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rustc: make TyLayout::field(NonZero<*T>, 0) return &T.

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Eduard-Mihai Burtescu 2017-09-24 11:56:23 +03:00
parent de3e581e29
commit abbc1ddbd0
1 changed files with 11 additions and 5 deletions
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16
src/librustc/ty/layout.rs
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@ -2033,7 +2033,17 @@ impl<'a, 'tcx> TyLayout<'tcx> {
ty::TyAdt(def, substs) => {
match self.variants {
Variants::Single { index } => {
def.variants[index].fields[i].ty(tcx, substs)
let mut field_ty = def.variants[index].fields[i].ty(tcx, substs);
// Treat NonZero<*T> as containing &T.
// This is especially useful for fat pointers.
if Some(def.did) == tcx.lang_items().non_zero() {
if let ty::TyRawPtr(mt) = field_ty.sty {
field_ty = tcx.mk_ref(tcx.types.re_erased, mt);
}
}
field_ty
}
// Discriminant field for enums (where applicable).
@ -2109,10 +2119,6 @@ impl<'a, 'tcx> TyLayout<'tcx> {
let offset = self.fields.offset(0);
if let Abi::Scalar(value) = field.abi {
Ok(Some((offset, value)))
} else if let ty::TyRawPtr(_) = field.ty.sty {
// If `NonZero` contains a non-scalar `*T`, it's
// a fat pointer, which starts with a thin pointer.
Ok(Some((offset, Pointer)))
} else {
Ok(None)
}