[Bug fortran/67429] [5/6 Regression] Missing part of error messages.

["manu at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67429

--- Comment #9 from Manuel LÃpez-IbÃÃez <manu at gcc dot gnu.org> ---
Even with the original patch applied to r227391, I cannot reproduce the error
that you get. On x86_64-linux-gnu, I get:

Starting program: /home/manuel/test1/226953M/build/gcc/f951
~/test1/src/gcc/testsuite/gfortran.dg/pr65045.f90
/home/manuel/test1/src/gcc/testsuite/gfortran.dg/pr65045.f90:7:6: Error: Symbol
âiâ at (1) is not appropriate for an expression
/home/manuel/test1/src/gcc/testsuite/gfortran.dg/pr65045.f90:9:59:

    else          ! { dg-error "Unexpected ELSE statement" }
                                                           1
Error: Unexpected ELSE statement at (1)
/home/manuel/test1/src/gcc/testsuite/gfortran.dg/pr65045.f90:10:6: Error: âiâ
at (1) is not a variable
/home/manuel/test1/src/gcc/testsuite/gfortran.dg/pr65045.f90:11:6:

    end if        ! { dg-error "Expecting END BLOCK statement" }
      1
Error: Expecting END BLOCK statement at (1)
/home/manuel/test1/src/gcc/testsuite/gfortran.dg/pr65045.f90:13:8:

 print*,i         ! { dg-error "not appropriate for an expression" }
        1
Error: Symbol âiâ at (1) is not appropriate for an expression


However, there is a bug indeed. The first caret line is not printed because
there was a previous buffered error at the same location that later got
cleared. However, clearing it does not reset context->last_location, which is
checked in gfc_diagnostic_starter.

This patch seems to fix it:

Index: error.c
===================================================================
--- error.c     (revision 227391)
+++ error.c     (working copy)
@@ -755,10 +755,13 @@ gfc_clear_pp_buffer (output_buffer *this
   pretty_printer *pp = global_dc->printer;
   output_buffer *tmp_buffer = pp->buffer;
   pp->buffer = this_buffer;
   pp_clear_output_area (pp);
   pp->buffer = tmp_buffer;
+  /* We need to reset last_location, otherwise we may skip caret lines
+     when we actually give a diagnostic.  */
+  global_dc->last_location = UNKNOWN_LOCATION;
 }



However, it is not a very nice solution. It may happen that we give an error at
location X, then we buffer some errors, then we clear them, so we reset last
location to UNKNOWN, then we give an error at location X and we will get a
duplicated caret line. Thus, it would be better if last_location was only
updated when we actually flush the output text. However, that would require
some deeper changes, probably in diagnostic.c and in fortran/error.c to handle
both buffered and not buffered output_buffers. On the other hand, I'm not sure
the previous Fortran diagnostic machinery cared about duplicated caret lines,
thus perhaps the above is enough.

BTW, you should use %qs instead of '%s' in order to get quoting localized to
the user's language and color highlighting.