diff --git a/shape.h b/shape.h
index e8733f499e..d4bf26d9a5 100644
--- a/shape.h
+++ b/shape.h
@@ -150,7 +150,6 @@ RCLASS_SET_SHAPE_ID(VALUE obj, shape_id_t shape_id)
     set_shape_id_in_flags(obj, shape_id);
 }
 
-rb_shape_t *rb_shape_get_root_shape(void);
 int32_t rb_shape_id_offset(void);
 
 rb_shape_t *rb_shape_get_parent(rb_shape_t *shape);