From b52f23614601652a99ec6c27aec77bd327363b31 Mon Sep 17 00:00:00 2001
From: Christian Kamm <mail@ckamm.de>
Date: Fri, 5 Aug 2022 20:24:53 +0200
Subject: [PATCH] Implement Discriminator trait for generated instructions

Access to the discriminators is useful when doing instruction
introspection where you may want to determine the type of other
instructions for your program.
---
 lang/syn/src/codegen/program/instruction.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/lang/syn/src/codegen/program/instruction.rs b/lang/syn/src/codegen/program/instruction.rs
index 9191d05d..9052ad88 100644
--- a/lang/syn/src/codegen/program/instruction.rs
+++ b/lang/syn/src/codegen/program/instruction.rs
@@ -138,6 +138,11 @@ pub fn generate(program: &Program) -> proc_macro2::TokenStream {
                 let sighash_tts: proc_macro2::TokenStream =
                     format!("{:?}", sighash_arr).parse().unwrap();
                 quote! {
+                    impl anchor_lang::Discriminator for #ix_name_camel {
+                        fn discriminator() -> [u8; 8] {
+                            #sighash_tts
+                        }
+                    }
                     impl anchor_lang::InstructionData for #ix_name_camel {
                         fn data(&self) -> Vec<u8> {
                             let mut d = #sighash_tts.to_vec();