diff --git a/ofborg/src/acl.rs b/ofborg/src/acl.rs
index 69f77d0..62b8efb 100644
--- a/ofborg/src/acl.rs
+++ b/ofborg/src/acl.rs
@@ -36,10 +36,9 @@ impl ACL {
                 System::X8664Linux,
                 System::Aarch64Linux,
             ]
-        } else if self.can_build_restricted(user, repo) {
-            vec![System::X8664Linux, System::Aarch64Linux]
         } else {
-            vec![]
+            // allow everybody to issue aarch64-linux and x8664-linux builds
+            vec![System::X8664Linux, System::Aarch64Linux]
         }
     }
 
diff --git a/ofborg/src/commentparser.rs b/ofborg/src/commentparser.rs
index ea098e6..f7b8896 100644
--- a/ofborg/src/commentparser.rs
+++ b/ofborg/src/commentparser.rs
@@ -244,5 +244,4 @@ baz",
             parse("@ofborg build foo bar baz.Baz")
         );
     }
-
 }
diff --git a/ofborg/src/notifyworker.rs b/ofborg/src/notifyworker.rs
index 801df26..aa125be 100644
--- a/ofborg/src/notifyworker.rs
+++ b/ofborg/src/notifyworker.rs
@@ -11,7 +11,7 @@ pub struct NotifyWorker<T: SimpleNotifyWorker> {
 pub trait SimpleNotifyWorker {
     type J;
 
-    fn consumer(&self, job: &Self::J, notifier: &mut NotificationReceiver);
+    fn consumer(&self, job: &Self::J, notifier: &mut dyn NotificationReceiver);
 
     fn msg_to_job(
         &self,
diff --git a/ofborg/src/outpathdiff.rs b/ofborg/src/outpathdiff.rs
index 769b79e..668367c 100644
--- a/ofborg/src/outpathdiff.rs
+++ b/ofborg/src/outpathdiff.rs
@@ -110,7 +110,7 @@ type Package = String;
 type Architecture = String;
 type OutPath = String;
 
-pub fn parse_lines(data: &mut BufRead) -> PackageOutPaths {
+pub fn parse_lines(data: &mut dyn BufRead) -> PackageOutPaths {
     data.lines()
         .filter_map(|line| match line {
             Ok(line) => Some(line),
@@ -191,5 +191,4 @@ gnome3.evolution_data_server.aarch64-linux                                 /nix/
         );
         assert_eq!(parse_lines(&mut Cursor::new(TEST_LINES)), expect);
     }
-
 }
diff --git a/ofborg/src/systems.rs b/ofborg/src/systems.rs
index 140f1bc..f296270 100644
--- a/ofborg/src/systems.rs
+++ b/ofborg/src/systems.rs
@@ -5,15 +5,17 @@ pub enum System {
     X8664Darwin,
 }
 
-impl System {
-    pub fn to_string(&self) -> String {
+impl std::fmt::Display for System {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
         match self {
-            System::X8664Linux => String::from("x86_64-linux"),
-            System::Aarch64Linux => String::from("aarch64-linux"),
-            System::X8664Darwin => String::from("x86_64-darwin"),
+            System::X8664Linux => write!(f, "x86_64-linux"),
+            System::Aarch64Linux => write!(f, "aarch64-linux"),
+            System::X8664Darwin => write!(f, "x86_64-darwin"),
         }
     }
+}
 
+impl System {
     pub fn as_build_destination(&self) -> (Option<String>, Option<String>) {
         (None, Some(format!("build-inputs-{}", self.to_string())))
     }
diff --git a/ofborg/src/tagger.rs b/ofborg/src/tagger.rs
index 11535d1..b2d0d2b 100644
--- a/ofborg/src/tagger.rs
+++ b/ofborg/src/tagger.rs
@@ -340,15 +340,6 @@ mod tests {
             PackageArchSrc { linux, darwin: 0 }
         }
 
-        pub fn darwin(darwin: usize) -> PackageArchSrc {
-            PackageArchSrc::linux(0).and_darwin(darwin)
-        }
-
-        pub fn and_linux(mut self, linux: usize) -> PackageArchSrc {
-            self.linux = linux;
-            self
-        }
-
         pub fn and_darwin(mut self, darwin: usize) -> PackageArchSrc {
             self.darwin = darwin;
             self
diff --git a/ofborg/src/tasks/build.rs b/ofborg/src/tasks/build.rs
index e0499bf..f5ed3d0 100644
--- a/ofborg/src/tasks/build.rs
+++ b/ofborg/src/tasks/build.rs
@@ -41,7 +41,7 @@ impl BuildWorker {
     fn actions<'a, 'b>(
         &self,
         job: &'b buildjob::BuildJob,
-        receiver: &'a mut notifyworker::NotificationReceiver,
+        receiver: &'a mut dyn notifyworker::NotificationReceiver,
     ) -> JobActions<'a, 'b> {
         JobActions::new(&self.system, &self.identity, job, receiver)
     }
@@ -50,7 +50,7 @@ impl BuildWorker {
 pub struct JobActions<'a, 'b> {
     system: String,
     identity: String,
-    receiver: &'a mut notifyworker::NotificationReceiver,
+    receiver: &'a mut dyn notifyworker::NotificationReceiver,
     job: &'b buildjob::BuildJob,
     line_counter: u64,
     snippet_log: VecDeque<String>,
@@ -66,7 +66,7 @@ impl<'a, 'b> JobActions<'a, 'b> {
         system: &str,
         identity: &str,
         job: &'b buildjob::BuildJob,
-        receiver: &'a mut notifyworker::NotificationReceiver,
+        receiver: &'a mut dyn notifyworker::NotificationReceiver,
     ) -> JobActions<'a, 'b> {
         let (log_exchange, log_routing_key) = job
             .logs
@@ -279,7 +279,7 @@ impl notifyworker::SimpleNotifyWorker for BuildWorker {
     fn consumer(
         &self,
         job: &buildjob::BuildJob,
-        notifier: &mut notifyworker::NotificationReceiver,
+        notifier: &mut dyn notifyworker::NotificationReceiver,
     ) {
         let mut actions = self.actions(&job, notifier);
 
diff --git a/ofborg/src/tasks/evaluate.rs b/ofborg/src/tasks/evaluate.rs
index 941e5ea..61f2bcf 100644
--- a/ofborg/src/tasks/evaluate.rs
+++ b/ofborg/src/tasks/evaluate.rs
@@ -156,7 +156,7 @@ impl<E: stats::SysEvents + 'static> worker::SimpleWorker for EvaluationWorker<E>
             }
         };
 
-        let mut evaluation_strategy: Box<eval::EvaluationStrategy> = if job.is_nixpkgs() {
+        let mut evaluation_strategy: Box<dyn eval::EvaluationStrategy> = if job.is_nixpkgs() {
             Box::new(eval::NixpkgsStrategy::new(
                 &job,
                 &pull,