diff --git a/src/interval/interval.h b/src/interval/interval.h
index 5729bb5a2..b2f4bf7d3 100644
--- a/src/interval/interval.h
+++ b/src/interval/interval.h
@@ -44,9 +44,10 @@ public:
     // [n,n]
     template<typename T2> interval(T2 const & n):m_lower(n), m_upper(n) { set_closed_endpoints();}
     // copy constructor
-    interval(interval const & n);
+    interval(interval<T> const & n);
     // move constructor
-    interval(interval && src);
+    interval(interval<T> && src);
+
     // [l,u], (l,u], [l,u), (l,u)
     template<typename T2> interval(T2 const & l, T2 const & u, bool l_open = false, bool u_open = false):m_lower(l), m_upper(u) {
         m_lower_open = l_open; m_upper_open = u_open; m_lower_inf  = false; m_upper_inf  = false;
diff --git a/src/interval/interval_def.h b/src/interval/interval_def.h
index e9cbcc04c..881b267a3 100644
--- a/src/interval/interval_def.h
+++ b/src/interval/interval_def.h
@@ -53,7 +53,7 @@ interval<T>::interval():
 }
 
 template<typename T>
-interval<T>::interval(interval const & n):
+interval<T>::interval(interval<T> const & n):
     m_lower(n.m_lower),
     m_upper(n.m_upper),
     m_lower_open(n.m_lower_open),
@@ -64,7 +64,7 @@ interval<T>::interval(interval const & n):
 }
 
 template<typename T>
-interval<T>::interval(interval && n):
+interval<T>::interval(interval<T> && n):
     m_lower(std::move(n.m_lower)),
     m_upper(std::move(n.m_upper)),
     m_lower_open(n.m_lower_open),