diff --git a/packages/babel-parser/src/plugins/flow.js b/packages/babel-parser/src/plugins/flow.js
index b85563cd0e44..9a6aeb61aee3 100644
--- a/packages/babel-parser/src/plugins/flow.js
+++ b/packages/babel-parser/src/plugins/flow.js
@@ -1991,7 +1991,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       }
     }
 
-    isAssignable(node: Node, isBinding?: boolean): boolean {
+    isAssignable(node: N.Node, isBinding?: boolean): boolean {
       switch (node.type) {
         case "Identifier":
         case "ObjectPattern":