diff --git a/src/hb-array.hh b/src/hb-array.hh
index aa9508fc5..5af474bce 100644
--- a/src/hb-array.hh
+++ b/src/hb-array.hh
@@ -56,19 +56,19 @@ struct hb_array_t : hb_iter_with_fallback_t<hb_array_t<Type>, Type&>
   hb_array_t& operator= (const hb_array_t&) = default;
   hb_array_t& operator= (hb_array_t&&) = default;
 
-  hb_array_t (std::nullptr_t) : hb_array_t () {}
-  hb_array_t (Type *array_, unsigned int length_) : arrayZ (array_), length (length_) {}
+  constexpr hb_array_t (std::nullptr_t) : hb_array_t () {}
+  constexpr hb_array_t (Type *array_, unsigned int length_) : arrayZ (array_), length (length_) {}
   template <unsigned int length_>
-  hb_array_t (Type (&array_)[length_]) : hb_array_t (array_, length_) {}
+  constexpr hb_array_t (Type (&array_)[length_]) : hb_array_t (array_, length_) {}
 
   template <typename U,
 	    hb_enable_if (hb_is_cr_convertible(U, Type))>
-  hb_array_t (const hb_array_t<U> &o) :
+  constexpr hb_array_t (const hb_array_t<U> &o) :
     hb_iter_with_fallback_t<hb_array_t, Type&> (),
     arrayZ (o.arrayZ), length (o.length), backwards_length (o.backwards_length) {}
   template <typename U,
 	    hb_enable_if (hb_is_cr_convertible(U, Type))>
-  hb_array_t& operator = (const hb_array_t<U> &o)
+  constexpr hb_array_t& operator = (const hb_array_t<U> &o)
   { arrayZ = o.arrayZ; length = o.length; backwards_length = o.backwards_length; return *this; }
 
   /*
@@ -314,19 +314,19 @@ struct hb_sorted_array_t :
   hb_sorted_array_t& operator= (const hb_sorted_array_t&) = default;
   hb_sorted_array_t& operator= (hb_sorted_array_t&&) = default;
 
-  hb_sorted_array_t (std::nullptr_t) : hb_sorted_array_t () {}
-  hb_sorted_array_t (Type *array_, unsigned int length_) : hb_array_t<Type> (array_, length_) {}
+  constexpr hb_sorted_array_t (std::nullptr_t) : hb_sorted_array_t () {}
+  constexpr hb_sorted_array_t (Type *array_, unsigned int length_) : hb_array_t<Type> (array_, length_) {}
   template <unsigned int length_>
-  hb_sorted_array_t (Type (&array_)[length_]) : hb_array_t<Type> (array_) {}
+  constexpr hb_sorted_array_t (Type (&array_)[length_]) : hb_array_t<Type> (array_) {}
 
   template <typename U,
 	    hb_enable_if (hb_is_cr_convertible(U, Type))>
-  hb_sorted_array_t (const hb_array_t<U> &o) :
+  constexpr hb_sorted_array_t (const hb_array_t<U> &o) :
     hb_iter_t<hb_sorted_array_t, Type&> (),
     hb_array_t<Type> (o) {}
   template <typename U,
 	    hb_enable_if (hb_is_cr_convertible(U, Type))>
-  hb_sorted_array_t& operator = (const hb_array_t<U> &o)
+  constexpr hb_sorted_array_t& operator = (const hb_array_t<U> &o)
   { hb_array_t<Type> (*this) = o; return *this; }
 
   /* Iterator implementation. */