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.

The attached patch stores a namespace pointer in the statement label structure so that if a label is deleted early for some reason, it will be deleted from the proper namespace.

Louis