From 786fae6a7fca5529a926b0adffddcd9b4de73d13 Mon Sep 17 00:00:00 2001
From: Peter Burns <rictic@gmail.com>
Date: Mon, 26 Feb 2018 08:59:53 -0800
Subject: [PATCH] ExportNamedDeclaration#source can be null (#23909)

e.g. this named declaration has a source:
```javascript
export {foo} from './bar.js';
```

and this one does not:
```javascript
export const foo = 10;
```

Try it out at https://astexplorer.net/ to confirm.
---
 types/babel-types/index.d.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/types/babel-types/index.d.ts b/types/babel-types/index.d.ts
index cbed3e076c..b1de338923 100644
--- a/types/babel-types/index.d.ts
+++ b/types/babel-types/index.d.ts
@@ -422,7 +422,7 @@ export interface ExportNamedDeclaration extends Node {
     type: "ExportNamedDeclaration";
     declaration: Declaration;
     specifiers: ExportSpecifier[];
-    source: StringLiteral;
+    source: StringLiteral | null;
 }
 
 export interface ExportSpecifier extends Node {