pt.c (instantiate_decl): Abort if we see a member constant instantiation that doesn't already have its...

        * pt.c (instantiate_decl): Abort if we see a member constant
        instantiation that doesn't already have its initializer.
        Downgrade explicit instantiation without definition to pedwarn.

        * cp-tree.h (DECL_TINFO_FN_P, SET_DECL_TINFO_FN_P): Remove.
        * class.c (build_vtable_entry): Don't check DECL_TINFO_FN_P.
        (import_export_decl): Check tinfo_decl_p, not DECL_TINFO_FN_P.

        * cp-tree.h (CLASSTYPE_VTABLE_NEEDS_WRITING): Remove.
        (pending_vtables): Remove.
        * decl2.c (pending_vtables): Remove.
        (import_export_vtable): Use CLASSTYPE_INTERFACE_ONLY, not
        CLASSTYPE_VTABLE_NEEDS_WRITING.
        (import_export_class): Likewise.
        (init_decl2): Don't mark pending_vtables.
        * lex.c (handle_pragma_vtable): Just sorry.
        * pt.c (instantiate_class_template): Don't mess with
        CLASSTYPE_VTABLE_NEEDS_WRITING.
        (mark_class_instantiated): Likewise.
        * ptree.c (print_lang_type): Don't print it.
        * semantics.c (begin_class_definition): Don't set it.

        * pt.c (template_tail): Replace with last_pending_template.
        (maybe_templates, maybe_template_tail): Remove.
        (add_pending_template): Adjust.
        (instantiate_pending_templates): Adjust.

        * cp-tree.h (struct saved_scope): Remove lang_stack field.
        (current_lang_stack): Remove.
        * decl.c (maybe_push_to_top_level): Don't initialize it.
        (duplicate_decls): Use current_lang_depth.
        (xref_basetypes): Likewise.
        * class.c (current_lang_depth): New fn.
        (push_lang_context): Use more varray functionality.
        (pop_lang_context): Likewise.

From-SVN: r40724