1 files changed, 13 insertions, 0 deletions

diff --git a/crates/ra_syntax/src/ast/make.rs b/crates/ra_syntax/src/ast/make.rs
index 192c610f1..42116afbb 100644
--- a/crates/ra_syntax/src/ast/make.rs
+++ b/crates/ra_syntax/src/ast/make.rs
@@ -64,6 +64,19 @@ pub fn use_item(use_tree: ast::UseTree) -> ast::UseItem {
     ast_from_text(&format!("use {};", use_tree))
 }
 
+pub fn type_alias_def(
+    name: ast::Name,
+    bounds: Option<ast::TypeBoundList>,
+    ty: Option<ast::TypeRef>,
+) -> ast::TypeAliasDef {
+    match (bounds, ty) {
+        (None, None) => ast_from_text(&format!("type {};", name)),
+        (None, Some(ty)) => ast_from_text(&format!("type {} = {};", name, ty)),
+        (Some(bounds), None) => ast_from_text(&format!("type {}: {};", name, bounds)),
+        (Some(bounds), Some(ty)) => ast_from_text(&format!("type {}: {} = {};", name, bounds, ty)),
+    }
+}
+
 pub fn record_field(name: ast::NameRef, expr: Option<ast::Expr>) -> ast::RecordField {
     return match expr {
         Some(expr) => from_text(&format!("{}: {}", name, expr)),