Possible patch for PR fortran/66056

[FX]

> The problem:  Statement labels within a type declaration are put in the statement label tree belonging to the type declaration's namespace's (instead of the current namespace).  When the line is otherwise empty and an error is issued, gfc_free_st_label tries to delete the label from the label tree belonging to the current namespace and then frees the label structure, leaving an invalid statement label pointer in the type declaration's namespace's label tree.  When that namespace is cleaned up, bad things can happen.

Seems OK.
Please post patches with full ChangeLog entry, stating how they were tested (“bootstraped and regtested on x86_64-linux”, for example). And of course, do an actual full regression-test :)

If that was done, then OK to commit.

Thanks,
FX