https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102145
--- Comment #11 from Rimvydas (RJ) <rimvydas.jas at gmail dot com> --- (In reply to Steve Kargl from comment #10) > Yes, I know -std=legacy implies -fallow-argument-mismatch. The > option degrades an ERROR to a WARNING. That is all it does. > With -std=legacy, gfortran is acknowledging that a user is > throwing potential garbage at it. [snip] > If -pedantic or -pedantic-error > turns the warning back into an error, so what? The user can > remove the idiotic option. Telling gfortran you want -std=legacy > and -pedantic is an oxymoron. Nobody would complain if compiler acted consistently and error would happen only with -pedantic-errors. See gcc/testsuite/gfortran.dg/hollerith8.f90 how it is affected by -std=legacy vs -std=legacy -pedantic vs -std=f2008, specifically the part: call wrtout (9hHELLO YOU, 9) Warning: Legacy Extension: Hollerith constant at (1) Users would be satisfied with: Warning: Legacy extension: Invalid argument mismatch at (1). It not so hard to acknowledge that consistency was broken and it is still easily fixable. There is nothing oxy about -pedantic not giving hard error when there is -pedantic-errors for this. > The Fortran standard for more that 55 years has said argument > mismatch is invalid Fortran. In the old days, Fortran processors > lacked the ability to diagnose the problem. gfortran can, under > some circumstance, diagnose the issue and should tell the user > via an error message that the Fortran code is invalid. Still there is no good reason to break older codebases that were accepted 3 years ago with -std=legacy or -std=gnu -fallow-argument-mismatch if -std=f2008 strictly rejects them. > I'll also point out that you stated some projects have started to > remove -pedantic because -fallow-argument-mismatch is throwing > an error. Why are these projects using -pedantic if the projects > are not actively fixing the reported warnings. It seems the > issue with -fallow-argument-mismatch is doing what it ought to > do. That is, encourage user to FIX THEIR INVALID FORTRAN CODE. Previously -pedantic was used in makefile recipes to check (usually in a separate compilation) for new warnings differences between compiler releases about new legacy or deleted features, because it is easier way than diff standard texts or code changes in compiler frontend. Sadly these recipes are being removed now. As for fixing part, consider: program test stop 1 contains subroutine todo1 call mpi_send(1) end subroutine subroutine todo2 call mpi_send(1.) end subroutine end program Hard diagnostic is now issued even for unreachable code parts and this forces users to simply move out code parts giving hard errors to separate fortran sources by use of wrappers without interfaces (often with real bugs when code changes getting merged from different development branches). Not only this forces anyone debugging such changes to rely on LTO alone, but encourages avoiding use of -Werror or -Werror=foo to prevent issues in future compiler releases because compiler has growing inconsistency reputation. > I don't care what other Fortran vendors do. Other Fortran vendors > have a monetary reason to bend to the purses of users. MPI issue is not what other Fortran vendors are doing. The given MPI implementation (possibly MPI vendor optimized or debugging one) needs to provide mpi.mod or mpi_f08.mod modules for every gfortran major version just to import information about MPI interfaces. This is why f77 mpif.h (usually without explicit interfaces or use of "!gcc$ attributes no_arg_check :: arg") include way is still preferred. As for last bit, it is quite surprising and really unnecessary in modern times. If you need to know, then all depends on the given friend and how consistent he/she is. :)
