diff --git a/File.zig b/File.zig
index 1db505589ff401e3205789f4aa492cbabbdf8c02..a1d6235508020f784bfd9556e10f543f1bd00d4c 100644
--- a/File.zig
+++ b/File.zig
@@ -26,7 +26,7 @@ pub fn read(self: File, buffer: []u8) ReadError!usize {
 
 pub fn anyReadable(self: File) nio.AnyReadable {
     const S = struct {
-        fn foo(s: *anyopaque, buffer: []u8) anyerror!usize {
+        fn foo(s: *allowzero anyopaque, buffer: []u8) anyerror!usize {
             const fd: nfs.Handle = @enumFromInt(@intFromPtr(s));
             const f: File = .{ .fd = fd };
             return f.read(buffer);