diff --git a/src/fstring.cpp b/src/fstring.cpp
index 6fefd216..bfff3f9d 100644
--- a/src/fstring.cpp
+++ b/src/fstring.cpp
@@ -443,24 +443,6 @@ const FString& FString::operator >> (float& num)
   return *this;
 }
 
-//----------------------------------------------------------------------
-wchar_t& FString::operator [] (std::size_t pos)
-{
-  if ( pos >= length )
-    throw std::out_of_range("");  // Invalid index position
-
-  return string[pos];
-}
-
-//----------------------------------------------------------------------
-const wchar_t& FString::operator [] (std::size_t pos) const
-{
-  if ( pos >= length )
-    throw std::out_of_range("");  // Invalid index position
-
-  return string[pos];
-}
-
 //----------------------------------------------------------------------
 const FString& FString::operator () ()
 {
diff --git a/src/include/final/fstring.h b/src/include/final/fstring.h
index 10738cea..73ac4866 100644
--- a/src/include/final/fstring.h
+++ b/src/include/final/fstring.h
@@ -137,8 +137,6 @@ class FString
     wchar_t&       operator [] (IndexT);
     template <typename IndexT>
     const wchar_t& operator [] (IndexT) const;
-    wchar_t&       operator [] (std::size_t);
-    const wchar_t& operator [] (std::size_t) const;
     const FString& operator () ();
 
     bool operator <  (const FString&) const;
@@ -292,12 +290,22 @@ inline const char* FString::getClassName()
 //----------------------------------------------------------------------
 template <typename IndexT>
 inline wchar_t& FString::operator [] (IndexT pos)
-{ return string[std::size_t(pos)]; }
+{
+  if ( pos < 0 || pos >= IndexT(length) )
+    throw std::out_of_range("");  // Invalid index position
+
+  return string[std::size_t(pos)];
+}
 
 //----------------------------------------------------------------------
 template <typename IndexT>
 inline const wchar_t& FString::operator [] (IndexT pos) const
-{ return string[std::size_t(pos)]; }
+{
+  if ( pos < 0 || pos >= IndexT(length) )
+    throw std::out_of_range("");  // Invalid index position
+
+  return string[std::size_t(pos)];
+}
 
 //----------------------------------------------------------------------
 template <class CharT>