addFailedDeclaration

fn addFailedDeclaration(
    wip_decls: *WipDecls,
    gz: *GenZir,
    kind: Zir.Inst.Declaration.Unwrapped.Kind,
    name: Zir.NullTerminatedString,
    src_node: Ast.Node.Index,
    is_pub: bool,
) !void {
    const decl_inst = try gz.makeDeclaration(src_node);
    wip_decls.nextDecl(decl_inst);

    var dummy_gz = gz.makeSubBlock(&gz.base);

    var value_gz = gz.makeSubBlock(&gz.base); // scope doesn't matter here
    _ = try value_gz.add(.{
        .tag = .extended,
        .data = .{ .extended = .{
            .opcode = .astgen_error,
            .small = undefined,
            .operand = undefined,
        } },
    });

    try setDeclaration(decl_inst, .{
        .src_hash = @splat(0), // use a fixed hash to represent an AstGen failure; we don't care about source changes if AstGen still failed!
        .src_line = gz.astgen.source_line,
        .src_column = gz.astgen.source_column,
        .kind = kind,
        .name = name,
        .is_pub = is_pub,
        .is_threadlocal = false,
        .linkage = .normal,
        .type_gz = &dummy_gz,
        .align_gz = &dummy_gz,
        .linksection_gz = &dummy_gz,
        .addrspace_gz = &dummy_gz,
        .value_gz = &value_gz,
    });
}