juspay/hyperswitch · error · syn::Error

This macro cannot be used on structs with no fields

Error message

This macro cannot be used on structs with no fields

What it means

Error "This macro cannot be used on structs with no fields" thrown in juspay/hyperswitch.

Source

Thrown at crates/router_derive/src/macros/helpers.rs:60

        .into_iter()
        .filter(|attr| attr.path().is_ident(ident))
        .try_fold(Vec::new(), |mut vec, attr| {
            vec.extend(attr.parse_args_with(Punctuated::<T, Token![,]>::parse_terminated)?);
            Ok(vec)
        })
}

pub(super) fn get_struct_fields(
    data: syn::Data,
) -> syn::Result<Punctuated<syn::Field, syn::token::Comma>> {
    if let syn::Data::Struct(syn::DataStruct {
        fields: syn::Fields::Named(syn::FieldsNamed { ref named, .. }),
        ..
    }) = data
    {
        Ok(named.to_owned())
    } else {
        Err(syn::Error::new(
            Span::call_site(),
            "This macro cannot be used on structs with no fields",
        ))
    }
}

View on GitHub (pinned to 705a321950)

Solutions

1. Add at least one field to the struct, or remove the derive macro from the empty struct

When it happens

Trigger: Thrown at crates/router_derive/src/macros/helpers.rs:60 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of juspay/hyperswitch@705a321950 (2026-08-19). Data as JSON: /api/errors/7ce2c46b8b8c0680. Report an issue: GitHub.