Impl ToTokens for syn::Error and syn::Result<T: ToTokens>?

[marcianx]

I had a foo: syn::Result<Expr> and wrote:

foo
    .map(ToTokens::into_token_stream)
    .unwrap_or_else(syn::Error::into_compile_error)
    .into()

and it made me wonder:

1. Why can't we just do quote! { #foo } given that syn::Error has an idiomatic conversion to a TokenStream -- IOW, implement ToTokens for syn::Result<T: ToTokens>.
2. Does it make sense to also implement ToTokens for syn::Error?

Thoughts?