Rationale:

The proposed resolution is consistent with the way that destructors of other classes derived from exception are handled.

Proposed resolution:

Remove the declaration of ~failure().

With the change in [res.on.exception.handling] to state "An implementation may strengthen the exception-specification for a non-virtual function by removing listed exceptions." (issue 119) and the following declaration of ~failure() in ios_base::failure

    namespace std {
       class ios_base::failure : public exception {
       public:
           ...
           virtual ~failure();
           ...
       };
     }

the class failure cannot be implemented since in [type.info] the destructor of class exception has an empty exception specification:

    namespace std {
       class exception {
       public:
         ...
         virtual ~exception() throw();
         ...
       };
     }