Only expect mono consts in CFI

compiler/rustc_middle/src/ty/consts.rs

@@ -521,6 +521,10 @@ impl<'tcx> Const<'tcx> {
         self.try_to_valtree()?.try_to_scalar()
     }
 
+    pub fn try_to_bool(self) -> Option<bool> {
+        self.try_to_scalar()?.to_bool().ok()
+    }
+
     #[inline]
     pub fn try_to_target_usize(self, tcx: TyCtxt<'tcx>) -> Option<u64> {
         self.try_to_valtree()?.try_to_target_usize(tcx)

compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/encode.rs

@@ -145,7 +145,7 @@ fn encode_const<'tcx>(
                     let _ = write!(s, "{val}");
                 }
                 ty::Bool => {
-                    let val = c.try_eval_bool(tcx, ty::ParamEnv::reveal_all()).unwrap();
+                    let val = c.try_to_bool().expect("expected monomorphic const in cfi");
                     let _ = write!(s, "{val}");
                 }
                 _ => {
@@ -411,7 +411,7 @@ pub fn encode_ty<'tcx>(
 
         ty::Array(ty0, len) => {
             // A<array-length><element-type>
-            let len = len.eval_target_usize(tcx, ty::ParamEnv::reveal_all());
+            let len = len.try_to_target_usize(tcx).expect("expected monomorphic const in cfi");
             let mut s = String::from("A");
             let _ = write!(s, "{len}");
             s.push_str(&encode_ty(tcx, *ty0, dict, options));