rustc_trans: always use normalizing_infer_ctxt.

src/librustc_trans/trans/_match.rs

@@ -1351,7 +1351,7 @@ fn is_discr_reassigned(bcx: Block, discr: &ast::Expr, body: &ast::Expr) -> bool
         reassigned: false
     };
     {
-        let infcx = infer::new_infer_ctxt(bcx.tcx(), &bcx.tcx().tables, None, false);
+        let infcx = infer::normalizing_infer_ctxt(bcx.tcx(), &bcx.tcx().tables);
         let mut visitor = euv::ExprUseVisitor::new(&mut rc, &infcx);
         visitor.walk_expr(body);
     }

src/librustc_trans/trans/common.rs

@@ -936,7 +936,7 @@ pub fn normalize_and_test_predicates<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
            predicates);
 
     let tcx = ccx.tcx();
-    let infcx = infer::new_infer_ctxt(tcx, &tcx.tables, None, true);
+    let infcx = infer::normalizing_infer_ctxt(tcx, &tcx.tables);
     let mut selcx = traits::SelectionContext::new(&infcx);
     let mut fulfill_cx = infcx.fulfillment_cx.borrow_mut();
     let cause = traits::ObligationCause::dummy();

src/test/run-pass/issue-26805.rs

@@ -0,0 +1,15 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+struct NonOrd;
+
+fn main() {
+    let _: Box<Iterator<Item = _>> = Box::new(vec![NonOrd].into_iter());
+}