Avoid giving an inferctxt a defining use anchor

Author: oli-obk

compiler/rustc_const_eval/src/util/compare_types.rs

@@ -3,7 +3,7 @@
 //! FIXME: Move this to a more general place. The utility of this extends to
 //! other areas of the compiler as well.
 
-use rustc_infer::infer::{DefiningAnchor, TyCtxtInferExt};
+use rustc_infer::infer::TyCtxtInferExt;
 use rustc_infer::traits::ObligationCause;
 use rustc_middle::ty::{ParamEnv, Ty, TyCtxt};
 use rustc_trait_selection::traits::ObligationCtxt;
@@ -41,8 +41,7 @@ pub fn is_subtype<'tcx>(
         return true;
     }
 
-    let mut builder =
-        tcx.infer_ctxt().ignoring_regions().with_opaque_type_inference(DefiningAnchor::Bubble);
+    let mut builder = tcx.infer_ctxt().ignoring_regions();
     let infcx = builder.build();
     let ocx = ObligationCtxt::new_with_opaque_type_bubbling(&infcx);
     let cause = ObligationCause::dummy();

compiler/rustc_infer/src/infer/mod.rs

@@ -1318,7 +1318,6 @@ impl<'tcx> InferCtxt<'tcx> {
 
     #[instrument(level = "debug", skip(self), ret)]
     pub fn take_opaque_types(&self) -> opaque_types::OpaqueTypeMap<'tcx> {
-        debug_assert_ne!(self.old_defining_use_anchor, DefiningAnchor::Error);
         std::mem::take(&mut self.inner.borrow_mut().opaque_type_storage.opaque_types)
     }