mirror of
https://github.com/rust-lang/rust-analyzer
synced 2025-01-21 01:24:13 +00:00
272 lines
9.7 KiB
Rust
272 lines
9.7 KiB
Rust
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//! Compute the binary representation of a type
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use chalk_ir::{AdtId, TyKind};
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pub(self) use hir_def::layout::*;
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use hir_def::LocalFieldId;
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use crate::{db::HirDatabase, Interner, Substitution, Ty};
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use self::adt::univariant;
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pub use self::{
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adt::{layout_of_adt_query, layout_of_adt_recover},
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target::current_target_data_layout_query,
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};
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macro_rules! user_error {
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($x: expr) => {
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return Err(LayoutError::UserError(format!($x)))
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};
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}
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mod adt;
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mod target;
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fn scalar_unit(dl: &TargetDataLayout, value: Primitive) -> Scalar {
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Scalar::Initialized { value, valid_range: WrappingRange::full(value.size(dl)) }
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}
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fn scalar(dl: &TargetDataLayout, value: Primitive) -> Layout {
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Layout::scalar(dl, scalar_unit(dl, value))
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}
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fn scalar_pair(dl: &TargetDataLayout, a: Scalar, b: Scalar) -> Layout {
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let b_align = b.align(dl);
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let align = a.align(dl).max(b_align).max(dl.aggregate_align);
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let b_offset = a.size(dl).align_to(b_align.abi);
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let size = b_offset.checked_add(b.size(dl), dl).unwrap().align_to(align.abi);
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// HACK(nox): We iter on `b` and then `a` because `max_by_key`
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// returns the last maximum.
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let largest_niche = Niche::from_scalar(dl, b_offset, b)
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.into_iter()
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.chain(Niche::from_scalar(dl, Size::ZERO, a))
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.max_by_key(|niche| niche.available(dl));
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Layout {
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variants: Variants::Single,
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fields: FieldsShape::Arbitrary {
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offsets: vec![Size::ZERO, b_offset],
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memory_index: vec![0, 1],
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},
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abi: Abi::ScalarPair(a, b),
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largest_niche,
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align,
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size,
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}
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}
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pub fn layout_of_ty(db: &dyn HirDatabase, ty: &Ty) -> Result<Layout, LayoutError> {
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let dl = &*db.current_target_data_layout();
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Ok(match ty.kind(Interner) {
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TyKind::Adt(AdtId(def), subst) => db.layout_of_adt(*def, subst.clone())?,
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TyKind::Scalar(s) => match s {
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chalk_ir::Scalar::Bool => Layout::scalar(
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dl,
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Scalar::Initialized {
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value: Primitive::Int(Integer::I8, false),
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valid_range: WrappingRange { start: 0, end: 1 },
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},
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),
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chalk_ir::Scalar::Char => Layout::scalar(
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dl,
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Scalar::Initialized {
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value: Primitive::Int(Integer::I32, false),
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valid_range: WrappingRange { start: 0, end: 0x10FFFF },
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},
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),
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chalk_ir::Scalar::Int(i) => scalar(
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dl,
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Primitive::Int(
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match i {
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chalk_ir::IntTy::Isize => dl.ptr_sized_integer(),
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chalk_ir::IntTy::I8 => Integer::I8,
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chalk_ir::IntTy::I16 => Integer::I16,
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chalk_ir::IntTy::I32 => Integer::I32,
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chalk_ir::IntTy::I64 => Integer::I64,
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chalk_ir::IntTy::I128 => Integer::I128,
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},
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false,
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),
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),
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chalk_ir::Scalar::Uint(i) => scalar(
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dl,
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Primitive::Int(
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match i {
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chalk_ir::UintTy::Usize => dl.ptr_sized_integer(),
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chalk_ir::UintTy::U8 => Integer::I8,
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chalk_ir::UintTy::U16 => Integer::I16,
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chalk_ir::UintTy::U32 => Integer::I32,
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chalk_ir::UintTy::U64 => Integer::I64,
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chalk_ir::UintTy::U128 => Integer::I128,
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},
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true,
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),
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),
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chalk_ir::Scalar::Float(f) => scalar(
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dl,
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match f {
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chalk_ir::FloatTy::F32 => Primitive::F32,
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chalk_ir::FloatTy::F64 => Primitive::F64,
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},
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),
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},
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TyKind::Tuple(len, tys) => {
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let kind = if *len == 0 { StructKind::AlwaysSized } else { StructKind::MaybeUnsized };
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univariant(
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dl,
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&tys.iter(Interner)
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.map(|k| layout_of_ty(db, k.assert_ty_ref(Interner)))
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.collect::<Result<Vec<_>, _>>()?,
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&ReprOptions::default(),
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kind,
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)?
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}
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TyKind::Array(element, count) => {
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let count = match count.data(Interner).value {
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chalk_ir::ConstValue::Concrete(c) => match c.interned {
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hir_def::type_ref::ConstScalar::Int(x) => x as u64,
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hir_def::type_ref::ConstScalar::UInt(x) => x as u64,
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hir_def::type_ref::ConstScalar::Unknown => {
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user_error!("unknown const generic parameter")
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}
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_ => user_error!("mismatched type of const generic parameter"),
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},
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_ => return Err(LayoutError::HasPlaceholder),
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};
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let element = layout_of_ty(db, element)?;
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let size = element.size.checked_mul(count, dl).ok_or(LayoutError::SizeOverflow)?;
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let abi = if count != 0 && matches!(element.abi, Abi::Uninhabited) {
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Abi::Uninhabited
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} else {
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Abi::Aggregate { sized: true }
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};
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let largest_niche = if count != 0 { element.largest_niche } else { None };
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Layout {
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variants: Variants::Single,
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fields: FieldsShape::Array { stride: element.size, count },
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abi,
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largest_niche,
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align: element.align,
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size,
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}
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}
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TyKind::Slice(element) => {
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let element = layout_of_ty(db, element)?;
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Layout {
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variants: Variants::Single,
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fields: FieldsShape::Array { stride: element.size, count: 0 },
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abi: Abi::Aggregate { sized: false },
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largest_niche: None,
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align: element.align,
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size: Size::ZERO,
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}
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}
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// Potentially-wide pointers.
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TyKind::Ref(_, _, pointee) | TyKind::Raw(_, pointee) => {
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let mut data_ptr = scalar_unit(dl, Primitive::Pointer);
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if matches!(ty.kind(Interner), TyKind::Ref(..)) {
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data_ptr.valid_range_mut().start = 1;
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}
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// let pointee = tcx.normalize_erasing_regions(param_env, pointee);
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// if pointee.is_sized(tcx.at(DUMMY_SP), param_env) {
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// return Ok(tcx.intern_layout(LayoutS::scalar(cx, data_ptr)));
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// }
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let unsized_part = struct_tail_erasing_lifetimes(db, pointee.clone());
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let metadata = match unsized_part.kind(Interner) {
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TyKind::Slice(_) | TyKind::Str => {
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scalar_unit(dl, Primitive::Int(dl.ptr_sized_integer(), false))
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}
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TyKind::Dyn(..) => {
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let mut vtable = scalar_unit(dl, Primitive::Pointer);
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vtable.valid_range_mut().start = 1;
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vtable
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}
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_ => {
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// pointee is sized
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return Ok(Layout::scalar(dl, data_ptr));
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}
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};
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// Effectively a (ptr, meta) tuple.
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scalar_pair(dl, data_ptr, metadata)
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}
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TyKind::FnDef(_, _) => {
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univariant(dl, &[], &ReprOptions::default(), StructKind::AlwaysSized)?
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}
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TyKind::Str => Layout {
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variants: Variants::Single,
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fields: FieldsShape::Array { stride: Size::from_bytes(1), count: 0 },
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abi: Abi::Aggregate { sized: false },
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largest_niche: None,
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align: dl.i8_align,
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size: Size::ZERO,
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},
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TyKind::Never => Layout {
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variants: Variants::Single,
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fields: FieldsShape::Primitive,
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abi: Abi::Uninhabited,
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largest_niche: None,
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align: dl.i8_align,
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size: Size::ZERO,
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},
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TyKind::Dyn(_) | TyKind::Foreign(_) => {
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let mut unit = univariant(dl, &[], &ReprOptions::default(), StructKind::AlwaysSized)?;
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match unit.abi {
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Abi::Aggregate { ref mut sized } => *sized = false,
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_ => user_error!("bug"),
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}
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unit
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}
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TyKind::Function(_) => {
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let mut ptr = scalar_unit(dl, Primitive::Pointer);
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ptr.valid_range_mut().start = 1;
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Layout::scalar(dl, ptr)
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}
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TyKind::Closure(_, _)
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| TyKind::OpaqueType(_, _)
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| TyKind::Generator(_, _)
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| TyKind::GeneratorWitness(_, _) => return Err(LayoutError::NotImplemented),
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TyKind::AssociatedType(_, _)
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| TyKind::Error
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| TyKind::Alias(_)
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| TyKind::Placeholder(_)
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| TyKind::BoundVar(_)
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| TyKind::InferenceVar(_, _) => return Err(LayoutError::HasPlaceholder),
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})
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}
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fn struct_tail_erasing_lifetimes(db: &dyn HirDatabase, pointee: Ty) -> Ty {
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match pointee.kind(Interner) {
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TyKind::Adt(AdtId(adt), subst) => match adt {
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&hir_def::AdtId::StructId(i) => {
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let data = db.struct_data(i);
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let mut it = data.variant_data.fields().iter().rev();
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match it.next() {
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Some((f, _)) => field_ty(db, i.into(), f, subst),
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None => pointee,
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}
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}
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_ => pointee,
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},
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_ => pointee,
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}
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}
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fn field_ty(
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db: &dyn HirDatabase,
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def: hir_def::VariantId,
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fd: LocalFieldId,
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subst: &Substitution,
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) -> Ty {
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db.field_types(def)[fd].clone().substitute(Interner, subst)
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}
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#[cfg(test)]
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mod tests;
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