lang: Remove `EventIndex` (#3244)

CHANGELOG.md

@@ -90,6 +90,7 @@ The minor version will be incremented upon a breaking change and the patch versi
 - ts: Upgrade `typescript` to `5.5.4` and remove the generic parameters of `SimulateResponse` ([#3221](https://github.com/coral-xyz/anchor/pull/3221)).
 - ts: Remove `StateCoder`([#3224](https://github.com/coral-xyz/anchor/pull/3224)).
 - cli: Accept integers for `warp_slot` ([#3235](https://github.com/coral-xyz/anchor/pull/3235)).
+- lang: Remove `EventIndex` ([#3244](https://github.com/coral-xyz/anchor/pull/3244)).
 
 ## [0.30.1] - 2024-06-20
 

lang/attribute/event/src/lib.rs

@@ -42,7 +42,7 @@ pub fn event(
         .unwrap_or_else(|| gen_discriminator("event", event_name));
 
     let ret = quote! {
-        #[derive(anchor_lang::__private::EventIndex, AnchorSerialize, AnchorDeserialize)]
+        #[derive(AnchorSerialize, AnchorDeserialize)]
         #event_strct
 
         impl anchor_lang::Event for #event_name {
@@ -72,14 +72,6 @@ pub fn event(
     proc_macro::TokenStream::from(ret)
 }
 
-// EventIndex is a marker macro. It functionally does nothing other than
-// allow one to mark fields with the `#[index]` inert attribute, which is
-// used to add metadata to IDLs.
-#[proc_macro_derive(EventIndex, attributes(index))]
-pub fn derive_event(_item: proc_macro::TokenStream) -> proc_macro::TokenStream {
-    proc_macro::TokenStream::from(quote! {})
-}
-
 /// Logs an event that can be subscribed to by clients.
 /// Uses the [`sol_log_data`](https://docs.rs/solana-program/latest/solana_program/log/fn.sol_log_data.html)
 /// syscall which results in the following log:

lang/attribute/program/src/declare_program/mods/events.rs

@@ -16,7 +16,6 @@ pub fn gen_events_mod(idl: &Idl) -> proc_macro2::TokenStream {
             .expect("Type must exist");
 
         quote! {
-            #[derive(anchor_lang::__private::EventIndex)]
             #ty_def
 
             impl anchor_lang::Event for #name {

lang/src/lib.rs

@@ -452,7 +452,6 @@ pub mod prelude {
 #[doc(hidden)]
 pub mod __private {
     pub use anchor_attribute_account::ZeroCopyAccessor;
-    pub use anchor_attribute_event::EventIndex;
     pub use base64;
     pub use bytemuck;
 

tests/events/programs/events/src/lib.rs

@@ -46,13 +46,11 @@ pub struct TestEventCpi {}
 #[event]
 pub struct MyEvent {
     pub data: u64,
-    #[index]
     pub label: String,
 }
 
 #[event]
 pub struct MyOtherEvent {
     pub data: u64,
-    #[index]
     pub label: String,
 }