diff --git a/src/array_view.hh b/src/array_view.hh
index 14f7e5b4..4e3d7775 100644
--- a/src/array_view.hh
+++ b/src/array_view.hh
@@ -15,49 +15,49 @@ class ArrayView
 public:
     using size_t = std::size_t;
 
-    ArrayView()
+    constexpr ArrayView()
         : m_pointer(nullptr), m_size(0) {}
 
-    ArrayView(const T& oneval)
+    constexpr ArrayView(const T& oneval)
         : m_pointer(&oneval), m_size(1) {}
 
-    ArrayView(const T* pointer, size_t size)
+    constexpr ArrayView(const T* pointer, size_t size)
         : m_pointer(pointer), m_size(size) {}
 
-    ArrayView(const T* begin, const T* end)
+    constexpr ArrayView(const T* begin, const T* end)
         : m_pointer(begin), m_size(end - begin) {}
 
     template<size_t N>
-    ArrayView(const T(&array)[N]) : m_pointer(array), m_size(N) {}
+    constexpr ArrayView(const T(&array)[N]) : m_pointer(array), m_size(N) {}
 
     template<typename Iterator>
-    ArrayView(const Iterator& begin, const Iterator& end)
+    constexpr ArrayView(const Iterator& begin, const Iterator& end)
         : m_pointer(&(*begin)), m_size(end - begin) {}
 
     template<typename Alloc>
-    ArrayView(const std::vector<T, Alloc>& v)
+    constexpr ArrayView(const std::vector<T, Alloc>& v)
         : m_pointer(&v[0]), m_size(v.size()) {}
 
-    ArrayView(const std::initializer_list<T>& v)
+    constexpr ArrayView(const std::initializer_list<T>& v)
         : m_pointer(v.begin()), m_size(v.size()) {}
 
-    const T* pointer() const { return m_pointer; }
-    size_t size() const { return m_size; }
-    const T& operator[](size_t n) const { return *(m_pointer + n); }
+    constexpr const T* pointer() const { return m_pointer; }
+    constexpr size_t size() const { return m_size; }
+    constexpr const T& operator[](size_t n) const { return *(m_pointer + n); }
 
-    const T* begin() const { return m_pointer; }
-    const T* end()   const { return m_pointer+m_size; }
+    constexpr const T* begin() const { return m_pointer; }
+    constexpr const T* end()   const { return m_pointer+m_size; }
 
     using reverse_iterator = std::reverse_iterator<const T*>;
-    reverse_iterator rbegin() const { return reverse_iterator(m_pointer+m_size); }
-    reverse_iterator rend()   const { return reverse_iterator(m_pointer); }
+    constexpr reverse_iterator rbegin() const { return reverse_iterator(m_pointer+m_size); }
+    constexpr reverse_iterator rend()   const { return reverse_iterator(m_pointer); }
 
-    const T& front() const { return *m_pointer; }
-    const T& back()  const { return *(m_pointer + m_size - 1); }
+    constexpr const T& front() const { return *m_pointer; }
+    constexpr const T& back()  const { return *(m_pointer + m_size - 1); }
 
-    bool empty() const { return m_size == 0; }
+    constexpr bool empty() const { return m_size == 0; }
 
-    ArrayView subrange(size_t first, size_t count) const
+    constexpr ArrayView subrange(size_t first, size_t count) const
     {
         return ArrayView(m_pointer + first, count);
     }