-Wno-tabs according to the manual currently is active for -pedantic, -std=f95, and -Wall. It should be active for -std=f2003 as well. Finally, it's not actually active for -pedantic.
% cat xtabs.f90 print *, "hi" end -std=f2003 and -pedantic don't work: % gfortran -std=f2003 xtabs.f90 % % gfortran -pedantic xtabs.f90 % -std=f95 and -Wall do work: % gfortran -std=f95 xtabs.f90 xtabs.f90:1.1: print *, "hi" 1 Warning: Nonconforming tab character at (1) % gfortran -Wall xtabs.f90 xtabs.f90:1.1: print *, "hi" 1 Warning: Nonconforming tab character at (1) -- Summary: -Wno-tabs should be active for -std=f2003 and -pedantic Product: gcc Version: 4.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: jb at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30605