1 #![feature(array_windows)]
2 #![feature(bool_to_option)]
3 #![feature(crate_visibility_modifier)]
4 #![feature(control_flow_enum)]
6 #![recursion_limit = "256"]
7 #![cfg_attr(not(bootstrap), allow(rustc::potential_query_instability))]
12 extern crate rustc_middle;
14 use rustc_hir::lang_items::LangItem;
15 use rustc_middle::traits;
16 use rustc_middle::ty::adjustment::CustomCoerceUnsized;
17 use rustc_middle::ty::query::Providers;
18 use rustc_middle::ty::{self, Ty, TyCtxt};
25 fn custom_coerce_unsize_info<'tcx>(
29 ) -> CustomCoerceUnsized {
30 let def_id = tcx.require_lang_item(LangItem::CoerceUnsized, None);
32 let trait_ref = ty::Binder::dummy(ty::TraitRef {
34 substs: tcx.mk_substs_trait(source_ty, &[target_ty.into()]),
37 match tcx.codegen_fulfill_obligation((ty::ParamEnv::reveal_all(), trait_ref)) {
38 Ok(traits::ImplSource::UserDefined(traits::ImplSourceUserDefinedData {
41 })) => tcx.coerce_unsized_info(impl_def_id).custom_kind.unwrap(),
43 bug!("invalid `CoerceUnsized` impl_source: {:?}", impl_source);
48 pub fn provide(providers: &mut Providers) {
49 partitioning::provide(providers);
50 polymorphize::provide(providers);