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rustdoc: slightly clean up the synthesis of blanket impls
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,141 +1,130 @@ | ||
| use crate::rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt; | ||
| use rustc_hir as hir; | ||
| use rustc_infer::infer::{DefineOpaqueTypes, InferOk, TyCtxtInferExt}; | ||
| use rustc_infer::traits; | ||
| use rustc_middle::ty::ToPredicate; | ||
| use rustc_middle::ty::{self, ToPredicate}; | ||
| use rustc_span::def_id::DefId; | ||
| use rustc_span::DUMMY_SP; | ||
| use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt; | ||
|
|
||
| use super::*; | ||
| use thin_vec::ThinVec; | ||
|
|
||
| pub(crate) struct BlanketImplFinder<'a, 'tcx> { | ||
| pub(crate) cx: &'a mut core::DocContext<'tcx>, | ||
| } | ||
| use crate::clean; | ||
| use crate::clean::{ | ||
| clean_middle_assoc_item, clean_middle_ty, clean_trait_ref_with_bindings, clean_ty_generics, | ||
| }; | ||
| use crate::core::DocContext; | ||
|
|
||
| #[instrument(level = "debug", skip(cx))] | ||
| pub(crate) fn synthesize_blanket_impls( | ||
| cx: &mut DocContext<'_>, | ||
| item_def_id: DefId, | ||
| ) -> Vec<clean::Item> { | ||
| let tcx = cx.tcx; | ||
| let ty = tcx.type_of(item_def_id); | ||
|
|
||
| impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> { | ||
| pub(crate) fn get_blanket_impls(&mut self, item_def_id: DefId) -> Vec<Item> { | ||
| let cx = &mut self.cx; | ||
| let ty = cx.tcx.type_of(item_def_id); | ||
| let mut blanket_impls = Vec::new(); | ||
| for trait_def_id in tcx.all_traits() { | ||
| if !cx.cache.effective_visibilities.is_reachable(tcx, trait_def_id) | ||
| || cx.generated_synthetics.get(&(ty.skip_binder(), trait_def_id)).is_some() | ||
| { | ||
| continue; | ||
| } | ||
| // NOTE: doesn't use `for_each_relevant_impl` to avoid looking at anything besides blanket impls | ||
| let trait_impls = tcx.trait_impls_of(trait_def_id); | ||
| 'blanket_impls: for &impl_def_id in trait_impls.blanket_impls() { | ||
| trace!("considering impl `{impl_def_id:?}` for trait `{trait_def_id:?}`"); | ||
|
|
||
| trace!("get_blanket_impls({ty:?})"); | ||
| let mut impls = Vec::new(); | ||
| for trait_def_id in cx.tcx.all_traits() { | ||
| if !cx.cache.effective_visibilities.is_reachable(cx.tcx, trait_def_id) | ||
| || cx.generated_synthetics.get(&(ty.skip_binder(), trait_def_id)).is_some() | ||
| { | ||
| let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap(); | ||
| if !matches!(trait_ref.skip_binder().self_ty().kind(), ty::Param(_)) { | ||
| continue; | ||
| } | ||
| // NOTE: doesn't use `for_each_relevant_impl` to avoid looking at anything besides blanket impls | ||
| let trait_impls = cx.tcx.trait_impls_of(trait_def_id); | ||
| 'blanket_impls: for &impl_def_id in trait_impls.blanket_impls() { | ||
| trace!( | ||
| "get_blanket_impls: Considering impl for trait '{:?}' {:?}", | ||
| trait_def_id, | ||
| impl_def_id | ||
| ); | ||
| let trait_ref = cx.tcx.impl_trait_ref(impl_def_id).unwrap(); | ||
| if !matches!(trait_ref.skip_binder().self_ty().kind(), ty::Param(_)) { | ||
| continue; | ||
| } | ||
| let infcx = cx.tcx.infer_ctxt().build(); | ||
| let args = infcx.fresh_args_for_item(DUMMY_SP, item_def_id); | ||
| let impl_ty = ty.instantiate(infcx.tcx, args); | ||
| let param_env = ty::ParamEnv::empty(); | ||
| let infcx = tcx.infer_ctxt().build(); | ||
| let args = infcx.fresh_args_for_item(DUMMY_SP, item_def_id); | ||
| let impl_ty = ty.instantiate(tcx, args); | ||
| let param_env = ty::ParamEnv::empty(); | ||
|
|
||
| let impl_args = infcx.fresh_args_for_item(DUMMY_SP, impl_def_id); | ||
| let impl_trait_ref = trait_ref.instantiate(infcx.tcx, impl_args); | ||
| let impl_args = infcx.fresh_args_for_item(DUMMY_SP, impl_def_id); | ||
| let impl_trait_ref = trait_ref.instantiate(tcx, impl_args); | ||
|
|
||
| // Require the type the impl is implemented on to match | ||
| // our type, and ignore the impl if there was a mismatch. | ||
| let Ok(eq_result) = infcx.at(&traits::ObligationCause::dummy(), param_env).eq( | ||
| DefineOpaqueTypes::Yes, | ||
| impl_trait_ref.self_ty(), | ||
| impl_ty, | ||
| ) else { | ||
| continue; | ||
| }; | ||
| let InferOk { value: (), obligations } = eq_result; | ||
| // FIXME(eddyb) ignoring `obligations` might cause false positives. | ||
| drop(obligations); | ||
| // Require the type the impl is implemented on to match | ||
| // our type, and ignore the impl if there was a mismatch. | ||
| let Ok(eq_result) = infcx.at(&traits::ObligationCause::dummy(), param_env).eq( | ||
| DefineOpaqueTypes::Yes, | ||
| impl_trait_ref.self_ty(), | ||
| impl_ty, | ||
| ) else { | ||
| continue; | ||
| }; | ||
| let InferOk { value: (), obligations } = eq_result; | ||
| // FIXME(eddyb) ignoring `obligations` might cause false positives. | ||
| drop(obligations); | ||
|
|
||
| trace!( | ||
| "invoking predicate_may_hold: param_env={:?}, impl_trait_ref={:?}, impl_ty={:?}", | ||
| let predicates = tcx | ||
| .predicates_of(impl_def_id) | ||
| .instantiate(tcx, impl_args) | ||
| .predicates | ||
| .into_iter() | ||
| .chain(Some(ty::Binder::dummy(impl_trait_ref).to_predicate(tcx))); | ||
| for predicate in predicates { | ||
| let obligation = traits::Obligation::new( | ||
| tcx, | ||
| traits::ObligationCause::dummy(), | ||
| param_env, | ||
| impl_trait_ref, | ||
| impl_ty | ||
| predicate, | ||
| ); | ||
| let predicates = cx | ||
| .tcx | ||
| .predicates_of(impl_def_id) | ||
| .instantiate(cx.tcx, impl_args) | ||
| .predicates | ||
| .into_iter() | ||
| .chain(Some(ty::Binder::dummy(impl_trait_ref).to_predicate(infcx.tcx))); | ||
| for predicate in predicates { | ||
| debug!("testing predicate {predicate:?}"); | ||
| let obligation = traits::Obligation::new( | ||
| infcx.tcx, | ||
| traits::ObligationCause::dummy(), | ||
| param_env, | ||
| predicate, | ||
| ); | ||
| match infcx.evaluate_obligation(&obligation) { | ||
| Ok(eval_result) if eval_result.may_apply() => {} | ||
| Err(traits::OverflowError::Canonical) => {} | ||
| _ => continue 'blanket_impls, | ||
| } | ||
| match infcx.evaluate_obligation(&obligation) { | ||
| Ok(eval_result) if eval_result.may_apply() => {} | ||
| Err(traits::OverflowError::Canonical) => {} | ||
| _ => continue 'blanket_impls, | ||
| } | ||
| debug!( | ||
| "get_blanket_impls: found applicable impl for trait_ref={:?}, ty={:?}", | ||
| trait_ref, ty | ||
| ); | ||
| } | ||
| debug!("found applicable impl for trait ref {trait_ref:?}"); | ||
|
|
||
| cx.generated_synthetics.insert((ty.skip_binder(), trait_def_id)); | ||
| cx.generated_synthetics.insert((ty.skip_binder(), trait_def_id)); | ||
|
|
||
| impls.push(Item { | ||
| name: None, | ||
| attrs: Default::default(), | ||
| item_id: ItemId::Blanket { impl_id: impl_def_id, for_: item_def_id }, | ||
| kind: Box::new(ImplItem(Box::new(Impl { | ||
| unsafety: hir::Unsafety::Normal, | ||
| generics: clean_ty_generics( | ||
| cx, | ||
| cx.tcx.generics_of(impl_def_id), | ||
| cx.tcx.explicit_predicates_of(impl_def_id), | ||
| ), | ||
| // FIXME(eddyb) compute both `trait_` and `for_` from | ||
| // the post-inference `trait_ref`, as it's more accurate. | ||
| trait_: Some(clean_trait_ref_with_bindings( | ||
| cx, | ||
| ty::Binder::dummy(trait_ref.instantiate_identity()), | ||
| ThinVec::new(), | ||
| )), | ||
| for_: clean_middle_ty( | ||
| ty::Binder::dummy(ty.instantiate_identity()), | ||
| cx, | ||
| None, | ||
| None, | ||
| ), | ||
| items: cx | ||
| .tcx | ||
| .associated_items(impl_def_id) | ||
| .in_definition_order() | ||
| .filter(|item| !item.is_impl_trait_in_trait()) | ||
| .map(|item| clean_middle_assoc_item(item, cx)) | ||
| .collect::<Vec<_>>(), | ||
| polarity: ty::ImplPolarity::Positive, | ||
| kind: ImplKind::Blanket(Box::new(clean_middle_ty( | ||
| ty::Binder::dummy(trait_ref.instantiate_identity().self_ty()), | ||
| cx, | ||
| None, | ||
| None, | ||
| ))), | ||
| }))), | ||
| cfg: None, | ||
| inline_stmt_id: None, | ||
| }); | ||
| } | ||
| blanket_impls.push(clean::Item { | ||
| name: None, | ||
| attrs: Default::default(), | ||
| item_id: clean::ItemId::Blanket { impl_id: impl_def_id, for_: item_def_id }, | ||
| kind: Box::new(clean::ImplItem(Box::new(clean::Impl { | ||
| unsafety: hir::Unsafety::Normal, | ||
| generics: clean_ty_generics( | ||
| cx, | ||
| tcx.generics_of(impl_def_id), | ||
| tcx.explicit_predicates_of(impl_def_id), | ||
| ), | ||
| // FIXME(eddyb) compute both `trait_` and `for_` from | ||
| // the post-inference `trait_ref`, as it's more accurate. | ||
| trait_: Some(clean_trait_ref_with_bindings( | ||
| cx, | ||
| ty::Binder::dummy(trait_ref.instantiate_identity()), | ||
| ThinVec::new(), | ||
| )), | ||
| for_: clean_middle_ty( | ||
| ty::Binder::dummy(ty.instantiate_identity()), | ||
| cx, | ||
| None, | ||
| None, | ||
| ), | ||
| items: tcx | ||
| .associated_items(impl_def_id) | ||
| .in_definition_order() | ||
| .filter(|item| !item.is_impl_trait_in_trait()) | ||
| .map(|item| clean_middle_assoc_item(item, cx)) | ||
| .collect(), | ||
| polarity: ty::ImplPolarity::Positive, | ||
| kind: clean::ImplKind::Blanket(Box::new(clean_middle_ty( | ||
| ty::Binder::dummy(trait_ref.instantiate_identity().self_ty()), | ||
| cx, | ||
| None, | ||
| None, | ||
| ))), | ||
| }))), | ||
| cfg: None, | ||
| inline_stmt_id: None, | ||
| }); | ||
| } | ||
|
|
||
| impls | ||
| } | ||
|
|
||
| blanket_impls | ||
| } |
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