From 340e9c13f42191a1caa6092d811ed930a64c1f7b Mon Sep 17 00:00:00 2001
From: acheron <98934430+acheroncrypto@users.noreply.github.com>
Date: Thu, 12 Sep 2024 21:00:29 +0200
Subject: [PATCH] lang: Remove `EventIndex` (#3244)

---
 CHANGELOG.md                                           |  1 +
 lang/attribute/event/src/lib.rs                        | 10 +---------
 .../program/src/declare_program/mods/events.rs         |  1 -
 lang/src/lib.rs                                        |  1 -
 tests/events/programs/events/src/lib.rs                |  2 --
 5 files changed, 2 insertions(+), 13 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 186a36bdd9..ca0351d6b1 100644
--- a/CHANGELOG.md
+++ b/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
 
diff --git a/lang/attribute/event/src/lib.rs b/lang/attribute/event/src/lib.rs
index 76182fc465..19258fbe21 100644
--- a/lang/attribute/event/src/lib.rs
+++ b/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:
diff --git a/lang/attribute/program/src/declare_program/mods/events.rs b/lang/attribute/program/src/declare_program/mods/events.rs
index eff282952e..2d54970559 100644
--- a/lang/attribute/program/src/declare_program/mods/events.rs
+++ b/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 {
diff --git a/lang/src/lib.rs b/lang/src/lib.rs
index a27114e4d3..dd4d3b64b8 100644
--- a/lang/src/lib.rs
+++ b/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;
 
diff --git a/tests/events/programs/events/src/lib.rs b/tests/events/programs/events/src/lib.rs
index ff3f57c0e3..c1c8e59526 100644
--- a/tests/events/programs/events/src/lib.rs
+++ b/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,
 }