diff --git a/Lake/DSL/DeclUtil.lean b/Lake/DSL/DeclUtil.lean
index adee1a5ae8..8f00843de0 100644
--- a/Lake/DSL/DeclUtil.lean
+++ b/Lake/DSL/DeclUtil.lean
@@ -52,6 +52,7 @@ syntax simpleBinder :=
   ident <|> bracketedSimpleBinder
 
 abbrev SimpleBinder := TSyntax ``simpleBinder
+open Lean.Parser.Term in
 def expandOptSimpleBinder (stx? : Option SimpleBinder) : MacroM FunBinder := do
   match stx? with
   | some stx =>