attributes: update to syn 2.0 (#2516)

## Motivation

syn 2.0 is out!

## Solution

Update to syn 2.0 🚀

Co-authored-by: David Barsky <me@davidbarsky.com>
Co-authored-by: Eliza Weisman <eliza@buoyant.io>

tracing-attributes/Cargo.toml

@@ -40,16 +40,15 @@ async-await = []
 
 [dependencies]
 proc-macro2 = "1.0.40"
-syn = { version = "1.0.98", default-features = false, features = ["full", "parsing", "printing", "visit-mut", "clone-impls", "extra-traits", "proc-macro"] }
+syn = { version = "2.0", default-features = false, features = ["full", "parsing", "printing", "visit-mut", "clone-impls", "extra-traits", "proc-macro"] }
 quote = "1.0.20"
 
 [dev-dependencies]
 tracing = { path = "../tracing", version = "0.1.35" }
 tracing-mock = { path = "../tracing-mock", features = ["tokio-test"] }
 tracing-subscriber = { path = "../tracing-subscriber", version = "0.3.0", features = ["env-filter"] }
 tokio-test = "0.4.2"
-tracing-core = { path = "../tracing-core", version = "0.1.28"}
-async-trait = "0.1.56"
+async-trait = "0.1.67"
 trybuild = "1.0.64"
 rustversion = "1.0.9"
 

tracing-attributes/src/attr.rs

@@ -252,7 +252,7 @@ impl Parse for Skips {
         let _ = input.parse::<kw::skip>();
         let content;
         let _ = syn::parenthesized!(content in input);
-        let names: Punctuated<Ident, Token![,]> = content.parse_terminated(Ident::parse_any)?;
+        let names = content.parse_terminated(Ident::parse_any, Token![,])?;
         let mut skips = HashSet::new();
         for name in names {
             if skips.contains(&name) {
@@ -303,7 +303,7 @@ impl Parse for Fields {
         let _ = input.parse::<kw::fields>();
         let content;
         let _ = syn::parenthesized!(content in input);
-        let fields: Punctuated<_, Token![,]> = content.parse_terminated(Field::parse)?;
+        let fields = content.parse_terminated(Field::parse, Token![,])?;
         Ok(Self(fields))
     }
 }
@@ -348,7 +348,7 @@ impl ToTokens for Field {
             let name = &self.name;
             let kind = &self.kind;
             tokens.extend(quote! {
-                #name = #kind#value
+                #name = #kind #value
             })
         } else if self.kind == FieldKind::Value {
             // XXX(eliza): I don't like that fields without values produce

tracing-attributes/src/expand.rs

@@ -477,10 +477,7 @@ fn param_names(pat: Pat, record_type: RecordType) -> Box<dyn Iterator<Item = (Id
                 .into_iter()
                 .flat_map(|p| param_names(p, RecordType::Debug)),
         ),
-        Pat::TupleStruct(PatTupleStruct {
-            pat: PatTuple { elems, .. },
-            ..
-        }) => Box::new(
+        Pat::TupleStruct(PatTupleStruct { elems, .. }) => Box::new(
             elems
                 .into_iter()
                 .flat_map(|p| param_names(p, RecordType::Debug)),
@@ -564,7 +561,7 @@ impl<'block> AsyncInfo<'block> {
         // last expression of the block: it determines the return value of the
         // block, this is quite likely a `Box::pin` statement or an async block
         let (last_expr_stmt, last_expr) = block.stmts.iter().rev().find_map(|stmt| {
-            if let Stmt::Expr(expr) = stmt {
+            if let Stmt::Expr(expr, _semi) = stmt {
                 Some((stmt, expr))
             } else {
                 None