diff --git a/src/renderer/painter.cpp b/src/renderer/painter.cpp
index bdc883b5b..6abd51390 100644
--- a/src/renderer/painter.cpp
+++ b/src/renderer/painter.cpp
@@ -304,7 +304,7 @@ void Painter::renderLayer(util::ptr<StyleLayer> layer_desc, const Tile::ID* id,
             return;
         }
 
-        StyleSource &style_source = *layer_desc->bucket->style_source;
+        StyleSource const& style_source = *layer_desc->bucket->style_source;
 
         // Skip this layer if there is no data.
         if (!style_source.source) {