use rustc_middle::ty;
+use rustc_session::config::TraitSolver;
use crate::infer::canonical::OriginalQueryValues;
use crate::infer::InferCtxt;
+use crate::solve::{Certainty, Goal, InferCtxtEvalExt, MaybeCause};
use crate::traits::{EvaluationResult, OverflowError, PredicateObligation, SelectionContext};
pub trait InferCtxtExt<'tcx> {
_ => obligation.param_env.without_const(),
};
- let c_pred = self
- .canonicalize_query_keep_static(param_env.and(obligation.predicate), &mut _orig_values);
- // Run canonical query. If overflow occurs, rerun from scratch but this time
- // in standard trait query mode so that overflow is handled appropriately
- // within `SelectionContext`.
- self.tcx.at(obligation.cause.span()).evaluate_obligation(c_pred)
+ if self.tcx.sess.opts.unstable_opts.trait_solver != TraitSolver::Next {
+ let c_pred = self.canonicalize_query_keep_static(
+ param_env.and(obligation.predicate),
+ &mut _orig_values,
+ );
+ self.tcx.at(obligation.cause.span()).evaluate_obligation(c_pred)
+ } else {
+ self.probe(|snapshot| {
+ if let Ok((_, certainty)) =
+ self.evaluate_root_goal(Goal::new(self.tcx, param_env, obligation.predicate))
+ {
+ match certainty {
+ Certainty::Yes => {
+ if self.opaque_types_added_in_snapshot(snapshot) {
+ Ok(EvaluationResult::EvaluatedToOkModuloOpaqueTypes)
+ } else if self.region_constraints_added_in_snapshot(snapshot).is_some()
+ {
+ Ok(EvaluationResult::EvaluatedToOkModuloRegions)
+ } else {
+ Ok(EvaluationResult::EvaluatedToOk)
+ }
+ }
+ Certainty::Maybe(MaybeCause::Ambiguity) => {
+ Ok(EvaluationResult::EvaluatedToAmbig)
+ }
+ Certainty::Maybe(MaybeCause::Overflow) => Err(OverflowError::Canonical),
+ }
+ } else {
+ Ok(EvaluationResult::EvaluatedToErr)
+ }
+ })
+ }
}
// Helper function that canonicalizes and runs the query. If an
&self,
obligation: &PredicateObligation<'tcx>,
) -> EvaluationResult {
+ // Run canonical query. If overflow occurs, rerun from scratch but this time
+ // in standard trait query mode so that overflow is handled appropriately
+ // within `SelectionContext`.
match self.evaluate_obligation(obligation) {
Ok(result) => result,
Err(OverflowError::Canonical) => {