diff --git a/src/hb-array.hh b/src/hb-array.hh
index 5af474bce..0beffb078 100644
--- a/src/hb-array.hh
+++ b/src/hb-array.hh
@@ -68,7 +68,7 @@ struct hb_array_t : hb_iter_with_fallback_t<hb_array_t<Type>, Type&>
     arrayZ (o.arrayZ), length (o.length), backwards_length (o.backwards_length) {}
   template <typename U,
 	    hb_enable_if (hb_is_cr_convertible(U, Type))>
-  constexpr hb_array_t& operator = (const hb_array_t<U> &o)
+  hb_array_t& operator = (const hb_array_t<U> &o)
   { arrayZ = o.arrayZ; length = o.length; backwards_length = o.backwards_length; return *this; }
 
   /*
@@ -326,7 +326,7 @@ struct hb_sorted_array_t :
     hb_array_t<Type> (o) {}
   template <typename U,
 	    hb_enable_if (hb_is_cr_convertible(U, Type))>
-  constexpr hb_sorted_array_t& operator = (const hb_array_t<U> &o)
+  hb_sorted_array_t& operator = (const hb_array_t<U> &o)
   { hb_array_t<Type> (*this) = o; return *this; }
 
   /* Iterator implementation. */