diff --git a/src/support/docstring.cpp b/src/support/docstring.cpp
index c232fec5fc..8ea76f95ec 100644
--- a/src/support/docstring.cpp
+++ b/src/support/docstring.cpp
@@ -109,10 +109,16 @@ docstring const from_local8bit(std::string const & s)
 }
 
 
-const char* to_local8bit_failure::what() const throw()
-{
-	return "A string could not be converted from unicode to the local 8 bit encoding.";
-}
+/// Exception thrown by to_local8bit if the string could not be converted
+class to_local8bit_failure : public std::bad_cast {
+public:
+	to_local8bit_failure() throw() : std::bad_cast() {}
+	virtual ~to_local8bit_failure() throw() {}
+	virtual const char* what() const throw()
+	{
+		return "A string could not be converted from unicode to the local 8 bit encoding.";
+	}
+};
 
 
 std::string const to_local8bit(docstring const & s)
diff --git a/src/support/docstring.h b/src/support/docstring.h
index 73ba552095..fc00e347c2 100644
--- a/src/support/docstring.h
+++ b/src/support/docstring.h
@@ -16,7 +16,6 @@
 #include "support/types.h"
 
 #include <string>
-//#include <typeinfo>
 
 namespace lyx {
 
@@ -41,14 +40,6 @@ std::string const to_utf8(docstring const &);
 /// convert \p s from the encoding of the locale to ucs4.
 docstring const from_local8bit(std::string const & s);
 
-/// Exception thrown by to_local8bit if the string could not be converted
-class to_local8bit_failure /*: public std::bad_cast*/ {
-public:
-	to_local8bit_failure() throw() /*: std::bad_cast()*/ {}
-	virtual ~to_local8bit_failure() throw() {}
-	virtual const char* what() const throw();
-};
-
 /**
  * Convert \p s from ucs4 to the encoding of the locale.
  * This may fail and throw an exception, the caller is expected to act