Re: c++/10864: [diagnostic] Unreadable error message for "no match for 'A < B' operator" if A,B are templates

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=10864

For reference:

GCC with StlFilt:
pr10864.cpp: In member function
   `bool less<X<vector<string>, vector<string> > >::foo()':
pr10864.cpp:10:   instantiated from here
pr10864.cpp:5: error: no match for
   `X<vector<string>, vector<string> > < X<vector<string>, vector<string> >'
    operator


Comeau:
"pr10864.cpp", line 5: error: no operator "<" matches these operands
            operand types are: X<std::vector<std::string,
                      std::allocator<std::string>>, std::vector<std::string,
                      std::allocator<std::string>>> <
                      X<std::vector<std::string,
std::allocator<std::string>>,
                      std::vector<std::string, std::allocator<std::string>>>
        bool foo () { return T() < T(); }
                                 ^

          detected during instantiation of "bool less<T>::foo() [with
                    T=X<std::vector<std::string,
std::allocator<std::string>>,
                    std::vector<std::string, std::allocator<std::string>>>]"
                    at line 10


Comeau with StlFilt (yes, it screws indentation a little):
pr10864.cpp(5): error: no operator "<" matches these operands
    operand types are: X<vector<string>, vector<string>> < X<vector<string>,
  vector<string>>
        bool foo () { return T() < T(); }
                                 ^
          detected during instantiation of "bool less<X<vector<string>,
   vector<string>>>::foo()" at line 10


Giovanni Bajo