fix headers

Author: SteveBronder

stan/math/prim/fun/square.hpp

@@ -1,9 +1,8 @@
 #ifndef STAN_MATH_PRIM_FUN_SQUARE_HPP
 #define STAN_MATH_PRIM_FUN_SQUARE_HPP
 
-#include <stan/math/prim/meta.hpp>
 #include <stan/math/prim/fun/Eigen.hpp>
-#include <stan/math/prim/fun/square.hpp>
+#include <stan/math/prim/meta.hpp>
 #include <stan/math/prim/functor/apply_scalar_unary.hpp>
 #include <stan/math/prim/functor/apply_vector_unary.hpp>
 #include <cmath>
@@ -49,7 +48,7 @@ struct square_fun {
  */
 template <
     typename Container,
-    require_not_container_st<std::is_arithmetic, Container>* = nullptr,
+    require_not_stan_scalar_t<Container>* = nullptr,
     require_not_var_matrix_t<Container>* = nullptr,
     require_not_nonscalar_prim_or_rev_kernel_expression_t<Container>* = nullptr>
 inline auto square(const Container& x) {

stan/math/rev/fun/divide.hpp

@@ -4,7 +4,6 @@
 #include <stan/math/prim/meta.hpp>
 #include <stan/math/rev/meta.hpp>
 #include <stan/math/rev/core.hpp>
-#include <stan/math/rev/core/typedefs.hpp>
 #include <stan/math/rev/fun/to_arena.hpp>
 #include <stan/math/rev/fun/value_of.hpp>
 

stan/math/rev/fun/square.hpp

@@ -32,7 +32,7 @@ namespace math {
  * @param x Variable to square.
  * @return Square of variable.
  */
-inline var square(const var& x) {
+inline var square(var x) {
   return make_callback_var(square(x.val()), [x](auto& vi) mutable {
     x.adj() += vi.adj() * 2.0 * x.val();
   });

stan/math/rev/fun/to_arena.hpp

@@ -3,7 +3,7 @@
 
 #include <stan/math/prim/fun/Eigen.hpp>
 #include <stan/math/rev/meta.hpp>
-#include <stan/math/rev/core/arena_matrix.hpp>
+#include <stan/math/rev/core.hpp>
 #include <vector>
 #include <cstring>
 

stan/math/rev/functor/apply_scalar_unary.hpp

@@ -2,7 +2,7 @@
 #define STAN_MATH_REV_FUNCTOR_APPLY_SCALAR_UNARY_HPP
 
 #include <stan/math/prim/functor/apply_scalar_unary.hpp>
-#include <stan/math/rev/core/var.hpp>
+#include <stan/math/rev/core.hpp>
 
 namespace stan {
 namespace math {

stan/math/rev/functor/gradient.hpp

@@ -1,9 +1,10 @@
 #ifndef STAN_MATH_REV_FUNCTOR_GRADIENT_HPP
 #define STAN_MATH_REV_FUNCTOR_GRADIENT_HPP
 
+#include <stan/math/prim/fun/Eigen.hpp>
 #include <stan/math/rev/meta.hpp>
 #include <stan/math/rev/core.hpp>
-#include <stan/math/prim/fun/Eigen.hpp>
+#include <stan/math/rev/fun.hpp>
 #include <stdexcept>
 
 namespace stan {