diff --git a/schemars/src/make_schema.rs b/schemars/src/make_schema.rs
index 401a5d4..ab8a6ee 100644
--- a/schemars/src/make_schema.rs
+++ b/schemars/src/make_schema.rs
@@ -234,7 +234,7 @@ macro_rules! map_impl {
                 let mut extensions = Map::new();
                 extensions.insert(
                     "additionalProperties".to_owned(),
-                    json!(gen.subschema_for::<T>())
+                    json!(gen.subschema_for::<V>())
                 );
                 SchemaObject {
                     instance_type: Some(InstanceType::Object.into()),