From b3c285fa25d0ae1c1d439fe5ff6c097b8bdbc8ad Mon Sep 17 00:00:00 2001
From: Austin Hicks <camlorn@camlorn.net>
Date: Tue, 22 Nov 2016 14:10:52 -0500
Subject: [PATCH] Fix checking to see if the last field of a struct can be
 unsized.

---
 src/librustc/ty/layout.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/librustc/ty/layout.rs b/src/librustc/ty/layout.rs
index 6d7625bf15d4..0210b77dba06 100644
--- a/src/librustc/ty/layout.rs
+++ b/src/librustc/ty/layout.rs
@@ -1167,7 +1167,7 @@ impl<'a, 'gcx, 'tcx> Layout {
                         let param_env = tcx.construct_parameter_environment(DUMMY_SP, def.did, ROOT_CODE_EXTENT);
                         let fields = &def.variants[0].fields;
                         let last_field = &fields[fields.len()-1];
-                        let always_sized = last_field.unsubst_ty().is_sized(tcx, &param_env, DUMMY_SP);
+                        let always_sized = last_field.ty(tcx, param_env.free_substs).is_sized(tcx, &param_env, DUMMY_SP);
                         if !always_sized { StructKind::MaybeUnsizedUnivariant }
                         else { StructKind::AlwaysSizedUnivariant }
                     };