From f8d3f401df47cf680180c357fabdc8c76c2a08ab Mon Sep 17 00:00:00 2001 From: Bastian Kauschke Date: Tue, 22 Sep 2020 10:54:09 +0200 Subject: [PATCH] walk hir to get const evaluatable predicates --- compiler/rustc_typeck/src/collect.rs | 143 ++++++++++-------- .../cross_crate_predicate.stderr | 20 +-- .../let-bindings.stderr | 6 +- 3 files changed, 96 insertions(+), 73 deletions(-) diff --git a/compiler/rustc_typeck/src/collect.rs b/compiler/rustc_typeck/src/collect.rs index fd2cd03a9c1..d341e7eec41 100644 --- a/compiler/rustc_typeck/src/collect.rs +++ b/compiler/rustc_typeck/src/collect.rs @@ -37,12 +37,11 @@ use rustc_middle::hir::map::Map; use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs}; use rustc_middle::mir::mono::Linkage; use rustc_middle::ty::query::Providers; -use rustc_middle::ty::subst::{InternalSubsts, SubstsRef}; +use rustc_middle::ty::subst::InternalSubsts; use rustc_middle::ty::util::Discr; use rustc_middle::ty::util::IntTypeExt; use rustc_middle::ty::{self, AdtKind, Const, ToPolyTraitRef, Ty, TyCtxt}; use rustc_middle::ty::{ReprOptions, ToPredicate, WithConstness}; -use rustc_middle::ty::{TypeFoldable, TypeVisitor}; use rustc_session::config::SanitizerSet; use rustc_session::lint; use rustc_session::parse::feature_err; @@ -51,8 +50,6 @@ use rustc_span::{Span, DUMMY_SP}; use rustc_target::spec::abi; use rustc_trait_selection::traits::error_reporting::suggestions::NextTypeParamName; -use smallvec::SmallVec; - mod type_of; struct OnlySelfBounds(bool); @@ -1676,65 +1673,10 @@ fn predicates_defined_on(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicate } } - if tcx.features().const_evaluatable_checked { - let const_evaluatable = const_evaluatable_predicates_of(tcx, def_id, &result); - if !const_evaluatable.is_empty() { - result.predicates = tcx - .arena - .alloc_from_iter(result.predicates.iter().copied().chain(const_evaluatable)); - } - } - debug!("predicates_defined_on({:?}) = {:?}", def_id, result); result } -pub fn const_evaluatable_predicates_of<'tcx>( - tcx: TyCtxt<'tcx>, - def_id: DefId, - predicates: &ty::GenericPredicates<'tcx>, -) -> Vec<(ty::Predicate<'tcx>, Span)> { - #[derive(Default)] - struct ConstCollector<'tcx> { - ct: SmallVec<[(ty::WithOptConstParam, SubstsRef<'tcx>, Span); 4]>, - curr_span: Span, - } - - impl<'tcx> TypeVisitor<'tcx> for ConstCollector<'tcx> { - fn visit_const(&mut self, ct: &'tcx Const<'tcx>) -> bool { - if let ty::ConstKind::Unevaluated(def, substs, None) = ct.val { - self.ct.push((def, substs, self.curr_span)); - } - false - } - } - - let mut collector = ConstCollector::default(); - for &(pred, span) in predicates.predicates.iter() { - collector.curr_span = span; - pred.visit_with(&mut collector); - } - - match tcx.def_kind(def_id) { - DefKind::Fn | DefKind::AssocFn => { - tcx.fn_sig(def_id).visit_with(&mut collector); - } - _ => (), - } - debug!("const_evaluatable_predicates_of({:?}) = {:?}", def_id, collector.ct); - - // We only want unique const evaluatable predicates. - collector.ct.sort(); - collector.ct.dedup(); - collector - .ct - .into_iter() - .map(move |(def_id, subst, span)| { - (ty::PredicateAtom::ConstEvaluatable(def_id, subst).to_predicate(tcx), span) - }) - .collect() -} - /// Returns a list of all type predicates (explicit and implicit) for the definition with /// ID `def_id`. This includes all predicates returned by `predicates_defined_on`, plus /// `Self: Trait` predicates for traits. @@ -2061,6 +2003,10 @@ fn explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicat })) } + if tcx.features().const_evaluatable_checked { + predicates.extend(const_evaluatable_predicates_of(tcx, def_id.expect_local())); + } + let mut predicates: Vec<_> = predicates.into_iter().collect(); // Subtle: before we store the predicates into the tcx, we @@ -2087,6 +2033,85 @@ fn explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicat result } +fn const_evaluatable_predicates_of<'tcx>( + tcx: TyCtxt<'tcx>, + def_id: LocalDefId, +) -> FxIndexSet<(ty::Predicate<'tcx>, Span)> { + struct ConstCollector<'tcx> { + tcx: TyCtxt<'tcx>, + preds: FxIndexSet<(ty::Predicate<'tcx>, Span)>, + } + + impl<'tcx> intravisit::Visitor<'tcx> for ConstCollector<'tcx> { + type Map = Map<'tcx>; + + fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap { + intravisit::NestedVisitorMap::None + } + + fn visit_anon_const(&mut self, c: &'tcx hir::AnonConst) { + let def_id = self.tcx.hir().local_def_id(c.hir_id); + let ct = ty::Const::from_anon_const(self.tcx, def_id); + if let ty::ConstKind::Unevaluated(def, substs, None) = ct.val { + let span = self.tcx.hir().span(c.hir_id); + self.preds.insert(( + ty::PredicateAtom::ConstEvaluatable(def, substs).to_predicate(self.tcx), + span, + )); + } + } + + // Look into `TyAlias`. + fn visit_ty(&mut self, ty: &'tcx hir::Ty<'tcx>) { + use ty::fold::{TypeFoldable, TypeVisitor}; + struct TyAliasVisitor<'a, 'tcx> { + tcx: TyCtxt<'tcx>, + preds: &'a mut FxIndexSet<(ty::Predicate<'tcx>, Span)>, + span: Span, + } + + impl<'a, 'tcx> TypeVisitor<'tcx> for TyAliasVisitor<'a, 'tcx> { + fn visit_const(&mut self, ct: &'tcx Const<'tcx>) -> bool { + if let ty::ConstKind::Unevaluated(def, substs, None) = ct.val { + self.preds.insert(( + ty::PredicateAtom::ConstEvaluatable(def, substs).to_predicate(self.tcx), + self.span, + )); + } + false + } + } + + if let hir::TyKind::Path(hir::QPath::Resolved(None, path)) = ty.kind { + if let Res::Def(DefKind::TyAlias, def_id) = path.res { + let mut visitor = + TyAliasVisitor { tcx: self.tcx, preds: &mut self.preds, span: path.span }; + self.tcx.type_of(def_id).visit_with(&mut visitor); + } + } + + intravisit::walk_ty(self, ty) + } + } + + let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); + let node = tcx.hir().get(hir_id); + + let mut collector = ConstCollector { tcx, preds: FxIndexSet::default() }; + if let Some(generics) = node.generics() { + warn!("const_evaluatable_predicates_of({:?}): visit_generics", def_id); + collector.visit_generics(generics); + } + + if let Some(fn_sig) = tcx.hir().fn_sig_by_hir_id(hir_id) { + warn!("const_evaluatable_predicates_of({:?}): visit_fn_decl", def_id); + collector.visit_fn_decl(fn_sig.decl); + } + warn!("const_evaluatable_predicates_of({:?}) = {:?}", def_id, collector.preds); + + collector.preds +} + fn projection_ty_from_predicates( tcx: TyCtxt<'tcx>, key: ( diff --git a/src/test/ui/const-generics/const_evaluatable_checked/cross_crate_predicate.stderr b/src/test/ui/const-generics/const_evaluatable_checked/cross_crate_predicate.stderr index e8afb495e60..e7da191e670 100644 --- a/src/test/ui/const-generics/const_evaluatable_checked/cross_crate_predicate.stderr +++ b/src/test/ui/const-generics/const_evaluatable_checked/cross_crate_predicate.stderr @@ -4,10 +4,10 @@ error: constant expression depends on a generic parameter LL | let _ = const_evaluatable_lib::test1::(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | - ::: $DIR/auxiliary/const_evaluatable_lib.rs:6:41 + ::: $DIR/auxiliary/const_evaluatable_lib.rs:6:10 | LL | [u8; std::mem::size_of::() - 1]: Sized, - | ----- required by this bound in `test1` + | ---------------------------- required by this bound in `test1` | = note: this may fail depending on what value the parameter takes @@ -17,10 +17,10 @@ error: constant expression depends on a generic parameter LL | let _ = const_evaluatable_lib::test1::(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | - ::: $DIR/auxiliary/const_evaluatable_lib.rs:6:41 + ::: $DIR/auxiliary/const_evaluatable_lib.rs:4:27 | -LL | [u8; std::mem::size_of::() - 1]: Sized, - | ----- required by this bound in `test1` +LL | pub fn test1() -> [u8; std::mem::size_of::() - 1] + | ---------------------------- required by this bound in `test1` | = note: this may fail depending on what value the parameter takes @@ -30,10 +30,10 @@ error: constant expression depends on a generic parameter LL | let _ = const_evaluatable_lib::test1::(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | - ::: $DIR/auxiliary/const_evaluatable_lib.rs:6:41 + ::: $DIR/auxiliary/const_evaluatable_lib.rs:6:10 | LL | [u8; std::mem::size_of::() - 1]: Sized, - | ----- required by this bound in `test1::{{constant}}#1` + | ---------------------------- required by this bound in `test1::{{constant}}#1` | = note: this may fail depending on what value the parameter takes @@ -43,10 +43,10 @@ error: constant expression depends on a generic parameter LL | let _ = const_evaluatable_lib::test1::(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | - ::: $DIR/auxiliary/const_evaluatable_lib.rs:6:41 + ::: $DIR/auxiliary/const_evaluatable_lib.rs:4:27 | -LL | [u8; std::mem::size_of::() - 1]: Sized, - | ----- required by this bound in `test1::{{constant}}#1` +LL | pub fn test1() -> [u8; std::mem::size_of::() - 1] + | ---------------------------- required by this bound in `test1::{{constant}}#1` | = note: this may fail depending on what value the parameter takes diff --git a/src/test/ui/const-generics/const_evaluatable_checked/let-bindings.stderr b/src/test/ui/const-generics/const_evaluatable_checked/let-bindings.stderr index 5749defb3e1..b76e300663d 100644 --- a/src/test/ui/const-generics/const_evaluatable_checked/let-bindings.stderr +++ b/src/test/ui/const-generics/const_evaluatable_checked/let-bindings.stderr @@ -1,10 +1,8 @@ -error: overly complex generic constant +error: constant expression depends on a generic parameter --> $DIR/let-bindings.rs:6:68 | LL | fn test() -> [u8; { let x = N; N + 1 }] where [u8; { let x = N; N + 1 }]: Default { - | ^^^^^^-^^^^^^^^^^^^^ - | | - | unsupported statement + | ^^^^^^^^^^^^^^^^^^^^ required by this bound in `test::{{constant}}#0` | = help: consider moving this anonymous constant into a `const` function