[Bug c++/67499] c++ template/overload diagnostic compression

2021-08-23 Thread manu at gcc dot gnu.org via Gcc-bugs 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67499

--- Comment #11 from Manuel López-Ibáñez  ---
And Clang output:

:5:13: error: invalid operands to binary expression ('std::ostream'
(aka 'basic_ostream') and 'foo')
  std::cout << bar;
  ~ ^  ~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/system_error:279:5:
note: candidate function template not viable: no known conversion from 'foo' to
'const std::error_code' for 2nd argument
operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __e)
^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ostream:505:5:
note: candidate function template not viable: no known conversion from 'foo' to
'char' for 2nd argument
operator<<(basic_ostream<_CharT, _Traits>& __out, char __c)
^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ostream:511:5:
note: candidate function template not viable: no known conversion from 'foo' to
'char' for 2nd argument
operator<<(basic_ostream& __out, char __c)
^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ostream:517:5:
note: candidate function template not viable: no known conversion from 'foo' to
'signed char' for 2nd argument
operator<<(basic_ostream& __out, signed char __c)
^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ostream:522:5:
note: candidate function template not viable: no known conversion from 'foo' to
'unsigned char' for 2nd argument
operator<<(basic_ostream& __out, unsigned char __c)
^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ostream:600:5:
note: candidate function template not viable: no known conversion from 'foo' to
'const char *' for 2nd argument
operator<<(basic_ostream& __out, const char* __s)
^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ostream:613:5:
note: candidate function template not viable: no known conversion from 'foo' to
'const signed char *' for 2nd argument
operator<<(basic_ostream& __out, const signed char* __s)
^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ostream:618:5:
note: candidate function template not viable: no known conversion from 'foo' to
'const unsigned char *' for 2nd argument
operator<<(basic_ostream& __out, const unsigned char* __s)
^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ostream.tcc:302:5:
note: candidate function template not viable: no known conversion from 'foo' to
'const char *' for 2nd argument
operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s)
^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ostream:500:5:
note: candidate template ignored: deduced conflicting types for parameter
'_CharT' ('char' vs. 'foo')
operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c)
^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/basic_string.h:3591:5:
note: candidate template ignored: could not match
'basic_string'
against 'foo'
operator<<(basic_ostream<_CharT, _Traits>& __os,
^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ostream:583:5:
note: candidate template ignored: could not match 'const _CharT *' against
'foo'
operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s)
^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/type_traits:2230:46:
note: candidate template ignored: disabled by 'enable_if' [with _Ostream =
std::basic_ostream &, _Tp = foo]
using __enable_if_t = typename enable_if<_Cond, _Tp>::type;
 ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ostream:108:7:
note: candidate function not viable: no known conversion from 'foo' to
'std::basic_ostream::__ostream_type
&(*)(std::basic_ostream::__ostream_type &)' (aka 'basic_ostream> &(*)(basic_ostream> &)')
for 1st argument
  operator<<(__ostream_type& (*__pf)(__ostream_type&))
  ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ostream:117:7:
note: candidate function not viable: no known conversion from 'foo' to
'std::basic_ostream::__ios_type &(*)(std::basic_ostream::__ios_type
&)' (aka 'basic_ios> &(*)(basic_ios> &)') for 1st argument
  operator<<(__ios_type& (*__pf)(__ios_type&))
  ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ostream:127:7:
note: candidate function not viable:

[Bug c++/67499] c++ template/overload diagnostic compression

2021-08-23 Thread manu at gcc dot gnu.org via Gcc-bugs 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67499

--- Comment #10 from Manuel López-Ibáñez  ---
This is the current GCC output:

```
: In function 'int main()':
:5:13: error: no match for 'operator<<' (operand types are
'std::ostream' {aka 'std::basic_ostream'} and 'foo')
5 |   std::cout << bar;
  |   ~ ^~ ~~~
  ||   |
  ||   foo
  |std::ostream {aka std::basic_ostream}
In file included from
/opt/compiler-explorer/gcc-trunk-20210823/include/c++/12.0.0/iostream:39,
 from :1:
/opt/compiler-explorer/gcc-trunk-20210823/include/c++/12.0.0/ostream:108:7:
note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type&
std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ostream<_CharT,
_Traits>::__ostream_type& (*)(std::basic_ostream<_CharT,
_Traits>::__ostream_type&)) [with _CharT = char; _Traits =
std::char_traits; std::basic_ostream<_CharT, _Traits>::__ostream_type =
std::basic_ostream]'
  108 |   operator<<(__ostream_type& (*__pf)(__ostream_type&))
  |   ^~~~
/opt/compiler-explorer/gcc-trunk-20210823/include/c++/12.0.0/ostream:108:36:
note:   no known conversion for argument 1 from 'foo' to
'std::basic_ostream::__ostream_type&
(*)(std::basic_ostream::__ostream_type&)' {aka 'std::basic_ostream&
(*)(std::basic_ostream&)'}
  108 |   operator<<(__ostream_type& (*__pf)(__ostream_type&))
  |  ~~^~
/opt/compiler-explorer/gcc-trunk-20210823/include/c++/12.0.0/ostream:117:7:
note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type&
std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ostream<_CharT,
_Traits>::__ios_type& (*)(std::basic_ostream<_CharT, _Traits>::__ios_type&))
[with _CharT = char; _Traits = std::char_traits;
std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream;
std::basic_ostream<_CharT, _Traits>::__ios_type = std::basic_ios]'
  117 |   operator<<(__ios_type& (*__pf)(__ios_type&))
  |   ^~~~
/opt/compiler-explorer/gcc-trunk-20210823/include/c++/12.0.0/ostream:117:32:
note:   no known conversion for argument 1 from 'foo' to
'std::basic_ostream::__ios_type&
(*)(std::basic_ostream::__ios_type&)' {aka 'std::basic_ios&
(*)(std::basic_ios&)'}
  117 |   operator<<(__ios_type& (*__pf)(__ios_type&))
  |  ~~^~
/opt/compiler-explorer/gcc-trunk-20210823/include/c++/12.0.0/ostream:127:7:
note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type&
std::basic_ostream<_CharT, _Traits>::operator<<(std::ios_base&
(*)(std::ios_base&)) [with _CharT = char; _Traits = std::char_traits;
std::basic_ostream<_CharT, _Traits>::__ostream_type =
std::basic_ostream]'
  127 |   operator<<(ios_base& (*__pf) (ios_base&))
  |   ^~~~
/opt/compiler-explorer/gcc-trunk-20210823/include/c++/12.0.0/ostream:127:30:
note:   no known conversion for argument 1 from 'foo' to 'std::ios_base&
(*)(std::ios_base&)'
  127 |   operator<<(ios_base& (*__pf) (ios_base&))
  |  ^
/opt/compiler-explorer/gcc-trunk-20210823/include/c++/12.0.0/ostream:166:7:
note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type&
std::basic_ostream<_CharT, _Traits>::operator<<(long int) [with _CharT = char;
_Traits = std::char_traits; std::basic_ostream<_CharT,
_Traits>::__ostream_type = std::basic_ostream]'
  166 |   operator<<(long __n)
  |   ^~~~
/opt/compiler-explorer/gcc-trunk-20210823/include/c++/12.0.0/ostream:166:23:
note:   no known conversion for argument 1 from 'foo' to 'long int'
  166 |   operator<<(long __n)
  |  ~^~~
/opt/compiler-explorer/gcc-trunk-20210823/include/c++/12.0.0/ostream:170:7:
note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type&
std::basic_ostream<_CharT, _Traits>::operator<<(long unsigned int) [with _CharT
= char; _Traits = std::char_traits; std::basic_ostream<_CharT,
_Traits>::__ostream_type = std::basic_ostream]'
  170 |   operator<<(unsigned long __n)
  |   ^~~~
/opt/compiler-explorer/gcc-trunk-20210823/include/c++/12.0.0/ostream:170:32:
note:   no known conversion for argument 1 from 'foo' to 'long unsigned int'
  170 |   operator<<(unsigned long __n)
  |  ~~^~~
/opt/compiler-explorer/gcc-trunk-20210823/include/c++/12.0.0/ostream:174:7:
note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type&
std::basic_ostream<_CharT, _Traits>::operator<<(bool) [with _CharT = char;
_Traits = std::char_traits; std::basic_ostream<_CharT,
_Traits>::__ostream_type = std::basic_ostream]'
  174 |   operator<<(bool __n)
  |   ^~~~
/opt/compiler-explorer/gcc-trunk-20210823/include/c++/12.0.0/ostream:174:23:
note:   no known conversion for argument 1 from 'foo' to 'bool'
  174 |   operator<<(bool __n)
  |  ~^~~
In file included from

[Bug c++/67499] c++ template/overload diagnostic compression

2021-08-23 Thread pinskia at gcc dot gnu.org via Gcc-bugs 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67499

Andrew Pinski  changed:

   What|Removed |Added

   Last reconfirmed|2015-09-08 00:00:00 |2021-8-22

--- Comment #9 from Andrew Pinski  ---
Maybe when there are so many overloads don't display them? Though that feels
worse but at least we do have the first line:
: In function 'int main()':
:6:13: error: no match for 'operator<<' (operand types are
'std::ostream' {aka 'std::basic_ostream'} and 'foo')
6 |   std::cout << bar;
  |   ~ ^~ ~~~
  ||   |
  ||   foo
  |std::ostream {aka std::basic_ostream}


MSVC outputs 18 overloads.  ICC/EDG outputs no overloads.
GCC and clang outputs a lot (libc++ has less than libstdc++).

[Bug c++/67499] c++ template/overload diagnostic compression

2015-09-09 Thread manu at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67499

--- Comment #8 from Manuel López-Ibáñez  ---
> If we were outputting html, it would be much easier, we could print the
> error message and have javascript so that clicking in appropriate places
> displays the candidates, the reason for substitution failure, what a type is
> an alias for, etc. This is something IDEs could do. But with text, we have
> to print everything that might be useful.

GCC outputting html (or XML:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=19165#c10 and later comments)
seems much more unlikely than someone deciding to implement at least one of my
points above. Anyone that needs such HTML output will already use Clang, which
had HTML output 6 years ago) instead of spending a few years trying to
implement it in GCC.

[Bug c++/67499] c++ template/overload diagnostic compression

2015-09-09 Thread glisse at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67499

--- Comment #6 from Marc Glisse  ---
(In reply to Manuel López-Ibáñez from comment #5)

> /usr/include/c++/4.8/ostream:548:5: note: template
> std::basic_ostream& std::operator<<(std::basic_ostream _Traits>&, const unsigned char*)
>  operator<<(basic_ostream& __out, const unsigned char*
> __s)
>  ^
> /usr/include/c++/4.8/ostream:548:5: note:   template argument
> deduction/substitution failed: cannot convert type ‘foo’ to type ‘const
> unsigned char*’

I am against removing information, most of it is useful in some cases. You can
organize things better, have some overridable limits, etc, but in a number of
cases g++ is actually printing too little information, not too much. We need to
make the wall of text easier to understand / navigate, not remove information
from it. In the example above, you dropped the information that it is 'bar'
(the second argument) that cannot be converted, which, for a function with more
arguments and templates and typedefs all over the place, might not be obvious
at all.

If we were outputting html, it would be much easier, we could print the error
message and have javascript so that clicking in appropriate places displays the
candidates, the reason for substitution failure, what a type is an alias for,
etc. This is something IDEs could do. But with text, we have to print
everything that might be useful.

[Bug c++/67499] c++ template/overload diagnostic compression

2015-09-09 Thread manu at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67499

--- Comment #7 from Manuel López-Ibáñez  ---
(In reply to Marc Glisse from comment #6)
> In the example above, you dropped the
> information that it is 'bar' (the second argument) that cannot be converted,
> which, for a function with more arguments and templates and typedefs all
> over the place, might not be obvious at all.

This info is already implied by the error:

test.cc:5:15: error: no match for ‘operator<<’ (operand types are ‘std::ostream
{aka std::basic_ostream}’ and ‘foo’)
 std::cout << bar;
   ^

It is also inconsistently printed for some conversions:

/usr/include/c++/4.8/ostream:543:5: note: template
std::basic_ostream& std::operator<<(std::basic_ostream&, const signed char*)
 operator<<(basic_ostream& __out, const signed char* __s)
 ^
/usr/include/c++/4.8/ostream:543:5: note:   template argument
deduction/substitution failed:
test.cc:5:18: note:   cannot convert ‘bar’ (type ‘foo’) to type ‘const signed
char*’
 std::cout << bar;
  ^

but not for others:

/usr/include/c++/4.8/ostream:245:7: note: std::basic_ostream<_CharT,
_Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(const
void*) [with _CharT = char; _Trai
ts = std::char_traits; std::basic_ostream<_CharT,
_Traits>::__ostream_type = std::basic_ostream]
   operator<<(const void* __p)
   ^
/usr/include/c++/4.8/ostream:245:7: note:   no known conversion for argument 1
from ‘foo’ to ‘const void*’


Note that I'm ok with printing:

/usr/include/c++/4.8/ostream:543:5: note:   template argument
deduction/substitution failed: cannot convert ‘bar’ (type ‘foo’) to type ‘const
signed char*’

or even:

/usr/include/c++/4.8/ostream:543:5: note:   template argument
deduction/substitution failed: cannot convert ‘bar’ (type ‘foo’) to type ‘const
signed char*’ for argument 1

My point is to not print:

test.cc:5:18: note:  X
 std::cout << bar;
  ^

for the error AND for every candidate. 

For example, we could print:

test.cc:5:15: error: no match for ‘operator<<’ (operand types are ‘std::ostream
{aka std::basic_ostream}’ and ‘foo’)
 std::cout << bar;
   ^
test.cc:5:18: note: template argument deduction/substitution failed: cannot
convert ‘bar’ (type ‘foo’) 
 std::cout << bar;
  ^
/usr/include/c++/4.8/ostream:245:7: note: candidate 1:  no known conversion for
argument 1 from ‘foo’ to ‘const void*’ for 'std::basic_ostream<_CharT,
_Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(const
void*) [with _CharT = char; _Traits = std::char_traits;
std::basic_ostream<_CharT, _Traits>::__ostream_type =
std::basic_ostream]'
   operator<<(const void* __p)
   ^
/usr/include/c++/4.8/ostream:543:5: note: candidate 2: cannot convert type
‘foo’ to type ‘const signed char*’ for 'template
std::basic_ostream& std::operator<<(std::basic_ostream&, const signed char*)'
 operator<<(basic_ostream& __out, const signed char* __s)
 ^
[etc.]

> If we were outputting html, it would be much easier, we could print the
> error message and have javascript so that clicking in appropriate places
> displays the candidates, the reason for substitution failure, what a type is
> an alias for, etc. This is something IDEs could do. But with text, we have
> to print everything that might be useful.

We could still print it in a smarter, nicer looking and consistent way, without
repeating the same info several times (in the example above, there are only 108
unique lines out of 193).

[Bug c++/67499] c++ template/overload diagnostic compression

2015-09-08 Thread trippels at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67499

--- Comment #4 from Markus Trippelsdorf  ---
Well, clang isn't much better by default:

markus@x4 tmp % clang++ -stdlib=libc++ -c foo.cxx 2>&1 | wc -l
97
markus@x4 tmp % clang++ -c foo.cxx 2>&1 | wc -l
88

[Bug c++/67499] c++ template/overload diagnostic compression

2015-09-08 Thread trippels at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67499

Markus Trippelsdorf  changed:

   What|Removed |Added

 CC||trippels at gcc dot gnu.org

--- Comment #1 from Markus Trippelsdorf  ---
-Wfatal-errors is always an option.

[Bug c++/67499] c++ template/overload diagnostic compression

2015-09-08 Thread manu at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67499

Manuel López-Ibáñez  changed:

   What|Removed |Added

 CC||manu at gcc dot gnu.org

--- Comment #5 from Manuel López-Ibáñez  ---
There are several ways this output could be "easily" improved:

1) One problem with GCC's output is that it becomes difficult to track where
each candidate is listed in the wall of text. We could print something like
(also currently the candidates are not actually quoted, which is unusual when
printing source code):

note: candidate 1: %qD
...
note: candidate 2: %qD


2) Also, we print two times the same include stack for two different candidates
because we print a candidate from a different file in the middle. 

In file included from /usr/include/c++/4.8/ostream:612:0,
 from /usr/include/c++/4.8/iostream:39,
 from test.cc:1:
/usr/include/c++/4.8/bits/ostream.tcc:91:5: note: std::basic_ostream<_CharT,
_Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(short int) [with
_CharT = char; _Traits = std::char_traits]
 basic_ostream<_CharT, _Traits>::
 ^
/usr/include/c++/4.8/bits/ostream.tcc:91:5: note:   no known conversion for
argument 1 from ‘foo’ to ‘short int’
In file included from /usr/include/c++/4.8/iostream:39:0,
 from test.cc:1:
/usr/include/c++/4.8/ostream:181:7: note: std::basic_ostream<_CharT,
_Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(short
unsigned int) [with _CharT = char; _Traits = std::char_traits;
std::basic_ostream<_CharT, _Traits>::__ostr
eam_type = std::basic_ostream]
   operator<<(unsigned short __n)
   ^
/usr/include/c++/4.8/ostream:181:7: note:   no known conversion for argument 1
from ‘foo’ to ‘short unsigned int’
In file included from /usr/include/c++/4.8/ostream:612:0,
 from /usr/include/c++/4.8/iostream:39,
 from test.cc:1:
/usr/include/c++/4.8/bits/ostream.tcc:105:5: note: std::basic_ostream<_CharT,
_Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(int) [with _CharT =
char; _Traits = std::char_traits]
 basic_ostream<_CharT, _Traits>::
 ^

This is a lot of repetitive noise. The candidates could be sorted to reduce
this noise.


3) We print the reason in a different line than the candidate, with the caret
line in the middle. Thus, the caret line does not serve as a visual separation
between candidates.

/usr/include/c++/4.8/ostream:232:7: note: std::basic_ostream<_CharT,
_Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long
double) [with _CharT = char; _Traits = std::char_traits;
std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream]
   operator<<(long double __f)
   ^
/usr/include/c++/4.8/ostream:232:7: note:   no known conversion for argument 1
from ‘foo’ to ‘long double’
/usr/include/c++/4.8/ostream:245:7: note: std::basic_ostream<_CharT,
_Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(const
void*) [with _CharT = char; _Traits = std::char_traits;
std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream]
   operator<<(const void* __p)
   ^
/usr/include/c++/4.8/ostream:245:7: note:   no known conversion for argument 1
from ‘foo’ to ‘const void*’

Instead, we could print the reason after the candidate, perhaps even within the
same line. Maybe:

/usr/include/c++/4.8/ostream:232:7: note: candidate 5: no known conversion for
argument 1 from ‘foo’ to ‘long double’ for 'std::basic_ostream<_CharT,
_Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long
double) [with _CharT = char; _Traits = std::char_traits;
std::basic_ostream<_CharT, _Traits>::__ostream_type =
std::basic_ostream]'
   operator<<(long double __f)
   ^
/usr/include/c++/4.8/ostream:245:7: note: candidate 6: no known conversion for
argument 1 from ‘foo’ to ‘const void*’ for 'std::basic_ostream<_CharT,
_Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(const
void*) [with _CharT = char; _Traits = std::char_traits;
std::basic_ostream<_CharT, _Traits>::__ostream_type =
std::basic_ostream]'
   operator<<(const void* __p)
   ^

4) The candidate output is too verbose in some cases:

/usr/include/c++/4.8/ostream:548:5: note: template
std::basic_ostream& std::operator<<(std::basic_ostream&, const unsigned char*)
 operator<<(basic_ostream& __out, const unsigned char* __s)
 ^
/usr/include/c++/4.8/ostream:548:5: note:   template argument
deduction/substitution failed:
test.cc:5:18: note:   cannot convert ‘bar’ (type ‘foo’) to type ‘const unsigned
char*’
 std::cout << bar;
  ^

The above could simply say:

/usr/include/c++/4.8/ostream:548:5: note: template
std::basic_ostream& std::operator<<(std::basic_ostream

[Bug c++/67499] c++ template/overload diagnostic compression

2015-09-08 Thread redi at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67499

Jonathan Wakely  changed:

   What|Removed |Added

   Keywords||diagnostic
 Status|UNCONFIRMED |NEW
   Last reconfirmed||2015-09-08
 Ever confirmed|0   |1
   Severity|normal  |enhancement

--- Comment #2 from Jonathan Wakely  ---
For the specific case of ostreams and operator<< see also PR 58713

[Bug c++/67499] c++ template/overload diagnostic compression

2015-09-08 Thread dmalcolm at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67499

--- Comment #3 from David Malcolm  ---
(we were chatting on IRC, I suggested Frank file this)

It might be worth looking at Clang for inspiration; see e.g.:
  http://clang.llvm.org/diagnostics.html  ("Template Type Diffing")
though that's not quite the same thing.