diff --git a/lib/std/os/uefi/tables/boot_services.zig b/lib/std/os/uefi/tables/boot_services.zig
index 506961315dcf2a001b7914072b441a9d8c9c816f..2070f8192cb7b286f185c0ad1fa95b5f98c49a5f 100644
--- a/lib/std/os/uefi/tables/boot_services.zig
+++ b/lib/std/os/uefi/tables/boot_services.zig
@@ -1239,7 +1239,7 @@ fn protocolInterfaces(
     ) = undefined;
     result[0] = handle_arg;
 
-    var idx: usize = 1;
+    comptime var idx: usize = 1;
     inline for (interfaces) |interface| {
         const InterfacePtr = @TypeOf(interface);
         const Interface = switch (@typeInfo(InterfacePtr)) {