Rollup merge of #107272 - compiler-errors:new-solver-more-predicates, r=lcnr

Implement ObjectSafe and WF in the new solver

r? ``@lcnr``

compiler/rustc_trait_selection/src/solve/mod.rs

@@ -277,12 +277,15 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
                         param_env,
                         predicate: (def_id, substs, kind),
                     }),
+                ty::PredicateKind::ObjectSafe(trait_def_id) => {
+                    self.compute_object_safe_goal(trait_def_id)
+                }
+                ty::PredicateKind::WellFormed(arg) => {
+                    self.compute_well_formed_goal(Goal { param_env, predicate: arg })
+                }
                 ty::PredicateKind::Ambiguous => self.make_canonical_response(Certainty::AMBIGUOUS),
                 // FIXME: implement these predicates :)
-                ty::PredicateKind::WellFormed(_)
-                | ty::PredicateKind::ObjectSafe(_)
-                | ty::PredicateKind::ConstEvaluatable(_)
-                | ty::PredicateKind::ConstEquate(_, _) => {
+                ty::PredicateKind::ConstEvaluatable(_) | ty::PredicateKind::ConstEquate(_, _) => {
                     self.make_canonical_response(Certainty::Yes)
                 }
                 ty::PredicateKind::TypeWellFormedFromEnv(..) => {
@@ -362,6 +365,32 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
             Err(NoSolution)
         }
     }
+
+    fn compute_object_safe_goal(&mut self, trait_def_id: DefId) -> QueryResult<'tcx> {
+        if self.tcx().is_object_safe(trait_def_id) {
+            self.make_canonical_response(Certainty::Yes)
+        } else {
+            Err(NoSolution)
+        }
+    }
+
+    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),
+            }
+        })
+    }
 }
 
 impl<'tcx> EvalCtxt<'_, 'tcx> {

compiler/rustc_trait_selection/src/traits/wf.rs

@@ -4,8 +4,8 @@ use rustc_hir as hir;
 use rustc_hir::lang_items::LangItem;
 use rustc_middle::ty::subst::{GenericArg, GenericArgKind, SubstsRef};
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitable};
-use rustc_span::def_id::{DefId, LocalDefId};
-use rustc_span::Span;
+use rustc_span::def_id::{DefId, LocalDefId, CRATE_DEF_ID};
+use rustc_span::{Span, DUMMY_SP};
 
 use std::iter;
 /// Returns the set of obligations needed to make `arg` well-formed.
@@ -75,6 +75,34 @@ pub fn obligations<'tcx>(
     Some(result)
 }
 
+/// Compute the predicates that are required for a type to be well-formed.
+///
+/// This is only intended to be used in the new solver, since it does not
+/// take into account recursion depth or proper error-reporting spans.
+pub fn unnormalized_obligations<'tcx>(
+    infcx: &InferCtxt<'tcx>,
+    param_env: ty::ParamEnv<'tcx>,
+    arg: GenericArg<'tcx>,
+) -> Option<Vec<traits::PredicateObligation<'tcx>>> {
+    if let ty::GenericArgKind::Lifetime(..) = arg.unpack() {
+        return Some(vec![]);
+    }
+
+    debug_assert_eq!(arg, infcx.resolve_vars_if_possible(arg));
+
+    let mut wf = WfPredicates {
+        tcx: infcx.tcx,
+        param_env,
+        body_id: CRATE_DEF_ID,
+        span: DUMMY_SP,
+        out: vec![],
+        recursion_depth: 0,
+        item: None,
+    };
+    wf.compute(arg);
+    Some(wf.out)
+}
+
 /// Returns the obligations that make this trait reference
 /// well-formed. For example, if there is a trait `Set` defined like
 /// `trait Set<K:Eq>`, then the trait reference `Foo: Set<Bar>` is WF