Normalize in needs_drop_raw

Author: matthewjasper

src/librustc/ty/util.rs

@@ -1122,9 +1122,19 @@ fn needs_drop_raw<'tcx>(tcx: TyCtxt<'tcx>, query: ty::ParamEnvAnd<'tcx, Ty<'tcx>
 
         // Can refer to a type which may drop.
         // FIXME(eddyb) check this against a ParamEnv.
-        ty::Dynamic(..) | ty::Projection(..) | ty::Param(_) | ty::Bound(..) |
+        ty::Dynamic(..) | ty::Param(_) | ty::Bound(..) |
         ty::Placeholder(..) | ty::Opaque(..) | ty::Infer(_) | ty::Error => true,
 
+        ty::Projection(..) => {
+            let normalized = tcx.normalize_erasing_regions(param_env, ty);
+            if let ty::Projection(..) = normalized.kind {
+                // Failed to normalize - assume that drop is required
+                true
+            } else {
+                needs_drop(normalized)
+            }
+        }
+
         ty::UnnormalizedProjection(..) => bug!("only used with chalk-engine"),
 
         // Zero-length arrays never contain anything to drop.