diff --git a/compiler/rustc_ty_utils/src/consts.rs b/compiler/rustc_ty_utils/src/consts.rs index 22cfd7e1985..5f7cafe2722 100644 --- a/compiler/rustc_ty_utils/src/consts.rs +++ b/compiler/rustc_ty_utils/src/consts.rs @@ -1,84 +1,77 @@ use rustc_middle::ty::{self, TyCtxt}; use rustc_target::abi::VariantIdx; -/// Tries to destructure constants of type Array or Adt into the constants +use std::iter; + +/// Tries to destructure array, ADT or tuple constants into the constants /// of its fields. pub(crate) fn destructure_const<'tcx>( tcx: TyCtxt<'tcx>, const_: ty::Const<'tcx>, ) -> ty::DestructuredConst<'tcx> { - if let ty::ConstKind::Value(valtree) = const_.kind() { - let branches = match valtree { - ty::ValTree::Branch(b) => b, - _ => bug!("cannot destructure constant {:?}", const_), - }; - - let (fields, variant) = match const_.ty().kind() { - ty::Array(inner_ty, _) | ty::Slice(inner_ty) => { - // construct the consts for the elements of the array/slice - let field_consts = branches - .iter() - .map(|b| { - tcx.mk_const(ty::ConstS { kind: ty::ConstKind::Value(*b), ty: *inner_ty }) - }) - .collect::>(); - debug!(?field_consts); - - (field_consts, None) - } - ty::Adt(def, _) if def.variants().is_empty() => bug!("unreachable"), - ty::Adt(def, substs) => { - let variant_idx = if def.is_enum() { - VariantIdx::from_u32(branches[0].unwrap_leaf().try_to_u32().unwrap()) - } else { - VariantIdx::from_u32(0) - }; - let fields = &def.variant(variant_idx).fields; - let mut field_consts = Vec::with_capacity(fields.len()); - - // Note: First element inValTree corresponds to variant of enum - let mut valtree_idx = if def.is_enum() { 1 } else { 0 }; - for field in fields { - let field_ty = field.ty(tcx, substs); - let field_valtree = branches[valtree_idx]; // first element of branches is variant - let field_const = tcx.mk_const(ty::ConstS { - kind: ty::ConstKind::Value(field_valtree), - ty: field_ty, - }); - field_consts.push(field_const); - valtree_idx += 1; - } - debug!(?field_consts); - - (field_consts, Some(variant_idx)) - } - ty::Tuple(elem_tys) => { - let fields = elem_tys - .iter() - .enumerate() - .map(|(i, elem_ty)| { - let elem_valtree = branches[i]; - tcx.mk_const(ty::ConstS { - kind: ty::ConstKind::Value(elem_valtree), - ty: elem_ty, - }) - }) - .collect::>(); - - (fields, None) - } - _ => bug!("cannot destructure constant {:?}", const_), - }; - - let fields = tcx.arena.alloc_from_iter(fields.into_iter()); - - ty::DestructuredConst { variant, fields } - } else { + let ty::ConstKind::Value(valtree) = const_.kind() else { bug!("cannot destructure constant {:?}", const_) - } + }; + + let branches = match valtree { + ty::ValTree::Branch(b) => b, + _ => bug!("cannot destructure constant {:?}", const_), + }; + + let (fields, variant) = match const_.ty().kind() { + ty::Array(inner_ty, _) | ty::Slice(inner_ty) => { + // construct the consts for the elements of the array/slice + let field_consts = branches + .iter() + .map(|b| tcx.mk_const(ty::ConstS { kind: ty::ConstKind::Value(*b), ty: *inner_ty })) + .collect::>(); + debug!(?field_consts); + + (field_consts, None) + } + ty::Adt(def, _) if def.variants().is_empty() => bug!("unreachable"), + ty::Adt(def, substs) => { + let (variant_idx, branches) = if def.is_enum() { + let (head, rest) = branches.split_first().unwrap(); + (VariantIdx::from_u32(head.unwrap_leaf().try_to_u32().unwrap()), rest) + } else { + (VariantIdx::from_u32(0), branches) + }; + let fields = &def.variant(variant_idx).fields; + let mut field_consts = Vec::with_capacity(fields.len()); + + for (field, field_valtree) in iter::zip(fields, branches) { + let field_ty = field.ty(tcx, substs); + let field_const = tcx.mk_const(ty::ConstS { + kind: ty::ConstKind::Value(*field_valtree), + ty: field_ty, + }); + field_consts.push(field_const); + } + debug!(?field_consts); + + (field_consts, Some(variant_idx)) + } + ty::Tuple(elem_tys) => { + let fields = iter::zip(*elem_tys, branches) + .map(|(elem_ty, elem_valtree)| { + tcx.mk_const(ty::ConstS { + kind: ty::ConstKind::Value(*elem_valtree), + ty: elem_ty, + }) + }) + .collect::>(); + + (fields, None) + } + _ => bug!("cannot destructure constant {:?}", const_), + }; + + let fields = tcx.arena.alloc_from_iter(fields.into_iter()); + + ty::DestructuredConst { variant, fields } } pub fn provide(providers: &mut ty::query::Providers) { - *providers = - ty::query::Providers { destructure_const, ..*providers }; + *providers = ty::query::Providers { destructure_const, ..*providers }; } diff --git a/src/test/ui/const-generics/issue-66451.rs b/src/test/ui/const-generics/issue-66451.rs index 76505d18875..3335f7d5984 100644 --- a/src/test/ui/const-generics/issue-66451.rs +++ b/src/test/ui/const-generics/issue-66451.rs @@ -17,7 +17,7 @@ fn main() { Foo { value: 3, nested: &Bar(4), - } + } }> = Test; let y: Test<{ Foo {