feat(sol-macro): improve type expansion (#302)

* feat(sol-macro): improve type expansion

* chore: update test fixtures

* chore: unremove spans

* bless

crates/sol-macro/src/expand/event.rs

@@ -1,7 +1,6 @@
 //! [`ItemEvent`] expansion.
 
-use super::{anon_name, expand_tuple_types, expand_type, ExpCtxt};
-use crate::expand::ty::expand_event_tokenize_func;
+use super::{anon_name, expand_tuple_types, expand_type, ty, ExpCtxt};
 use ast::{EventParameter, ItemEvent, SolIdent, Spanned};
 use proc_macro2::TokenStream;
 use quote::{quote, quote_spanned};
@@ -93,7 +92,7 @@ pub(super) fn expand(cx: &ExpCtxt<'_>, event: &ItemEvent) -> Result<TokenStream>
         .enumerate()
         .map(|(i, p)| expand_event_topic_field(i, p, p.name.as_ref()));
 
-    let tokenize_body_impl = expand_event_tokenize_func(event.parameters.iter());
+    let tokenize_body_impl = ty::expand_event_tokenize_func(event.parameters.iter());
 
     let encode_topics_impl = encode_first_topic
         .into_iter()
@@ -176,15 +175,13 @@ fn expand_event_topic_field(
     name: Option<&SolIdent>,
 ) -> TokenStream {
     let name = anon_name((i, name));
-
-    if param.indexed_as_hash() {
-        quote! {
-            #name: <::alloy_sol_types::sol_data::FixedBytes<32> as ::alloy_sol_types::SolType>::RustType
-        }
+    let ty = if param.indexed_as_hash() {
+        ty::expand_rust_type(&ast::Type::FixedBytes(
+            name.span(),
+            core::num::NonZeroU16::new(32).unwrap(),
+        ))
     } else {
-        let ty = expand_type(&param.ty);
-        quote! {
-            #name: <#ty as ::alloy_sol_types::SolType>::RustType
-        }
-    }
+        ty::expand_rust_type(&param.ty)
+    };
+    quote!(#name: #ty)
 }

crates/sol-macro/src/expand/mod.rs

@@ -2,14 +2,15 @@
 
 use crate::{
     attr::{self, SolAttrs},
+    expand::ty::expand_rust_type,
     utils::{self, ExprArray},
 };
 use ast::{
     File, Item, ItemError, ItemEvent, ItemFunction, Parameters, SolIdent, SolPath, Spanned, Type,
     VariableDeclaration, Visit,
 };
-use proc_macro2::{Ident, Span, TokenStream};
-use quote::{format_ident, quote};
+use proc_macro2::{Delimiter, Group, Ident, Punct, Spacing, Span, TokenStream, TokenTree};
+use quote::{format_ident, quote, TokenStreamExt};
 use std::{borrow::Borrow, collections::HashMap, fmt::Write};
 use syn::{parse_quote, Attribute, Error, Result};
 
@@ -429,32 +430,21 @@ impl ExpCtxt<'_> {
 }
 
 // helper functions
+
 /// Expands a list of parameters into a list of struct fields.
-///
-/// See [`expand_field`].
 fn expand_fields<P>(params: &Parameters<P>) -> impl Iterator<Item = TokenStream> + '_ {
-    params
-        .iter()
-        .enumerate()
-        .map(|(i, var)| expand_field(i, &var.ty, var.name.as_ref(), var.attrs.as_ref()))
-}
-
-/// Expands a single parameter into a struct field.
-fn expand_field(
-    i: usize,
-    ty: &Type,
-    name: Option<&SolIdent>,
-    attrs: &Vec<Attribute>,
-) -> TokenStream {
-    let name = anon_name((i, name));
-    let ty = expand_type(ty);
-    quote! {
-        #(#attrs)*
-        pub #name: <#ty as ::alloy_sol_types::SolType>::RustType
-    }
+    params.iter().enumerate().map(|(i, var)| {
+        let name = anon_name((i, var.name.as_ref()));
+        let ty = expand_rust_type(&var.ty);
+        let attrs = &var.attrs;
+        quote! {
+            #(#attrs)*
+            pub #name: #ty
+        }
+    })
 }
 
-/// Generates an anonymous name from an integer. Used in `anon_name`
+/// Generates an anonymous name from an integer. Used in [`anon_name`].
 #[inline]
 pub fn generate_name(i: usize) -> Ident {
     format_ident!("_{i}")
@@ -516,18 +506,21 @@ fn expand_from_into_tuples<P>(name: &Ident, fields: &Parameters<P>) -> TokenStre
     }
 }
 
-/// Returns
-/// - `(#(#expanded,)*)`
-/// - `(#(<#expanded as ::alloy_sol_types::SolType>::RustType,)*)`
+/// Returns `(sol_tuple, rust_tuple)`
 fn expand_tuple_types<'a, I: IntoIterator<Item = &'a Type>>(
     types: I,
 ) -> (TokenStream, TokenStream) {
-    let mut sol_tuple = TokenStream::new();
-    let mut rust_tuple = TokenStream::new();
+    let mut sol = TokenStream::new();
+    let mut rust = TokenStream::new();
+    let comma = Punct::new(',', Spacing::Alone);
     for ty in types {
-        let expanded = expand_type(ty);
-        sol_tuple.extend(quote!(#expanded,));
-        rust_tuple.extend(quote!(<#expanded as ::alloy_sol_types::SolType>::RustType,));
+        ty::rec_expand_type(ty, &mut sol);
+        sol.append(comma.clone());
+
+        ty::rec_expand_rust_type(ty, &mut rust);
+        rust.append(comma.clone());
     }
-    (quote!((#sol_tuple)), quote!((#rust_tuple)))
+    let wrap_in_parens =
+        |stream| TokenStream::from(TokenTree::Group(Group::new(Delimiter::Parenthesis, stream)));
+    (wrap_in_parens(sol), wrap_in_parens(rust))
 }

crates/sol-macro/src/expand/struct.rs

@@ -3,7 +3,7 @@
 use super::{
     expand_fields, expand_from_into_tuples, expand_type, ty::expand_tokenize_func, ExpCtxt,
 };
-use ast::{Item, ItemStruct, Spanned, Type, VariableDeclaration};
+use ast::{Item, ItemStruct, Spanned, Type};
 use proc_macro2::TokenStream;
 use quote::quote;
 use std::num::NonZeroU16;
@@ -48,8 +48,8 @@ pub(super) fn expand(cx: &ExpCtxt<'_>, s: &ItemStruct) -> Result<TokenStream> {
     let encode_data_impl = match fields.len() {
         0 => unreachable!("struct with zero fields"),
         1 => {
-            let VariableDeclaration { ty, name, .. } = fields.first().unwrap();
-            let ty = expand_type(ty);
+            let name = *field_names.first().unwrap();
+            let ty = field_types.first().unwrap();
             quote!(<#ty as ::alloy_sol_types::SolType>::eip712_data_word(&self.#name).0.to_vec())
         }
         _ => quote! {

crates/sol-macro/src/expand/ty.rs

@@ -3,17 +3,29 @@
 use super::ExpCtxt;
 use crate::expand::generate_name;
 use ast::{EventParameter, Item, Parameters, Spanned, Type, TypeArray, VariableDeclaration};
-use proc_macro2::{Literal, TokenStream};
+use proc_macro2::{Ident, Literal, TokenStream};
 use quote::{quote, quote_spanned, ToTokens};
 use std::{fmt, num::NonZeroU16};
 
-/// Expands a single [`Type`] recursively.
+/// Expands a single [`Type`] recursively to its `alloy_sol_types::sol_data`
+/// equivalent.
 pub fn expand_type(ty: &Type) -> TokenStream {
     let mut tokens = TokenStream::new();
     rec_expand_type(ty, &mut tokens);
     tokens
 }
 
+/// Expands a single [`Type`] recursively to its Rust type equivalent.
+///
+/// This is the same as `<#expand_type(ty) as SolType>::RustType`, but generates
+/// nicer code for documentation and IDE/LSP support when the type is not
+/// ambiguous.
+pub fn expand_rust_type(ty: &Type) -> TokenStream {
+    let mut tokens = TokenStream::new();
+    rec_expand_rust_type(ty, &mut tokens);
+    tokens
+}
+
 /// Expands a [`VariableDeclaration`] into an invocation of its types tokenize
 /// method.
 fn expand_tokenize_statement(var: &VariableDeclaration, i: usize) -> TokenStream {
@@ -59,35 +71,31 @@ pub fn expand_event_tokenize_func<'a>(
 }
 
 /// The [`expand_type`] recursive implementation.
-fn rec_expand_type(ty: &Type, tokens: &mut TokenStream) {
+pub fn rec_expand_type(ty: &Type, tokens: &mut TokenStream) {
     let tts = match *ty {
         Type::Address(span, _) => quote_spanned! {span=> ::alloy_sol_types::sol_data::Address },
         Type::Bool(span) => quote_spanned! {span=> ::alloy_sol_types::sol_data::Bool },
         Type::String(span) => quote_spanned! {span=> ::alloy_sol_types::sol_data::String },
         Type::Bytes(span) => quote_spanned! {span=> ::alloy_sol_types::sol_data::Bytes },
 
         Type::FixedBytes(span, size) => {
-            debug_assert!(size.get() <= 32);
+            assert!(size.get() <= 32);
             let size = Literal::u16_unsuffixed(size.get());
-            quote_spanned! {span=>
-                ::alloy_sol_types::sol_data::FixedBytes<#size>
-            }
+            quote_spanned! {span=> ::alloy_sol_types::sol_data::FixedBytes<#size> }
         }
         Type::Int(span, size) | Type::Uint(span, size) => {
             let name = match ty {
                 Type::Int(..) => "Int",
                 Type::Uint(..) => "Uint",
                 _ => unreachable!(),
             };
-            let name = syn::Ident::new(name, span);
+            let name = Ident::new(name, span);
 
             let size = size.map_or(256, NonZeroU16::get);
-            debug_assert!(size <= 256 && size % 8 == 0);
+            assert!(size <= 256 && size % 8 == 0);
             let size = Literal::u16_unsuffixed(size);
 
-            quote_spanned! {span=>
-                ::alloy_sol_types::sol_data::#name<#size>
-            }
+            quote_spanned! {span=> ::alloy_sol_types::sol_data::#name<#size> }
         }
 
         Type::Tuple(ref tuple) => {
@@ -103,13 +111,9 @@ fn rec_expand_type(ty: &Type, tokens: &mut TokenStream) {
             let ty = expand_type(&array.ty);
             let span = array.span();
             if let Some(size) = array.size() {
-                quote_spanned! {span=>
-                    ::alloy_sol_types::sol_data::FixedArray<#ty, #size>
-                }
+                quote_spanned! {span=> ::alloy_sol_types::sol_data::FixedArray<#ty, #size> }
             } else {
-                quote_spanned! {span=>
-                    ::alloy_sol_types::sol_data::Array<#ty>
-                }
+                quote_spanned! {span=> ::alloy_sol_types::sol_data::Array<#ty> }
             }
         }
         Type::Function(ref function) => quote_spanned! {function.span()=>
@@ -124,6 +128,82 @@ fn rec_expand_type(ty: &Type, tokens: &mut TokenStream) {
     tokens.extend(tts);
 }
 
+// IMPORTANT: Keep in sync with `sol-types/src/types/data_type.rs`
+/// The [`expand_rust_type`] recursive implementation.
+pub fn rec_expand_rust_type(ty: &Type, tokens: &mut TokenStream) {
+    // Display sizes that match with the Rust type, otherwise we lose information
+    // (e.g. `uint24` displays the same as `uint32` because both use `u32`)
+    fn allowed_int_size(size: Option<NonZeroU16>) -> bool {
+        matches!(
+            size.map_or(256, NonZeroU16::get),
+            8 | 16 | 32 | 64 | 128 | 256
+        )
+    }
+
+    let tts = match *ty {
+        Type::Address(span, _) => quote_spanned! {span=> ::alloy_sol_types::private::Address },
+        Type::Bool(span) => return Ident::new("bool", span).to_tokens(tokens),
+        Type::String(span) => quote_spanned! {span=> ::alloy_sol_types::private::String },
+        Type::Bytes(span) => quote_spanned! {span=> ::alloy_sol_types::private::Vec<u8> },
+
+        Type::FixedBytes(span, size) => {
+            assert!(size.get() <= 32);
+            let size = Literal::u16_unsuffixed(size.get());
+            quote_spanned! {span=> ::alloy_sol_types::private::FixedBytes<#size> }
+        }
+        Type::Int(span, size) | Type::Uint(span, size) if allowed_int_size(size) => {
+            let size = size.map_or(256, NonZeroU16::get);
+            if size <= 128 {
+                let name = match ty {
+                    Type::Int(..) => "i",
+                    Type::Uint(..) => "u",
+                    _ => unreachable!(),
+                };
+                return Ident::new(&format!("{name}{size}"), span).to_tokens(tokens)
+            }
+            assert_eq!(size, 256);
+            match ty {
+                Type::Int(..) => quote_spanned! {span=> ::alloy_sol_types::private::I256 },
+                Type::Uint(..) => quote_spanned! {span=> ::alloy_sol_types::private::U256 },
+                _ => unreachable!(),
+            }
+        }
+
+        Type::Tuple(ref tuple) => {
+            return tuple.paren_token.surround(tokens, |tokens| {
+                for pair in tuple.types.pairs() {
+                    let (ty, comma) = pair.into_tuple();
+                    rec_expand_rust_type(ty, tokens);
+                    comma.to_tokens(tokens);
+                }
+            })
+        }
+        Type::Array(ref array) => {
+            let ty = expand_rust_type(&array.ty);
+            let span = array.span();
+            if let Some(size) = array.size() {
+                quote_spanned! {span=> [#ty; #size] }
+            } else {
+                quote_spanned! {span=> ::alloy_sol_types::private::Vec<#ty> }
+            }
+        }
+        Type::Function(ref function) => quote_spanned! {function.span()=>
+            ::alloy_sol_types::private::Function
+        },
+        Type::Mapping(ref mapping) => quote_spanned! {mapping.span()=>
+            ::core::compile_error!("Mapping types are not supported here")
+        },
+
+        // Exhaustive fallback to `SolType::RustType`
+        ref ty @ (Type::Int(..) | Type::Uint(..) | Type::Custom(_)) => {
+            let span = ty.span();
+            let ty = expand_type(ty);
+            quote_spanned! {span=> <#ty as ::alloy_sol_types::SolType>::RustType }
+        }
+    };
+    tokens.extend(tts);
+}
+
 /// Calculates the base ABI-encoded size of the given parameters in bytes.
 ///
 /// See [`type_base_data_size`] for more information.

crates/sol-types/src/lib.rs

@@ -206,7 +206,9 @@ pub mod private {
         string::{String, ToString},
         vec::Vec,
     };
-    pub use alloy_primitives::{bytes, keccak256, Bytes, FixedBytes, B256, U256};
+    pub use alloy_primitives::{
+        bytes, keccak256, Address, Bytes, FixedBytes, Function, Signed, Uint, B256, I256, U256,
+    };
     pub use core::{convert::From, default::Default, option::Option, result::Result};
 
     pub use Option::{None, Some};

crates/sol-types/src/types/data_type.rs

@@ -14,6 +14,9 @@ use alloy_primitives::{
 };
 use core::{borrow::Borrow, fmt::*, hash::Hash, marker::PhantomData, ops::*};
 
+// IMPORTANT: Keep in sync with `rec_expand_rust_type` in
+// `sol-macro/src/expand/ty.rs`
+
 /// Bool - `bool`
 pub struct Bool;
 

crates/sol-types/tests/sol.rs

@@ -1,4 +1,4 @@
-use alloy_primitives::{keccak256, Address, B256, U256};
+use alloy_primitives::{keccak256, Address, B256, I256, U256};
 use alloy_sol_types::{eip712_domain, sol, SolCall, SolError, SolStruct, SolType};
 use serde::Serialize;
 use serde_json::Value;
@@ -133,15 +133,18 @@ fn function() {
 #[test]
 fn error() {
     sol! {
-        error SomeError(uint256 a);
+        error SomeError(int a, bool b);
     }
 
-    let sig = "SomeError(uint256)";
+    let sig = "SomeError(int256,bool)";
     assert_eq!(SomeError::SIGNATURE, sig);
     assert_eq!(SomeError::SELECTOR, keccak256(sig)[..4]);
 
-    let e = SomeError { a: U256::from(1) };
-    assert_eq!(e.encoded_size(), 32);
+    let e = SomeError {
+        a: I256::ZERO,
+        b: false,
+    };
+    assert_eq!(e.encoded_size(), 64);
 }
 
 // https://github.com/alloy-rs/core/issues/158