do we need this

Author: molpopgen

src/traits.rs

@@ -209,6 +209,7 @@ where
     }
 
     fn edges(&self) -> &crate::EdgeTable {
+        todo!("can only trigger with with Box<&thing that impl TableAccess>");
         T::edges(self)
     }
     fn sites(&self) -> &crate::SiteTable {

tests/test_table_traits.rs

@@ -101,6 +101,10 @@ impl IteratorOutput {
     }
 }
 
+struct TablesHolder<'tables> {
+    tables: &'tables tskit::TableCollection,
+}
+
 fn validate_output_from_tables(tables: tskit::TableCollection) {
     let tables_output = IteratorOutput::new_from_tables(&tables);
     let access_output = IteratorOutput::new_from_table_access(&tables);
@@ -149,6 +153,20 @@ fn test_traits_with_table_collection() {
     validate_output_from_tables(tables)
 }
 
+#[test]
+fn test_traits_with_table_collection_holder() {
+    let tables = make_tables();
+    let tref = &tables;
+    let tables_output = IteratorOutput::new_from_tables(tref);
+    let access_output = IteratorOutput::new_from_table_access(tref);
+    assert_eq!(tables_output, access_output);
+    let iteration_output = IteratorOutput::new_from_table_iteration(tref);
+    assert_eq!(tables_output, iteration_output);
+    let boxed = Box::new(tref);
+    let dynamic_output = IteratorOutput::new_from_dyn(&boxed);
+    assert_eq!(tables_output, dynamic_output);
+}
+
 #[test]
 fn test_traits_with_tree_sequence() {
     let mut tables = make_tables();