From 26d85614e922853cec8d70147aa10198355fd482 Mon Sep 17 00:00:00 2001
From: Alasdair McLeay <alasdair.mcleay@me.com>
Date: Thu, 22 Mar 2018 08:43:53 +0000
Subject: [PATCH] Possible fix for #374

---
 src/index.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/index.js b/src/index.js
index 87ff46e..2f6562f 100644
--- a/src/index.js
+++ b/src/index.js
@@ -358,7 +358,7 @@ function build(dest, { selector = '', mq = '', supp = '', src = {} }) {
   src = flatten(src)
 
   src.forEach(_src => {
-    if(isLikeRule(_src)) {
+    if(isLikeRule(_src) && idFor(_src) !== 'nil') {
       let reg = _getRegistered(_src)
       if(reg.type !== 'css') { throw new Error('cannot merge this rule') }
       _src = reg.style