From 650a23163b0c9d5feedf5e6a321a0cd664494402 Mon Sep 17 00:00:00 2001
From: jmkiley <jordan.kiley@mapbox.com>
Date: Thu, 19 Sep 2019 15:16:19 -0700
Subject: [PATCH] [ios] Add type check

---
 platform/darwin/src/NSExpression+MGLAdditions.mm | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/platform/darwin/src/NSExpression+MGLAdditions.mm b/platform/darwin/src/NSExpression+MGLAdditions.mm
index ee598bfdd5d..1918dbaa3e4 100644
--- a/platform/darwin/src/NSExpression+MGLAdditions.mm
+++ b/platform/darwin/src/NSExpression+MGLAdditions.mm
@@ -1056,8 +1056,8 @@ - (id)mgl_jsonExpressionObject {
         case NSFunctionExpressionType: {
             NSString *function = self.function;
 
-            BOOL hasCollectionProperty = !(self.arguments.firstObject.expressionType == NSConstantValueExpressionType || self.arguments.firstObject.expressionType == NSKeyPathExpressionType
-            || self.arguments.firstObject.expressionType == NSVariableExpressionType ||  !self.arguments.firstObject.expressionType
+            BOOL hasCollectionProperty = !( ! [self.arguments.firstObject isKindOfClass: [self class]] || self.arguments.firstObject.expressionType == NSConstantValueExpressionType || self.arguments.firstObject.expressionType == NSKeyPathExpressionType
+            || self.arguments.firstObject.expressionType == NSVariableExpressionType
                 );
             NSString *op = MGLExpressionOperatorsByFunctionNames[function];
             if (op) {