///
/// Note that generic parameters in fields only get lazily substituted
/// by using something like `adt_def.all_fields().map(|field| field.ty(tcx, substs))`.
- Adt(&'tcx AdtDef, SubstsRef<'tcx>),
+ Adt(AdtDef<'tcx>, SubstsRef<'tcx>),
/// An unsized FFI type that is opaque to Rust. Written as `extern type T`.
Foreign(DefId),
#[inline]
pub fn is_simd(self) -> bool {
match self.kind() {
- Adt(def, _) => def.repr.simd(),
+ Adt(def, _) => def.repr().simd(),
_ => false,
}
}
pub fn simd_size_and_type(self, tcx: TyCtxt<'tcx>) -> (u64, Ty<'tcx>) {
match self.kind() {
Adt(def, substs) => {
- assert!(def.repr.simd(), "`simd_size_and_type` called on non-SIMD type");
+ assert!(def.repr().simd(), "`simd_size_and_type` called on non-SIMD type");
let variant = def.non_enum_variant();
let f0_ty = variant.fields[0].ty(tcx, substs);
}
#[inline]
- pub fn ty_adt_def(self) -> Option<&'tcx AdtDef> {
+ pub fn ty_adt_def(self) -> Option<AdtDef<'tcx>> {
match self.kind() {
- Adt(adt, _) => Some(adt),
+ Adt(adt, _) => Some(*adt),
_ => None,
}
}
/// Iterates over tuple fields.
/// Panics when called on anything but a tuple.
+ #[inline]
pub fn tuple_fields(self) -> &'tcx List<Ty<'tcx>> {
match self.kind() {
Tuple(substs) => substs,
variant_index: VariantIdx,
) -> Option<Discr<'tcx>> {
match self.kind() {
- TyKind::Adt(adt, _) if adt.variants.is_empty() => {
+ TyKind::Adt(adt, _) if adt.variants().is_empty() => {
// This can actually happen during CTFE, see
// https://github.com/rust-lang/rust/issues/89765.
None
/// Returns the type of the discriminant of this type.
pub fn discriminant_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
match self.kind() {
- ty::Adt(adt, _) if adt.is_enum() => adt.repr.discr_type().to_ty(tcx),
+ ty::Adt(adt, _) if adt.is_enum() => adt.repr().discr_type().to_ty(tcx),
ty::Generator(_, substs, _) => substs.as_generator().discr_ty(tcx),
ty::Param(_) | ty::Projection(_) | ty::Opaque(..) | ty::Infer(ty::TyVar(_)) => {
}
}
- /// Returns the type of metadata for (potentially fat) pointers to this type.
+ /// Returns the type of metadata for (potentially fat) pointers to this type,
+ /// and a boolean signifying if this is conditional on this type being `Sized`.
pub fn ptr_metadata_ty(
self,
tcx: TyCtxt<'tcx>,
normalize: impl FnMut(Ty<'tcx>) -> Ty<'tcx>,
- ) -> Ty<'tcx> {
+ ) -> (Ty<'tcx>, bool) {
let tail = tcx.struct_tail_with_normalize(self, normalize);
match tail.kind() {
// Sized types
| ty::Closure(..)
| ty::Never
| ty::Error(_)
+ // Extern types have metadata = ().
| ty::Foreign(..)
// If returned by `struct_tail_without_normalization` this is a unit struct
// without any fields, or not a struct, and therefore is Sized.
| ty::Adt(..)
// If returned by `struct_tail_without_normalization` this is the empty tuple,
// a.k.a. unit type, which is Sized
- | ty::Tuple(..) => tcx.types.unit,
+ | ty::Tuple(..) => (tcx.types.unit, false),
- ty::Str | ty::Slice(_) => tcx.types.usize,
+ ty::Str | ty::Slice(_) => (tcx.types.usize, false),
ty::Dynamic(..) => {
let dyn_metadata = tcx.lang_items().dyn_metadata().unwrap();
- tcx.type_of(dyn_metadata).subst(tcx, &[tail.into()])
+ (tcx.type_of(dyn_metadata).subst(tcx, &[tail.into()]), false)
},
- ty::Projection(_)
- | ty::Param(_)
- | ty::Opaque(..)
- | ty::Infer(ty::TyVar(_))
+ // type parameters only have unit metadata if they're sized, so return true
+ // to make sure we double check this during confirmation
+ ty::Param(_) | ty::Projection(_) | ty::Opaque(..) => (tcx.types.unit, true),
+
+ ty::Infer(ty::TyVar(_))
| ty::Bound(..)
| ty::Placeholder(..)
| ty::Infer(ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => {
- bug!("`ptr_metadata_ty` applied to unexpected type: {:?}", tail)
+ bug!("`ptr_metadata_ty` applied to unexpected type: {:?} (tail = {:?})", self, tail)
}
}
}
}
}
}
+
+ /// Fast path helper for primitives which are always `Copy` and which
+ /// have a side-effect-free `Clone` impl.
+ ///
+ /// Returning true means the type is known to be pure and `Copy+Clone`.
+ /// Returning `false` means nothing -- could be `Copy`, might not be.
+ ///
+ /// This is mostly useful for optimizations, as there are the types
+ /// on which we can replace cloning with dereferencing.
+ pub fn is_trivially_pure_clone_copy(self) -> bool {
+ match self.kind() {
+ ty::Bool | ty::Char | ty::Never => true,
+
+ // These aren't even `Clone`
+ ty::Str | ty::Slice(..) | ty::Foreign(..) | ty::Dynamic(..) => false,
+
+ ty::Int(..) | ty::Uint(..) | ty::Float(..) => true,
+
+ // The voldemort ZSTs are fine.
+ ty::FnDef(..) => true,
+
+ ty::Array(element_ty, _len) => element_ty.is_trivially_pure_clone_copy(),
+
+ // A 100-tuple isn't "trivial", so doing this only for reasonable sizes.
+ ty::Tuple(field_tys) => {
+ field_tys.len() <= 3 && field_tys.iter().all(Self::is_trivially_pure_clone_copy)
+ }
+
+ // Sometimes traits aren't implemented for every ABI or arity,
+ // because we can't be generic over everything yet.
+ ty::FnPtr(..) => false,
+
+ // Definitely absolutely not copy.
+ ty::Ref(_, _, hir::Mutability::Mut) => false,
+
+ // Thin pointers & thin shared references are pure-clone-copy, but for
+ // anything with custom metadata it might be more complicated.
+ ty::Ref(_, _, hir::Mutability::Not) | ty::RawPtr(..) => false,
+
+ ty::Generator(..) | ty::GeneratorWitness(..) => false,
+
+ // Might be, but not "trivial" so just giving the safe answer.
+ ty::Adt(..) | ty::Closure(..) | ty::Opaque(..) => false,
+
+ ty::Projection(..) | ty::Param(..) | ty::Infer(..) | ty::Error(..) => false,
+
+ ty::Bound(..) | ty::Placeholder(..) => {
+ bug!("`is_trivially_pure_clone_copy` applied to unexpected type: {:?}", self);
+ }
+ }
+ }
}
/// Extra information about why we ended up with a particular variance.
projects / rust.git / blobdiff