Re: error message formatting

[Alexandre Oliva <oliva@dcc.unicamp.br>]

Mark Mitchell writes:

> We have to be careful that we don't introduce ambiguity in the
> process.  It may be possible to do so by dropping defaulted arguments,

>   template <class T, class U = T**>
>   void f();

>   template <class T*, class U = T*>
>   void f();

`classs T*' is not a valid template argument declaration.

However, the raised issue is a valid one.  Suppose one declares:

template <typename T, int i = 1> void f();
template <typename T, char e = '\0'> void f();

Then he calls f<int>().  The compiler must report an ambiguity but, if 
we remove trailing default arguments, the error message would look
like:

?:?:Template function call is ambiguous.  Available specializations are:
?:?:	f<int>()
?:?:	f<int>()

This would seem rather confusing, although line numbers might help.

-- 
Alexandre Oliva
mailto:oliva@dcc.unicamp.br mailto:aoliva@acm.org
http://www.dcc.unicamp.br/~oliva
Universidade Estadual de Campinas, SP, Brasil