use rustc_middle::ty::abstract_const::NotConstEvaluatable;
use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams};
use rustc_middle::ty::fold::BottomUpFolder;
-use rustc_middle::ty::print::with_no_trimmed_paths;
use rustc_middle::ty::relate::TypeRelation;
use rustc_middle::ty::SubstsRef;
use rustc_middle::ty::{self, EarlyBinder, PolyProjectionPredicate, ToPolyTraitRef, ToPredicate};
let unbound_input_types =
stack.fresh_trait_pred.skip_binder().trait_ref.substs.types().any(|ty| ty.is_fresh());
- if stack.obligation.polarity() != ty::ImplPolarity::Negative {
- // This check was an imperfect workaround for a bug in the old
- // intercrate mode; it should be removed when that goes away.
- if unbound_input_types && self.intercrate {
- debug!("evaluate_stack --> unbound argument, intercrate --> ambiguous",);
- // Heuristics: show the diagnostics when there are no candidates in crate.
- if self.intercrate_ambiguity_causes.is_some() {
- debug!("evaluate_stack: intercrate_ambiguity_causes is some");
- if let Ok(candidate_set) = self.assemble_candidates(stack) {
- if !candidate_set.ambiguous && candidate_set.vec.is_empty() {
- let trait_ref = stack.obligation.predicate.skip_binder().trait_ref;
- let self_ty = trait_ref.self_ty();
- let cause = with_no_trimmed_paths!({
- IntercrateAmbiguityCause::DownstreamCrate {
- trait_desc: trait_ref.print_only_trait_path().to_string(),
- self_desc: if self_ty.has_concrete_skeleton() {
- Some(self_ty.to_string())
- } else {
- None
- },
- }
- });
-
- debug!(?cause, "evaluate_stack: pushing cause");
- self.intercrate_ambiguity_causes.as_mut().unwrap().insert(cause);
- }
- }
- }
- return Ok(EvaluatedToAmbig);
- }
- }
-
if unbound_input_types
&& stack.iter().skip(1).any(|prev| {
stack.obligation.param_env == prev.obligation.param_env