use `TypingEnv` when no `infcx` is available

the behavior of the type system not only depends on the current
assumptions, but also the currentnphase of the compiler. This is
mostly necessary as we need to decide whether and how to reveal
opaque types. We track this via the `TypingMode`.

1 files changed, 2 insertions, 2 deletions

diff --git a/compiler/rustc_transmute/src/maybe_transmutable/mod.rs b/compiler/rustc_transmute/src/maybe_transmutable/mod.rs
index 9dabcea706f..023c8fad781 100644
--- a/compiler/rustc_transmute/src/maybe_transmutable/mod.rs
+++ b/compiler/rustc_transmute/src/maybe_transmutable/mod.rs
@@ -31,7 +31,7 @@ where
 #[cfg(feature = "rustc")]
 mod rustc {
     use rustc_middle::ty::layout::LayoutCx;
-    use rustc_middle::ty::{ParamEnv, Ty, TyCtxt};
+    use rustc_middle::ty::{Ty, TyCtxt, TypingEnv};
 
     use super::*;
     use crate::layout::tree::rustc::Err;
@@ -43,7 +43,7 @@ mod rustc {
         pub(crate) fn answer(self) -> Answer<<TyCtxt<'tcx> as QueryContext>::Ref> {
             let Self { src, dst, assume, context } = self;
 
-            let layout_cx = LayoutCx::new(context, ParamEnv::reveal_all());
+            let layout_cx = LayoutCx::new(context, TypingEnv::fully_monomorphized());
 
             // Convert `src` and `dst` from their rustc representations, to `Tree`-based
             // representations.