[Bug libfortran/83282] missing comma in format changes output

[jvdelisle at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83282

--- Comment #5 from Jerry DeLisle <jvdelisle at gcc dot gnu.org> ---
With -std=f95 we get:

$ gfc -std=f95 pr83282.f90 
pr83282.f90:1:13:

    1 |    write(*,'(aa)') "ab", "bc"
      |             1
Error: GNU Extension: Missing comma at (1)
pr83282.f90:2:17:

    2 |    write(*,'(a"bc")') "ab"
      |                 1
Error: GNU Extension: Missing comma at (1)
pr83282.f90:3:17:

    3 |    write(*,'(a"cd"a)') "ab", "bc"
      |                 1
Error: GNU Extension: Missing comma at (1)

and -pedantic gives:

$ gfc -pedantic  pr83282.f90 
pr83282.f90:1:13:

    1 |    write(*,'(aa)') "ab", "bc"
      |             1
Warning: GNU Extension: Missing comma at (1)
pr83282.f90:2:17:

    2 |    write(*,'(a"bc")') "ab"
      |                 1
Warning: GNU Extension: Missing comma at (1)
pr83282.f90:3:17:

    3 |    write(*,'(a"cd"a)') "ab", "bc"
      |                 1
Warning: GNU Extension: Missing comma at (1)

I wonder if we should reject the missing comma outright and only allow it for
-std=legacy?