serde version after 1.0.157 report unexpected token with svgbobdoc::transform!

[CurryPseudo]

Minimal example:

Cargo.toml:

[package]
name = "playground"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
serde = { version = "=1.0.157", features = ["derive"] }
svgbobdoc = "0.3.0"

lib.rs:

use serde::Serialize;

// This compiles ok
#[doc = svgbobdoc::transform!(
/// Foo
)]
pub struct Foo0;

// This compiles failed
#[doc = svgbobdoc::transform!(
/// Foo
)]
#[derive(Serialize)]
pub struct Foo1;

playground on  main [!] via 🦀 v1.68.0 took 3s
➜ : cargo build
   Compiling playground v0.1.0 (C:\Dev\playground)
error: unexpected token
  --> src\lib.rs:10:29
   |
10 | #[doc = svgbobdoc::transform!(
   |                             ^

error: could not compile `playground` due to previous error

[oli-obk]

This is probably a syn issue. Can you try using an older serde version that still works for you, but updating the syn version with cargo update -p syn?

[CurryPseudo]

With serde version 1.0.156, cargo update -p syn seems doing nothing.
Here is the diff in Cargo.lock while switching serde from 1.0.156 to 1.0.157:

--- a/Cargo.lock
+++ b/Cargo.lock
@@ -36,22 +36,22 @@ dependencies = [
 
 [[package]]
 name = "serde"
-version = "1.0.156"
+version = "1.0.157"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "314b5b092c0ade17c00142951e50ced110ec27cea304b1037c6969246c2469a4"
+checksum = "707de5fcf5df2b5788fca98dd7eab490bc2fd9b7ef1404defc462833b83f25ca"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.156"
+version = "1.0.157"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d7e29c4601e36bcec74a223228dce795f4cd3616341a4af93520ca1a837c087d"
+checksum = "78997f4555c22a7971214540c4a661291970619afd56de19f77e0de86296e1e5"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.4",
 ]
 
 [[package]]
@@ -63,7 +63,7 @@ dependencies = [
  "base64",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 1.0.109",
  "unicode-width",
 ]
 
@@ -78,6 +78,17 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "syn"
+version = "2.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2c622ae390c9302e214c31013517c2061ecb2699935882c60a9b37f82f8625ae"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.8"

There is a new syn version added, but svgbobdoc is still using syn 1.0.109:

[[package]]
name = "svgbobdoc"
version = "0.3.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "f2c04b93fc15d79b39c63218f15e3fdffaa4c227830686e3b7c5f41244eb3e50"
dependencies = [
 "base64",
 "proc-macro2",
 "quote",
 "syn 1.0.109",
 "unicode-width",
]

[CurryPseudo]

This appears on every derive macro which uses syn 2.0, for example thiserror:

use thiserror::Error;

// This compiles ok
#[doc = svgbobdoc::transform!(
/// Foo
)]
pub struct Foo0;

// This compiles failed
#[doc = svgbobdoc::transform!(
/// Foo
)]
#[derive(Error)]
pub struct Foo1;

Close now.