1 files changed, 18 insertions, 0 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/engine.rs b/compiler/rustc_trait_selection/src/traits/engine.rs
new file mode 100644
index 00000000000..4d477886979
--- /dev/null
+++ b/compiler/rustc_trait_selection/src/traits/engine.rs
@@ -0,0 +1,18 @@
+use rustc_middle::ty::TyCtxt;
+
+use super::TraitEngine;
+use super::{ChalkFulfillmentContext, FulfillmentContext};
+
+pub trait TraitEngineExt<'tcx> {
+    fn new(tcx: TyCtxt<'tcx>) -> Box<Self>;
+}
+
+impl<'tcx> TraitEngineExt<'tcx> for dyn TraitEngine<'tcx> {
+    fn new(tcx: TyCtxt<'tcx>) -> Box<Self> {
+        if tcx.sess.opts.debugging_opts.chalk {
+            Box::new(ChalkFulfillmentContext::new())
+        } else {
+            Box::new(FulfillmentContext::new())
+        }
+    }
+}