diff --git a/src/builder/dataflow.rs b/src/builder/dataflow.rs
index 7de7a112d..8b41f0608 100644
--- a/src/builder/dataflow.rs
+++ b/src/builder/dataflow.rs
@@ -61,7 +61,7 @@ impl<T: AsMut<Hugr> + AsRef<Hugr>> DFGBuilder<T> {
             parent,
             match input_resources.map(|inp| inp.union(&signature.resource_reqs)) {
                 // TODO: Make this NodeType::open_resources
-                None => NodeType::pure(output),
+                None => NodeType::new(output, signature.resource_reqs),
                 Some(rs) => NodeType::new(output, rs),
             },
         )?;
diff --git a/src/hugr/validate.rs b/src/hugr/validate.rs
index d94a0a5c8..904d79aac 100644
--- a/src/hugr/validate.rs
+++ b/src/hugr/validate.rs
@@ -743,8 +743,10 @@ mod test {
     use cool_asserts::assert_matches;
 
     use super::*;
-    use crate::builder::{BuildError, ModuleBuilder};
-    use crate::builder::{Container, Dataflow, DataflowSubContainer, HugrBuilder};
+    use crate::builder::{
+        BuildError, Container, DFGBuilder, Dataflow, DataflowHugr, DataflowSubContainer,
+        HugrBuilder, ModuleBuilder,
+    };
     use crate::hugr::{HugrError, HugrMut, NodeType};
     use crate::ops::dataflow::IOTrait;
     use crate::ops::{self, LeafOp, OpType};
@@ -1280,4 +1282,22 @@ mod test {
         assert_matches!(handle, Err(ValidationError::TgtExceedsSrcResources { .. }));
         Ok(())
     }
+
+    #[test]
+    fn parent_signature_mismatch() -> Result<(), BuildError> {
+        let main_signature = AbstractSignature::new_df(type_row![NAT], type_row![NAT])
+            .with_resource_delta(&ResourceSet::singleton(&"R".into()));
+
+        let builder = DFGBuilder::new(main_signature)?;
+        let [w] = builder.input_wires_arr();
+        let hugr = builder.finish_hugr_with_outputs([w]);
+
+        assert_matches!(
+            hugr,
+            Err(BuildError::InvalidHUGR(
+                ValidationError::TgtExceedsSrcResources { .. }
+            ))
+        );
+        Ok(())
+    }
 }