1 files changed, 30 insertions, 11 deletions

diff --git a/ops/fast_call.rs b/ops/fast_call.rs
index 8f6348ec4..07bf87026 100644
--- a/ops/fast_call.rs
+++ b/ops/fast_call.rs
@@ -141,10 +141,19 @@ pub(crate) fn generate(
   if optimizer.has_fast_callback_option
     || optimizer.needs_opstate()
     || optimizer.is_async
+    || optimizer.needs_fast_callback_option
   {
-    fast_fn_inputs.push(parse_quote! {
+    let decl = parse_quote! {
       fast_api_callback_options: *mut #core::v8::fast_api::FastApiCallbackOptions
-    });
+    };
+
+    if optimizer.has_fast_callback_option {
+      // Replace last parameter.
+      assert!(fast_fn_inputs.pop().is_some());
+      fast_fn_inputs.push(decl);
+    } else {
+      fast_fn_inputs.push(decl);
+    }
 
     input_variants.push(q!({ CallbackOptions }));
   }
@@ -162,14 +171,10 @@ pub(crate) fn generate(
 
   let mut output_transforms = q!({});
 
-  if optimizer.needs_opstate() || optimizer.is_async {
-    // Grab the op_state identifier, the first one. ¯\_(ツ)_/¯
-    let op_state = match idents.first() {
-      Some(ident) if optimizer.has_opstate_in_parameters() => ident.clone(),
-      // fn op_foo() -> Result<...>
-      _ => Ident::new("op_state", Span::call_site()),
-    };
-
+  if optimizer.needs_opstate()
+    || optimizer.is_async
+    || optimizer.has_fast_callback_option
+  {
     // Dark arts 🪄 ✨
     //
     // - V8 calling convention guarantees that the callback options pointer is non-null.
@@ -179,13 +184,27 @@ pub(crate) fn generate(
     let prelude = q!({
       let __opts: &mut v8::fast_api::FastApiCallbackOptions =
         unsafe { &mut *fast_api_callback_options };
+    });
+
+    pre_transforms.push_tokens(&prelude);
+  }
+
+  if optimizer.needs_opstate() || optimizer.is_async {
+    // Grab the op_state identifier, the first one. ¯\_(ツ)_/¯
+    let op_state = match idents.first() {
+      Some(ident) if optimizer.has_opstate_in_parameters() => ident.clone(),
+      // fn op_foo() -> Result<...>
+      _ => Ident::new("op_state", Span::call_site()),
+    };
+
+    let ctx = q!({
       let __ctx = unsafe {
         &*(v8::Local::<v8::External>::cast(unsafe { __opts.data.data }).value()
           as *const _ops::OpCtx)
       };
     });
 
-    pre_transforms.push_tokens(&prelude);
+    pre_transforms.push_tokens(&ctx);
     pre_transforms.push_tokens(&match optimizer.is_async {
       false => q!(
         Vars {