slint-ui/slint · error · syn::Error

Only `struct` with named field are supported

Error message

Only `struct` with named field are supported

What it means

Error "Only `struct` with named field are supported" thrown in slint-ui/slint.

Source

Thrown at internal/core-macros/lib.rs:29

use proc_macro::TokenStream;
use quote::quote;

mod slint_doc;

/// This derive macro is used with structures in the run-time library that are meant
/// to be exposed to the language. The structure is introspected for properties and fields
/// marked with the `rtti_field` attribute and generates run-time type information for use
/// with the interpreter.
/// In addition all `Property<T> foo` fields get a convenient getter function generated
/// that works on a `Pin<&Self>` receiver.
#[proc_macro_derive(SlintElement, attributes(rtti_field))]
pub fn slint_element(input: TokenStream) -> TokenStream {
    let input = syn::parse_macro_input!(input as syn::DeriveInput);

    let fields = match &input.data {
        syn::Data::Struct(syn::DataStruct { fields: f @ syn::Fields::Named(..), .. }) => f,
        _ => {
            return syn::Error::new(
                input.ident.span(),
                "Only `struct` with named field are supported",
            )
            .to_compile_error()
            .into();
        }
    };

    let mut pub_prop_field_names = Vec::new();
    let mut pub_prop_field_names_normalized = Vec::new();
    let mut pub_prop_field_types = Vec::new();
    let mut property_names = Vec::new();
    let mut property_visibility = Vec::new();
    let mut property_types = Vec::new();

    for field in fields {
        if let Some(property_type) = property_type(&field.ty) {
            let name = field.ident.as_ref().unwrap();

View on GitHub (pinned to 3fd8f2ec03)

Solutions

1. Use a struct with named fields with this macro.
2. Convert tuple structs into named-field structs.

When it happens

Trigger: Thrown at internal/core-macros/lib.rs:29 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of slint-ui/slint@3fd8f2ec03 (2026-08-19). Data as JSON: /api/errors/62268eda2a7ed337. Report an issue: GitHub.