[Bug ada/81328] New: Wrong order of error messages

["porton at narod dot ru" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81328

            Bug ID: 81328
           Summary: Wrong order of error messages
           Product: gcc
           Version: 7.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ada
          Assignee: unassigned at gcc dot gnu.org
          Reporter: porton at narod dot ru
  Target Milestone: ---

Created attachment 41688
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41688&action=edit
A source with a deliberate error

GNAT provides an error list for my erroneous input in wrong order.

I sent a minimized code where this is not a problem, but I got this GNAT
behavior in real code, what lead me to try to first fix the first error (which
in reality was caused by the second error), but it was unexpected that to fix
the first error I first need to fix the second error.

The output order of compilation errors should be such that the programmer would
be able to fix the errors in the order of compiler output, rather than to make
the programmer to guess that he needs first look into the next error.

Here is compilation of my erroneous source (the error is missing `with
Auxiliary;` in www.ads file):

$ gnatgcc -c www.adb
www.adb:6:14: "From_Handle" is not visible
www.adb:6:14: non-visible declaration at limited_handled_record.ads:7
www.ads:6:61: "Auxiliary" is undefined
www.ads:6:70: instantiation abandoned
www.ads:8:28: "WWW_Handled_Record" is undefined (more references follow)

To make From_Handle visible, I need first note that the problem is caused by
Auxiliary being undefined. The message that it is not visible is confusing,
because it is not just not visible but in reality undefined.

$ gnatgcc -v
Using built-in specs.
COLLECT_GCC=gnatgcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/7/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 7.1.0-7'
--with-bugurl=file:///usr/share/doc/gcc-7/README.Bugs
--enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr
--with-gcc-major-version-only --program-suffix=-7
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-vtable-verify --enable-libmpx --enable-plugin --enable-default-pie
--with-system-zlib --with-target-system-zlib --enable-objc-gc=auto
--enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64
--with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic
--enable-offload-targets=nvptx-none --without-cuda-driver
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu
Thread model: posix
gcc version 7.1.0 (Debian 7.1.0-7)