lang: Fix using const generics with `declare_program!` (#2965)

CHANGELOG.md

@@ -26,6 +26,7 @@ The minor version will be incremented upon a breaking change and the patch versi
 - idl: Fix path resolution of the `Cargo.lock` of the project when generating idls for external types ([#2946](https://github.com/coral-xyz/anchor/pull/2946)).
 - idl: Fix potential panic on external type resolution ([#2954](https://github.com/coral-xyz/anchor/pull/2954)).
 - lang: Fix using defined types in instruction parameters with `declare_program!` ([#2959](https://github.com/coral-xyz/anchor/pull/2959)).
+- lang: Fix using const generics with `declare_program!` ([#2965](https://github.com/coral-xyz/anchor/pull/2965)).
 
 ### Breaking
 

lang/attribute/program/src/declare_program/common.rs

@@ -104,8 +104,15 @@ pub fn convert_idl_type_def_to_ts(
             .generics
             .iter()
             .map(|generic| match generic {
-                IdlTypeDefGeneric::Type { name } => format_ident!("{name}"),
-                IdlTypeDefGeneric::Const { name, ty } => format_ident!("{name}: {ty}"),
+                IdlTypeDefGeneric::Type { name } => {
+                    let name = format_ident!("{}", name);
+                    quote! { #name }
+                }
+                IdlTypeDefGeneric::Const { name, ty } => {
+                    let name = format_ident!("{}", name);
+                    let ty = format_ident!("{}", ty);
+                    quote! { const #name: #ty }
+                }
             })
             .collect::<Vec<_>>();
         if generics.is_empty() {