https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119856
--- Comment #2 from Walter Spector <w6ws at earthlink dot net> --- Having suffered through porting Fortran programs from one compiler to another, and one system to another, uncountable times over the past 50 years, I am one who doesn't like "legacy" extensions to be enabled by default. They are traps just waiting to be sprung. So in the rare case where I want specific extensions, I like options to explicitly turn them on. It seems that if I compile with -std=legacy, the compiler somehow indicates to the run-time library to allow the missing commas extension: $ gfortran -std=legacy -g badfmt.f90 $ ./a.out hi3 hi3 hi3 hi3 hi3 $ With this in mind, I would suggest issuing a diagnostic at compile time whenever possible - unless -std=legacy is specified. In the case of run-time formats, without -std=legacy there isn't a way to check at compile time. So perhaps the run-time error message could indicate that it would work if the code were compiled with -std=legacy.
