Update to syn 2

Cargo.toml

@@ -18,7 +18,7 @@ proc-macro = true
 miniserde = "0.1"
 
 [dependencies]
-syn = { version = "1.0", features = ["derive", "full"] }
+syn = { version = "2", features = ["derive", "full"] }
 quote = "1.0"
 proc-macro2 = "1.0"
 miniserde = "0.1" # TODO: remove

src/attr.rs

@@ -1,5 +1,5 @@
 use crate::TagType;
-use syn::{Attribute, DataEnum, Error, Field, Fields, Lit, Meta, NestedMeta, Result, Variant};
+use syn::{Attribute, DataEnum, Error, Field, Fields, LitStr, Result, Variant};
 
 pub(crate) fn tag_type(attrs: &[Attribute], enumeration: &DataEnum) -> Result<TagType> {
     let mut tag_type = None;
@@ -7,52 +7,35 @@ pub(crate) fn tag_type(attrs: &[Attribute], enumeration: &DataEnum) -> Result<Ta
     let mut content = None;
 
     for attr in attrs {
-        if !attr.path.is_ident("serde") {
+        if !attr.path().is_ident("serde") {
             continue;
         }
-
-        let list = match attr.parse_meta()? {
-            Meta::List(list) => list,
-            other => return Err(Error::new_spanned(other, "unsupported attribute")),
-        };
-
-        for meta in &list.nested {
-            match meta {
-                NestedMeta::Meta(Meta::NameValue(value)) => {
-                    if value.path.is_ident("tag") {
-                        if let Lit::Str(s) = &value.lit {
-                            if tag.is_some() {
-                                return Err(Error::new_spanned(meta, "duplicate tag attribute"));
-                            }
-                            tag = Some(s.value());
-                            continue;
-                        }
-                    } else if value.path.is_ident("content") {
-                        if let Lit::Str(s) = &value.lit {
-                            if content.is_some() {
-                                return Err(Error::new_spanned(
-                                    meta,
-                                    "duplicate content attribute",
-                                ));
-                            }
-                            content = Some(s.value());
-                            continue;
-                        }
-                    }
+        attr.parse_nested_meta(|meta| {
+            if meta.path.is_ident("tag") {
+                let value: LitStr = meta.value()?.parse()?;
+                if tag.is_some() {
+                    return Err(meta.error("duplicate tag attribute"));
                 }
-                NestedMeta::Meta(Meta::Path(path)) => {
-                    if path.is_ident("untagged") {
-                        if tag_type.is_some() {
-                            return Err(Error::new_spanned(meta, "duplicate tag attribute"));
-                        }
-                        tag_type = Some(TagType::Untagged);
-                        continue;
-                    }
-                }
-                _ => (),
+                tag = Some(value.value());
+                return Ok(());
             }
-            return Err(Error::new_spanned(meta, "unsupported attribute"));
-        }
+            if meta.path.is_ident("content") {
+                let value: LitStr = meta.value()?.parse()?;
+                if content.is_some() {
+                    return Err(meta.error("duplicate content attribute"));
+                }
+                content = Some(value.value());
+                return Ok(());
+            }
+            if meta.path.is_ident("untagged") {
+                if tag_type.is_some() {
+                    return Err(meta.error("duplicate tag attribute"));
+                }
+                tag_type = Some(TagType::Untagged);
+                return Ok(());
+            }
+            Err(meta.error("unsupported attribute"))
+        })?;
     }
     if let Some(ty) = tag_type {
         return Ok(ty);
@@ -84,29 +67,20 @@ fn attr_rename(attrs: &[Attribute]) -> Result<Option<String>> {
     let mut rename = None;
 
     for attr in attrs {
-        if !attr.path.is_ident("serde") {
+        if !attr.path().is_ident("serde") {
             continue;
         }
-
-        let list = match attr.parse_meta()? {
-            Meta::List(list) => list,
-            other => return Err(Error::new_spanned(other, "unsupported attribute")),
-        };
-
-        for meta in &list.nested {
-            if let NestedMeta::Meta(Meta::NameValue(value)) = meta {
-                if value.path.is_ident("rename") {
-                    if let Lit::Str(s) = &value.lit {
-                        if rename.is_some() {
-                            return Err(Error::new_spanned(meta, "duplicate rename attribute"));
-                        }
-                        rename = Some(s.value());
-                        continue;
-                    }
+        attr.parse_nested_meta(|meta| {
+            if meta.path.is_ident("rename") {
+                let value: LitStr = meta.value()?.parse()?;
+                if rename.is_some() {
+                    return Err(meta.error("duplicate rename attribute"));
                 }
+                rename = Some(value.value());
+                return Ok(());
             }
-            return Err(Error::new_spanned(meta, "unsupported attribute"));
-        }
+            Err(meta.error("unsupported attribute"))
+        })?;
     }
 
     Ok(rename)

src/bound.rs

@@ -1,13 +1,13 @@
 use proc_macro2::{Span, TokenStream};
 use syn::punctuated::Punctuated;
 use syn::{
-    parse_quote, GenericParam, Generics, Lifetime, LifetimeDef, TypeParamBound, WhereClause,
+    parse_quote, GenericParam, Generics, Lifetime, LifetimeParam, TypeParamBound, WhereClause,
     WherePredicate,
 };
 
 pub fn with_lifetime_bound(generics: &Generics, lifetime: &str) -> Generics {
     let bound = Lifetime::new(lifetime, Span::call_site());
-    let def = LifetimeDef {
+    let def = LifetimeParam {
         attrs: Vec::new(),
         lifetime: bound.clone(),
         colon_token: None,