diff options
Diffstat (limited to 'compiler/rustc_ty_utils/src/consts.rs')
| -rw-r--r-- | compiler/rustc_ty_utils/src/consts.rs | 572 |
1 files changed, 260 insertions, 312 deletions
diff --git a/compiler/rustc_ty_utils/src/consts.rs b/compiler/rustc_ty_utils/src/consts.rs index e057bb668..f8ff31f97 100644 --- a/compiler/rustc_ty_utils/src/consts.rs +++ b/compiler/rustc_ty_utils/src/consts.rs @@ -1,10 +1,11 @@ use rustc_errors::ErrorGuaranteed; use rustc_hir::def::DefKind; use rustc_hir::def_id::LocalDefId; -use rustc_index::vec::IndexVec; use rustc_middle::mir::interpret::{LitToConstError, LitToConstInput}; -use rustc_middle::ty::abstract_const::{CastKind, Node, NodeId}; -use rustc_middle::ty::{self, TyCtxt, TypeVisitable}; +use rustc_middle::thir::visit; +use rustc_middle::thir::visit::Visitor; +use rustc_middle::ty::abstract_const::CastKind; +use rustc_middle::ty::{self, Expr, TyCtxt, TypeVisitable}; use rustc_middle::{mir, thir}; use rustc_span::Span; use rustc_target::abi::VariantIdx; @@ -31,10 +32,8 @@ pub(crate) fn destructure_const<'tcx>( 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::<Vec<_>>(); + let field_consts = + branches.iter().map(|b| tcx.mk_const(*b, *inner_ty)).collect::<Vec<_>>(); debug!(?field_consts); (field_consts, None) @@ -52,10 +51,7 @@ pub(crate) fn destructure_const<'tcx>( 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, - }); + let field_const = tcx.mk_const(*field_valtree, field_ty); field_consts.push(field_const); } debug!(?field_consts); @@ -64,12 +60,7 @@ pub(crate) fn destructure_const<'tcx>( } 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, - }) - }) + .map(|(elem_ty, elem_valtree)| tcx.mk_const(*elem_valtree, elem_ty)) .collect::<Vec<_>>(); (fields, None) @@ -82,328 +73,278 @@ pub(crate) fn destructure_const<'tcx>( ty::DestructuredConst { variant, fields } } -pub struct AbstractConstBuilder<'a, 'tcx> { - tcx: TyCtxt<'tcx>, - body_id: thir::ExprId, - body: &'a thir::Thir<'tcx>, - /// The current WIP node tree. - nodes: IndexVec<NodeId, Node<'tcx>>, -} - -impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> { - fn root_span(&self) -> Span { - self.body.exprs[self.body_id].span - } - - fn error(&mut self, sub: GenericConstantTooComplexSub) -> Result<!, ErrorGuaranteed> { - let reported = self.tcx.sess.emit_err(GenericConstantTooComplex { - span: self.root_span(), - maybe_supported: None, - sub, - }); - - Err(reported) +/// We do not allow all binary operations in abstract consts, so filter disallowed ones. +fn check_binop(op: mir::BinOp) -> bool { + use mir::BinOp::*; + match op { + Add | Sub | Mul | Div | Rem | BitXor | BitAnd | BitOr | Shl | Shr | Eq | Lt | Le | Ne + | Ge | Gt => true, + Offset => false, } +} - fn maybe_supported_error( - &mut self, - sub: GenericConstantTooComplexSub, - ) -> Result<!, ErrorGuaranteed> { - let reported = self.tcx.sess.emit_err(GenericConstantTooComplex { - span: self.root_span(), - maybe_supported: Some(()), - sub, - }); - - Err(reported) +/// While we currently allow all unary operations, we still want to explicitly guard against +/// future changes here. +fn check_unop(op: mir::UnOp) -> bool { + use mir::UnOp::*; + match op { + Not | Neg => true, } +} - #[instrument(skip(tcx, body, body_id), level = "debug")] - pub fn new( - tcx: TyCtxt<'tcx>, - (body, body_id): (&'a thir::Thir<'tcx>, thir::ExprId), - ) -> Result<Option<AbstractConstBuilder<'a, 'tcx>>, ErrorGuaranteed> { - let builder = AbstractConstBuilder { tcx, body_id, body, nodes: IndexVec::new() }; - - struct IsThirPolymorphic<'a, 'tcx> { - is_poly: bool, - thir: &'a thir::Thir<'tcx>, +fn recurse_build<'tcx>( + tcx: TyCtxt<'tcx>, + body: &thir::Thir<'tcx>, + node: thir::ExprId, + root_span: Span, +) -> Result<ty::Const<'tcx>, ErrorGuaranteed> { + use thir::ExprKind; + let node = &body.exprs[node]; + + let maybe_supported_error = |a| maybe_supported_error(tcx, a, root_span); + let error = |a| error(tcx, a, root_span); + + Ok(match &node.kind { + // I dont know if handling of these 3 is correct + &ExprKind::Scope { value, .. } => recurse_build(tcx, body, value, root_span)?, + &ExprKind::PlaceTypeAscription { source, .. } + | &ExprKind::ValueTypeAscription { source, .. } => { + recurse_build(tcx, body, source, root_span)? } - - use crate::rustc_middle::thir::visit::Visitor; - use thir::visit; - - impl<'a, 'tcx> IsThirPolymorphic<'a, 'tcx> { - fn expr_is_poly(&mut self, expr: &thir::Expr<'tcx>) -> bool { - if expr.ty.has_non_region_param() { - return true; + &ExprKind::Literal { lit, neg } => { + let sp = node.span; + match tcx.at(sp).lit_to_const(LitToConstInput { lit: &lit.node, ty: node.ty, neg }) { + Ok(c) => c, + Err(LitToConstError::Reported(guar)) => { + tcx.const_error_with_guaranteed(node.ty, guar) } - - match expr.kind { - thir::ExprKind::NamedConst { substs, .. } => substs.has_non_region_param(), - thir::ExprKind::ConstParam { .. } => true, - thir::ExprKind::Repeat { value, count } => { - self.visit_expr(&self.thir()[value]); - count.has_non_region_param() - } - _ => false, + Err(LitToConstError::TypeError) => { + bug!("encountered type error in lit_to_const") } } + } + &ExprKind::NonHirLiteral { lit, user_ty: _ } => { + let val = ty::ValTree::from_scalar_int(lit); + tcx.mk_const(val, node.ty) + } + &ExprKind::ZstLiteral { user_ty: _ } => { + let val = ty::ValTree::zst(); + tcx.mk_const(val, node.ty) + } + &ExprKind::NamedConst { def_id, substs, user_ty: _ } => { + let uneval = ty::UnevaluatedConst::new(ty::WithOptConstParam::unknown(def_id), substs); + tcx.mk_const(uneval, node.ty) + } + ExprKind::ConstParam { param, .. } => tcx.mk_const(*param, node.ty), - fn pat_is_poly(&mut self, pat: &thir::Pat<'tcx>) -> bool { - if pat.ty.has_non_region_param() { - return true; - } + ExprKind::Call { fun, args, .. } => { + let fun = recurse_build(tcx, body, *fun, root_span)?; - match pat.kind { - thir::PatKind::Constant { value } => value.has_non_region_param(), - thir::PatKind::Range(box thir::PatRange { lo, hi, .. }) => { - lo.has_non_region_param() || hi.has_non_region_param() - } - _ => false, - } + let mut new_args = Vec::<ty::Const<'tcx>>::with_capacity(args.len()); + for &id in args.iter() { + new_args.push(recurse_build(tcx, body, id, root_span)?); } + let new_args = tcx.mk_const_list(new_args.iter()); + tcx.mk_const(Expr::FunctionCall(fun, new_args), node.ty) } - - impl<'a, 'tcx> visit::Visitor<'a, 'tcx> for IsThirPolymorphic<'a, 'tcx> { - fn thir(&self) -> &'a thir::Thir<'tcx> { - &self.thir - } - - #[instrument(skip(self), level = "debug")] - fn visit_expr(&mut self, expr: &thir::Expr<'tcx>) { - self.is_poly |= self.expr_is_poly(expr); - if !self.is_poly { - visit::walk_expr(self, expr) - } + &ExprKind::Binary { op, lhs, rhs } if check_binop(op) => { + let lhs = recurse_build(tcx, body, lhs, root_span)?; + let rhs = recurse_build(tcx, body, rhs, root_span)?; + tcx.mk_const(Expr::Binop(op, lhs, rhs), node.ty) + } + &ExprKind::Unary { op, arg } if check_unop(op) => { + let arg = recurse_build(tcx, body, arg, root_span)?; + tcx.mk_const(Expr::UnOp(op, arg), node.ty) + } + // This is necessary so that the following compiles: + // + // ``` + // fn foo<const N: usize>(a: [(); N + 1]) { + // bar::<{ N + 1 }>(); + // } + // ``` + ExprKind::Block { block } => { + if let thir::Block { stmts: box [], expr: Some(e), .. } = &body.blocks[*block] { + recurse_build(tcx, body, *e, root_span)? + } else { + maybe_supported_error(GenericConstantTooComplexSub::BlockNotSupported(node.span))? } - - #[instrument(skip(self), level = "debug")] - fn visit_pat(&mut self, pat: &thir::Pat<'tcx>) { - self.is_poly |= self.pat_is_poly(pat); - if !self.is_poly { - visit::walk_pat(self, pat); - } + } + // `ExprKind::Use` happens when a `hir::ExprKind::Cast` is a + // "coercion cast" i.e. using a coercion or is a no-op. + // This is important so that `N as usize as usize` doesnt unify with `N as usize`. (untested) + &ExprKind::Use { source } => { + let arg = recurse_build(tcx, body, source, root_span)?; + tcx.mk_const(Expr::Cast(CastKind::Use, arg, node.ty), node.ty) + } + &ExprKind::Cast { source } => { + let arg = recurse_build(tcx, body, source, root_span)?; + tcx.mk_const(Expr::Cast(CastKind::As, arg, node.ty), node.ty) + } + ExprKind::Borrow { arg, .. } => { + let arg_node = &body.exprs[*arg]; + + // Skip reborrows for now until we allow Deref/Borrow/AddressOf + // expressions. + // FIXME(generic_const_exprs): Verify/explain why this is sound + if let ExprKind::Deref { arg } = arg_node.kind { + recurse_build(tcx, body, arg, root_span)? + } else { + maybe_supported_error(GenericConstantTooComplexSub::BorrowNotSupported(node.span))? } } - - let mut is_poly_vis = IsThirPolymorphic { is_poly: false, thir: body }; - visit::walk_expr(&mut is_poly_vis, &body[body_id]); - debug!("AbstractConstBuilder: is_poly={}", is_poly_vis.is_poly); - if !is_poly_vis.is_poly { - return Ok(None); + // FIXME(generic_const_exprs): We may want to support these. + ExprKind::AddressOf { .. } | ExprKind::Deref { .. } => maybe_supported_error( + GenericConstantTooComplexSub::AddressAndDerefNotSupported(node.span), + )?, + ExprKind::Repeat { .. } | ExprKind::Array { .. } => { + maybe_supported_error(GenericConstantTooComplexSub::ArrayNotSupported(node.span))? } + ExprKind::NeverToAny { .. } => { + maybe_supported_error(GenericConstantTooComplexSub::NeverToAnyNotSupported(node.span))? + } + ExprKind::Tuple { .. } => { + maybe_supported_error(GenericConstantTooComplexSub::TupleNotSupported(node.span))? + } + ExprKind::Index { .. } => { + maybe_supported_error(GenericConstantTooComplexSub::IndexNotSupported(node.span))? + } + ExprKind::Field { .. } => { + maybe_supported_error(GenericConstantTooComplexSub::FieldNotSupported(node.span))? + } + ExprKind::ConstBlock { .. } => { + maybe_supported_error(GenericConstantTooComplexSub::ConstBlockNotSupported(node.span))? + } + ExprKind::Adt(_) => { + maybe_supported_error(GenericConstantTooComplexSub::AdtNotSupported(node.span))? + } + // dont know if this is correct + ExprKind::Pointer { .. } => { + error(GenericConstantTooComplexSub::PointerNotSupported(node.span))? + } + ExprKind::Yield { .. } => { + error(GenericConstantTooComplexSub::YieldNotSupported(node.span))? + } + ExprKind::Continue { .. } | ExprKind::Break { .. } | ExprKind::Loop { .. } => { + error(GenericConstantTooComplexSub::LoopNotSupported(node.span))? + } + ExprKind::Box { .. } => error(GenericConstantTooComplexSub::BoxNotSupported(node.span))?, - Ok(Some(builder)) - } - - /// We do not allow all binary operations in abstract consts, so filter disallowed ones. - fn check_binop(op: mir::BinOp) -> bool { - use mir::BinOp::*; - match op { - Add | Sub | Mul | Div | Rem | BitXor | BitAnd | BitOr | Shl | Shr | Eq | Lt | Le - | Ne | Ge | Gt => true, - Offset => false, + ExprKind::Unary { .. } => unreachable!(), + // we handle valid unary/binary ops above + ExprKind::Binary { .. } => { + error(GenericConstantTooComplexSub::BinaryNotSupported(node.span))? + } + ExprKind::LogicalOp { .. } => { + error(GenericConstantTooComplexSub::LogicalOpNotSupported(node.span))? + } + ExprKind::Assign { .. } | ExprKind::AssignOp { .. } => { + error(GenericConstantTooComplexSub::AssignNotSupported(node.span))? + } + ExprKind::Closure { .. } | ExprKind::Return { .. } => { + error(GenericConstantTooComplexSub::ClosureAndReturnNotSupported(node.span))? + } + // let expressions imply control flow + ExprKind::Match { .. } | ExprKind::If { .. } | ExprKind::Let { .. } => { + error(GenericConstantTooComplexSub::ControlFlowNotSupported(node.span))? + } + ExprKind::InlineAsm { .. } => { + error(GenericConstantTooComplexSub::InlineAsmNotSupported(node.span))? } - } - /// While we currently allow all unary operations, we still want to explicitly guard against - /// future changes here. - fn check_unop(op: mir::UnOp) -> bool { - use mir::UnOp::*; - match op { - Not | Neg => true, + // we dont permit let stmts so `VarRef` and `UpvarRef` cant happen + ExprKind::VarRef { .. } + | ExprKind::UpvarRef { .. } + | ExprKind::StaticRef { .. } + | ExprKind::ThreadLocalRef(_) => { + error(GenericConstantTooComplexSub::OperationNotSupported(node.span))? } - } + }) +} - /// Builds the abstract const by walking the thir and bailing out when - /// encountering an unsupported operation. - pub fn build(mut self) -> Result<&'tcx [Node<'tcx>], ErrorGuaranteed> { - debug!("AbstractConstBuilder::build: body={:?}", &*self.body); - self.recurse_build(self.body_id)?; +struct IsThirPolymorphic<'a, 'tcx> { + is_poly: bool, + thir: &'a thir::Thir<'tcx>, +} - Ok(self.tcx.arena.alloc_from_iter(self.nodes.into_iter())) - } +fn error<'tcx>( + tcx: TyCtxt<'tcx>, + sub: GenericConstantTooComplexSub, + root_span: Span, +) -> Result<!, ErrorGuaranteed> { + let reported = tcx.sess.emit_err(GenericConstantTooComplex { + span: root_span, + maybe_supported: None, + sub, + }); + + Err(reported) +} - fn recurse_build(&mut self, node: thir::ExprId) -> Result<NodeId, ErrorGuaranteed> { - use thir::ExprKind; - let node = &self.body.exprs[node]; - Ok(match &node.kind { - // I dont know if handling of these 3 is correct - &ExprKind::Scope { value, .. } => self.recurse_build(value)?, - &ExprKind::PlaceTypeAscription { source, .. } - | &ExprKind::ValueTypeAscription { source, .. } => self.recurse_build(source)?, - &ExprKind::Literal { lit, neg } => { - let sp = node.span; - let constant = match self.tcx.at(sp).lit_to_const(LitToConstInput { - lit: &lit.node, - ty: node.ty, - neg, - }) { - Ok(c) => c, - Err(LitToConstError::Reported) => self.tcx.const_error(node.ty), - Err(LitToConstError::TypeError) => { - bug!("encountered type error in lit_to_const") - } - }; - - self.nodes.push(Node::Leaf(constant)) - } - &ExprKind::NonHirLiteral { lit, user_ty: _ } => { - let val = ty::ValTree::from_scalar_int(lit); - self.nodes.push(Node::Leaf(ty::Const::from_value(self.tcx, val, node.ty))) - } - &ExprKind::ZstLiteral { user_ty: _ } => { - let val = ty::ValTree::zst(); - self.nodes.push(Node::Leaf(ty::Const::from_value(self.tcx, val, node.ty))) - } - &ExprKind::NamedConst { def_id, substs, user_ty: _ } => { - let uneval = - ty::UnevaluatedConst::new(ty::WithOptConstParam::unknown(def_id), substs); +fn maybe_supported_error<'tcx>( + tcx: TyCtxt<'tcx>, + sub: GenericConstantTooComplexSub, + root_span: Span, +) -> Result<!, ErrorGuaranteed> { + let reported = tcx.sess.emit_err(GenericConstantTooComplex { + span: root_span, + maybe_supported: Some(()), + sub, + }); + + Err(reported) +} - let constant = self - .tcx - .mk_const(ty::ConstS { kind: ty::ConstKind::Unevaluated(uneval), ty: node.ty }); +impl<'a, 'tcx> IsThirPolymorphic<'a, 'tcx> { + fn expr_is_poly(&mut self, expr: &thir::Expr<'tcx>) -> bool { + if expr.ty.has_non_region_param() { + return true; + } - self.nodes.push(Node::Leaf(constant)) + match expr.kind { + thir::ExprKind::NamedConst { substs, .. } => substs.has_non_region_param(), + thir::ExprKind::ConstParam { .. } => true, + thir::ExprKind::Repeat { value, count } => { + self.visit_expr(&self.thir()[value]); + count.has_non_region_param() } + _ => false, + } + } + fn pat_is_poly(&mut self, pat: &thir::Pat<'tcx>) -> bool { + if pat.ty.has_non_region_param() { + return true; + } - ExprKind::ConstParam { param, .. } => { - let const_param = self - .tcx - .mk_const(ty::ConstS { kind: ty::ConstKind::Param(*param), ty: node.ty }); - self.nodes.push(Node::Leaf(const_param)) + match pat.kind { + thir::PatKind::Constant { value } => value.has_non_region_param(), + thir::PatKind::Range(box thir::PatRange { lo, hi, .. }) => { + lo.has_non_region_param() || hi.has_non_region_param() } + _ => false, + } + } +} - ExprKind::Call { fun, args, .. } => { - let fun = self.recurse_build(*fun)?; - - let mut new_args = Vec::<NodeId>::with_capacity(args.len()); - for &id in args.iter() { - new_args.push(self.recurse_build(id)?); - } - let new_args = self.tcx.arena.alloc_slice(&new_args); - self.nodes.push(Node::FunctionCall(fun, new_args)) - } - &ExprKind::Binary { op, lhs, rhs } if Self::check_binop(op) => { - let lhs = self.recurse_build(lhs)?; - let rhs = self.recurse_build(rhs)?; - self.nodes.push(Node::Binop(op, lhs, rhs)) - } - &ExprKind::Unary { op, arg } if Self::check_unop(op) => { - let arg = self.recurse_build(arg)?; - self.nodes.push(Node::UnaryOp(op, arg)) - } - // This is necessary so that the following compiles: - // - // ``` - // fn foo<const N: usize>(a: [(); N + 1]) { - // bar::<{ N + 1 }>(); - // } - // ``` - ExprKind::Block { block } => { - if let thir::Block { stmts: box [], expr: Some(e), .. } = &self.body.blocks[*block] - { - self.recurse_build(*e)? - } else { - self.maybe_supported_error(GenericConstantTooComplexSub::BlockNotSupported( - node.span, - ))? - } - } - // `ExprKind::Use` happens when a `hir::ExprKind::Cast` is a - // "coercion cast" i.e. using a coercion or is a no-op. - // This is important so that `N as usize as usize` doesnt unify with `N as usize`. (untested) - &ExprKind::Use { source } => { - let arg = self.recurse_build(source)?; - self.nodes.push(Node::Cast(CastKind::Use, arg, node.ty)) - } - &ExprKind::Cast { source } => { - let arg = self.recurse_build(source)?; - self.nodes.push(Node::Cast(CastKind::As, arg, node.ty)) - } - ExprKind::Borrow { arg, .. } => { - let arg_node = &self.body.exprs[*arg]; - - // Skip reborrows for now until we allow Deref/Borrow/AddressOf - // expressions. - // FIXME(generic_const_exprs): Verify/explain why this is sound - if let ExprKind::Deref { arg } = arg_node.kind { - self.recurse_build(arg)? - } else { - self.maybe_supported_error(GenericConstantTooComplexSub::BorrowNotSupported( - node.span, - ))? - } - } - // FIXME(generic_const_exprs): We may want to support these. - ExprKind::AddressOf { .. } | ExprKind::Deref { .. } => self.maybe_supported_error( - GenericConstantTooComplexSub::AddressAndDerefNotSupported(node.span), - )?, - ExprKind::Repeat { .. } | ExprKind::Array { .. } => self.maybe_supported_error( - GenericConstantTooComplexSub::ArrayNotSupported(node.span), - )?, - ExprKind::NeverToAny { .. } => self.maybe_supported_error( - GenericConstantTooComplexSub::NeverToAnyNotSupported(node.span), - )?, - ExprKind::Tuple { .. } => self.maybe_supported_error( - GenericConstantTooComplexSub::TupleNotSupported(node.span), - )?, - ExprKind::Index { .. } => self.maybe_supported_error( - GenericConstantTooComplexSub::IndexNotSupported(node.span), - )?, - ExprKind::Field { .. } => self.maybe_supported_error( - GenericConstantTooComplexSub::FieldNotSupported(node.span), - )?, - ExprKind::ConstBlock { .. } => self.maybe_supported_error( - GenericConstantTooComplexSub::ConstBlockNotSupported(node.span), - )?, - ExprKind::Adt(_) => self - .maybe_supported_error(GenericConstantTooComplexSub::AdtNotSupported(node.span))?, - // dont know if this is correct - ExprKind::Pointer { .. } => { - self.error(GenericConstantTooComplexSub::PointerNotSupported(node.span))? - } - ExprKind::Yield { .. } => { - self.error(GenericConstantTooComplexSub::YieldNotSupported(node.span))? - } - ExprKind::Continue { .. } | ExprKind::Break { .. } | ExprKind::Loop { .. } => { - self.error(GenericConstantTooComplexSub::LoopNotSupported(node.span))? - } - ExprKind::Box { .. } => { - self.error(GenericConstantTooComplexSub::BoxNotSupported(node.span))? - } +impl<'a, 'tcx> visit::Visitor<'a, 'tcx> for IsThirPolymorphic<'a, 'tcx> { + fn thir(&self) -> &'a thir::Thir<'tcx> { + &self.thir + } - ExprKind::Unary { .. } => unreachable!(), - // we handle valid unary/binary ops above - ExprKind::Binary { .. } => { - self.error(GenericConstantTooComplexSub::BinaryNotSupported(node.span))? - } - ExprKind::LogicalOp { .. } => { - self.error(GenericConstantTooComplexSub::LogicalOpNotSupported(node.span))? - } - ExprKind::Assign { .. } | ExprKind::AssignOp { .. } => { - self.error(GenericConstantTooComplexSub::AssignNotSupported(node.span))? - } - ExprKind::Closure { .. } | ExprKind::Return { .. } => { - self.error(GenericConstantTooComplexSub::ClosureAndReturnNotSupported(node.span))? - } - // let expressions imply control flow - ExprKind::Match { .. } | ExprKind::If { .. } | ExprKind::Let { .. } => { - self.error(GenericConstantTooComplexSub::ControlFlowNotSupported(node.span))? - } - ExprKind::InlineAsm { .. } => { - self.error(GenericConstantTooComplexSub::InlineAsmNotSupported(node.span))? - } + #[instrument(skip(self), level = "debug")] + fn visit_expr(&mut self, expr: &thir::Expr<'tcx>) { + self.is_poly |= self.expr_is_poly(expr); + if !self.is_poly { + visit::walk_expr(self, expr) + } + } - // we dont permit let stmts so `VarRef` and `UpvarRef` cant happen - ExprKind::VarRef { .. } - | ExprKind::UpvarRef { .. } - | ExprKind::StaticRef { .. } - | ExprKind::ThreadLocalRef(_) => { - self.error(GenericConstantTooComplexSub::OperationNotSupported(node.span))? - } - }) + #[instrument(skip(self), level = "debug")] + fn visit_pat(&mut self, pat: &thir::Pat<'tcx>) { + self.is_poly |= self.pat_is_poly(pat); + if !self.is_poly { + visit::walk_pat(self, pat); + } } } @@ -411,7 +352,7 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> { pub fn thir_abstract_const<'tcx>( tcx: TyCtxt<'tcx>, def: ty::WithOptConstParam<LocalDefId>, -) -> Result<Option<&'tcx [Node<'tcx>]>, ErrorGuaranteed> { +) -> Result<Option<ty::Const<'tcx>>, ErrorGuaranteed> { if tcx.features().generic_const_exprs { match tcx.def_kind(def.did) { // FIXME(generic_const_exprs): We currently only do this for anonymous constants, @@ -424,10 +365,17 @@ pub fn thir_abstract_const<'tcx>( } let body = tcx.thir_body(def)?; + let (body, body_id) = (&*body.0.borrow(), body.1); + + let mut is_poly_vis = IsThirPolymorphic { is_poly: false, thir: body }; + visit::walk_expr(&mut is_poly_vis, &body[body_id]); + if !is_poly_vis.is_poly { + return Ok(None); + } + + let root_span = body.exprs[body_id].span; - AbstractConstBuilder::new(tcx, (&*body.0.borrow(), body.1))? - .map(AbstractConstBuilder::build) - .transpose() + Some(recurse_build(tcx, body, body_id, root_span)).transpose() } else { Ok(None) } |