diff --git a/gdb/common/array-view.h b/gdb/common/array-view.h
--- a/gdb/common/array-view.h
+++ b/gdb/common/array-view.h
@@ -85,7 +85,7 @@ public:
   using value_type = T;
   using reference = T &;
   using const_reference = const T &;
-  using size_type = size_t;
+  using size_type = ULONGEST;
 
   /* Default construction creates an empty view.  */
   constexpr array_view () noexcept
@@ -114,7 +114,7 @@ public:
      count.  */
   template<typename U,
 	   typename = Requires<DecayedConvertible<U>>>
-  constexpr array_view (U *array, size_t size) noexcept
+  constexpr array_view (U *array, ULONGEST size) noexcept
     : m_array (array), m_size (size)
   {}
 
@@ -128,7 +128,7 @@ public:
   {}
 
   /* Create an array view from an array.  */
-  template<typename U, size_t Size,
+  template<typename U, ULONGEST Size,
 	   typename = Requires<DecayedConvertible<U>>>
   constexpr array_view (U (&array)[Size]) noexcept
     : m_array (array), m_size (Size)
@@ -161,9 +161,9 @@ public:
   /*constexpr14*/ T *end () noexcept { return m_array + m_size; }
   constexpr const T *end () const noexcept { return m_array + m_size; }
 
-  /*constexpr14*/ reference operator[] (size_t index) noexcept
+  /*constexpr14*/ reference operator[] (ULONGEST index) noexcept
   { return m_array[index]; }
-  constexpr const_reference operator[] (size_t index) const noexcept
+  constexpr const_reference operator[] (ULONGEST index) const noexcept
   { return m_array[index]; }
 
   constexpr size_type size () const noexcept { return m_size; }
@@ -196,7 +196,7 @@ operator== (const gdb::array_view<T> &lhs, const gdb::array_view<T> &rhs)
   if (lhs.size () != rhs.size ())
     return false;
 
-  for (size_t i = 0; i < lhs.size (); i++)
+  for (ULONGEST i = 0; i < lhs.size (); i++)
     if (!(lhs[i] == rhs[i]))
       return false;