diff --git a/crates/syntax/src/ast/edit_in_place.rs b/crates/syntax/src/ast/edit_in_place.rs
index 61580a5cae..9a5c122e27 100644
--- a/crates/syntax/src/ast/edit_in_place.rs
+++ b/crates/syntax/src/ast/edit_in_place.rs
@@ -293,22 +293,21 @@ impl ast::GenericParamList {
     pub fn syntax_editor_add_generic_param(
         &self,
         editor: &mut SyntaxEditor,
-        generic_param: ast::GenericParam,
+        new_param: ast::GenericParam,
     ) {
         match self.generic_params().last() {
-            Some(last_param) => {
-                let position = crate::syntax_editor::Position::after(last_param.syntax());
-                let elements = vec![
-                    make::token(T![,]).into(),
-                    make::tokens::single_space().into(),
-                    generic_param.syntax().clone().into(),
-                ];
-                editor.insert_all(position, elements);
+            Some(_) => {
+                let mut params =
+                    self.generic_params().map(|param| param.clone()).collect::<Vec<_>>();
+                params.push(new_param.into());
+                let new_param_list = make::generic_param_list(params);
+
+                editor.replace(self.syntax(), new_param_list.syntax());
             }
             None => {
-                let after_l_angle =
-                    crate::syntax_editor::Position::after(self.l_angle_token().unwrap());
-                editor.insert(after_l_angle, generic_param.syntax());
+                let position = crate::syntax_editor::Position::after(self.l_angle_token().unwrap());
+                let new_param_list = make::generic_param_list(once(new_param.clone()));
+                editor.insert(position, new_param_list.syntax());
             }
         }
     }