Add forward declaration to stan_print.hpp

Fixes printing arrays-of-tuples
stan-dev · Jul 25, 2023 · d29f5f9 · d29f5f9
1 parent 2e87eca
commit d29f5f9
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/stan/math/prim/fun/stan_print.hpp b/stan/math/prim/fun/stan_print.hpp
@@ -52,6 +52,10 @@ void stan_print(std::ostream* o, const EigMat& x) {
   *o << ']';
 }
 
+// forward decl to allow the next two overloads to call each other
+template <typename T, require_tuple_t<T>* = nullptr>
+void stan_print(std::ostream* o, const T& x);
+
 template <typename T, require_std_vector_t<T>* = nullptr>
 void stan_print(std::ostream* o, const T& x) {
   *o << '[';