---

yaml
---
r: 146298
b: refs/heads/try2
c: ac311ec
h: refs/heads/master
v: v3

Author: jld

[refs]

@@ -5,7 +5,7 @@ refs/heads/snap-stage3: 78a7676898d9f80ab540c6df5d4c9ce35bb50463
 refs/heads/try: 519addf6277dbafccbb4159db4b710c37eaa2ec5
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
-refs/heads/try2: 25f953437d2bc3983b03c0d17cf56de40acec45b
+refs/heads/try2: ac311ecaab5d5a92fa86e9b201971bf92bcfbf99
 refs/heads/dist-snap: ba4081a5a8573875fed17545846f6f6902c8ba8d
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503

branches/try2/src/librustc/middle/trans/adt.rs

@@ -221,21 +221,21 @@ fn represent_type_uncached(cx: &mut CrateContext, t: ty::t) -> Repr {
 /// For use in lint or similar, where being sound but slightly incomplete is acceptable.
 pub fn is_ffi_safe(tcx: ty::ctxt, def_id: ast::DefId) -> bool {
     match ty::get(ty::lookup_item_type(tcx, def_id).ty).sty {
-        ty::ty_enum(def_id, ref substs) => {
-            let cases = get_cases(tcx, def_id, substs);
+        ty::ty_enum(def_id, _) => {
+            let variants = ty::enum_variants(tcx, def_id);
             // Univariant => like struct/tuple.
-            if cases.len() <= 2 {
+            if variants.len() <= 1 {
                 return true;
             }
             let hint = ty::lookup_repr_hint(tcx, def_id);
             // Appropriate representation explicitly selected?
             if hint.is_ffi_safe() {
                 return true;
             }
-            // Conservative approximation of nullable pointers, for Option<~T> etc.
-            if cases.len() == 2 && hint == attr::ReprAny &&
-                (cases[0].tys.is_empty() && cases[1].find_ptr().is_some() ||
-                 cases[1].tys.is_empty() && cases[0].find_ptr().is_some()) {
+            // Option<~T> and similar are used in FFI.  Rather than try to resolve type parameters
+            // and recognize this case exactly, this overapproximates -- assuming that if a
+            // non-C-like enum is being used in FFI then the user knows what they're doing.
+            if variants.iter().any(|vi| !vi.args.is_empty()) {
                 return true;
             }
             false