Recursion limit error while expanding `#[wasm_bindgen]` on structs, when wasm-bindgen is not a direct dependency

Author: cocorigonCreated Aug 23, 2026Updated Aug 23, 2026

Describe the bug

When wasm-bindgen is pulled as a transitive dependency (through web-sys for example), and not declared as a direct dependency of the crate, the #[wasm_bindgen] macro reaches a recursion limit error when annotated on any struct. The macro works fine on functions though.

Version

web-sys 0.3.104 wasm-bindgen 0.2.127

Minimal reproduction

src/lib.rs:

rust

use web_sys::wasm_bindgen::{self, prelude::wasm_bindgen};

#[wasm_bindgen]
pub struct MyStruct;

Cargo.toml:

toml

[package]
name = "wasm-bindgen-recursion-limit"
edition = "2024"

[dependencies]
web-sys = "0.3.104"

Then run cargo build.

Expected behavior

The project builds.

Actual behavior

txt

error: recursion limit reached while expanding `#[wasm_bindgen]`
 --> src/lib.rs:3:1
  |
3 | #[wasm_bindgen]
  | ^^^^^^^^^^^^^^^
  |
  = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`wasm_bindgen_recursion_limit`)
  = note: this error originates in the attribute macro `wasm_bindgen` (in Nightly builds, run with -Z macro-backtrace for more info)

error: could not compile `wasm-bindgen-recursion-limit` (lib) due to 1 previous error

Severity

Annoyance.

Adding wasm-bindgen = "*" to the Cargo dependencies works around the issue.

Source: wasm-bindgen/wasm-bindgen

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