From 4547b622d8d29df964fa2914213088b148c498fc Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:18:32 +0200 Subject: Merging upstream version 1.67.1+dfsg1. Signed-off-by: Daniel Baumann --- .../src/traits/error_reporting/ambiguity.rs | 52 ++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs (limited to 'compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs') diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs new file mode 100644 index 000000000..752b53fbc --- /dev/null +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs @@ -0,0 +1,52 @@ +use rustc_hir::def_id::DefId; +use rustc_infer::infer::InferCtxt; +use rustc_infer::traits::{Obligation, ObligationCause, TraitObligation}; +use rustc_span::DUMMY_SP; + +use crate::traits::ObligationCtxt; + +pub fn recompute_applicable_impls<'tcx>( + infcx: &InferCtxt<'tcx>, + obligation: &TraitObligation<'tcx>, +) -> Vec { + let tcx = infcx.tcx; + let param_env = obligation.param_env; + let dummy_cause = ObligationCause::dummy(); + let impl_may_apply = |impl_def_id| { + let ocx = ObligationCtxt::new_in_snapshot(infcx); + let placeholder_obligation = + infcx.replace_bound_vars_with_placeholders(obligation.predicate); + let obligation_trait_ref = + ocx.normalize(&dummy_cause, param_env, placeholder_obligation.trait_ref); + + let impl_substs = infcx.fresh_substs_for_item(DUMMY_SP, impl_def_id); + let impl_trait_ref = tcx.bound_impl_trait_ref(impl_def_id).unwrap().subst(tcx, impl_substs); + let impl_trait_ref = ocx.normalize(&ObligationCause::dummy(), param_env, impl_trait_ref); + + if let Err(_) = ocx.eq(&dummy_cause, param_env, obligation_trait_ref, impl_trait_ref) { + return false; + } + + let impl_predicates = tcx.predicates_of(impl_def_id).instantiate(tcx, impl_substs); + ocx.register_obligations( + impl_predicates + .predicates + .iter() + .map(|&predicate| Obligation::new(tcx, dummy_cause.clone(), param_env, predicate)), + ); + + ocx.select_where_possible().is_empty() + }; + + let mut impls = Vec::new(); + tcx.for_each_relevant_impl( + obligation.predicate.def_id(), + obligation.predicate.skip_binder().trait_ref.self_ty(), + |impl_def_id| { + if infcx.probe(move |_snapshot| impl_may_apply(impl_def_id)) { + impls.push(impl_def_id) + } + }, + ); + impls +} -- cgit v1.2.3