) => write!(f, "Unknown error: {}", err),
             Error::UnsupportedModelError => write!(f, "Unsupported Nitrokey model"),
@@ -129,6 +112,7 @@ impl fmt::Display for Error {
 
 /// An error reported by the Nitrokey device in the response packet.
 #[derive(Clone, Copy, Debug, PartialEq)]
+#[non_exhaustive]
 pub enum CommandError {
     /// A packet with a wrong checksum has been sent or received.
     WrongCrc,
@@ -195,6 +179,7 @@ impl fmt::Display for CommandError {
 
 /// A device communication error.
 #[derive(Clone, Copy, Debug, PartialEq)]
+#[non_exhaustive]
 pub enum CommunicationError {
     /// Could not connect to a Nitrokey device.
     NotConnected,
@@ -233,6 +218,7 @@ impl fmt::Display for CommunicationError {
 
 /// A library usage error.
 #[derive(Clone, Copy, Debug, PartialEq)]
+#[non_exhaustive]
 pub enum LibraryError {
     /// A supplied string exceeded a length limit.
     StringTooLong,
@@ -271,3 +257,22 @@ impl fmt::Display for LibraryError {
         })
     }
 }
+
+// build our own static assertion that Error implements error::Error, Send, Sync, 'static
+
+struct Helper<T>(T);
+
+trait Assert {
+    fn assert() -> bool;
+}
+
+impl<T: error::Error + Send + Sync + 'static> Assert for Helper<T> {
+    fn assert() -> bool {
+        true
+    }
+}
+
+#[allow(unused)]
+fn assert_error_impl() {
+    let _ = Helper::<Error>::assert();
+}