introduce PredicateAtom

[rust.git] / src / librustc_trait_selection / traits / mod.rs

diff --git a/src/librustc_trait_selection/traits/mod.rs b/src/librustc_trait_selection/traits/mod.rs
index e8006129e3ef8666f8148c34c7f185a97cbe282e..afa48c2f76cf8a0fb79b77e4a6a246518c7e68a1 100644 (file)
--- a/src/librustc_trait_selection/traits/mod.rs
+++ b/src/librustc_trait_selection/traits/mod.rs
@@ -328,8 +328,8 @@ pub fn normalize_param_env_or_error<'tcx>(
     // This works fairly well because trait matching  does not actually care about param-env
     // TypeOutlives predicates - these are normally used by regionck.
     let outlives_predicates: Vec<_> = predicates
-        .drain_filter(|predicate| match predicate.kind() {
-            ty::PredicateKind::TypeOutlives(..) => true,
+        .drain_filter(|predicate| match predicate.skip_binders() {
+            ty::PredicateAtom::TypeOutlives(..) => true,
             _ => false,
         })
         .collect();
@@ -418,15 +418,14 @@ pub fn fully_normalize<'a, 'tcx, T>(
     Ok(resolved_value)
 }
 
-/// Normalizes the predicates and checks whether they hold in an empty
-/// environment. If this returns false, then either normalize
-/// encountered an error or one of the predicates did not hold. Used
-/// when creating vtables to check for unsatisfiable methods.
-pub fn normalize_and_test_predicates<'tcx>(
+/// Normalizes the predicates and checks whether they hold in an empty environment. If this
+/// returns true, then either normalize encountered an error or one of the predicates did not
+/// hold. Used when creating vtables to check for unsatisfiable methods.
+pub fn impossible_predicates<'tcx>(
     tcx: TyCtxt<'tcx>,
     predicates: Vec<ty::Predicate<'tcx>>,
 ) -> bool {
-    debug!("normalize_and_test_predicates(predicates={:?})", predicates);
+    debug!("impossible_predicates(predicates={:?})", predicates);
 
     let result = tcx.infer_ctxt().enter(|infcx| {
         let param_env = ty::ParamEnv::reveal_all();
@@ -443,22 +442,23 @@ pub fn normalize_and_test_predicates<'tcx>(
             fulfill_cx.register_predicate_obligation(&infcx, obligation);
         }
 
-        fulfill_cx.select_all_or_error(&infcx).is_ok()
+        fulfill_cx.select_all_or_error(&infcx).is_err()
     });
-    debug!("normalize_and_test_predicates(predicates={:?}) = {:?}", predicates, result);
+    debug!("impossible_predicates(predicates={:?}) = {:?}", predicates, result);
     result
 }
 
-fn substitute_normalize_and_test_predicates<'tcx>(
+fn subst_and_check_impossible_predicates<'tcx>(
     tcx: TyCtxt<'tcx>,
     key: (DefId, SubstsRef<'tcx>),
 ) -> bool {
-    debug!("substitute_normalize_and_test_predicates(key={:?})", key);
+    debug!("subst_and_check_impossible_predicates(key={:?})", key);
 
-    let predicates = tcx.predicates_of(key.0).instantiate(tcx, key.1).predicates;
-    let result = normalize_and_test_predicates(tcx, predicates);
+    let mut predicates = tcx.predicates_of(key.0).instantiate(tcx, key.1).predicates;
+    predicates.retain(|predicate| !predicate.needs_subst());
+    let result = impossible_predicates(tcx, predicates);
 
-    debug!("substitute_normalize_and_test_predicates(key={:?}) = {:?}", key, result);
+    debug!("subst_and_check_impossible_predicates(key={:?}) = {:?}", key, result);
     result
 }
 
@@ -510,7 +510,7 @@ fn vtable_methods<'tcx>(
             // Note that this method could then never be called, so we
             // do not want to try and codegen it, in that case (see #23435).
             let predicates = tcx.predicates_of(def_id).instantiate_own(tcx, substs);
-            if !normalize_and_test_predicates(tcx, predicates.predicates) {
+            if impossible_predicates(tcx, predicates.predicates) {
                 debug!("vtable_methods: predicates do not hold");
                 return None;
             }
@@ -558,8 +558,8 @@ pub fn provide(providers: &mut ty::query::Providers) {
         specializes: specialize::specializes,
         codegen_fulfill_obligation: codegen::codegen_fulfill_obligation,
         vtable_methods,
-        substitute_normalize_and_test_predicates,
         type_implements_trait,
+        subst_and_check_impossible_predicates,
         ..*providers
     };
 }