diff --git a/crates/pacdef_core/src/backend/actual/python.rs b/crates/pacdef_core/src/backend/actual/python.rs
index aa45b15..116c38d 100644
--- a/crates/pacdef_core/src/backend/actual/python.rs
+++ b/crates/pacdef_core/src/backend/actual/python.rs
@@ -40,7 +40,7 @@ impl Backend for Python {
     }
 
     fn make_dependency(&self, _packages: &[Package]) -> Result<ExitStatus> {
-        todo!()
+        panic!("not supported by {}", BINARY)
     }
 }
 
diff --git a/crates/pacdef_core/src/backend/actual/rust.rs b/crates/pacdef_core/src/backend/actual/rust.rs
index 6c77940..a95a9c6 100644
--- a/crates/pacdef_core/src/backend/actual/rust.rs
+++ b/crates/pacdef_core/src/backend/actual/rust.rs
@@ -41,7 +41,7 @@ impl Backend for Rust {
     }
 
     fn make_dependency(&self, _: &[Package]) -> Result<ExitStatus> {
-        unreachable!("cargo does not have unmanaged packages")
+        panic!("not supported by {}", BINARY)
     }
 }