1 files changed, 7 insertions, 3 deletions
diff --git a/src/mbgl/style/expression/is_constant.cpp b/src/mbgl/style/expression/is_constant.cpp
index 3b20f49a86..9704168a41 100644
--- a/src/mbgl/style/expression/is_constant.cpp
+++ b/src/mbgl/style/expression/is_constant.cpp
@@ -17,18 +17,22 @@ bool isFeatureConstant(const Expression& expression) {
             return false;
         } else if (name == "has" && parameterCount && *parameterCount == 1) {
             return false;
-        } else if (0 == name.rfind(filter, 0)) {
-            // Legacy filters begin with "filter-" and are never constant.
-            return false;
         } else if (
             name == "properties" ||
             name == "geometry-type" ||
             name == "id"
         ) {
             return false;
+        } else if (0u == name.rfind(filter, 0u)) {
+            // Legacy filters begin with "filter-" and are never constant.
+            return false;
         }
     }
 
+    if (expression.getKind() == Kind::FormatSectionOverride) {
+        return false;
+    }
+
     if (expression.getKind() == Kind::CollatorExpression) {
         // Although the results of a Collator expression with fixed arguments
         // generally shouldn't change between executions, we can't serialize them