[Bug c++/85110] Missing underlines for some bad arguments

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85110

--- Comment #7 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Author: dmalcolm
Date: Wed Aug 29 13:52:22 2018
New Revision: 263957

URL: https://gcc.gnu.org/viewcvs?rev=263957&root=gcc&view=rev
Log:
C++: underline param in print_conversion_rejection (more PR c++/85110)

Consider this bogus code (from g++.dg/diagnostic/param-type-mismatch-2.C):

struct s4 { static int member_1 (int one, const char **two, float three); };

int test_4 (int first, const char *second, float third)
{
  return s4::member_1 (first, second, third);
}

Before this patch, g++ emits:

demo.cc: In function 'int test_4(int, const char*, float)':
demo.cc:5:44: error: no matching function for call to 's4::member_1(int&, const
char*&, float&)'
5 |   return s4::member_1 (first, second, third);
  |                                            ^
demo.cc:1:24: note: candidate: 'static int s4::member_1(int, const char**,
float)'
1 | struct s4 { static int member_1 (int one, const char **two, float three);
};
  |                        ^~~~~~~~
demo.cc:1:24: note:   no known conversion for argument 2 from 'const char*' to
'const char**'

With this patch, it highlights the pertinent parameter in the
"no known conversion" note:

demo.cc: In function 'int test_4(int, const char*, float)':
demo.cc:5:44: error: no matching function for call to 's4::member_1(int&, const
char*&, float&)'
5 |   return s4::member_1 (first, second, third);
  |                                            ^
demo.cc:1:24: note: candidate: 'static int s4::member_1(int, const char**,
float)'
1 | struct s4 { static int member_1 (int one, const char **two, float three);
};
  |                        ^~~~~~~~
demo.cc:1:56: note:   no known conversion for argument 2 from 'const char*' to
'const char**'
1 | struct s4 { static int member_1 (int one, const char **two, float three);
};
  |                                           ~~~~~~~~~~~~~^~~

gcc/cp/ChangeLog:
        PR c++/85110
        * call.c (print_conversion_rejection): Add "fn" param and use it
        for "no known conversion" messages to underline the pertinent
        param.
        (print_z_candidate): Supply "fn" to the new param above.

gcc/testsuite/ChangeLog:
        PR c++/85110
        * g++.dg/diagnostic/param-type-mismatch-2.C: Update expected
        output to reflect underlining of pertinent parameter in decl
        for "no known conversion" messages.


Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/call.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/g++.dg/diagnostic/param-type-mismatch-2.C