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Commit | Line | Data |
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f20569fa XL |
1 | use quote::quote; |
2 | ||
3 | pub fn type_foldable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream { | |
4 | if let syn::Data::Union(_) = s.ast().data { | |
5 | panic!("cannot derive on union") | |
6 | } | |
7 | ||
8 | s.add_bounds(synstructure::AddBounds::Generics); | |
9 | let body_visit = s.each(|bind| { | |
10 | quote! { | |
11 | ::rustc_middle::ty::fold::TypeFoldable::visit_with(#bind, __folder)?; | |
12 | } | |
13 | }); | |
14 | s.bind_with(|_| synstructure::BindStyle::Move); | |
15 | let body_fold = s.each_variant(|vi| { | |
16 | let bindings = vi.bindings(); | |
17 | vi.construct(|_, index| { | |
18 | let bind = &bindings[index]; | |
19 | quote! { | |
20 | ::rustc_middle::ty::fold::TypeFoldable::fold_with(#bind, __folder) | |
21 | } | |
22 | }) | |
23 | }); | |
24 | ||
25 | s.bound_impl( | |
26 | quote!(::rustc_middle::ty::fold::TypeFoldable<'tcx>), | |
27 | quote! { | |
28 | fn super_fold_with<__F: ::rustc_middle::ty::fold::TypeFolder<'tcx>>( | |
29 | self, | |
30 | __folder: &mut __F | |
31 | ) -> Self { | |
32 | match self { #body_fold } | |
33 | } | |
34 | ||
35 | fn super_visit_with<__F: ::rustc_middle::ty::fold::TypeVisitor<'tcx>>( | |
36 | &self, | |
37 | __folder: &mut __F | |
38 | ) -> ::std::ops::ControlFlow<__F::BreakTy> { | |
39 | match *self { #body_visit } | |
40 | ::std::ops::ControlFlow::CONTINUE | |
41 | } | |
42 | }, | |
43 | ) | |
44 | } |