You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: try_from.rs
    path of file: ./repos/derive_more/impl/src
    
    the code of the file until where you have to start completion: //! Implementation of a [`TryFrom`] derive macro.

use proc_macro2::{Literal, TokenStream};
use quote::{format_ident, quote, ToTokens};
use syn::spanned::Spanned as _;

use crate::utils::{
    attr::{self, ParseMultiple as _},
    Spanning,
};

/// Expands a [`TryFrom`] derive macro.
pub fn expand(input: &syn::DeriveInput, _: &'static str) -> syn::Result<TokenStream> {
    match &input.data {
        syn::Data::Struct(data) => Err(syn::Error::
    
pub fn expand(input: &syn::DeriveInput, _: &'static str) -> syn::Result<TokenStream> {
    match &input.data {
        syn::Data::Struct(data) => Err(syn::Error::new(
            data.struct_token.span(),
            "`TryFrom` cannot be derived for structs",
        )),
        syn::Data::Enum(data) => Ok(Expansion {
            repr: attr::ReprInt::parse_attrs(&input.attrs, &format_ident!("repr"))?
                .map(Spanning::into_inner)
                .unwrap_or_default(),
            attr: ItemAttribute::parse_attrs(&input.attrs, &format_ident!("try_from"))?
                .map(|attr| {
                    if matches!(attr.item, ItemAttribute::Types(_)) {
                        Err(syn::Error::new(
                            attr.span,
                            "`#[try_from(repr(...))]` attribute is not supported yet",
                        ))
                    } else {
                        Ok(attr.item)
                    }
                })
                .transpose()?,
            ident: input.ident.clone(),
            generics: input.generics.clone(),
            variants: data.variants.clone().into_iter().collect(),
        }
        .into_token_stream()),
        syn::Data::Union(data) => Err(syn::Error::new(
            data.union_token.span(),
            "`TryFrom` cannot be derived for unions",
        )),
    }
}