diff --git a/src/main.rs b/src/main.rs
index 62f5bf1..c3e3fa0 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -305,28 +305,31 @@ fn main() -> Result<(), Error> {
                         let id = unwrap_node!(x, SimpleIdentifier).unwrap();
                         pickle.register_declaration(&syntax_tree, id);
                     }
-                    // Instantiations, end-labels.
-                    RefNode::ModuleIdentifier(x) => {
+                    // Interface Declaration.
+                    RefNode::InterfaceDeclaration(x) => {
                         let id = unwrap_node!(x, SimpleIdentifier).unwrap();
-                        // an instantiation is potentially also a declaration (order doesn't matter)
                         pickle.register_declaration(&syntax_tree, id);
-                        let id = unwrap_node!(x, SimpleIdentifier).unwrap();
-                        pickle.register_usage(&syntax_tree, id);
                     }
-                    // Interface Declaration.
-                    RefNode::InterfaceDeclaration(x) => {
+                    // Package declarations.
+                    RefNode::PackageDeclaration(x) => {
                         let id = unwrap_node!(x, SimpleIdentifier).unwrap();
                         pickle.register_declaration(&syntax_tree, id);
                     }
-                    // Interface identifier.
-                    RefNode::InterfaceIdentifier(x) => {
+                    _ => (),
+                }
+            }
+            // Iterate again and check for usage
+            for node in &syntax_tree {
+                match node {
+                    // Instantiations, end-labels.
+                    RefNode::ModuleIdentifier(x) => {
                         let id = unwrap_node!(x, SimpleIdentifier).unwrap();
                         pickle.register_usage(&syntax_tree, id);
                     }
-                    // Package declarations.
-                    RefNode::PackageDeclaration(x) => {
+                    // Interface identifier.
+                    RefNode::InterfaceIdentifier(x) => {
                         let id = unwrap_node!(x, SimpleIdentifier).unwrap();
-                        pickle.register_declaration(&syntax_tree, id);
+                        pickle.register_usage(&syntax_tree, id);
                     }
                     // Package Qualifier (i.e., explicit package constants).
                     RefNode::ClassScope(x) => {
diff --git a/test/modules.sv b/test/modules.sv
index d0ca5d7..1308af6 100644
--- a/test/modules.sv
+++ b/test/modules.sv
@@ -1,10 +1,12 @@
 module module_1;
     module_2 i_module_2();
+    module_external i_external_module();
 endmodule
 
 module module_2 #();
 endmodule
 
+// Another one bites the dust.
 module /* test */ module_3 #()(
     input clk_i
 );