[core] Immutable Impls

1 files changed, 5 insertions, 1 deletions

diff --git a/src/mbgl/annotation/render_annotation_source.cpp b/src/mbgl/annotation/render_annotation_source.cpp
index a62d2d51d3..718f7a16e6 100644
--- a/src/mbgl/annotation/render_annotation_source.cpp
+++ b/src/mbgl/annotation/render_annotation_source.cpp
@@ -9,11 +9,15 @@ namespace mbgl {
 
 using namespace style;
 
-RenderAnnotationSource::RenderAnnotationSource(const AnnotationSource::Impl& impl_)
+RenderAnnotationSource::RenderAnnotationSource(Immutable<AnnotationSource::Impl> impl_)
     : RenderSource(impl_) {
     tilePyramid.setObserver(this);
 }
 
+const AnnotationSource::Impl& RenderAnnotationSource::impl() const {
+    return static_cast<const AnnotationSource::Impl&>(*baseImpl);
+}
+
 bool RenderAnnotationSource::isLoaded() const {
     return tilePyramid.isLoaded();
 }