chore: update syn to 2

Author: robjtede

.cspell.yml

@@ -1,12 +1,16 @@
 version: "0.2"
 words:
   - clippy
+  - codegen
   - direnv
+  - elems
   - msrv
   - nextest
   - nixos
   - nixpkgs
   - nonminimal
   - pkgs
+  - punct
   - RUSTDOCFLAGS
   - taplo
+  - toks

CHANGELOG.md

@@ -6,6 +6,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ## Unreleased
 
+- Update `syn` requirement to `2`.
+
 ## 0.6.5
 
 - Improve support for async functions and mutable borrows in contracts.

Cargo.lock

@@ -3,11 +3,12 @@ name = "contracts"
 version = "0.6.5"
 description = "Design-by-contract attributes"
 authors = ["karroffel <[email protected]>"]
-edition = "2018"
-repository = "https://github.com/x52dev/contracts"
-license = "MPL-2.0"
 categories = ["development-tools", "development-tools::procedural-macro-helpers"]
 keywords = ["design-by-contract", "precondition", "postcondition", "invariant", "verification"]
+repository = "https://github.com/x52dev/contracts"
+license = "MPL-2.0"
+edition = "2018"
+rust-version = "1.65"
 
 [lib]
 name = "contracts"
@@ -21,6 +22,6 @@ override_log = []
 mirai_assertions = []
 
 [dependencies]
-proc-macro2 = "1.0"
-quote = "1.0"
-syn = { version = "1.0", features = ["extra-traits", "full", "visit", "visit-mut"] }
+proc-macro2 = "1"
+quote = "1"
+syn = { version = "2", features = ["extra-traits", "full", "visit", "visit-mut"] }

Cargo.toml

@@ -9,8 +9,8 @@
 [![dependency status](https://deps.rs/crate/contracts/0.6.5/status.svg)](https://deps.rs/crate/contracts/0.6.5)
 ![MIT or Apache 2.0 licensed](https://img.shields.io/crates/l/contracts.svg)
 <br />
-[![CI](https://github.com/x52dev/contracts-rs/actions/workflows/ci.yml/badge.svg)](https://github.com/x52dev/contracts-rs/actions/workflows/ci.yml)
-[![codecov](https://codecov.io/gh/x52dev/contracts-rs/graph/badge.svg?token=OpYe6I7dj5)](https://codecov.io/gh/x52dev/contracts-rs)
+[![CI](https://github.com/x52dev/contracts/actions/workflows/ci.yml/badge.svg)](https://github.com/x52dev/contracts-rs/actions/workflows/ci.yml)
+[![codecov](https://codecov.io/gh/x52dev/contracts/graph/badge.svg?token=OpYe6I7dj5)](https://codecov.io/gh/x52dev/contracts-rs)
 ![Version](https://img.shields.io/crates/msrv/contracts.svg)
 [![Download](https://img.shields.io/crates/d/contracts.svg)](https://crates.io/crates/contracts)
 

README.md

@@ -4,7 +4,7 @@
 
 use proc_macro2::TokenStream;
 use quote::ToTokens;
-use syn::{FnArg, ImplItem, ImplItemMethod, Item, ItemFn, ItemImpl};
+use syn::{FnArg, ImplItem, ImplItemFn, Item, ItemFn, ItemImpl};
 
 use crate::implementation::{ContractMode, ContractType, FuncWithContracts};
 
@@ -53,7 +53,7 @@ fn invariant_impl(
 
     let invariant_ident = syn::Ident::new(&name, proc_macro2::Span::call_site());
 
-    fn method_uses_self(method: &ImplItemMethod) -> bool {
+    fn method_uses_self(method: &ImplItemFn) -> bool {
         let inputs = &method.sig.inputs;
 
         if !inputs.is_empty() {
@@ -64,7 +64,7 @@ fn invariant_impl(
     }
 
     for item in &mut impl_def.items {
-        if let ImplItem::Method(method) = item {
+        if let ImplItem::Fn(method) = item {
             // only implement invariants for methods that take `self`
             if !method_uses_self(method) {
                 continue;
@@ -75,7 +75,7 @@ fn invariant_impl(
                 #method
             };
 
-            let met: ImplItemMethod = syn::parse_quote!(#method_toks);
+            let met: ImplItemFn = syn::parse_quote!(#method_toks);
 
             *method = met;
         }

src/implementation/invariant.rs

@@ -12,7 +12,7 @@ pub(crate) mod traits;
 
 pub(crate) use ensures::ensures;
 pub(crate) use invariant::invariant;
-use proc_macro2::{Span, TokenStream, TokenTree};
+use proc_macro2::{Span, TokenStream};
 use quote::ToTokens;
 pub(crate) use requires::requires;
 use syn::{Expr, ItemFn};
@@ -166,23 +166,25 @@ impl FuncWithContracts {
             .attrs
             .iter()
             .filter_map(|a| {
-                let name = a.path.segments.last().unwrap().ident.to_string();
+                let name = a.path().segments.last().unwrap().ident.to_string();
                 let (ty, mode) = ContractType::contract_type_and_mode(&name)?;
                 Some((ty, mode, a))
             })
-            .map(|(ty, mode, a)| {
+            .map(|(ty, mode, attr)| {
                 // the tts on attributes contains the out parenthesis, so some
                 // code might be mistakenly parsed as tuples, that's not good!
                 //
                 // this is a hack to get to the inner token stream.
 
-                let tok_tree = a.tokens.clone().into_iter().next().unwrap();
-                let toks = match tok_tree {
-                    TokenTree::Group(group) => group.stream(),
-                    TokenTree::Ident(i) => i.into_token_stream(),
-                    TokenTree::Punct(p) => p.into_token_stream(),
-                    TokenTree::Literal(l) => l.into_token_stream(),
-                };
+                fn extract_first_arg_stream(attr: &syn::Attribute) -> TokenStream {
+                    match &attr.meta {
+                        syn::Meta::List(list) => list.tokens.clone(),
+                        syn::Meta::Path(path) => path.to_token_stream(),
+                        syn::Meta::NameValue(nv) => dbg!(nv.value.to_token_stream()),
+                    }
+                }
+
+                let toks = extract_first_arg_stream(attr);
 
                 Contract::from_toks(ty, mode, toks)
             });
@@ -197,7 +199,7 @@ impl FuncWithContracts {
                 .into_iter()
                 .filter(|attr| {
                     ContractType::contract_type_and_mode(
-                        &attr.path.segments.last().unwrap().ident.to_string(),
+                        &attr.path().segments.last().unwrap().ident.to_string(),
                     )
                     .is_none()
                 })

src/implementation/mod.rs

@@ -4,7 +4,7 @@
 
 use proc_macro2::TokenStream;
 use quote::ToTokens;
-use syn::{FnArg, ImplItem, ItemImpl, ItemTrait, Pat, TraitItem, TraitItemMethod};
+use syn::{FnArg, ImplItem, ItemImpl, ItemTrait, Pat, TraitItem, TraitItemFn};
 
 use crate::implementation::ContractType;
 
@@ -16,8 +16,8 @@ fn contract_method_impl_name(name: &str) -> String {
 /// Modifies a trait item in a way that it includes contracts.
 pub(crate) fn contract_trait_item_trait(_attrs: TokenStream, mut trait_: ItemTrait) -> TokenStream {
     /// Just rename the method to have an internal, generated name.
-    fn create_method_rename(method: &TraitItemMethod) -> TraitItemMethod {
-        let mut m: TraitItemMethod = (*method).clone();
+    fn create_method_rename(method: &TraitItemFn) -> TraitItemFn {
+        let mut m = method.clone();
 
         // rename method and modify attributes
         {
@@ -35,8 +35,8 @@ pub(crate) fn contract_trait_item_trait(_attrs: TokenStream, mut trait_: ItemTra
             new_attrs.extend(
                 m.attrs
                     .iter()
-                    .filter(|a| {
-                        let name = a.path.segments.last().unwrap().ident.to_string();
+                    .filter(|attr| {
+                        let name = attr.path().segments.last().unwrap().ident.to_string();
 
                         ContractType::contract_type_and_mode(&name).is_none()
                     })
@@ -55,7 +55,7 @@ pub(crate) fn contract_trait_item_trait(_attrs: TokenStream, mut trait_: ItemTra
     /// includes contracts.
     ///
     /// This new function forwards the call to the actual implementation.
-    fn create_method_wrapper(method: &TraitItemMethod) -> TraitItemMethod {
+    fn create_method_wrapper(method: &TraitItemFn) -> TraitItemFn {
         struct ArgInfo {
             call_toks: proc_macro2::TokenStream,
         }
@@ -92,7 +92,7 @@ pub(crate) fn contract_trait_item_trait(_attrs: TokenStream, mut trait_: ItemTra
             }
         }
 
-        let mut m: TraitItemMethod = (*method).clone();
+        let mut m = method.clone();
 
         let argument_data = m
             .sig
@@ -138,7 +138,7 @@ pub(crate) fn contract_trait_item_trait(_attrs: TokenStream, mut trait_: ItemTra
             m.attrs
                 .iter()
                 .filter(|a| {
-                    let name = a.path.segments.last().unwrap().ident.to_string();
+                    let name = a.path().segments.last().unwrap().ident.to_string();
                     // is doc?
                     if name == "doc" {
                         return true;
@@ -168,11 +168,11 @@ pub(crate) fn contract_trait_item_trait(_attrs: TokenStream, mut trait_: ItemTra
         .items
         .iter()
         .filter_map(|item| {
-            if let TraitItem::Method(m) = item {
+            if let TraitItem::Fn(m) = item {
                 let rename = create_method_rename(m);
                 let wrapper = create_method_wrapper(m);
 
-                Some(vec![TraitItem::Method(rename), TraitItem::Method(wrapper)])
+                Some(vec![TraitItem::Fn(rename), TraitItem::Fn(wrapper)])
             } else {
                 None
             }
@@ -183,7 +183,7 @@ pub(crate) fn contract_trait_item_trait(_attrs: TokenStream, mut trait_: ItemTra
     // remove all previous methods
     trait_
         .items
-        .retain(|item| !matches!(item, TraitItem::Method(_)));
+        .retain(|item| !matches!(item, TraitItem::Fn(_)));
 
     // add back new methods
     trait_.items.extend(funcs);
@@ -198,7 +198,7 @@ pub(crate) fn contract_trait_item_impl(_attrs: TokenStream, impl_: ItemImpl) ->
         let mut impl_: ItemImpl = impl_;
 
         impl_.items.iter_mut().for_each(|it| {
-            if let ImplItem::Method(method) = it {
+            if let ImplItem::Fn(method) = it {
                 let new_name = contract_method_impl_name(&method.sig.ident.to_string());
                 let new_ident = syn::Ident::new(&new_name, method.sig.ident.span());