Auto merge of #106253 - nbdd0121:upcast, r=compiler-errors

[rust.git] / compiler / rustc_trait_selection / src / solve / mod.rs

diff --git a/compiler/rustc_trait_selection/src/solve/mod.rs b/compiler/rustc_trait_selection/src/solve/mod.rs
index 7880cbad5fe0382ee1dfe44a27e91f42a9453a54..dd16672cc7a0110fe6917dd9d73f45c7cbf925f4 100644 (file)
--- a/compiler/rustc_trait_selection/src/solve/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/mod.rs
@@ -13,14 +13,12 @@
 // preserves universes and creates a unique var (in the highest universe) for each
 // appearance of a region.
 
-// FIXME: `CanonicalVarValues` should be interned and `Copy`.
-
 // FIXME: uses of `infcx.at` need to enable deferred projection equality once that's implemented.
 
 use std::mem;
 
 use rustc_hir::def_id::DefId;
-use rustc_infer::infer::canonical::{Canonical, CanonicalVarKind, CanonicalVarValues};
+use rustc_infer::infer::canonical::{Canonical, CanonicalVarValues};
 use rustc_infer::infer::canonical::{OriginalQueryValues, QueryRegionConstraints, QueryResponse};
 use rustc_infer::infer::{InferCtxt, InferOk, TyCtxtInferExt};
 use rustc_infer::traits::query::NoSolution;
@@ -225,7 +223,7 @@ fn make_canonical_response(&self, certainty: Certainty) -> QueryResult<'tcx> {
         let external_constraints = take_external_constraints(self.infcx)?;
 
         Ok(self.infcx.canonicalize_response(Response {
-            var_values: self.var_values.clone(),
+            var_values: self.var_values,
             external_constraints,
             certainty,
         }))
@@ -335,15 +333,13 @@ fn compute_subtype_goal(
             // That won't actually reflect in the query response, so it seems moot.
             self.make_canonical_response(Certainty::AMBIGUOUS)
         } else {
-            self.infcx.probe(|_| {
-                let InferOk { value: (), obligations } = self
-                    .infcx
-                    .at(&ObligationCause::dummy(), goal.param_env)
-                    .sub(goal.predicate.a, goal.predicate.b)?;
-                self.evaluate_all_and_make_canonical_response(
-                    obligations.into_iter().map(|pred| pred.into()).collect(),
-                )
-            })
+            let InferOk { value: (), obligations } = self
+                .infcx
+                .at(&ObligationCause::dummy(), goal.param_env)
+                .sub(goal.predicate.a, goal.predicate.b)?;
+            self.evaluate_all_and_make_canonical_response(
+                obligations.into_iter().map(|pred| pred.into()).collect(),
+            )
         }
     }
 
@@ -365,7 +361,7 @@ fn compute_closure_kind_goal(
     }
 
     fn compute_object_safe_goal(&mut self, trait_def_id: DefId) -> QueryResult<'tcx> {
-        if self.tcx().is_object_safe(trait_def_id) {
+        if self.tcx().check_is_object_safe(trait_def_id) {
             self.make_canonical_response(Certainty::Yes)
         } else {
             Err(NoSolution)
@@ -376,22 +372,22 @@ fn compute_well_formed_goal(
         &mut self,
         goal: Goal<'tcx, ty::GenericArg<'tcx>>,
     ) -> QueryResult<'tcx> {
-        self.infcx.probe(|_| {
-            match crate::traits::wf::unnormalized_obligations(
-                self.infcx,
-                goal.param_env,
-                goal.predicate,
-            ) {
-                Some(obligations) => self.evaluate_all_and_make_canonical_response(
-                    obligations.into_iter().map(|o| o.into()).collect(),
-                ),
-                None => self.make_canonical_response(Certainty::AMBIGUOUS),
-            }
-        })
+        match crate::traits::wf::unnormalized_obligations(
+            self.infcx,
+            goal.param_env,
+            goal.predicate,
+        ) {
+            Some(obligations) => self.evaluate_all_and_make_canonical_response(
+                obligations.into_iter().map(|o| o.into()).collect(),
+            ),
+            None => self.make_canonical_response(Certainty::AMBIGUOUS),
+        }
     }
 }
 
 impl<'tcx> EvalCtxt<'_, 'tcx> {
+    // Recursively evaluates a list of goals to completion, returning the certainty
+    // of all of the goals.
     fn evaluate_all(
         &mut self,
         mut goals: Vec<Goal<'tcx, ty::Predicate<'tcx>>>,
@@ -428,6 +424,10 @@ fn evaluate_all(
         })
     }
 
+    // Recursively evaluates a list of goals to completion, making a query response.
+    //
+    // This is just a convenient way of calling [`EvalCtxt::evaluate_all`],
+    // then [`EvalCtxt::make_canonical_response`].
     fn evaluate_all_and_make_canonical_response(
         &mut self,
         goals: Vec<Goal<'tcx, ty::Predicate<'tcx>>>,
@@ -481,32 +481,11 @@ pub(super) fn response_no_constraints<'tcx>(
     goal: Canonical<'tcx, impl Sized>,
     certainty: Certainty,
 ) -> QueryResult<'tcx> {
-    let var_values = goal
-        .variables
-        .iter()
-        .enumerate()
-        .map(|(i, info)| match info.kind {
-            CanonicalVarKind::Ty(_) | CanonicalVarKind::PlaceholderTy(_) => {
-                tcx.mk_ty(ty::Bound(ty::INNERMOST, ty::BoundVar::from_usize(i).into())).into()
-            }
-            CanonicalVarKind::Region(_) | CanonicalVarKind::PlaceholderRegion(_) => {
-                let br = ty::BoundRegion {
-                    var: ty::BoundVar::from_usize(i),
-                    kind: ty::BrAnon(i as u32, None),
-                };
-                tcx.mk_region(ty::ReLateBound(ty::INNERMOST, br)).into()
-            }
-            CanonicalVarKind::Const(_, ty) | CanonicalVarKind::PlaceholderConst(_, ty) => tcx
-                .mk_const(ty::ConstKind::Bound(ty::INNERMOST, ty::BoundVar::from_usize(i)), ty)
-                .into(),
-        })
-        .collect();
-
     Ok(Canonical {
         max_universe: goal.max_universe,
         variables: goal.variables,
         value: Response {
-            var_values: CanonicalVarValues { var_values },
+            var_values: CanonicalVarValues::make_identity(tcx, goal.variables),
             external_constraints: Default::default(),
             certainty,
         },