diff --git a/range.cpp b/range.cpp
index 29463d5d..55b8d763 100644
--- a/range.cpp
+++ b/range.cpp
@@ -80,8 +80,10 @@ range<T>::clamp (T val) const
 template <typename T>
 void
 range<T>::expand (T val) {
-    min = std::min (min, val);
-    max = std::max (max, val);
+    // The arguments to min and max are such that expansion from initial NaN
+    // values should change both min and max to be that value.
+    min = std::min (val, min);
+    max = std::max (val, max);
 }
 
 
diff --git a/test/range.cpp b/test/range.cpp
index bfa764f3..78d98213 100644
--- a/test/range.cpp
+++ b/test/range.cpp
@@ -27,6 +27,15 @@ main (int, char **) {
 
     CHECK_HARD ( range<uint16_t>::UNLIMITED.contains (numeric_limits<uint16_t>::min()));
     CHECK_HARD ( range<uint16_t>::UNLIMITED.contains (numeric_limits<uint16_t>::max()));
+
+    {
+        range<double> initial_nan (numeric_limits<double>::quiet_NaN (),
+                                   numeric_limits<double>::quiet_NaN ());
+        initial_nan.expand (1.0);
+        CHECK_EQ (initial_nan.min, 1.0);
+        CHECK_EQ (initial_nan.max, 1.0);
+    }
+
     return EXIT_SUCCESS;
 }