From b22ae519550df63ca683bc7e27ff9f4f0be1c382 Mon Sep 17 00:00:00 2001
From: Jennifer Thakar <jathak@google.com>
Date: Fri, 15 Feb 2019 21:53:17 +0000
Subject: [PATCH] Fix bug in RecursiveStatementVisitor (#596)

The value of an `AtRule` can be null, so it should not be visited in that case.

Ran across this issue when I attempted to run the module migrator on a stylesheet containing `@font-face` (which has children, but no value).
---
 lib/src/visitor/recursive_statement.dart | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/src/visitor/recursive_statement.dart b/lib/src/visitor/recursive_statement.dart
index 183a1b9d..b6fbba8b 100644
--- a/lib/src/visitor/recursive_statement.dart
+++ b/lib/src/visitor/recursive_statement.dart
@@ -29,7 +29,7 @@ abstract class RecursiveStatementVisitor<T> implements StatementVisitor<T> {
 
   T visitAtRule(AtRule node) {
     visitInterpolation(node.name);
-    visitInterpolation(node.value);
+    if (node.value != null) visitInterpolation(node.value);
     return node.children == null ? null : visitChildren(node);
   }