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Commit | Line | Data |
---|---|---|
ba9703b0 | 1 | use crate::rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt; |
dfeec247 | 2 | use rustc_hir as hir; |
74b04a01 XL |
3 | use rustc_infer::infer::{InferOk, TyCtxtInferExt}; |
4 | use rustc_infer::traits; | |
ba9703b0 | 5 | use rustc_middle::ty::subst::Subst; |
a2a8927a | 6 | use rustc_middle::ty::ToPredicate; |
dfeec247 | 7 | use rustc_span::DUMMY_SP; |
b7449926 | 8 | |
b7449926 XL |
9 | use super::*; |
10 | ||
923072b8 FG |
11 | pub(crate) struct BlanketImplFinder<'a, 'tcx> { |
12 | pub(crate) cx: &'a mut core::DocContext<'tcx>, | |
b7449926 XL |
13 | } |
14 | ||
532ac7d7 | 15 | impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> { |
923072b8 | 16 | pub(crate) fn get_blanket_impls(&mut self, item_def_id: DefId) -> Vec<Item> { |
6a06907d | 17 | let param_env = self.cx.tcx.param_env(item_def_id); |
04454e1e | 18 | let ty = self.cx.tcx.bound_type_of(item_def_id); |
48663c56 | 19 | |
c295e0f8 | 20 | trace!("get_blanket_impls({:?})", ty); |
b7449926 | 21 | let mut impls = Vec::new(); |
5099ac24 FG |
22 | self.cx.with_all_traits(|cx, all_traits| { |
23 | for &trait_def_id in all_traits { | |
24 | if !cx.cache.access_levels.is_public(trait_def_id) | |
04454e1e | 25 | || cx.generated_synthetics.get(&(ty.0, trait_def_id)).is_some() |
5099ac24 FG |
26 | { |
27 | continue; | |
28 | } | |
29 | // NOTE: doesn't use `for_each_relevant_impl` to avoid looking at anything besides blanket impls | |
30 | let trait_impls = cx.tcx.trait_impls_of(trait_def_id); | |
31 | for &impl_def_id in trait_impls.blanket_impls() { | |
32 | trace!( | |
33 | "get_blanket_impls: Considering impl for trait '{:?}' {:?}", | |
34 | trait_def_id, | |
35 | impl_def_id | |
36 | ); | |
04454e1e FG |
37 | let trait_ref = cx.tcx.bound_impl_trait_ref(impl_def_id).unwrap(); |
38 | let is_param = matches!(trait_ref.0.self_ty().kind(), ty::Param(_)); | |
5099ac24 FG |
39 | let may_apply = is_param && cx.tcx.infer_ctxt().enter(|infcx| { |
40 | let substs = infcx.fresh_substs_for_item(DUMMY_SP, item_def_id); | |
41 | let ty = ty.subst(infcx.tcx, substs); | |
04454e1e | 42 | let param_env = EarlyBinder(param_env).subst(infcx.tcx, substs); |
b7449926 | 43 | |
5099ac24 FG |
44 | let impl_substs = infcx.fresh_substs_for_item(DUMMY_SP, impl_def_id); |
45 | let trait_ref = trait_ref.subst(infcx.tcx, impl_substs); | |
b7449926 | 46 | |
5099ac24 FG |
47 | // Require the type the impl is implemented on to match |
48 | // our type, and ignore the impl if there was a mismatch. | |
49 | let cause = traits::ObligationCause::dummy(); | |
50 | let eq_result = infcx.at(&cause, param_env).eq(trait_ref.self_ty(), ty); | |
51 | if let Ok(InferOk { value: (), obligations }) = eq_result { | |
52 | // FIXME(eddyb) ignoring `obligations` might cause false positives. | |
53 | drop(obligations); | |
b7449926 | 54 | |
5099ac24 FG |
55 | trace!( |
56 | "invoking predicate_may_hold: param_env={:?}, trait_ref={:?}, ty={:?}", | |
fc512014 | 57 | param_env, |
5099ac24 FG |
58 | trait_ref, |
59 | ty | |
fc512014 | 60 | ); |
5099ac24 FG |
61 | let predicates = cx |
62 | .tcx | |
63 | .predicates_of(impl_def_id) | |
64 | .instantiate(cx.tcx, impl_substs) | |
65 | .predicates | |
66 | .into_iter() | |
67 | .chain(Some( | |
68 | ty::Binder::dummy(trait_ref) | |
69 | .to_poly_trait_predicate() | |
70 | .map_bound(ty::PredicateKind::Trait) | |
71 | .to_predicate(infcx.tcx), | |
72 | )); | |
73 | for predicate in predicates { | |
74 | debug!("testing predicate {:?}", predicate); | |
75 | let obligation = traits::Obligation::new( | |
76 | traits::ObligationCause::dummy(), | |
77 | param_env, | |
78 | predicate, | |
79 | ); | |
80 | match infcx.evaluate_obligation(&obligation) { | |
81 | Ok(eval_result) if eval_result.may_apply() => {} | |
82 | Err(traits::OverflowError::Canonical) => {} | |
83 | Err(traits::OverflowError::ErrorReporting) => {} | |
84 | _ => { | |
85 | return false; | |
86 | } | |
fc512014 XL |
87 | } |
88 | } | |
5099ac24 FG |
89 | true |
90 | } else { | |
91 | false | |
b7449926 | 92 | } |
5099ac24 FG |
93 | }); |
94 | debug!( | |
95 | "get_blanket_impls: found applicable impl: {} for trait_ref={:?}, ty={:?}", | |
96 | may_apply, trait_ref, ty | |
97 | ); | |
98 | if !may_apply { | |
99 | continue; | |
b7449926 | 100 | } |
48663c56 | 101 | |
04454e1e | 102 | cx.generated_synthetics.insert((ty.0, trait_def_id)); |
48663c56 | 103 | |
5099ac24 FG |
104 | impls.push(Item { |
105 | name: None, | |
106 | attrs: Default::default(), | |
107 | visibility: Inherited, | |
04454e1e | 108 | item_id: ItemId::Blanket { impl_id: impl_def_id, for_: item_def_id }, |
5099ac24 FG |
109 | kind: box ImplItem(Impl { |
110 | unsafety: hir::Unsafety::Normal, | |
111 | generics: clean_ty_generics( | |
112 | cx, | |
113 | cx.tcx.generics_of(impl_def_id), | |
114 | cx.tcx.explicit_predicates_of(impl_def_id), | |
115 | ), | |
116 | // FIXME(eddyb) compute both `trait_` and `for_` from | |
117 | // the post-inference `trait_ref`, as it's more accurate. | |
04454e1e FG |
118 | trait_: Some(trait_ref.0.clean(cx)), |
119 | for_: ty.0.clean(cx), | |
5e7ed085 FG |
120 | items: cx.tcx |
121 | .associated_items(impl_def_id) | |
122 | .in_definition_order() | |
123 | .map(|x| x.clean(cx)) | |
124 | .collect::<Vec<_>>(), | |
5099ac24 | 125 | polarity: ty::ImplPolarity::Positive, |
04454e1e | 126 | kind: ImplKind::Blanket(box trait_ref.0.self_ty().clean(cx)), |
5099ac24 FG |
127 | }), |
128 | cfg: None, | |
129 | }); | |
130 | } | |
cdc7bbd5 | 131 | } |
5099ac24 FG |
132 | }); |
133 | ||
b7449926 XL |
134 | impls |
135 | } | |
136 | } |