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use proc_macro2;
use ast;
use attr;
use bound;
use syn;
pub fn build_impl_generics<F, G, H>(
item: &ast::Input,
trait_path: &syn::Path,
needs_debug_bound: F,
field_bound: G,
input_bound: H,
) -> syn::Generics
where
F: Fn(&attr::Field) -> bool,
G: Fn(&attr::Field) -> Option<&[syn::WherePredicate]>,
H: Fn(&attr::Input) -> Option<&[syn::WherePredicate]>,
{
let generics = bound::without_defaults(item.generics);
let generics = bound::with_where_predicates_from_fields(item, &generics, field_bound);
match input_bound(&item.attrs) {
Some(predicates) => bound::with_where_predicates(&generics, predicates),
None => bound::with_bound(item, &generics, needs_debug_bound, trait_path),
}
}
pub fn hygienic_type_parameter(item: &ast::Input, base: &str) -> syn::Ident {
let mut typaram = String::with_capacity(150);
typaram.push_str(base);
let typaram = item.generics.type_params().fold(typaram, |mut acc, ty| {
acc.push_str(&format!("{}", &ty.ident));
acc
});
syn::Ident::new(&typaram, proc_macro2::Span::call_site())
}