Begin to implement type system layer of unsafe binders

compiler/rustc_const_eval/src/const_eval/valtrees.rs

@@ -178,7 +178,8 @@ fn const_to_valtree_inner<'tcx>(
         | ty::Closure(..)
         | ty::CoroutineClosure(..)
         | ty::Coroutine(..)
-        | ty::CoroutineWitness(..) => Err(ValTreeCreationError::NonSupportedType(ty)),
+        | ty::CoroutineWitness(..)
+        | ty::UnsafeBinder(_) => Err(ValTreeCreationError::NonSupportedType(ty)),
     }
 }
 
@@ -358,7 +359,10 @@ pub fn valtree_to_const_value<'tcx>(
         | ty::FnPtr(..)
         | ty::Str
         | ty::Slice(_)
-        | ty::Dynamic(..) => bug!("no ValTree should have been created for type {:?}", ty.kind()),
+        | ty::Dynamic(..)
+        | ty::UnsafeBinder(_) => {
+            bug!("no ValTree should have been created for type {:?}", ty.kind())
+        }
     }
 }
 

compiler/rustc_const_eval/src/interpret/intrinsics.rs

@@ -90,6 +90,7 @@ pub(crate) fn eval_nullary_intrinsic<'tcx>(
             | ty::CoroutineClosure(_, _)
             | ty::Coroutine(_, _)
             | ty::CoroutineWitness(..)
+            | ty::UnsafeBinder(_)
             | ty::Never
             | ty::Tuple(_)
             | ty::Error(_) => ConstValue::from_target_usize(0u64, &tcx),

compiler/rustc_const_eval/src/interpret/stack.rs

@@ -505,6 +505,8 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 // We don't want to do any queries, so there is not much we can do with ADTs.
                 ty::Adt(..) => false,
 
+                ty::UnsafeBinder(ty) => is_very_trivially_sized(ty.skip_binder()),
+
                 ty::Alias(..) | ty::Param(_) | ty::Placeholder(..) => false,
 
                 ty::Infer(ty::TyVar(_)) => false,

compiler/rustc_const_eval/src/interpret/validity.rs

@@ -768,6 +768,7 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValidityVisitor<'rt, 'tcx, M> {
                 // Nothing to check.
                 interp_ok(true)
             }
+            ty::UnsafeBinder(_) => todo!("FIXME(unsafe_binder)"),
             // The above should be all the primitive types. The rest is compound, we
             // check them by visiting their fields/variants.
             ty::Adt(..)

compiler/rustc_const_eval/src/util/type_name.rs

@@ -38,7 +38,8 @@ impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
             | ty::FnPtr(..)
             | ty::Never
             | ty::Tuple(_)
-            | ty::Dynamic(_, _, _) => self.pretty_print_type(ty),
+            | ty::Dynamic(_, _, _)
+            | ty::UnsafeBinder(_) => self.pretty_print_type(ty),
 
             // Placeholders (all printed as `_` to uniformize them).
             ty::Param(_) | ty::Bound(..) | ty::Placeholder(_) | ty::Infer(_) | ty::Error(_) => {