https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54679
--- Comment #4 from Jerry DeLisle <jvdelisle at gcc dot gnu.org> --- I should have looked at this sooner. We actually do diagnose this, but our warning/error logic is not right. pr54679.f90:8:56: PRINT "(A,1X,I2,1X,A,1X,I2,1X,A,2(1X,I0,1X),A,2(1X,L0,1X))" 1 Warning: Extension: Missing positive width after L descriptor at (1)