update header include order for broadcast_array

SteveBronder · SteveBronder · commit f08f9667ac40 · 2026-04-23T13:42:52.000-04:00
diff --git a/stan/math/prim/functor/partials_propagator.hpp b/stan/math/prim/functor/partials_propagator.hpp
@@ -4,6 +4,7 @@
 #include <stan/math/prim/fun/Eigen.hpp>
 #include <stan/math/prim/meta/require_generics.hpp>
 #include <stan/math/prim/meta/return_type.hpp>
+#include <stan/math/prim/meta/plain_type.hpp>
 #include <stan/math/prim/functor/operands_and_partials.hpp>
 #include <vector>
 #include <type_traits>
