Conditional compilation

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Basic support for `dyn Trait` to allow cross-contract calls only with trait - [#1673](https://github.com/paritytech/ink/pull/1673)
 - E2E: auto detect contracts to be built - [#1691](https://github.com/paritytech/ink/pull/1691)
 - Add `set_code_hash` to `EnvAccess` - [#1698](https://github.com/paritytech/ink/pull/1698)
+- Support conditional compilation - [#1707](https://github.com/paritytech/ink/pull/1707)
 
 ## Version 4.0.1
 

crates/ink/codegen/src/generator/as_dependency/call_builder.rs

@@ -275,6 +275,14 @@ impl CallBuilder<'_> {
         let span = message.span();
         let message_ident = message.ident();
         let output_ident = generator::output_ident(message_ident);
+        let cfg_tokens = message.get_cfg_tokens();
+        let cfg_attrs: Vec<TokenStream2> = cfg_tokens
+            .iter()
+            .map(|token| {
+                quote_spanned!(span=>
+                    #[cfg #token])
+            })
+            .collect();
         let trait_info_id = generator::generate_reference_to_trait_info(span, trait_path);
         let (input_bindings, input_types): (Vec<_>, Vec<_>) = message
             .callable()
@@ -295,13 +303,15 @@ impl CallBuilder<'_> {
             .whitelisted_attributes()
             .filter_attr(message.attrs().to_vec());
         quote_spanned!(span=>
+            #( #cfg_attrs )*
             type #output_ident = <<<
                 Self
                 as ::ink::codegen::TraitCallForwarderFor<{#trait_info_id}>>::Forwarder
                 as ::ink::codegen::TraitCallBuilder>::Builder
                 as #trait_path>::#output_ident;
 
             #[inline]
+            #( #cfg_attrs )*
             #( #attrs )*
             fn #message_ident(
                 & #mut_token self

crates/ink/codegen/src/generator/as_dependency/contract_ref.rs

@@ -293,11 +293,21 @@ impl ContractRef<'_> {
         let mut_token = message.receiver().is_ref_mut().then(|| quote! { mut });
         let input_bindings = message.inputs().map(|input| &input.pat).collect::<Vec<_>>();
         let input_types = message.inputs().map(|input| &input.ty).collect::<Vec<_>>();
+        let cfg_tokens = message.get_cfg_tokens();
+        let cfg_attrs: Vec<TokenStream2> = cfg_tokens
+            .iter()
+            .map(|token| {
+                quote_spanned!(span=>
+                    #[cfg #token])
+            })
+            .collect();
         quote_spanned!(span=>
+            #( #cfg_attrs )*
             type #output_ident =
                 <<Self::__ink_TraitInfo as ::ink::codegen::TraitCallForwarder>::Forwarder as #trait_path>::#output_ident;
 
             #[inline]
+            #( #cfg_attrs )*
             fn #message_ident(
                 & #mut_token self
                 #( , #input_bindings : #input_types )*