PR c++/27668
        PR c++/27962
        * pt.c (process_template_parm) Store invalid template
        parameters as error_mark_node in the paramater list.
        (push_inline_template_parms_recursive): Handle invalid
        template parameters.
        (comp_template_parms): Likewise.
        (check_default_tmpl_arg): Likewise.
        (coerce_template_template_parms): Likewise.
        (mangle_class_name_for_template): Likewise.
        (tsubst_template_parms): Likewise.
        * error.c (dump_template_argument_list): Likewise.

        * g++.dg/template/crash55.C: New test.
        * g++.dg/template/nontype16.C: New test.
        * g++.dg/template/void2.C: Adjust error markers.
        * g++.dg/template/nontype5.C: Adjust error markers.

From-SVN: r115800