Update to syn 2

Author: dtolnay

.github/workflows/ci.yml

@@ -108,12 +108,12 @@ jobs:
       - run: cd serde && cargo build
 
   derive:
-    name: Rust 1.31.0
+    name: Rust 1.56.0
     runs-on: ubuntu-latest
     timeout-minutes: 45
     steps:
       - uses: actions/checkout@v3
-      - uses: dtolnay/rust-toolchain@1.31.0
+      - uses: dtolnay/rust-toolchain@1.56.0
       - run: cd serde && cargo check --no-default-features
       - run: cd serde && cargo check
       - run: cd serde_derive && cargo check

serde_derive/Cargo.toml

@@ -24,7 +24,7 @@ proc-macro = true
 [dependencies]
 proc-macro2 = "1.0"
 quote = "1.0"
-syn = "1.0.104"
+syn = "2.0"
 
 [dev-dependencies]
 serde = { version = "1.0", path = "../serde" }

serde_derive/src/bound.rs

@@ -200,10 +200,16 @@ pub fn with_bound(
                     for arg in &arguments.args {
                         match arg {
                             syn::GenericArgument::Type(arg) => self.visit_type(arg),
-                            syn::GenericArgument::Binding(arg) => self.visit_type(&arg.ty),
+                            syn::GenericArgument::AssocType(arg) => self.visit_type(&arg.ty),
                             syn::GenericArgument::Lifetime(_)
-                            | syn::GenericArgument::Constraint(_)
-                            | syn::GenericArgument::Const(_) => {}
+                            | syn::GenericArgument::Const(_)
+                            | syn::GenericArgument::AssocConst(_)
+                            | syn::GenericArgument::Constraint(_) => {}
+                            #[cfg_attr(
+                                all(test, exhaustive),
+                                deny(non_exhaustive_omitted_patterns)
+                            )]
+                            _ => {}
                         }
                     }
                 }
@@ -226,7 +232,9 @@ pub fn with_bound(
         fn visit_type_param_bound(&mut self, bound: &'ast syn::TypeParamBound) {
             match bound {
                 syn::TypeParamBound::Trait(bound) => self.visit_path(&bound.path),
-                syn::TypeParamBound::Lifetime(_) => {}
+                syn::TypeParamBound::Lifetime(_) | syn::TypeParamBound::Verbatim(_) => {}
+                #[cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
+                _ => {}
             }
         }
 
@@ -334,7 +342,7 @@ pub fn with_self_bound(
 
 pub fn with_lifetime_bound(generics: &syn::Generics, lifetime: &str) -> syn::Generics {
     let bound = syn::Lifetime::new(lifetime, Span::call_site());
-    let def = syn::LifetimeDef {
+    let def = syn::LifetimeParam {
         attrs: Vec::new(),
         lifetime: bound.clone(),
         colon_token: None,

serde_derive/src/de.rs

@@ -244,9 +244,9 @@ impl BorrowedLifetimes {
         }
     }
 
-    fn de_lifetime_def(&self) -> Option<syn::LifetimeDef> {
+    fn de_lifetime_param(&self) -> Option<syn::LifetimeParam> {
         match self {
-            BorrowedLifetimes::Borrowed(bounds) => Some(syn::LifetimeDef {
+            BorrowedLifetimes::Borrowed(bounds) => Some(syn::LifetimeParam {
                 attrs: Vec::new(),
                 lifetime: syn::Lifetime::new("'de", Span::call_site()),
                 colon_token: None,
@@ -3011,7 +3011,7 @@ struct InPlaceImplGenerics<'a>(&'a Parameters);
 impl<'a> ToTokens for DeImplGenerics<'a> {
     fn to_tokens(&self, tokens: &mut TokenStream) {
         let mut generics = self.0.generics.clone();
-        if let Some(de_lifetime) = self.0.borrowed.de_lifetime_def() {
+        if let Some(de_lifetime) = self.0.borrowed.de_lifetime_param() {
             generics.params = Some(syn::GenericParam::Lifetime(de_lifetime))
                 .into_iter()
                 .chain(generics.params)
@@ -3046,7 +3046,7 @@ impl<'a> ToTokens for InPlaceImplGenerics<'a> {
             .into_iter()
             .chain(generics.params)
             .collect();
-        if let Some(de_lifetime) = self.0.borrowed.de_lifetime_def() {
+        if let Some(de_lifetime) = self.0.borrowed.de_lifetime_param() {
             generics.params = Some(syn::GenericParam::Lifetime(de_lifetime))
                 .into_iter()
                 .chain(generics.params)
@@ -3071,8 +3071,8 @@ struct InPlaceTypeGenerics<'a>(&'a Parameters);
 impl<'a> ToTokens for DeTypeGenerics<'a> {
     fn to_tokens(&self, tokens: &mut TokenStream) {
         let mut generics = self.0.generics.clone();
-        if self.0.borrowed.de_lifetime_def().is_some() {
-            let def = syn::LifetimeDef {
+        if self.0.borrowed.de_lifetime_param().is_some() {
+            let def = syn::LifetimeParam {
                 attrs: Vec::new(),
                 lifetime: syn::Lifetime::new("'de", Span::call_site()),
                 colon_token: None,
@@ -3097,8 +3097,8 @@ impl<'a> ToTokens for InPlaceTypeGenerics<'a> {
             .chain(generics.params)
             .collect();
 
-        if self.0.borrowed.de_lifetime_def().is_some() {
-            let def = syn::LifetimeDef {
+        if self.0.borrowed.de_lifetime_param().is_some() {
+            let def = syn::LifetimeParam {
                 attrs: Vec::new(),
                 lifetime: syn::Lifetime::new("'de", Span::call_site()),
                 colon_token: None,
@@ -3122,8 +3122,8 @@ impl<'a> DeTypeGenerics<'a> {
 }
 
 #[cfg(feature = "deserialize_in_place")]
-fn place_lifetime() -> syn::LifetimeDef {
-    syn::LifetimeDef {
+fn place_lifetime() -> syn::LifetimeParam {
+    syn::LifetimeParam {
         attrs: Vec::new(),
         lifetime: syn::Lifetime::new("'place", Span::call_site()),
         colon_token: None,