diff --git a/pkg/sass-parser/lib/src/statement/return-rule.ts b/pkg/sass-parser/lib/src/statement/return-rule.ts
index 56608da5d..cc5c5aaec 100644
--- a/pkg/sass-parser/lib/src/statement/return-rule.ts
+++ b/pkg/sass-parser/lib/src/statement/return-rule.ts
@@ -78,7 +78,7 @@ export class ReturnRule
     if (returnExpression) returnExpression.parent = this;
     this._returnExpression = returnExpression;
   }
-  private _returnExpression?: Expression;
+  declare _returnExpression?: Expression;
 
   constructor(defaults: ReturnRuleProps);
   /** @hidden */