Add weight_args helper attribute

xcm/procedural/src/lib.rs

@@ -36,7 +36,7 @@ pub fn impl_conversion_functions_for_multilocation_v1(input: TokenStream) -> Tok
 		.into()
 }
 
-#[proc_macro_derive(XcmWeightInfoTrait)]
+#[proc_macro_derive(XcmWeightInfoTrait, attributes(weight_args))]
 pub fn derive_xcm_weight_info(item: TokenStream) -> TokenStream {
 	weight_info::derive(item)
 }

xcm/procedural/src/weight_info.rs

@@ -27,26 +27,32 @@ pub fn derive(item: proc_macro::TokenStream) -> proc_macro::TokenStream {
 
 	match data {
 		syn::Data::Enum(syn::DataEnum { variants, .. }) => {
-			let methods = variants.into_iter().map(|syn::Variant { ident, fields, .. }| {
-				let snake_cased_ident = format_ident!("{}", ident.to_string().to_snake_case());
-				let ref_fields =
-					fields.into_iter().enumerate().map(|(idx, syn::Field { ident, ty, .. })| {
-						let field_name = ident.unwrap_or_else(|| format_ident!("_{}", idx));
-						let field_ty = match ty {
-							syn::Type::Reference(r) => {
-								// If the type is already a reference, do nothing
-								quote::quote!(#r)
-							},
-							t => {
-								// Otherwise, make it a reference
-								quote::quote!(&#t)
-							},
-						};
+			let methods =
+				variants.into_iter().map(|syn::Variant { ident, fields, attrs, .. }| {
+					let snake_cased_ident = format_ident!("{}", ident.to_string().to_snake_case());
+					let ref_fields = parse_args_attr(attrs).unwrap_or_else(|| {
+						fields
+							.into_iter()
+							.enumerate()
+							.map(|(idx, syn::Field { ident, ty, .. })| {
+								let field_name = ident.unwrap_or_else(|| format_ident!("_{}", idx));
+								let field_ty = match ty {
+									syn::Type::Reference(r) => {
+										// If the type is already a reference, do nothing
+										quote::quote!(#r)
+									},
+									t => {
+										// Otherwise, make it a reference
+										quote::quote!(&#t)
+									},
+								};
 
-						quote::quote!(#field_name: #field_ty,)
+								quote::quote!(#field_name: #field_ty,)
+							})
+							.collect()
 					});
-				quote::quote!(fn #snake_cased_ident( #(#ref_fields)* ) -> Weight;)
-			});
+					quote::quote!(fn #snake_cased_ident( #ref_fields ) -> Weight;)
+				});
 
 			let res = quote::quote! {
 				pub trait XcmWeightInfo #generics {
@@ -65,3 +71,21 @@ pub fn derive(item: proc_macro::TokenStream) -> proc_macro::TokenStream {
 		},
 	}
 }
+
+fn parse_args_attr(attrs: Vec<syn::Attribute>) -> Option<proc_macro2::TokenStream> {
+	attrs.into_iter().find_map(|attr| {
+		attr.path.get_ident().filter(|ident| *ident == "weight_args").and_then(|_| {
+			attr.parse_args_with(|stream: syn::parse::ParseStream| {
+				let mut fields = Vec::new();
+				while !stream.is_empty() {
+					let ident: syn::Ident = stream.parse()?;
+					let _colon: syn::Token![:] = stream.parse()?;
+					let ty: syn::Type = stream.parse()?;
+					fields.push(quote::quote!(#ident: #ty));
+				}
+				Ok(quote::quote!( #(#fields),* ))
+			})
+			.ok()
+		})
+	})
+}

xcm/src/v3/mod.rs

@@ -35,13 +35,11 @@ pub use multiasset::{
 	AssetId, AssetInstance, Fungibility, MultiAsset, MultiAssetFilter, MultiAssets,
 	WildFungibility, WildMultiAsset,
 };
-pub use traits::{
-	Error, ExecuteXcm, Outcome, Result, SendError, SendResult, SendXcm, Weight, XcmWeightInfo,
-};
+pub use traits::{Error, ExecuteXcm, Outcome, Result, SendError, SendResult, SendXcm};
 // These parts of XCM v2 are unchanged in XCM v3, and are re-imported here.
 pub use super::v2::{
 	Ancestor, AncestorThen, BodyId, BodyPart, InteriorMultiLocation, Junction, Junctions,
-	MultiLocation, NetworkId, OriginKind, Parent, ParentThen, WeightLimit,
+	MultiLocation, NetworkId, OriginKind, Parent, ParentThen, Weight, WeightLimit,
 };
 
 /// This module's XCM version.
@@ -218,7 +216,7 @@ pub struct QueryResponseInfo {
 ///
 /// This is the inner XCM format and is version-sensitive. Messages are typically passed using the outer
 /// XCM format, known as `VersionedXcm`.
-#[derive(Derivative, Encode, Decode, TypeInfo)]
+#[derive(Derivative, Encode, Decode, TypeInfo, xcm_procedural::XcmWeightInfoTrait)]
 #[derivative(Clone(bound = ""), Eq(bound = ""), PartialEq(bound = ""), Debug(bound = ""))]
 #[codec(encode_bound())]
 #[codec(decode_bound())]
@@ -662,6 +660,7 @@ pub enum Instruction<Call> {
 	/// Kind: *Instruction*
 	///
 	/// Errors: *Fallible*.
+	#[weight_args()]
 	QueryPallet { module_name: Vec<u8>, response_info: QueryResponseInfo },
 
 	/// Ensure that a particular pallet with a particular version exists.
@@ -678,6 +677,7 @@ pub enum Instruction<Call> {
 	///
 	/// Errors:
 	/// - `ExpectationFalse`: In case any of the expectations are broken.
+	#[weight_args(index: &u32)]
 	ExpectPallet {
 		#[codec(compact)]
 		index: u32,
@@ -771,7 +771,7 @@ impl<Call> Instruction<Call> {
 				QueryPallet { module_name, response_info },
 			ExpectPallet { index, name, module_name, crate_major, min_crate_minor } =>
 				ExpectPallet { index, name, module_name, crate_major, min_crate_minor },
-			ReportTransactStatus(repsonse_info) => ReportTransactStatus(repsonse_info),
+			ReportTransactStatus(response_info) => ReportTransactStatus(response_info),
 			ClearTransactStatus => ClearTransactStatus,
 		}
 	}