diff --git a/lib/std/Io.zig b/lib/std/Io.zig
index 16d056ed0f..74ddd1dccf 100644
--- a/lib/std/Io.zig
+++ b/lib/std/Io.zig
@@ -287,7 +287,7 @@ pub const Operation = union(enum) {
             LockViolation,
         } || Io.UnexpectedError;
 
-        pub const Result = usize;
+        pub const Result = Error!usize;
     };
 
     pub const Result = Result: {
@@ -296,7 +296,7 @@ pub const Operation = union(enum) {
         var field_types: [operation_fields.len]type = undefined;
         for (operation_fields, &field_names, &field_types) |field, *field_name, *field_type| {
             field_name.* = field.name;
-            field_type.* = field.type.Error!field.type.Result;
+            field_type.* = field.type.Result;
         }
         break :Result @Union(.auto, Tag, &field_names, &field_types, &@splat(.{}));
     };