2009/4/14 Arthur Schwarz:
> --- On Mon, 4/13/09, Joe Buck wrote:
>
> them all.
>>
>> Consider
>>
>> #include <iostream>
>> struct Foo { int bar;};
>> int main() {
>> std::cerr << Foo();
>> }
>>
>> Try it, the result is ugly, and I often encounter this one
>
> (Personal opinion - not to be construed as wisdom).
> The issue with the result is:
> 1: There is no end-of-line between candidates (or anywhere).
Do you mean there is no blank line, or no newline characters at all?
I certainly get a newline after each candidate. Something's wrong if
you don't.
> 2: The candidate template is a large, untamed, and unruly beast.
The bigger problem is there isn't a single candidate, but several. As
suggested elsewhere, stlfilt helps make them more readable.
> 3: The diagnostic message is not clear. I think it should say
> that the compiler can't find something because of something.
The 'because of something' is far from simple. How can the compiler
tell you why there's no match for calling the operator with those
argument types?
It could be because of a typo, and one of the following was meant
instead of Foo():
typedef int Food;
int foo();
Or it could be that a header wasn't included, so the relevant operator
hasn't been declared. Or it could be that there's an operator in
scope for wide-character streams and the user meant to write to
std::wcout. I don't see how the compiler can determine which of those,
or other reasons, to point out. Giving the wrong suggestion could
make things even worse, by misleading you and distracting you from the
real cause.
> 4: Providing a full template for each candidate is (indeed)
> something of an overkill.
Other than doing what stlfilt does, how could you show less than the
full templates? The return type could be suppressed without loss of
information, but Joe's suggestion of not showing all the matches
strikes me as more useful than showing less of each match.
Jonathan
