Appearance: effect.move's reply follows an explicit toItem to the first target

crates/engine/src/cmd/effectcmd.rs

@@ -325,10 +325,10 @@ fn move_effect(s: &mut Session, p: &Value) -> Result<Value> {
         }
         Ok(done)
     })?;
-    // The reply names the object whose row the active item is (the first selected object, which
-    // need not paint first), as `effect.apply` does; the first target otherwise.
-    let anchor = if matches!(src, ItemTarget::Item { explicit: false, .. }) { src } else { dst };
-    let (index, item) = landed.get(anchor.anchor(s, &ids)).copied().unzip();
+    // The reply names the object whose row the destination is: the first selected object for the
+    // active item (which need not paint first), as `effect.apply` does; the first target for an
+    // explicit `toItem` or the object's effects.
+    let (index, item) = landed.get(dst.anchor(s, &ids)).copied().unzip();
     Ok(json!({ "ids": ids_json(&ids), "index": index, "item": item.flatten() }))
 }
 

crates/engine/src/tests/appearance.rs

@@ -560,6 +560,15 @@ fn move_reports_the_index_in_the_object_whose_row_it_names() {
     let r = run(&mut s, "effect.move", json!({"from": 1, "to": 0}));
     assert_eq!(r["ids"], json!([b.0]), "only b has a second effect in row 0");
     assert_eq!((r["item"].clone(), r["index"].clone()), (json!(0), json!(0)), "b's effect moved to the start of its row 0");
+    // From the active row to an explicit destination (here the object's effects, where b already
+    // has one), the reply names the first target, a.
+    run(&mut s, "select.set", json!({"ids": [b.0]}));
+    run(&mut s, "effect.apply", json!({"effect": "distort.twist", "item": null}));
+    run(&mut s, "select.set", json!({"ids": [b.0, a.0]}));
+    run(&mut s, "appearance.setActiveItem", json!({"index": 0}));
+    let r = run(&mut s, "effect.move", json!({"from": 0, "to": 9, "toItem": null}));
+    assert_eq!((node(&s, a).appearance.effects.len(), node(&s, b).appearance.effects.len()), (1, 2));
+    assert_eq!((r["item"].clone(), r["index"].clone()), (json!(null), json!(0)), "a's effects hold one effect");
 }
 
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