selection failure: recompute applicable impls

[rust.git] / compiler / rustc_trait_selection / src / traits / engine.rs

diff --git a/compiler/rustc_trait_selection/src/traits/engine.rs b/compiler/rustc_trait_selection/src/traits/engine.rs
index 21516c93efb53aa8b33e681938a61c1701f54d35..0eafc49816d49cbbef1bc84a93546fc3bbdb0f0c 100644 (file)
--- a/compiler/rustc_trait_selection/src/traits/engine.rs
+++ b/compiler/rustc_trait_selection/src/traits/engine.rs
@@ -38,7 +38,7 @@ fn new(tcx: TyCtxt<'tcx>) -> Box<Self> {
 
     fn new_in_snapshot(tcx: TyCtxt<'tcx>) -> Box<Self> {
         if tcx.sess.opts.unstable_opts.chalk {
-            Box::new(ChalkFulfillmentContext::new())
+            Box::new(ChalkFulfillmentContext::new_in_snapshot())
         } else {
             Box::new(FulfillmentContext::new_in_snapshot())
         }
@@ -119,13 +119,10 @@ pub fn eq<T: ToTrace<'tcx>>(
         expected: T,
         actual: T,
     ) -> Result<(), TypeError<'tcx>> {
-        match self.infcx.at(cause, param_env).eq(expected, actual) {
-            Ok(InferOk { obligations, value: () }) => {
-                self.register_obligations(obligations);
-                Ok(())
-            }
-            Err(e) => Err(e),
-        }
+        self.infcx
+            .at(cause, param_env)
+            .eq(expected, actual)
+            .map(|infer_ok| self.register_infer_ok_obligations(infer_ok))
     }
 
     pub fn sup<T: ToTrace<'tcx>>(
@@ -144,6 +141,10 @@ pub fn sup<T: ToTrace<'tcx>>(
         }
     }
 
+    pub fn select_where_possible(&self) -> Vec<FulfillmentError<'tcx>> {
+        self.engine.borrow_mut().select_where_possible(self.infcx)
+    }
+
     pub fn select_all_or_error(&self) -> Vec<FulfillmentError<'tcx>> {
         self.engine.borrow_mut().select_all_or_error(self.infcx)
     }