[Bug c++/96045] New: Wrong line and column diagnostic message in a class template instantiation

[Bug c++/96045] New: Wrong line and column diagnostic message in a class template instantiation

[haoxintu at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96045

            Bug ID: 96045
           Summary: Wrong line and column diagnostic message in a class
                    template instantiation
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Keywords: diagnostic
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: haoxintu at gmail dot com
  Target Milestone: ---

This simple code, bug.cc, GCC-trunk can not emit the right diagnostic
information.

$cat bug.cc
template <class> class A {};
struct A <int> 

$g++ -c bug.cc
bug.cc:3: error: expected unqualified-id at end of input

Noted that the number 3 is not a line number nor a column number.

While in Clang
$clang++ -c bug.cc
bug.cc:2:16: error: expected unqualified-id
struct A <int> 
               ^
1 error generated.

$g++ --version
g++ (GCC) 11.0.0 20200630 (experimental)
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[Bug c++/96045] [11 Regression] Wrong line and column diagnostic message in a class template instantiation

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96045

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |11.0
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2020-07-08
            Summary|Wrong line and column       |[11 Regression] Wrong line
                   |diagnostic message in a     |and column diagnostic
                   |class template              |message in a class template
                   |instantiation               |instantiation
             Status|UNCONFIRMED                 |NEW
                 CC|                            |mpolacek at gcc dot gnu.org

--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Confirmed.  Interestingly, GCC 10 was much better:

$ xg++-10 -c 96045.C
96045.C:2:8: error: expected unqualified-id at end of input
    2 | struct A <int>
      |        ^~~~~~~

[Bug c++/96045] [11 Regression] Wrong line and column diagnostic message in a class template instantiation

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96045

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Regressed with r11-338-g2a0225e47868fbfceaecaa5e2de96c1c5a2251ea

[Bug c++/96045] [11 Regression] Wrong line and column diagnostic message in a class template instantiation

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96045

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1

[Bug c++/96045] [11 Regression] Wrong line and column diagnostic message in a class template instantiation

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96045

--- Comment #3 from Jason Merrill <jason at gcc dot gnu.org> ---
Nathan, this PR points out that your change to EOF location means that we no
longer show the last line of source to give context for the error.  Why not
give the EOF token a location of the end of the last line?

[Bug c++/96045] [11 Regression] Wrong line and column diagnostic message in a class template instantiation

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96045

Nathan Sidwell <nathan at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |nathan at gcc dot gnu.org
             Status|NEW                         |ASSIGNED

--- Comment #4 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
There's two conflicting arguments.
a) the end of the file is just after the last \n  (the preprocessor makes sure
the file ends in \n).  That's the first column of a line that doesn't exist.

b) the EOF is just before the last \n (at the \n itself if you like).

IIRC cpplib was taking both positions, and leading to inconsistencies.  My
intent was #a, as that's the more logical position of being after the \n.  But
it may not be the best choice.  We do have to do some rewinding to deal with
that non-existent line #a creates.

[Bug c++/96045] [11 Regression] Wrong line and column diagnostic message in a class template instantiation

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96045

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Nathan Sidwell <nathan@gcc.gnu.org>:

https://gcc.gnu.org/g:745f22096c3a2a5e63d5bab1fb079e2c437cf9bc

commit r11-6325-g745f22096c3a2a5e63d5bab1fb079e2c437cf9bc
Author: Nathan Sidwell <nathan@acm.org>
Date:   Wed Dec 23 14:17:17 2020 -0800

    c++: EOF location [PR 96045]

    Setting the EOF token location to be the start of a line just after
    the ending newline is not most helpful.  While that location is
    probably the right place to report preprocessing and lexing issues,
    when parsing, the location just after the last token is better.  That
    way we get to point at some actual text.  Setting the location from
    the previous token has the advantage over just setting the location to
    be the end of the final line, in that any ending comments do not get
    considered, which I think is better.

            PR c++/96045
            gcc/cp/
            * parser.c (cp_lexer_new_main): Adjust EOF token location.
            gcc/testsuite/
            * g++.dg/diagnostic/pr96045-1.C: New.
            * g++.dg/diagnostic/pr96045-2.C: New.
            * g++.dg/diagnostic/pr96045-3.C: New.
            * c-c++-common/goacc/pr79428-1.c: Adjust EOF diagnostic location.
            * c-c++-common/gomp/pr79428-2.c: Likewise
            * c-c++-common/raw-string-6.c: Likewise
            * g++.dg/cpp0x/decltype63.C: Likewise
            * g++.dg/cpp0x/gen-attrs-64.C: Likewise
            * g++.dg/cpp0x/pr68726.C: Likewise
            * g++.dg/cpp0x/pr78341.C: Likewise
            * g++.dg/cpp1y/pr65202.C: Likewise
            * g++.dg/cpp1y/pr65340.C: Likewise
            * g++.dg/cpp1y/pr68578.C: Likewise
            * g++.dg/cpp1z/class-deduction44.C: Likewise
            * g++.dg/diagnostic/unclosed-extern-c.C: Likewise
            * g++.dg/diagnostic/unclosed-function.C: Likewise
            * g++.dg/diagnostic/unclosed-namespace.C: Likewise
            * g++.dg/diagnostic/unclosed-struct.C: Likewise
            * g++.dg/ext/pr84598.C: Likewise
            * g++.dg/other/switch4.C: Likewise
            * g++.dg/parse/attr4.C: Likewise
            * g++.dg/parse/cond4.C: Likewise
            * g++.dg/parse/crash10.C: Likewise
            * g++.dg/parse/crash18.C: Likewise
            * g++.dg/parse/crash27.C: Likewise
            * g++.dg/parse/crash34.C: Likewise
            * g++.dg/parse/crash35.C: Likewise
            * g++.dg/parse/crash52.C: Likewise
            * g++.dg/parse/crash59.C: Likewise
            * g++.dg/parse/crash61.C: Likewise
            * g++.dg/parse/crash67.C: Likewise
            * g++.dg/parse/error14.C: Likewise
            * g++.dg/parse/error56.C: Likewise
            * g++.dg/parse/invalid1.C: Likewise
            * g++.dg/parse/parameter-declaration-1.C: Likewise
            * g++.dg/parse/parser-pr28152-2.C: Likewise
            * g++.dg/parse/parser-pr28152.C: Likewise
            * g++.dg/parse/pr68722.C: Likewise
            * g++.dg/parse/pr96258.C: Likewise
            * g++.dg/pr46852.C: Likewise
            * g++.dg/pr46868.C: Likewise
            * g++.dg/template/crash115.C: Likewise
            * g++.dg/template/crash43.C: Likewise
            * g++.dg/template/crash90.C: Likewise
            * g++.dg/template/error-recovery1.C: Likewise
            * g++.dg/template/error57.C: Likewise
            * g++.old-deja/g++.other/crash31.C: Likewise

[Bug c++/96045] [11 Regression] Wrong line and column diagnostic message in a class template instantiation

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96045

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Iain D Sandoe <iains@gcc.gnu.org>:

https://gcc.gnu.org/g:6037ebeff1cd76385e88dd9cbcaf68ada85316fb

commit r11-6343-g6037ebeff1cd76385e88dd9cbcaf68ada85316fb
Author: Iain Sandoe <iain@sandoe.co.uk>
Date:   Sat Dec 26 19:46:50 2020 +0000

    Objective-C++ : Fix up testcase EOF diagnostics.

    Some Objective-C++ testcases need modification in reponse to the
    solution to PR 96045.

    gcc/testsuite/ChangeLog:

            PR c++/96045
            * obj-c++.dg/property/property-neg-6.mm: Adjust EOF
            diagnostic location.
            * obj-c++.dg/syntax-error-10.mm: Likewise.
            * obj-c++.dg/syntax-error-8.mm: Likewise.
            * obj-c++.dg/syntax-error-9.mm: Likewise.

[Bug c++/96045] [11 Regression] Wrong line and column diagnostic message in a class template instantiation

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96045

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Assuming fixed:
./cc1plus.20200929 -quiet pr96045.C
pr96045.C:3: error: expected unqualified-id at end of input
./cc1plus.20210107 -quiet pr96045.C
pr96045.C:2:15: error: expected unqualified-id at end of input
    2 | struct A <int>
      |               ^