diff --git a/compiler/rustc_hir_typeck/src/method/probe.rs b/compiler/rustc_hir_typeck/src/method/probe.rs index 2876e0b49db..7e480d66695 100644 --- a/compiler/rustc_hir_typeck/src/method/probe.rs +++ b/compiler/rustc_hir_typeck/src/method/probe.rs @@ -21,7 +21,7 @@ use rustc_middle::ty::AssocItem; use rustc_middle::ty::GenericParamDefKind; use rustc_middle::ty::ToPredicate; -use rustc_middle::ty::{self, ParamEnvAnd, Ty, TyCtxt, TypeFoldable, TypeVisitableExt}; +use rustc_middle::ty::{self, ParamEnvAnd, Ty, TyCtxt, TypeVisitableExt}; use rustc_middle::ty::{GenericArgs, GenericArgsRef}; use rustc_session::lint; use rustc_span::def_id::DefId; @@ -745,7 +745,6 @@ fn assemble_inherent_impl_probe(&mut self, impl_def_id: DefId) { } let (impl_ty, impl_args) = self.impl_ty_and_args(impl_def_id); - let impl_ty = impl_ty.instantiate(self.tcx, impl_args); debug!("impl_ty: {:?}", impl_ty); @@ -818,7 +817,7 @@ fn assemble_inherent_candidates_from_object(&mut self, self_ty: Ty<'tcx>) { return; } - let new_trait_ref = this.instantiate_bound_regions_with_erased(new_trait_ref); + let new_trait_ref = this.tcx.instantiate_bound_regions_with_erased(new_trait_ref); let (xform_self_ty, xform_ret_ty) = this.xform_self_ty(item, new_trait_ref.self_ty(), new_trait_ref.args); @@ -929,27 +928,12 @@ fn assemble_extension_candidates_for_all_traits(&mut self) { } } - fn matches_return_type( - &self, - method: ty::AssocItem, - self_ty: Option>, - expected: Ty<'tcx>, - ) -> bool { + fn matches_return_type(&self, method: ty::AssocItem, expected: Ty<'tcx>) -> bool { match method.kind { ty::AssocKind::Fn => self.probe(|_| { let args = self.fresh_args_for_item(self.span, method.def_id); let fty = self.tcx.fn_sig(method.def_id).instantiate(self.tcx, args); let fty = self.instantiate_binder_with_fresh_vars(self.span, infer::FnCall, fty); - - if let Some(self_ty) = self_ty { - if self - .at(&ObligationCause::dummy(), self.param_env) - .sup(DefineOpaqueTypes::No, fty.inputs()[0], self_ty) - .is_err() - { - return false; - } - } self.can_sub(self.param_env, fty.output(), expected) }), _ => false, @@ -1040,7 +1024,7 @@ fn candidate_method_names( .filter(|candidate| candidate_filter(&candidate.item)) .filter(|candidate| { if let Some(return_ty) = self.return_type { - self.matches_return_type(candidate.item, None, return_ty) + self.matches_return_type(candidate.item, return_ty) } else { true } @@ -1894,40 +1878,13 @@ fn xform_method_sig(&self, method: DefId, args: GenericArgsRef<'tcx>) -> ty::FnS fn_sig.instantiate(self.tcx, args) }; - self.instantiate_bound_regions_with_erased(xform_fn_sig) + self.tcx.instantiate_bound_regions_with_erased(xform_fn_sig) } /// Gets the type of an impl and generate generic parameters with inference vars. - fn impl_ty_and_args( - &self, - impl_def_id: DefId, - ) -> (ty::EarlyBinder>, GenericArgsRef<'tcx>) { - (self.tcx.type_of(impl_def_id), self.fresh_args_for_item(self.span, impl_def_id)) - } - - /// Replaces late-bound-regions bound by `value` with `'static` using - /// `ty::instantiate_bound_regions_with_erased`. - /// - /// This is only a reasonable thing to do during the *probe* phase, not the *confirm* phase, of - /// method matching. It is reasonable during the probe phase because we don't consider region - /// relationships at all. Therefore, we can just replace all the region variables with 'static - /// rather than creating fresh region variables. This is nice for two reasons: - /// - /// 1. Because the numbers of the region variables would otherwise be fairly unique to this - /// particular method call, it winds up creating fewer types overall, which helps for memory - /// usage. (Admittedly, this is a rather small effect, though measurable.) - /// - /// 2. It makes it easier to deal with higher-ranked trait bounds, because we can replace any - /// late-bound regions with 'static. Otherwise, if we were going to replace late-bound - /// regions with actual region variables as is proper, we'd have to ensure that the same - /// region got replaced with the same variable, which requires a bit more coordination - /// and/or tracking the instantiations and - /// so forth. - fn instantiate_bound_regions_with_erased(&self, value: ty::Binder<'tcx, T>) -> T - where - T: TypeFoldable>, - { - self.tcx.instantiate_bound_regions_with_erased(value) + fn impl_ty_and_args(&self, impl_def_id: DefId) -> (Ty<'tcx>, GenericArgsRef<'tcx>) { + let args = self.fresh_args_for_item(self.span, impl_def_id); + (self.tcx.type_of(impl_def_id).instantiate(self.tcx, args), args) } /// Determine if the given associated item type is relevant in the current context.