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: default_expr.rs
    path of file: ./repos/darling/core/src/codegen
    
    the code of the file until where you have to start completion: use proc_macro2::{Span, TokenStream};
use quote::{quote, quote_spanned, ToTokens, TokenStreamExt};
use syn::{spanned::Spanned, Ident, Path};

/
    
    fn to_tokens(&self, tokens: &mut TokenStream) {
        tokens.append_all(match *self {
            DefaultExpression::Inherit(ident) => {
                let dsn = Ident::new(DEFAULT_STRUCT_NAME, ::proc_macro2::Span::call_site());
                quote!(#dsn.#ident)
            }
            DefaultExpression::Explicit(path) => {
                // Use quote_spanned to properly set the span of the parentheses
                quote_spanned!(path.span()=>#path())
            }
            DefaultExpression::Trait { span } => {
                quote_spanned!(span=> ::darling::export::Default::default())
            }
        });
    }