don't normalize wf predicates

[rust.git] / compiler / rustc_middle / src / ty / mod.rs

diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 02da02568d7e525d535445eecbc5f52401ecbdba..a7833ab64310fc29513aac6f9c7eb015cc1f29ba 100644 (file)
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -124,6 +124,7 @@
 mod generics;
 mod impls_ty;
 mod instance;
+mod layout_sanity_check;
 mod list;
 mod parameterized;
 mod rvalue_scopes;
@@ -593,6 +594,29 @@ pub fn without_const(mut self, tcx: TyCtxt<'tcx>) -> Self {
         }
         self
     }
+
+    /// Whether this projection can be soundly normalized.
+    ///
+    /// Wf predicates must not be normalized, as normalization
+    /// can remove required bounds which would cause us to
+    /// unsoundly accept some programs. See #91068.
+    #[inline]
+    pub fn allow_normalization(self) -> bool {
+        match self.kind().skip_binder() {
+            PredicateKind::WellFormed(_) => false,
+            PredicateKind::Trait(_)
+            | PredicateKind::RegionOutlives(_)
+            | PredicateKind::TypeOutlives(_)
+            | PredicateKind::Projection(_)
+            | PredicateKind::ObjectSafe(_)
+            | PredicateKind::ClosureKind(_, _, _)
+            | PredicateKind::Subtype(_)
+            | PredicateKind::Coerce(_)
+            | PredicateKind::ConstEvaluatable(_)
+            | PredicateKind::ConstEquate(_, _)
+            | PredicateKind::TypeWellFormedFromEnv(_) => true,
+        }
+    }
 }
 
 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for Predicate<'tcx> {