hir typeck: fulfillment_cx ignore regions

compiler/rustc_trait_selection/src/traits/engine.rs

@@ -15,6 +15,8 @@ use rustc_middle::ty::{self, Ty, TyCtxt};
 
 pub trait TraitEngineExt<'tcx> {
     fn new(tcx: TyCtxt<'tcx>) -> Box<Self>;
+
+    fn new_ignoring_regions(tcx: TyCtxt<'tcx>) -> Box<Self>;
 }
 
 impl<'tcx> TraitEngineExt<'tcx> for dyn TraitEngine<'tcx> {
@@ -25,6 +27,14 @@ impl<'tcx> TraitEngineExt<'tcx> for dyn TraitEngine<'tcx> {
             Box::new(FulfillmentContext::new())
         }
     }
+
+    fn new_ignoring_regions(tcx: TyCtxt<'tcx>) -> Box<Self> {
+        if tcx.sess.opts.unstable_opts.chalk {
+            Box::new(ChalkFulfillmentContext::new())
+        } else {
+            Box::new(FulfillmentContext::new_ignoring_regions())
+        }
+    }
 }
 
 /// Used if you want to have pleasant experience when dealing