1 files changed, 67 insertions, 22 deletions

diff --git a/compiler/rustc_trait_selection/src/solve/fulfill.rs b/compiler/rustc_trait_selection/src/solve/fulfill.rs
index a6240666e..a55b984fd 100644
--- a/compiler/rustc_trait_selection/src/solve/fulfill.rs
+++ b/compiler/rustc_trait_selection/src/solve/fulfill.rs
@@ -1,16 +1,14 @@
 use std::mem;
 
-use rustc_data_structures::fx::FxHashMap;
-use rustc_infer::{
-    infer::InferCtxt,
-    traits::{
-        query::NoSolution, FulfillmentError, FulfillmentErrorCode, PredicateObligation,
-        SelectionError, TraitEngine,
-    },
+use rustc_infer::infer::InferCtxt;
+use rustc_infer::traits::{
+    query::NoSolution, FulfillmentError, FulfillmentErrorCode, MismatchedProjectionTypes,
+    PredicateObligation, SelectionError, TraitEngine,
 };
 use rustc_middle::ty;
+use rustc_middle::ty::error::{ExpectedFound, TypeError};
 
-use super::{search_graph, Certainty, EvalCtxt};
+use super::{Certainty, InferCtxtEvalExt};
 
 /// A trait engine using the new trait solver.
 ///
@@ -42,12 +40,7 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> {
         self.obligations.push(obligation);
     }
 
-    fn select_all_or_error(&mut self, infcx: &InferCtxt<'tcx>) -> Vec<FulfillmentError<'tcx>> {
-        let errors = self.select_where_possible(infcx);
-        if !errors.is_empty() {
-            return errors;
-        }
-
+    fn collect_remaining_errors(&mut self) -> Vec<FulfillmentError<'tcx>> {
         self.obligations
             .drain(..)
             .map(|obligation| FulfillmentError {
@@ -68,16 +61,65 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> {
             let mut has_changed = false;
             for obligation in mem::take(&mut self.obligations) {
                 let goal = obligation.clone().into();
-                let search_graph = &mut search_graph::SearchGraph::new(infcx.tcx);
-                let mut ecx = EvalCtxt::new_outside_solver(infcx, search_graph);
-                let (changed, certainty) = match ecx.evaluate_goal(goal) {
+                let (changed, certainty) = match infcx.evaluate_root_goal(goal) {
                     Ok(result) => result,
                     Err(NoSolution) => {
                         errors.push(FulfillmentError {
                             obligation: obligation.clone(),
-                            code: FulfillmentErrorCode::CodeSelectionError(
-                                SelectionError::Unimplemented,
-                            ),
+                            code: match goal.predicate.kind().skip_binder() {
+                                ty::PredicateKind::Clause(ty::Clause::Projection(_)) => {
+                                    FulfillmentErrorCode::CodeProjectionError(
+                                        // FIXME: This could be a `Sorts` if the term is a type
+                                        MismatchedProjectionTypes { err: TypeError::Mismatch },
+                                    )
+                                }
+                                ty::PredicateKind::AliasEq(_, _) => {
+                                    FulfillmentErrorCode::CodeProjectionError(
+                                        MismatchedProjectionTypes { err: TypeError::Mismatch },
+                                    )
+                                }
+                                ty::PredicateKind::Subtype(pred) => {
+                                    let (a, b) = infcx.instantiate_binder_with_placeholders(
+                                        goal.predicate.kind().rebind((pred.a, pred.b)),
+                                    );
+                                    let expected_found = ExpectedFound::new(true, a, b);
+                                    FulfillmentErrorCode::CodeSubtypeError(
+                                        expected_found,
+                                        TypeError::Sorts(expected_found),
+                                    )
+                                }
+                                ty::PredicateKind::Coerce(pred) => {
+                                    let (a, b) = infcx.instantiate_binder_with_placeholders(
+                                        goal.predicate.kind().rebind((pred.a, pred.b)),
+                                    );
+                                    let expected_found = ExpectedFound::new(false, a, b);
+                                    FulfillmentErrorCode::CodeSubtypeError(
+                                        expected_found,
+                                        TypeError::Sorts(expected_found),
+                                    )
+                                }
+                                ty::PredicateKind::ConstEquate(a, b) => {
+                                    let (a, b) = infcx.instantiate_binder_with_placeholders(
+                                        goal.predicate.kind().rebind((a, b)),
+                                    );
+                                    let expected_found = ExpectedFound::new(true, a, b);
+                                    FulfillmentErrorCode::CodeConstEquateError(
+                                        expected_found,
+                                        TypeError::ConstMismatch(expected_found),
+                                    )
+                                }
+                                ty::PredicateKind::Clause(_)
+                                | ty::PredicateKind::WellFormed(_)
+                                | ty::PredicateKind::ObjectSafe(_)
+                                | ty::PredicateKind::ClosureKind(_, _, _)
+                                | ty::PredicateKind::ConstEvaluatable(_)
+                                | ty::PredicateKind::TypeWellFormedFromEnv(_)
+                                | ty::PredicateKind::Ambiguous => {
+                                    FulfillmentErrorCode::CodeSelectionError(
+                                        SelectionError::Unimplemented,
+                                    )
+                                }
+                            },
                             root_obligation: obligation,
                         });
                         continue;
@@ -103,7 +145,10 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> {
         self.obligations.clone()
     }
 
-    fn relationships(&mut self) -> &mut FxHashMap<ty::TyVid, ty::FoundRelationships> {
-        unimplemented!("Should be moved out of `TraitEngine`")
+    fn drain_unstalled_obligations(
+        &mut self,
+        _: &InferCtxt<'tcx>,
+    ) -> Vec<PredicateObligation<'tcx>> {
+        unimplemented!()
     }
 }