diff --git a/crates/ra_assists/src/assists/move_bounds.rs b/crates/ra_assists/src/assists/move_bounds.rs
index 1d27832a37e..39ff512335b 100644
--- a/crates/ra_assists/src/assists/move_bounds.rs
+++ b/crates/ra_assists/src/assists/move_bounds.rs
@@ -1,11 +1,11 @@
 use hir::db::HirDatabase;
 use ra_syntax::{
-    ast::{self, make, AstNode, NameOwner, TypeBoundsOwner},
+    ast::{self, edit, make, AstNode, NameOwner, TypeBoundsOwner},
     SyntaxElement,
     SyntaxKind::*,
 };
 
-use crate::{ast_editor::AstEditor, Assist, AssistCtx, AssistId};
+use crate::{Assist, AssistCtx, AssistId};
 
 pub(crate) fn move_bounds_to_where_clause(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
     let type_param_list = ctx.node_at_offset::<ast::TypeParamList>()?;
@@ -43,9 +43,8 @@ pub(crate) fn move_bounds_to_where_clause(mut ctx: AssistCtx<impl HirDatabase>)
                     (type_param, without_bounds)
                 });
 
-            let mut ast_editor = AstEditor::new(type_param_list.clone());
-            ast_editor.replace_descendants(new_params);
-            ast_editor.into_text_edit(edit.text_edit_builder());
+            let new_type_param_list = edit::replace_descendants(&type_param_list, new_params);
+            edit.replace_ast(type_param_list.clone(), new_type_param_list);
 
             let where_clause = {
                 let predicates = type_param_list.type_params().filter_map(build_predicate);
diff --git a/crates/ra_assists/src/ast_editor.rs b/crates/ra_assists/src/ast_editor.rs
deleted file mode 100644
index 69abf28a1e6..00000000000
--- a/crates/ra_assists/src/ast_editor.rs
+++ /dev/null
@@ -1,53 +0,0 @@
-use std::{iter, ops::RangeInclusive};
-
-use ra_syntax::{
-    algo,
-    ast::{self, TypeBoundsOwner},
-    AstNode, SyntaxElement,
-};
-use ra_text_edit::TextEditBuilder;
-use rustc_hash::FxHashMap;
-
-pub struct AstEditor<N: AstNode> {
-    original_ast: N,
-    ast: N,
-}
-
-impl<N: AstNode> AstEditor<N> {
-    pub fn new(node: N) -> AstEditor<N>
-    where
-        N: Clone,
-    {
-        AstEditor { original_ast: node.clone(), ast: node }
-    }
-
-    pub fn into_text_edit(self, builder: &mut TextEditBuilder) {
-        algo::diff(&self.original_ast.syntax(), self.ast().syntax()).into_text_edit(builder)
-    }
-
-    pub fn ast(&self) -> &N {
-        &self.ast
-    }
-
-    pub fn replace_descendants<T: AstNode>(
-        &mut self,
-        replacement_map: impl Iterator<Item = (T, T)>,
-    ) -> &mut Self {
-        let map = replacement_map
-            .map(|(from, to)| (from.syntax().clone().into(), to.syntax().clone().into()))
-            .collect::<FxHashMap<_, _>>();
-        let new_syntax = algo::replace_descendants(self.ast.syntax(), &map);
-        self.ast = N::cast(new_syntax).unwrap();
-        self
-    }
-
-    #[must_use]
-    fn replace_children(
-        &self,
-        to_delete: RangeInclusive<SyntaxElement>,
-        mut to_insert: impl Iterator<Item = SyntaxElement>,
-    ) -> N {
-        let new_syntax = algo::replace_children(self.ast().syntax(), to_delete, &mut to_insert);
-        N::cast(new_syntax).unwrap()
-    }
-}
diff --git a/crates/ra_assists/src/lib.rs b/crates/ra_assists/src/lib.rs
index 3ca3320f7aa..91b2a1dcefb 100644
--- a/crates/ra_assists/src/lib.rs
+++ b/crates/ra_assists/src/lib.rs
@@ -7,7 +7,6 @@
 
 mod assist_ctx;
 mod marks;
-pub mod ast_editor;
 
 use hir::db::HirDatabase;
 use itertools::Itertools;
diff --git a/crates/ra_syntax/src/ast/edit.rs b/crates/ra_syntax/src/ast/edit.rs
index 9d0fd13838c..d0857d88b28 100644
--- a/crates/ra_syntax/src/ast/edit.rs
+++ b/crates/ra_syntax/src/ast/edit.rs
@@ -4,6 +4,7 @@
 use std::{iter, ops::RangeInclusive};
 
 use arrayvec::ArrayVec;
+use rustc_hash::FxHashMap;
 
 use crate::{
     algo,
@@ -216,6 +217,17 @@ fn strip_attrs_and_docs_inner(mut node: SyntaxNode) -> SyntaxNode {
     node
 }
 
+pub fn replace_descendants<N: AstNode, D: AstNode>(
+    parent: &N,
+    replacement_map: impl Iterator<Item = (D, D)>,
+) -> N {
+    let map = replacement_map
+        .map(|(from, to)| (from.syntax().clone().into(), to.syntax().clone().into()))
+        .collect::<FxHashMap<_, _>>();
+    let new_syntax = algo::replace_descendants(parent.syntax(), &map);
+    N::cast(new_syntax).unwrap()
+}
+
 // Note this is copy-pasted from fmt. It seems like fmt should be a separate
 // crate, but basic tree building should be this crate. However, tree building
 // might want to call into fmt...