chore: Refactor struct message generation

sylvia-derive/src/contract.rs

@@ -125,7 +125,7 @@ impl<'a> ContractInput<'a> {
     }
 
     fn emit_struct_msg(&self, msg_ty: MsgType) -> TokenStream {
-        StructMessage::new(self.item, msg_ty, &self.generics, &self.custom)
+        StructMessage::new(self.item, msg_ty, &self.generics, &self.error, &self.custom)
             .map_or(quote! {}, |msg| msg.emit())
     }
 

sylvia-derive/src/contract/communication/struct_msg.rs

@@ -1,29 +1,23 @@
 use crate::crate_module;
 use crate::parser::attributes::MsgAttrForwarding;
-use crate::parser::check_generics::CheckGenerics;
-use crate::parser::{Custom, MsgAttr, MsgType, ParsedSylviaAttributes};
+use crate::parser::variant_descs::AsVariantDescs;
+use crate::parser::{ContractErrorAttr, Custom, MsgType, ParsedSylviaAttributes};
 use crate::types::msg_field::MsgField;
-use crate::utils::{as_where_clause, emit_bracketed_generics, filter_wheres, process_fields};
-use proc_macro2::{Span, TokenStream};
+use crate::types::msg_variant::MsgVariants;
+use crate::utils::{as_where_clause, emit_bracketed_generics, filter_wheres};
+use proc_macro2::TokenStream;
 use proc_macro_error::emit_error;
 use quote::quote;
 use syn::spanned::Spanned;
-use syn::{
-    GenericParam, Ident, ImplItem, ImplItemFn, ItemImpl, ReturnType, Type, WhereClause,
-    WherePredicate,
-};
+use syn::{GenericParam, ItemImpl, Type};
 
 /// Representation of single struct message
 pub struct StructMessage<'a> {
+    source: &'a ItemImpl,
     contract_type: &'a Type,
-    fields: Vec<MsgField<'a>>,
-    function_name: &'a Ident,
-    generics: Vec<&'a GenericParam>,
-    unused_generics: Vec<&'a GenericParam>,
-    wheres: Vec<&'a WherePredicate>,
-    full_where: Option<&'a WhereClause>,
-    result: &'a ReturnType,
-    msg_attr: MsgAttr,
+    variants: MsgVariants<'a, GenericParam>,
+    generics: &'a [&'a GenericParam],
+    error: &'a ContractErrorAttr,
     custom: &'a Custom,
     msg_attrs_to_forward: Vec<MsgAttrForwarding>,
 }
@@ -32,138 +26,109 @@
     /// Creates new struct message of given type from impl block
     pub fn new(
         source: &'a ItemImpl,
-        ty: MsgType,
+        msg_ty: MsgType,
         generics: &'a [&'a GenericParam],
+        error: &'a ContractErrorAttr,
         custom: &'a Custom,
     ) -> Option<StructMessage<'a>> {
-        let mut generics_checker = CheckGenerics::new(generics);
-
         let contract_type = &source.self_ty;
 
-        let parsed = Self::parse_struct_message(source, ty);
-        let (method, msg_attr) = parsed?;
+        let variants = MsgVariants::new(
+            source.as_variants(),
+            msg_ty,
+            generics,
+            &source.generics.where_clause,
+        );
 
-        let function_name = &method.sig.ident;
-        let fields = process_fields(&method.sig, &mut generics_checker);
-        let (used_generics, unused_generics) = generics_checker.used_unused();
-        let wheres = filter_wheres(&source.generics.where_clause, generics, &used_generics);
+        if variants.variants().count() == 0 && variants.msg_ty() == MsgType::Instantiate {
+            emit_error!(
+                source.span(), "Missing instantiation message.";
+                note = source.span() => "`sylvia::contract` requires exactly one method marked with `#[sv::msg(instantiation)]` attribute."
+            );
+            return None;
+        } else if variants.variants().count() > 1 {
+            let mut variants = variants.variants();
+            let first_method = variants.next().map(|v| v.function_name());
+            let obsolete = variants.next().map(|v| v.function_name());
+            emit_error!(
+                first_method.span(), "More than one instantiation or migration message";
+                note = obsolete.span() => "Instantiation/Migration message previously defined here"
+            );
+            return None;
+        }
 
         let msg_attrs_to_forward = ParsedSylviaAttributes::new(source.attrs.iter())
             .msg_attrs_forward
             .into_iter()
-            .filter(|attr| attr.msg_type == ty)
+            .filter(|attr| attr.msg_type == msg_ty)
             .collect();
 
         Some(Self {
+            source,
             contract_type,
-            fields,
-            function_name,
-            generics: used_generics,
-            unused_generics,
-            wheres,
-            full_where: source.generics.where_clause.as_ref(),
-            result: &method.sig.output,
-            msg_attr,
+            variants,
+            generics,
+            error,
             custom,
             msg_attrs_to_forward,
         })
     }
 
-    fn parse_struct_message(source: &ItemImpl, ty: MsgType) -> Option<(&ImplItemFn, MsgAttr)> {
-        let mut methods = source.items.iter().filter_map(|item| match item {
-            ImplItem::Fn(method) => {
-                let attr = ParsedSylviaAttributes::new(method.attrs.iter()).msg_attr?;
-                if attr == ty {
-                    Some((method, attr))
-                } else {
-                    None
-                }
-            }
-            _ => None,
-        });
-
-        let (method, msg_attr) = if let Some(method) = methods.next() {
-            method
-        } else {
-            if ty == MsgType::Instantiate {
-                emit_error!(
-                    source.span(), "Missing instantiation message.";
-                    note = source.span() => "`sylvia::contract` requires exactly one method marked with `#[sv::msg(instantiation)]` attribute."
-                );
-            }
-            return None;
-        };
-
-        if let Some((obsolete, _)) = methods.next() {
-            emit_error!(
-                obsolete.span(), "More than one instantiation or migration message";
-                note = method.span() => "Instantiation/Migration message previously defined here"
-            );
-        }
-        Some((method, msg_attr))
-    }
-
     pub fn emit(&self) -> TokenStream {
-        use MsgAttr::*;
-
-        let instantiate_msg = Ident::new("InstantiateMsg", self.function_name.span());
-        let migrate_msg = Ident::new("MigrateMsg", self.function_name.span());
-
-        match &self.msg_attr {
-            Instantiate { .. } => self.emit_struct(&instantiate_msg),
-            Migrate { .. } => self.emit_struct(&migrate_msg),
-            _ => {
-                emit_error!(Span::mixed_site(), "Invalid message type");
-                quote! {}
-            }
-        }
-    }
-
-    pub fn emit_struct(&self, name: &Ident) -> TokenStream {
         let sylvia = crate_module();
 
         let Self {
+            source,
             contract_type,
-            fields,
-            function_name,
+            variants,
             generics,
-            unused_generics,
-            wheres,
-            full_where,
-            result,
-            msg_attr,
+            error,
             custom,
             msg_attrs_to_forward,
         } = self;
 
-        let ctx_type = msg_attr
+        let Some(variant) = variants.get_only_variant() else {
+            return quote! {};
+        };
+
+        let used_generics = variants.used_generics();
+        let unused_generics = variants.unused_generics();
+        let full_where = &source.generics.where_clause;
+        let wheres = filter_wheres(full_where, generics, used_generics);
+        let where_clause = as_where_clause(&wheres);
+        let bracketed_used_generics = emit_bracketed_generics(used_generics);
+        let bracketed_unused_generics = emit_bracketed_generics(unused_generics);
+
+        let ret_type = variant
             .msg_type()
-            .emit_ctx_type(&custom.query_or_default());
-        let fields_names: Vec<_> = fields.iter().map(MsgField::name).collect();
-        let parameters = fields.iter().map(MsgField::emit_method_field);
-        let fields = fields.iter().map(MsgField::emit_pub);
-
-        let where_clause = as_where_clause(wheres);
-        let generics = emit_bracketed_generics(generics);
-        let unused_generics = emit_bracketed_generics(unused_generics);
+            .emit_result_type(&custom.msg_or_default(), &error.error);
+        let name = variant.msg_type().emit_msg_name();
+        let function_name = variant.function_name();
+        let mut msg_name = variant.msg_type().emit_msg_name();
+        msg_name.set_span(function_name.span());
+
+        let ctx_type = variant.msg_type().emit_ctx_type(&custom.query_or_default());
+        let fields_names: Vec<_> = variant.fields().iter().map(MsgField::name).collect();
+        let parameters = variant.fields().iter().map(MsgField::emit_method_field);
+        let fields = variant.fields().iter().map(MsgField::emit_pub);
+
         let msg_attrs_to_forward = msg_attrs_to_forward.iter().map(|attr| &attr.attrs);
 
         quote! {
             #[allow(clippy::derive_partial_eq_without_eq)]
             #[derive(#sylvia ::serde::Serialize, #sylvia ::serde::Deserialize, Clone, Debug, PartialEq, #sylvia ::schemars::JsonSchema)]
             #( #[ #msg_attrs_to_forward ] )*
             #[serde(rename_all="snake_case")]
-            pub struct #name #generics {
+            pub struct #name #bracketed_used_generics {
                 #(#fields,)*
             }
 
-            impl #generics #name #generics #where_clause {
+            impl #bracketed_used_generics #name #bracketed_used_generics #where_clause {
                 pub fn new(#(#parameters,)*) -> Self {
                     Self { #(#fields_names,)* }
                 }
 
-                pub fn dispatch #unused_generics(self, contract: &#contract_type, ctx: #ctx_type)
-                    #result #full_where
+                pub fn dispatch #bracketed_unused_generics (self, contract: &#contract_type, ctx: #ctx_type) -> #ret_type #full_where
                 {
                     let Self { #(#fields_names,)* } = self;
                     contract.#function_name(Into::into(ctx), #(#fields_names,)*).map_err(Into::into)

sylvia-derive/src/parser/mod.rs

@@ -7,16 +7,19 @@
     ContractErrorAttr, ContractMessageAttr, Custom, Customs, FilteredOverrideEntryPoints, MsgAttr,
     MsgType, OverrideEntryPoint, ParsedSylviaAttributes, SylviaAttribute,
 };
+use check_generics::{CheckGenerics, GetPath};
 pub use entry_point::EntryPointArgs;
 
 use proc_macro_error::emit_error;
 use syn::punctuated::Punctuated;
 use syn::spanned::Spanned;
 use syn::{
-    parse_quote, GenericArgument, Ident, ImplItem, ItemImpl, ItemTrait, Path, PathArguments, Token,
-    TraitItem, Type,
+    parse_quote, FnArg, GenericArgument, Ident, ImplItem, ItemImpl, ItemTrait, Path, PathArguments,
+    Signature, Token, TraitItem, Type,
 };
 
+use crate::types::msg_field::MsgField;
+
 fn extract_generics_from_path(module: &Path) -> Punctuated<GenericArgument, Token![,]> {
     let generics = module
         .segments
@@ -64,3 +67,24 @@
         _ => (),
     }
 }
+
+pub fn process_fields<'s, Generic>(
+    sig: &'s Signature,
+    generics_checker: &mut CheckGenerics<Generic>,
+) -> Vec<MsgField<'s>>
+where
+    Generic: GetPath + PartialEq,
+{
+    sig.inputs
+        .iter()
+        .skip(2)
+        .filter_map(|arg| match arg {
+            FnArg::Receiver(item) => {
+                emit_error!(item.span(), "Unexpected `self` argument");
+                None
+            }
+
+            FnArg::Typed(item) => MsgField::new(item, generics_checker),
+        })
+        .collect()
+}

sylvia-derive/src/types/msg_variant.rs

@@ -3,8 +3,8 @@ use crate::fold::StripSelfPath;
 use crate::parser::attributes::VariantAttrForwarding;
 use crate::parser::check_generics::{CheckGenerics, GetPath};
 use crate::parser::variant_descs::VariantDescs;
-use crate::parser::{MsgAttr, MsgType};
-use crate::utils::{extract_return_type, filter_wheres, process_fields, SvCasing};
+use crate::parser::{process_fields, MsgAttr, MsgType};
+use crate::utils::{extract_return_type, filter_wheres, SvCasing};
 use convert_case::{Case, Casing};
 use proc_macro2::TokenStream;
 use quote::{quote, ToTokens};
@@ -246,6 +246,10 @@ where
         &self.unused_generics
     }
 
+    pub fn msg_ty(&self) -> MsgType {
+        self.msg_ty
+    }
+
     pub fn emit_phantom_match_arm(&self) -> TokenStream {
         let sylvia = crate_module();
         let Self { used_generics, .. } = self;

sylvia-derive/src/utils.rs

@@ -5,12 +5,11 @@ use quote::{quote, ToTokens};
 use syn::spanned::Spanned;
 use syn::visit::Visit;
 use syn::{
-    parse_quote, FnArg, GenericArgument, Ident, Path, PathArguments, ReturnType, Signature, Type,
-    WhereClause, WherePredicate,
+    parse_quote, GenericArgument, Ident, Path, PathArguments, ReturnType, Type, WhereClause,
+    WherePredicate,
 };
 
 use crate::parser::check_generics::{CheckGenerics, GetPath};
-use crate::types::msg_field::MsgField;
 
 pub fn filter_wheres<'a, Generic: GetPath + PartialEq>(
     clause: &'a Option<WhereClause>,
@@ -36,27 +35,6 @@ pub fn filter_wheres<'a, Generic: GetPath + PartialEq>(
         .unwrap_or_default()
 }
 
-pub fn process_fields<'s, Generic>(
-    sig: &'s Signature,
-    generics_checker: &mut CheckGenerics<Generic>,
-) -> Vec<MsgField<'s>>
-where
-    Generic: GetPath + PartialEq,
-{
-    sig.inputs
-        .iter()
-        .skip(2)
-        .filter_map(|arg| match arg {
-            FnArg::Receiver(item) => {
-                emit_error!(item.span(), "Unexpected `self` argument");
-                None
-            }
-
-            FnArg::Typed(item) => MsgField::new(item, generics_checker),
-        })
-        .collect()
-}
-
 pub fn extract_return_type(ret_type: &ReturnType) -> &Path {
     let ReturnType::Type(_, ty) = ret_type else {
         unreachable!()

sylvia/tests/ui/missing_method/msgs_misused.stderr

@@ -20,7 +20,7 @@ error: More than one instantiation or migration message
 
          = note: Instantiation/Migration message previously defined here
 
-  --> tests/ui/missing_method/msgs_misused.rs:35:5
+  --> tests/ui/missing_method/msgs_misused.rs:31:12
    |
-35 |     #[sv::msg(instantiate)]
-   |     ^
+31 |     pub fn instantiate(&self, ctx: InstantiateCtx) -> StdResult<Response> {
+   |            ^^^^^^^^^^^