diff --git a/src/OpenFOAM/containers/NamedEnum/NamedEnum.C b/src/OpenFOAM/containers/NamedEnum/NamedEnum.C
index 05733eadf2..f96bea14fe 100644
--- a/src/OpenFOAM/containers/NamedEnum/NamedEnum.C
+++ b/src/OpenFOAM/containers/NamedEnum/NamedEnum.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2011-2017 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2018 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -120,4 +120,25 @@ Foam::wordList Foam::NamedEnum<Enum, nEnum>::words()
 }
 
 
+template<class Enum, unsigned int nEnum>
+const char* Foam::NamedEnum<Enum, nEnum>::operator[](const Enum e) const
+{
+    unsigned int ue = unsigned(e);
+
+    if (ue < nEnum)
+    {
+        return names[ue];
+    }
+    else
+    {
+        FatalErrorInFunction
+            << "names array index " << ue << " out of range 0-"
+            << nEnum - 1
+            << exit(FatalError);
+
+        return names[0];
+    }
+}
+
+
 // ************************************************************************* //
diff --git a/src/OpenFOAM/containers/NamedEnum/NamedEnum.H b/src/OpenFOAM/containers/NamedEnum/NamedEnum.H
index e5ed68ddbf..7d9fae597b 100644
--- a/src/OpenFOAM/containers/NamedEnum/NamedEnum.H
+++ b/src/OpenFOAM/containers/NamedEnum/NamedEnum.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2011-2017 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2018 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -38,7 +38,6 @@ SourceFiles
 #include "HashTable.H"
 #include "stringList.H"
 #include "wordList.H"
-#include <type_traits>
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
@@ -108,10 +107,7 @@ public:
         }
 
         //- Return the name of the given enumeration element
-        const char* operator[](const Enum e) const
-        {
-            return names[unsigned(e)];
-        }
+        const char* operator[](const Enum e) const;
 };