Forbid RetagKind::TwoPhase as well

Author: JakobDegen

compiler/rustc_const_eval/src/transform/validate.rs

@@ -671,8 +671,8 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
                 // FIXME(JakobDegen) The validator should check that `self.mir_phase <
                 // DropsLowered`. However, this causes ICEs with generation of drop shims, which
                 // seem to fail to set their `MirPhase` correctly.
-                if *kind == RetagKind::Raw {
-                    self.fail(location, "explicit `RetagKind::Raw` is forbidden");
+                if *kind == RetagKind::Raw || *kind == RetagKind::TwoPhase {
+                    self.fail(location, format!("explicit `{:?}` is forbidden", kind));
                 }
             }
             StatementKind::StorageLive(..)

compiler/rustc_middle/src/mir/syntax.rs

@@ -323,8 +323,7 @@ pub enum StatementKind<'tcx> {
     /// For code that is not specific to stacked borrows, you should consider retags to read and
     /// modify the place in an opaque way.
     ///
-    /// Explicit `RetagKind::Raw` is not permitted - it is implicit as a part of
-    /// `Rvalue::AddressOf`.
+    /// Only `RetagKind::Default` and `RetagKind::FnEntry` are permitted.
     Retag(RetagKind, Box<Place<'tcx>>),
 
     /// Encodes a user's type ascription. These need to be preserved