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Fix multiple mistakes in adt::is_ffi_safe

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This commit is contained in:
Jed Davis 2013-10-03 10:11:24 -07:00
parent 25f953437d
commit ac311ecaab
1 changed files with 7 additions and 7 deletions
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14
src/librustc/middle/trans/adt.rs
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@ -221,10 +221,10 @@ 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. /// 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 { 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 { match ty::get(ty::lookup_item_type(tcx, def_id).ty).sty {
ty::ty_enum(def_id, ref substs) => { ty::ty_enum(def_id, _) => {
let cases = get_cases(tcx, def_id, substs); let variants = ty::enum_variants(tcx, def_id);
// Univariant => like struct/tuple. // Univariant => like struct/tuple.
if cases.len() <= 2 { if variants.len() <= 1 {
return true; return true;
} }
let hint = ty::lookup_repr_hint(tcx, def_id); let hint = ty::lookup_repr_hint(tcx, def_id);
@ -232,10 +232,10 @@ pub fn is_ffi_safe(tcx: ty::ctxt, def_id: ast::DefId) -> bool {
if hint.is_ffi_safe() { if hint.is_ffi_safe() {
return true; return true;
} }
// Conservative approximation of nullable pointers, for Option<~T> etc. // Option<~T> and similar are used in FFI. Rather than try to resolve type parameters
if cases.len() == 2 && hint == attr::ReprAny && // and recognize this case exactly, this overapproximates -- assuming that if a
(cases[0].tys.is_empty() && cases[1].find_ptr().is_some() || // non-C-like enum is being used in FFI then the user knows what they're doing.
cases[1].tys.is_empty() && cases[0].find_ptr().is_some()) { if variants.iter().any(|vi| !vi.args.is_empty()) {
return true; return true;
} }
false false