diff --git a/nac3core/src/codegen/mod.rs b/nac3core/src/codegen/mod.rs
index e25b6fe1..4df3ee99 100644
--- a/nac3core/src/codegen/mod.rs
+++ b/nac3core/src/codegen/mod.rs
@@ -20,7 +20,10 @@ use itertools::Itertools;
 use parking_lot::{Condvar, Mutex};
 use rustpython_parser::ast::Stmt;
 use std::collections::HashMap;
-use std::sync::Arc;
+use std::sync::{
+    atomic::{AtomicBool, Ordering},
+    Arc,
+};
 use std::thread;
 
 mod expr;
@@ -57,7 +60,7 @@ impl WithCall {
         WithCall { fp }
     }
 
-    pub fn run<'ctx>(&self, m: &Module<'ctx>)  {
+    pub fn run<'ctx>(&self, m: &Module<'ctx>) {
         (self.fp)(m)
     }
 }
@@ -65,6 +68,7 @@ impl WithCall {
 pub struct WorkerRegistry {
     sender: Arc<Sender<Option<CodeGenTask>>>,
     receiver: Arc<Receiver<Option<CodeGenTask>>>,
+    panicked: AtomicBool,
     task_count: Mutex<usize>,
     thread_count: usize,
     wait_condvar: Condvar,
@@ -75,7 +79,7 @@ impl WorkerRegistry {
         names: &[&str],
         top_level_ctx: Arc<TopLevelContext>,
         f: Arc<WithCall>,
-    ) -> Arc<WorkerRegistry> {
+    ) -> (Arc<WorkerRegistry>, Vec<thread::JoinHandle<()>>) {
         let (sender, receiver) = unbounded();
         let task_count = Mutex::new(0);
         let wait_condvar = Condvar::new();
@@ -84,26 +88,44 @@ impl WorkerRegistry {
             sender: Arc::new(sender),
             receiver: Arc::new(receiver),
             thread_count: names.len(),
+            panicked: AtomicBool::new(false),
             task_count,
             wait_condvar,
         });
 
+        let mut handles = Vec::new();
         for name in names.iter() {
             let top_level_ctx = top_level_ctx.clone();
             let registry = registry.clone();
+            let registry2 = registry.clone();
             let name = name.to_string();
             let f = f.clone();
-            thread::spawn(move || {
+            let handle = thread::spawn(move || {
                 registry.worker_thread(name, top_level_ctx, f);
             });
+            let handle = thread::spawn(move || {
+                if let Err(e) = handle.join() {
+                    if let Some(e) = e.downcast_ref::<&'static str>() {
+                        eprintln!("Got an error: {}", e);
+                    } else {
+                        eprintln!("Got an unknown error: {:?}", e);
+                    }
+                    registry2.panicked.store(true, Ordering::SeqCst);
+                    registry2.wait_condvar.notify_all();
+                }
+            });
+            handles.push(handle);
         }
-        registry
+        (registry, handles)
     }
 
-    pub fn wait_tasks_complete(&self) {
+    pub fn wait_tasks_complete(&self, handles: Vec<thread::JoinHandle<()>>) {
         {
             let mut count = self.task_count.lock();
             while *count != 0 {
+                if self.panicked.load(Ordering::SeqCst) {
+                    break;
+                }
                 self.wait_condvar.wait(&mut count);
             }
         }
@@ -113,9 +135,18 @@ impl WorkerRegistry {
         {
             let mut count = self.task_count.lock();
             while *count != self.thread_count {
+                if self.panicked.load(Ordering::SeqCst) {
+                    break;
+                }
                 self.wait_condvar.wait(&mut count);
             }
         }
+        for handle in handles {
+            handle.join().unwrap();
+        }
+        if self.panicked.load(Ordering::SeqCst) {
+            panic!("tasks panicked");
+        }
     }
 
     pub fn add_task(&self, task: CodeGenTask) {
@@ -137,8 +168,6 @@ impl WorkerRegistry {
             let result = gen_func(&context, builder, module, task, top_level_ctx.clone());
             builder = result.0;
             module = result.1;
-
-            println!("{}", *self.task_count.lock());
             *self.task_count.lock() -= 1;
             self.wait_condvar.notify_all();
         }
diff --git a/nac3core/src/codegen/test.rs b/nac3core/src/codegen/test.rs
index 54982897..e56c7b45 100644
--- a/nac3core/src/codegen/test.rs
+++ b/nac3core/src/codegen/test.rs
@@ -237,7 +237,7 @@ fn test_primitives() {
         .trim();
         assert_eq!(expected, module.print_to_string().to_str().unwrap().trim());
     })));
-    let registry = WorkerRegistry::create_workers(&threads, top_level, f);
+    let (registry, handles) = WorkerRegistry::create_workers(&threads, top_level, f);
     registry.add_task(task);
-    registry.wait_tasks_complete();
+    registry.wait_tasks_complete(handles);
 }