diff --git a/src/librustc/dep_graph/dep_node.rs b/src/librustc/dep_graph/dep_node.rs index 8d7fef90b754e..13cf7a9ec8f1e 100644 --- a/src/librustc/dep_graph/dep_node.rs +++ b/src/librustc/dep_graph/dep_node.rs @@ -579,6 +579,9 @@ define_dep_nodes!( <'tcx> [] GetPanicStrategy(CrateNum), [] IsNoBuiltins(CrateNum), [] ImplDefaultness(DefId), + [] CheckItemWellFormed(DefId), + [] CheckTraitItemWellFormed(DefId), + [] CheckImplItemWellFormed(DefId), [] ReachableNonGenerics(CrateNum), [] NativeLibraries(CrateNum), [] PluginRegistrarFn(CrateNum), diff --git a/src/librustc/ty/maps/mod.rs b/src/librustc/ty/maps/mod.rs index c1783654effef..4dcd7c20c33d5 100644 --- a/src/librustc/ty/maps/mod.rs +++ b/src/librustc/ty/maps/mod.rs @@ -298,6 +298,10 @@ define_maps! { <'tcx> [] fn impl_defaultness: ImplDefaultness(DefId) -> hir::Defaultness, + [] fn check_item_well_formed: CheckItemWellFormed(DefId) -> (), + [] fn check_trait_item_well_formed: CheckTraitItemWellFormed(DefId) -> (), + [] fn check_impl_item_well_formed: CheckImplItemWellFormed(DefId) -> (), + // The DefIds of all non-generic functions and statics in the given crate // that can be reached from outside the crate. // diff --git a/src/librustc/ty/maps/plumbing.rs b/src/librustc/ty/maps/plumbing.rs index bc7186f781a82..267d7da5e0c25 100644 --- a/src/librustc/ty/maps/plumbing.rs +++ b/src/librustc/ty/maps/plumbing.rs @@ -871,6 +871,9 @@ pub fn force_from_dep_node<'a, 'gcx, 'lcx>(tcx: TyCtxt<'a, 'gcx, 'lcx>, DepKind::GetPanicStrategy => { force!(panic_strategy, krate!()); } DepKind::IsNoBuiltins => { force!(is_no_builtins, krate!()); } DepKind::ImplDefaultness => { force!(impl_defaultness, def_id!()); } + DepKind::CheckItemWellFormed => { force!(check_item_well_formed, def_id!()); } + DepKind::CheckTraitItemWellFormed => { force!(check_trait_item_well_formed, def_id!()); } + DepKind::CheckImplItemWellFormed => { force!(check_impl_item_well_formed, def_id!()); } DepKind::ReachableNonGenerics => { force!(reachable_non_generics, krate!()); } DepKind::NativeLibraries => { force!(native_libraries, krate!()); } DepKind::PluginRegistrarFn => { force!(plugin_registrar_fn, krate!()); } diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs index dc9455487ede7..8b5d45d6aa118 100644 --- a/src/librustc_typeck/check/mod.rs +++ b/src/librustc_typeck/check/mod.rs @@ -718,6 +718,18 @@ fn typeck_item_bodies<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, crate_num: CrateNum })?) } +fn check_item_well_formed<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) { + wfcheck::check_item_well_formed(tcx, def_id); +} + +fn check_trait_item_well_formed<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) { + wfcheck::check_trait_item(tcx, def_id); +} + +fn check_impl_item_well_formed<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) { + wfcheck::check_impl_item(tcx, def_id); +} + pub fn provide(providers: &mut Providers) { *providers = Providers { typeck_item_bodies, @@ -725,6 +737,9 @@ pub fn provide(providers: &mut Providers) { has_typeck_tables, adt_destructor, used_trait_imports, + check_item_well_formed, + check_trait_item_well_formed, + check_impl_item_well_formed, ..*providers }; } diff --git a/src/librustc_typeck/check/wfcheck.rs b/src/librustc_typeck/check/wfcheck.rs index b94af0a1e0081..406ff9463a03c 100644 --- a/src/librustc_typeck/check/wfcheck.rs +++ b/src/librustc_typeck/check/wfcheck.rs @@ -26,17 +26,11 @@ use errors::{DiagnosticBuilder, DiagnosticId}; use rustc::hir::intravisit::{self, Visitor, NestedVisitorMap}; use rustc::hir; -pub struct CheckTypeWellFormedVisitor<'a, 'tcx:'a> { - tcx: TyCtxt<'a, 'tcx, 'tcx>, - code: ObligationCauseCode<'tcx>, -} - /// Helper type of a temporary returned by .for_item(...). /// Necessary because we can't write the following bound: /// F: for<'b, 'tcx> where 'gcx: 'tcx FnOnce(FnCtxt<'b, 'gcx, 'tcx>). struct CheckWfFcxBuilder<'a, 'gcx: 'a+'tcx, 'tcx: 'a> { inherited: super::InheritedBuilder<'a, 'gcx, 'tcx>, - code: ObligationCauseCode<'gcx>, id: ast::NodeId, span: Span, param_env: ty::ParamEnv<'tcx>, @@ -45,585 +39,597 @@ struct CheckWfFcxBuilder<'a, 'gcx: 'a+'tcx, 'tcx: 'a> { impl<'a, 'gcx, 'tcx> CheckWfFcxBuilder<'a, 'gcx, 'tcx> { fn with_fcx(&'tcx mut self, f: F) where F: for<'b> FnOnce(&FnCtxt<'b, 'gcx, 'tcx>, - &mut CheckTypeWellFormedVisitor<'b, 'gcx>) -> Vec> + TyCtxt<'b, 'gcx, 'gcx>) -> Vec> { - let code = self.code.clone(); let id = self.id; let span = self.span; let param_env = self.param_env; self.inherited.enter(|inh| { let fcx = FnCtxt::new(&inh, param_env, id); - let wf_tys = f(&fcx, &mut CheckTypeWellFormedVisitor { - tcx: fcx.tcx.global_tcx(), - code, - }); + let wf_tys = f(&fcx, fcx.tcx.global_tcx()); fcx.select_all_obligations_or_error(); fcx.regionck_item(id, span, &wf_tys); }); } } -impl<'a, 'gcx> CheckTypeWellFormedVisitor<'a, 'gcx> { - pub fn new(tcx: TyCtxt<'a, 'gcx, 'gcx>) - -> CheckTypeWellFormedVisitor<'a, 'gcx> { - CheckTypeWellFormedVisitor { - tcx, - code: ObligationCauseCode::MiscObligation - } - } - - /// Checks that the field types (in a struct def'n) or argument types (in an enum def'n) are - /// well-formed, meaning that they do not require any constraints not declared in the struct - /// definition itself. For example, this definition would be illegal: - /// - /// struct Ref<'a, T> { x: &'a T } - /// - /// because the type did not declare that `T:'a`. - /// - /// We do this check as a pre-pass before checking fn bodies because if these constraints are - /// not included it frequently leads to confusing errors in fn bodies. So it's better to check - /// the types first. - fn check_item_well_formed(&mut self, item: &hir::Item) { - let tcx = self.tcx; - debug!("check_item_well_formed(it.id={}, it.name={})", - item.id, - tcx.item_path_str(tcx.hir.local_def_id(item.id))); - - match item.node { - // Right now we check that every default trait implementation - // has an implementation of itself. Basically, a case like: - // - // `impl Trait for T {}` - // - // has a requirement of `T: Trait` which was required for default - // method implementations. Although this could be improved now that - // there's a better infrastructure in place for this, it's being left - // for a follow-up work. - // - // Since there's such a requirement, we need to check *just* positive - // implementations, otherwise things like: - // - // impl !Send for T {} - // - // won't be allowed unless there's an *explicit* implementation of `Send` - // for `T` - hir::ItemImpl(_, polarity, defaultness, _, ref trait_ref, ref self_ty, _) => { - let is_auto = tcx.impl_trait_ref(tcx.hir.local_def_id(item.id)) - .map_or(false, |trait_ref| tcx.trait_is_auto(trait_ref.def_id)); - if let (hir::Defaultness::Default { .. }, true) = (defaultness, is_auto) { - tcx.sess.span_err(item.span, "impls of auto traits cannot be default"); - } - if polarity == hir::ImplPolarity::Positive { - self.check_impl(item, self_ty, trait_ref); - } else { - // FIXME(#27579) what amount of WF checking do we need for neg impls? - if trait_ref.is_some() && !is_auto { - span_err!(tcx.sess, item.span, E0192, - "negative impls are only allowed for \ - auto traits (e.g., `Send` and `Sync`)") - } - } - } - hir::ItemFn(..) => { - self.check_item_fn(item); - } - hir::ItemStatic(..) => { - self.check_item_type(item); +/// Checks that the field types (in a struct def'n) or argument types (in an enum def'n) are +/// well-formed, meaning that they do not require any constraints not declared in the struct +/// definition itself. For example, this definition would be illegal: +/// +/// struct Ref<'a, T> { x: &'a T } +/// +/// because the type did not declare that `T:'a`. +/// +/// We do this check as a pre-pass before checking fn bodies because if these constraints are +/// not included it frequently leads to confusing errors in fn bodies. So it's better to check +/// the types first. +pub fn check_item_well_formed<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) { + let node_id = tcx.hir.as_local_node_id(def_id).unwrap(); + let item = tcx.hir.expect_item(node_id); + + debug!("check_item_well_formed(it.id={}, it.name={})", + item.id, + tcx.item_path_str(def_id)); + + match item.node { + // Right now we check that every default trait implementation + // has an implementation of itself. Basically, a case like: + // + // `impl Trait for T {}` + // + // has a requirement of `T: Trait` which was required for default + // method implementations. Although this could be improved now that + // there's a better infrastructure in place for this, it's being left + // for a follow-up work. + // + // Since there's such a requirement, we need to check *just* positive + // implementations, otherwise things like: + // + // impl !Send for T {} + // + // won't be allowed unless there's an *explicit* implementation of `Send` + // for `T` + hir::ItemImpl(_, polarity, defaultness, _, ref trait_ref, ref self_ty, _) => { + let is_auto = tcx.impl_trait_ref(tcx.hir.local_def_id(item.id)) + .map_or(false, |trait_ref| tcx.trait_is_auto(trait_ref.def_id)); + if let (hir::Defaultness::Default { .. }, true) = (defaultness, is_auto) { + tcx.sess.span_err(item.span, "impls of auto traits cannot be default"); } - hir::ItemConst(..) => { - self.check_item_type(item); + if polarity == hir::ImplPolarity::Positive { + check_impl(tcx, item, self_ty, trait_ref); + } else { + // FIXME(#27579) what amount of WF checking do we need for neg impls? + if trait_ref.is_some() && !is_auto { + span_err!(tcx.sess, item.span, E0192, + "negative impls are only allowed for \ + auto traits (e.g., `Send` and `Sync`)") + } } - hir::ItemStruct(ref struct_def, ref ast_generics) => { - self.check_type_defn(item, false, |fcx| { - vec![fcx.non_enum_variant(struct_def)] - }); + } + hir::ItemFn(..) => { + check_item_fn(tcx, item); + } + hir::ItemStatic(..) => { + check_item_type(tcx, item); + } + hir::ItemConst(..) => { + check_item_type(tcx, item); + } + hir::ItemStruct(ref struct_def, ref ast_generics) => { + check_type_defn(tcx, item, false, |fcx| { + vec![fcx.non_enum_variant(struct_def)] + }); - self.check_variances_for_type_defn(item, ast_generics); - } - hir::ItemUnion(ref struct_def, ref ast_generics) => { - self.check_type_defn(item, true, |fcx| { - vec![fcx.non_enum_variant(struct_def)] - }); + check_variances_for_type_defn(tcx, item, ast_generics); + } + hir::ItemUnion(ref struct_def, ref ast_generics) => { + check_type_defn(tcx, item, true, |fcx| { + vec![fcx.non_enum_variant(struct_def)] + }); - self.check_variances_for_type_defn(item, ast_generics); - } - hir::ItemEnum(ref enum_def, ref ast_generics) => { - self.check_type_defn(item, true, |fcx| { - fcx.enum_variants(enum_def) - }); + check_variances_for_type_defn(tcx, item, ast_generics); + } + hir::ItemEnum(ref enum_def, ref ast_generics) => { + check_type_defn(tcx, item, true, |fcx| { + fcx.enum_variants(enum_def) + }); - self.check_variances_for_type_defn(item, ast_generics); - } - hir::ItemTrait(..) => { - self.check_trait(item); - } - _ => {} + check_variances_for_type_defn(tcx, item, ast_generics); } + hir::ItemTrait(..) => { + check_trait(tcx, item); + } + _ => {} } +} - fn check_associated_item(&mut self, - item_id: ast::NodeId, - span: Span, - sig_if_method: Option<&hir::MethodSig>) { - let code = self.code.clone(); - self.for_id(item_id, span).with_fcx(|fcx, this| { - let item = fcx.tcx.associated_item(fcx.tcx.hir.local_def_id(item_id)); - - let (mut implied_bounds, self_ty) = match item.container { - ty::TraitContainer(_) => (vec![], fcx.tcx.mk_self_type()), - ty::ImplContainer(def_id) => (fcx.impl_implied_bounds(def_id, span), - fcx.tcx.type_of(def_id)) - }; +pub fn check_trait_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) { + let node_id = tcx.hir.as_local_node_id(def_id).unwrap(); + let trait_item = tcx.hir.expect_trait_item(node_id); + + let method_sig = match trait_item.node { + hir::TraitItemKind::Method(ref sig, _) => Some(sig), + _ => None + }; + check_associated_item(tcx, trait_item.id, trait_item.span, method_sig); +} + +pub fn check_impl_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) { + let node_id = tcx.hir.as_local_node_id(def_id).unwrap(); + let impl_item = tcx.hir.expect_impl_item(node_id); + + let method_sig = match impl_item.node { + hir::ImplItemKind::Method(ref sig, _) => Some(sig), + _ => None + }; + check_associated_item(tcx, impl_item.id, impl_item.span, method_sig); +} + +fn check_associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, + item_id: ast::NodeId, + span: Span, + sig_if_method: Option<&hir::MethodSig>) { + let code = ObligationCauseCode::MiscObligation; + for_id(tcx, item_id, span).with_fcx(|fcx, tcx| { + let item = fcx.tcx.associated_item(fcx.tcx.hir.local_def_id(item_id)); + + let (mut implied_bounds, self_ty) = match item.container { + ty::TraitContainer(_) => (vec![], fcx.tcx.mk_self_type()), + ty::ImplContainer(def_id) => (fcx.impl_implied_bounds(def_id, span), + fcx.tcx.type_of(def_id)) + }; - match item.kind { - ty::AssociatedKind::Const => { + match item.kind { + ty::AssociatedKind::Const => { + let ty = fcx.tcx.type_of(item.def_id); + let ty = fcx.normalize_associated_types_in(span, &ty); + fcx.register_wf_obligation(ty, span, code.clone()); + } + ty::AssociatedKind::Method => { + reject_shadowing_type_parameters(fcx.tcx, item.def_id); + let sig = fcx.tcx.fn_sig(item.def_id); + let sig = fcx.normalize_associated_types_in(span, &sig); + check_fn_or_method(tcx, fcx, span, sig, + item.def_id, &mut implied_bounds); + let sig_if_method = sig_if_method.expect("bad signature for method"); + check_method_receiver(fcx, sig_if_method, &item, self_ty); + } + ty::AssociatedKind::Type => { + if item.defaultness.has_value() { let ty = fcx.tcx.type_of(item.def_id); let ty = fcx.normalize_associated_types_in(span, &ty); fcx.register_wf_obligation(ty, span, code.clone()); } - ty::AssociatedKind::Method => { - reject_shadowing_type_parameters(fcx.tcx, item.def_id); - let sig = fcx.tcx.fn_sig(item.def_id); - let sig = fcx.normalize_associated_types_in(span, &sig); - this.check_fn_or_method(fcx, span, sig, - item.def_id, &mut implied_bounds); - let sig_if_method = sig_if_method.expect("bad signature for method"); - this.check_method_receiver(fcx, sig_if_method, &item, self_ty); - } - ty::AssociatedKind::Type => { - if item.defaultness.has_value() { - let ty = fcx.tcx.type_of(item.def_id); - let ty = fcx.normalize_associated_types_in(span, &ty); - fcx.register_wf_obligation(ty, span, code.clone()); - } - } } + } - implied_bounds - }) - } - - fn for_item<'tcx>(&self, item: &hir::Item) - -> CheckWfFcxBuilder<'a, 'gcx, 'tcx> { - self.for_id(item.id, item.span) - } + implied_bounds + }) +} - fn for_id<'tcx>(&self, id: ast::NodeId, span: Span) +fn for_item<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'gcx>, item: &hir::Item) -> CheckWfFcxBuilder<'a, 'gcx, 'tcx> { - let def_id = self.tcx.hir.local_def_id(id); - CheckWfFcxBuilder { - inherited: Inherited::build(self.tcx, def_id), - code: self.code.clone(), - id, - span, - param_env: self.tcx.param_env(def_id), - } + for_id(tcx, item.id, item.span) +} + +fn for_id<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'gcx>, id: ast::NodeId, span: Span) + -> CheckWfFcxBuilder<'a, 'gcx, 'tcx> { + let def_id = tcx.hir.local_def_id(id); + CheckWfFcxBuilder { + inherited: Inherited::build(tcx, def_id), + id, + span, + param_env: tcx.param_env(def_id), } +} - /// In a type definition, we check that to ensure that the types of the fields are well-formed. - fn check_type_defn(&mut self, item: &hir::Item, all_sized: bool, mut lookup_fields: F) - where F: for<'fcx, 'tcx> FnMut(&FnCtxt<'fcx, 'gcx, 'tcx>) -> Vec> - { - self.for_item(item).with_fcx(|fcx, this| { - let variants = lookup_fields(fcx); - let def_id = fcx.tcx.hir.local_def_id(item.id); - let packed = fcx.tcx.adt_def(def_id).repr.packed(); - - for variant in &variants { - // For DST, or when drop needs to copy things around, all - // intermediate types must be sized. - let needs_drop_copy = || { - packed && { - let ty = variant.fields.last().unwrap().ty; - let ty = fcx.tcx.erase_regions(&ty).lift_to_tcx(this.tcx) - .unwrap_or_else(|| { - span_bug!(item.span, "inference variables in {:?}", ty) - }); - ty.needs_drop(this.tcx, this.tcx.param_env(def_id)) - } - }; - let unsized_len = if - all_sized || - variant.fields.is_empty() || - needs_drop_copy() - { - 0 - } else { - 1 - }; - for field in &variant.fields[..variant.fields.len() - unsized_len] { - fcx.register_bound( - field.ty, - fcx.tcx.require_lang_item(lang_items::SizedTraitLangItem), - traits::ObligationCause::new(field.span, - fcx.body_id, - traits::FieldSized(match item.node.adt_kind() { - Some(i) => i, - None => bug!(), - }))); +/// In a type definition, we check that to ensure that the types of the fields are well-formed. +fn check_type_defn<'a, 'tcx, F>(tcx: TyCtxt<'a, 'tcx, 'tcx>, + item: &hir::Item, all_sized: bool, mut lookup_fields: F) + where F: for<'fcx, 'gcx, 'tcx2> FnMut(&FnCtxt<'fcx, 'gcx, 'tcx2>) -> Vec> +{ + for_item(tcx, item).with_fcx(|fcx, fcx_tcx| { + let variants = lookup_fields(fcx); + let def_id = fcx.tcx.hir.local_def_id(item.id); + let packed = fcx.tcx.adt_def(def_id).repr.packed(); + + for variant in &variants { + // For DST, or when drop needs to copy things around, all + // intermediate types must be sized. + let needs_drop_copy = || { + packed && { + let ty = variant.fields.last().unwrap().ty; + let ty = fcx.tcx.erase_regions(&ty).lift_to_tcx(fcx_tcx) + .unwrap_or_else(|| { + span_bug!(item.span, "inference variables in {:?}", ty) + }); + ty.needs_drop(fcx_tcx, fcx_tcx.param_env(def_id)) } + }; + let unsized_len = if + all_sized || + variant.fields.is_empty() || + needs_drop_copy() + { + 0 + } else { + 1 + }; + for field in &variant.fields[..variant.fields.len() - unsized_len] { + fcx.register_bound( + field.ty, + fcx.tcx.require_lang_item(lang_items::SizedTraitLangItem), + traits::ObligationCause::new(field.span, + fcx.body_id, + traits::FieldSized(match item.node.adt_kind() { + Some(i) => i, + None => bug!(), + }))); + } - // All field types must be well-formed. - for field in &variant.fields { - fcx.register_wf_obligation(field.ty, field.span, this.code.clone()) - } + // All field types must be well-formed. + for field in &variant.fields { + fcx.register_wf_obligation(field.ty, field.span, + ObligationCauseCode::MiscObligation) } + } - self.check_where_clauses(fcx, item.span, def_id); + check_where_clauses(tcx, fcx, item.span, def_id); - vec![] // no implied bounds in a struct def'n - }); - } + vec![] // no implied bounds in a struct def'n + }); +} - fn check_trait(&mut self, item: &hir::Item) { - let trait_def_id = self.tcx.hir.local_def_id(item.id); - self.for_item(item).with_fcx(|fcx, _| { - self.check_where_clauses(fcx, item.span, trait_def_id); - vec![] - }); - } +fn check_trait<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, item: &hir::Item) { + let trait_def_id = tcx.hir.local_def_id(item.id); + for_item(tcx, item).with_fcx(|fcx, _| { + check_where_clauses(tcx, fcx, item.span, trait_def_id); + vec![] + }); +} - fn check_item_fn(&mut self, item: &hir::Item) { - self.for_item(item).with_fcx(|fcx, this| { - let def_id = fcx.tcx.hir.local_def_id(item.id); - let sig = fcx.tcx.fn_sig(def_id); - let sig = fcx.normalize_associated_types_in(item.span, &sig); - let mut implied_bounds = vec![]; - this.check_fn_or_method(fcx, item.span, sig, - def_id, &mut implied_bounds); - implied_bounds - }) - } +fn check_item_fn<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, item: &hir::Item) { + for_item(tcx, item).with_fcx(|fcx, tcx| { + let def_id = fcx.tcx.hir.local_def_id(item.id); + let sig = fcx.tcx.fn_sig(def_id); + let sig = fcx.normalize_associated_types_in(item.span, &sig); + let mut implied_bounds = vec![]; + check_fn_or_method(tcx, fcx, item.span, sig, + def_id, &mut implied_bounds); + implied_bounds + }) +} - fn check_item_type(&mut self, - item: &hir::Item) - { - debug!("check_item_type: {:?}", item); +fn check_item_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, + item: &hir::Item) +{ + debug!("check_item_type: {:?}", item); - self.for_item(item).with_fcx(|fcx, this| { - let ty = fcx.tcx.type_of(fcx.tcx.hir.local_def_id(item.id)); - let item_ty = fcx.normalize_associated_types_in(item.span, &ty); + for_item(tcx, item).with_fcx(|fcx, _this| { + let ty = fcx.tcx.type_of(fcx.tcx.hir.local_def_id(item.id)); + let item_ty = fcx.normalize_associated_types_in(item.span, &ty); - fcx.register_wf_obligation(item_ty, item.span, this.code.clone()); + fcx.register_wf_obligation(item_ty, item.span, ObligationCauseCode::MiscObligation); - vec![] // no implied bounds in a const etc - }); - } + vec![] // no implied bounds in a const etc + }); +} - fn check_impl(&mut self, - item: &hir::Item, - ast_self_ty: &hir::Ty, - ast_trait_ref: &Option) - { - debug!("check_impl: {:?}", item); - - self.for_item(item).with_fcx(|fcx, this| { - let item_def_id = fcx.tcx.hir.local_def_id(item.id); - - match *ast_trait_ref { - Some(ref ast_trait_ref) => { - let trait_ref = fcx.tcx.impl_trait_ref(item_def_id).unwrap(); - let trait_ref = - fcx.normalize_associated_types_in( - ast_trait_ref.path.span, &trait_ref); - let obligations = - ty::wf::trait_obligations(fcx, - fcx.param_env, - fcx.body_id, - &trait_ref, - ast_trait_ref.path.span); - for obligation in obligations { - fcx.register_predicate(obligation); - } - } - None => { - let self_ty = fcx.tcx.type_of(item_def_id); - let self_ty = fcx.normalize_associated_types_in(item.span, &self_ty); - fcx.register_wf_obligation(self_ty, ast_self_ty.span, this.code.clone()); +fn check_impl<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, + item: &hir::Item, + ast_self_ty: &hir::Ty, + ast_trait_ref: &Option) +{ + debug!("check_impl: {:?}", item); + + for_item(tcx, item).with_fcx(|fcx, tcx| { + let item_def_id = fcx.tcx.hir.local_def_id(item.id); + + match *ast_trait_ref { + Some(ref ast_trait_ref) => { + let trait_ref = fcx.tcx.impl_trait_ref(item_def_id).unwrap(); + let trait_ref = + fcx.normalize_associated_types_in( + ast_trait_ref.path.span, &trait_ref); + let obligations = + ty::wf::trait_obligations(fcx, + fcx.param_env, + fcx.body_id, + &trait_ref, + ast_trait_ref.path.span); + for obligation in obligations { + fcx.register_predicate(obligation); } } + None => { + let self_ty = fcx.tcx.type_of(item_def_id); + let self_ty = fcx.normalize_associated_types_in(item.span, &self_ty); + fcx.register_wf_obligation(self_ty, ast_self_ty.span, + ObligationCauseCode::MiscObligation); + } + } - this.check_where_clauses(fcx, item.span, item_def_id); + check_where_clauses(tcx, fcx, item.span, item_def_id); - fcx.impl_implied_bounds(item_def_id, item.span) - }); - } + fcx.impl_implied_bounds(item_def_id, item.span) + }); +} - /// Checks where clauses and inline bounds that are declared on def_id. - fn check_where_clauses<'fcx, 'tcx>(&mut self, - fcx: &FnCtxt<'fcx, 'gcx, 'tcx>, - span: Span, - def_id: DefId) { - use ty::subst::Subst; - use rustc::ty::TypeFoldable; - - let mut predicates = fcx.tcx.predicates_of(def_id); - let mut substituted_predicates = Vec::new(); - - let generics = self.tcx.generics_of(def_id); - let is_our_default = |def: &ty::TypeParameterDef| - def.has_default && def.index >= generics.parent_count() as u32; - - // Check that concrete defaults are well-formed. See test `type-check-defaults.rs`. - // For example this forbids the declaration: - // struct Foo> { .. } - // Here the default `Vec<[u32]>` is not WF because `[u32]: Sized` does not hold. - for d in generics.types.iter().cloned().filter(is_our_default).map(|p| p.def_id) { - let ty = fcx.tcx.type_of(d); - // ignore dependent defaults -- that is, where the default of one type - // parameter includes another (e.g., ). In those cases, we can't - // be sure if it will error or not as user might always specify the other. - if !ty.needs_subst() { - fcx.register_wf_obligation(ty, fcx.tcx.def_span(d), self.code.clone()); - } +/// Checks where clauses and inline bounds that are declared on def_id. +fn check_where_clauses<'a, 'gcx, 'fcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'gcx>, + fcx: &FnCtxt<'fcx, 'gcx, 'tcx>, + span: Span, + def_id: DefId) { + use ty::subst::Subst; + use rustc::ty::TypeFoldable; + + let mut predicates = fcx.tcx.predicates_of(def_id); + let mut substituted_predicates = Vec::new(); + + let generics = tcx.generics_of(def_id); + let is_our_default = |def: &ty::TypeParameterDef| + def.has_default && def.index >= generics.parent_count() as u32; + + // Check that concrete defaults are well-formed. See test `type-check-defaults.rs`. + // For example this forbids the declaration: + // struct Foo> { .. } + // Here the default `Vec<[u32]>` is not WF because `[u32]: Sized` does not hold. + for d in generics.types.iter().cloned().filter(is_our_default).map(|p| p.def_id) { + let ty = fcx.tcx.type_of(d); + // ignore dependent defaults -- that is, where the default of one type + // parameter includes another (e.g., ). In those cases, we can't + // be sure if it will error or not as user might always specify the other. + if !ty.needs_subst() { + fcx.register_wf_obligation(ty, fcx.tcx.def_span(d), + ObligationCauseCode::MiscObligation); } + } - // Check that trait predicates are WF when params are substituted by their defaults. - // We don't want to overly constrain the predicates that may be written but we want to - // catch cases where a default my never be applied such as `struct Foo`. - // Therefore we check if a predicate which contains a single type param - // with a concrete default is WF with that default substituted. - // For more examples see tests `defaults-well-formedness.rs` and `type-check-defaults.rs`. - // - // First we build the defaulted substitution. - let substs = ty::subst::Substs::for_item(fcx.tcx, def_id, |def, _| { - // All regions are identity. - fcx.tcx.mk_region(ty::ReEarlyBound(def.to_early_bound_region_data())) - }, |def, _| { - // If the param has a default, - if is_our_default(def) { - let default_ty = fcx.tcx.type_of(def.def_id); - // and it's not a dependent default - if !default_ty.needs_subst() { - // then substitute with the default. - return default_ty; - } + // Check that trait predicates are WF when params are substituted by their defaults. + // We don't want to overly constrain the predicates that may be written but we want to + // catch cases where a default my never be applied such as `struct Foo`. + // Therefore we check if a predicate which contains a single type param + // with a concrete default is WF with that default substituted. + // For more examples see tests `defaults-well-formedness.rs` and `type-check-defaults.rs`. + // + // First we build the defaulted substitution. + let substs = ty::subst::Substs::for_item(fcx.tcx, def_id, |def, _| { + // All regions are identity. + fcx.tcx.mk_region(ty::ReEarlyBound(def.to_early_bound_region_data())) + }, |def, _| { + // If the param has a default, + if is_our_default(def) { + let default_ty = fcx.tcx.type_of(def.def_id); + // and it's not a dependent default + if !default_ty.needs_subst() { + // then substitute with the default. + return default_ty; } - // Mark unwanted params as err. - fcx.tcx.types.err - }); - // Now we build the substituted predicates. - for &pred in predicates.predicates.iter() { - struct CountParams { params: FxHashSet } - impl<'tcx> ty::fold::TypeVisitor<'tcx> for CountParams { - fn visit_ty(&mut self, t: Ty<'tcx>) -> bool { - match t.sty { - ty::TyParam(p) => { - self.params.insert(p.idx); - t.super_visit_with(self) - } - _ => t.super_visit_with(self) + } + // Mark unwanted params as err. + fcx.tcx.types.err + }); + // Now we build the substituted predicates. + for &pred in predicates.predicates.iter() { + struct CountParams { params: FxHashSet } + impl<'tcx> ty::fold::TypeVisitor<'tcx> for CountParams { + fn visit_ty(&mut self, t: Ty<'tcx>) -> bool { + match t.sty { + ty::TyParam(p) => { + self.params.insert(p.idx); + t.super_visit_with(self) } + _ => t.super_visit_with(self) } } - let mut param_count = CountParams { params: FxHashSet() }; - pred.visit_with(&mut param_count); - let substituted_pred = pred.subst(fcx.tcx, substs); - // Don't check non-defaulted params, dependent defaults or preds with multiple params. - if substituted_pred.references_error() || param_count.params.len() > 1 { - continue; - } - // Avoid duplication of predicates that contain no parameters, for example. - if !predicates.predicates.contains(&substituted_pred) { - substituted_predicates.push(substituted_pred); - } } - - predicates.predicates.extend(substituted_predicates); - let predicates = predicates.instantiate_identity(fcx.tcx); - let predicates = fcx.normalize_associated_types_in(span, &predicates); - - let obligations = - predicates.predicates - .iter() - .flat_map(|p| ty::wf::predicate_obligations(fcx, - fcx.param_env, - fcx.body_id, - p, - span)); - - for obligation in obligations { - fcx.register_predicate(obligation); + let mut param_count = CountParams { params: FxHashSet() }; + pred.visit_with(&mut param_count); + let substituted_pred = pred.subst(fcx.tcx, substs); + // Don't check non-defaulted params, dependent defaults or preds with multiple params. + if substituted_pred.references_error() || param_count.params.len() > 1 { + continue; + } + // Avoid duplication of predicates that contain no parameters, for example. + if !predicates.predicates.contains(&substituted_pred) { + substituted_predicates.push(substituted_pred); } } - fn check_fn_or_method<'fcx, 'tcx>(&mut self, - fcx: &FnCtxt<'fcx, 'gcx, 'tcx>, - span: Span, - sig: ty::PolyFnSig<'tcx>, - def_id: DefId, - implied_bounds: &mut Vec>) - { - let sig = fcx.normalize_associated_types_in(span, &sig); - let sig = fcx.tcx.liberate_late_bound_regions(def_id, &sig); - - for input_ty in sig.inputs() { - fcx.register_wf_obligation(&input_ty, span, self.code.clone()); - } - implied_bounds.extend(sig.inputs()); + predicates.predicates.extend(substituted_predicates); + let predicates = predicates.instantiate_identity(fcx.tcx); + let predicates = fcx.normalize_associated_types_in(span, &predicates); + + let obligations = + predicates.predicates + .iter() + .flat_map(|p| ty::wf::predicate_obligations(fcx, + fcx.param_env, + fcx.body_id, + p, + span)); + + for obligation in obligations { + fcx.register_predicate(obligation); + } +} - fcx.register_wf_obligation(sig.output(), span, self.code.clone()); +fn check_fn_or_method<'a, 'fcx, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'gcx>, + fcx: &FnCtxt<'fcx, 'gcx, 'tcx>, + span: Span, + sig: ty::PolyFnSig<'tcx>, + def_id: DefId, + implied_bounds: &mut Vec>) +{ + let sig = fcx.normalize_associated_types_in(span, &sig); + let sig = fcx.tcx.liberate_late_bound_regions(def_id, &sig); + + for input_ty in sig.inputs() { + fcx.register_wf_obligation(&input_ty, span, ObligationCauseCode::MiscObligation); + } + implied_bounds.extend(sig.inputs()); - // FIXME(#25759) return types should not be implied bounds - implied_bounds.push(sig.output()); + fcx.register_wf_obligation(sig.output(), span, ObligationCauseCode::MiscObligation); - self.check_where_clauses(fcx, span, def_id); - } + // FIXME(#25759) return types should not be implied bounds + implied_bounds.push(sig.output()); - fn check_method_receiver<'fcx, 'tcx>(&mut self, - fcx: &FnCtxt<'fcx, 'gcx, 'tcx>, - method_sig: &hir::MethodSig, - method: &ty::AssociatedItem, - self_ty: Ty<'tcx>) - { - // check that the method has a valid receiver type, given the type `Self` - debug!("check_method_receiver({:?}, self_ty={:?})", - method, self_ty); + check_where_clauses(tcx, fcx, span, def_id); +} - if !method.method_has_self_argument { - return; - } +fn check_method_receiver<'fcx, 'gcx, 'tcx>(fcx: &FnCtxt<'fcx, 'gcx, 'tcx>, + method_sig: &hir::MethodSig, + method: &ty::AssociatedItem, + self_ty: Ty<'tcx>) +{ + // check that the method has a valid receiver type, given the type `Self` + debug!("check_method_receiver({:?}, self_ty={:?})", + method, self_ty); + + if !method.method_has_self_argument { + return; + } - let span = method_sig.decl.inputs[0].span; + let span = method_sig.decl.inputs[0].span; - let sig = fcx.tcx.fn_sig(method.def_id); - let sig = fcx.normalize_associated_types_in(span, &sig); - let sig = fcx.tcx.liberate_late_bound_regions(method.def_id, &sig); + let sig = fcx.tcx.fn_sig(method.def_id); + let sig = fcx.normalize_associated_types_in(span, &sig); + let sig = fcx.tcx.liberate_late_bound_regions(method.def_id, &sig); - debug!("check_method_receiver: sig={:?}", sig); + debug!("check_method_receiver: sig={:?}", sig); - let self_ty = fcx.normalize_associated_types_in(span, &self_ty); - let self_ty = fcx.tcx.liberate_late_bound_regions( - method.def_id, - &ty::Binder(self_ty) - ); + let self_ty = fcx.normalize_associated_types_in(span, &self_ty); + let self_ty = fcx.tcx.liberate_late_bound_regions( + method.def_id, + &ty::Binder(self_ty) + ); - let self_arg_ty = sig.inputs()[0]; + let self_arg_ty = sig.inputs()[0]; - let cause = fcx.cause(span, ObligationCauseCode::MethodReceiver); - let self_arg_ty = fcx.normalize_associated_types_in(span, &self_arg_ty); - let self_arg_ty = fcx.tcx.liberate_late_bound_regions( - method.def_id, - &ty::Binder(self_arg_ty) - ); + let cause = fcx.cause(span, ObligationCauseCode::MethodReceiver); + let self_arg_ty = fcx.normalize_associated_types_in(span, &self_arg_ty); + let self_arg_ty = fcx.tcx.liberate_late_bound_regions( + method.def_id, + &ty::Binder(self_arg_ty) + ); - let mut autoderef = fcx.autoderef(span, self_arg_ty).include_raw_pointers(); + let mut autoderef = fcx.autoderef(span, self_arg_ty).include_raw_pointers(); - loop { - if let Some((potential_self_ty, _)) = autoderef.next() { - debug!("check_method_receiver: potential self type `{:?}` to match `{:?}`", - potential_self_ty, self_ty); + loop { + if let Some((potential_self_ty, _)) = autoderef.next() { + debug!("check_method_receiver: potential self type `{:?}` to match `{:?}`", + potential_self_ty, self_ty); - if fcx.infcx.can_eq(fcx.param_env, self_ty, potential_self_ty).is_ok() { - autoderef.finalize(); - if let Some(mut err) = fcx.demand_eqtype_with_origin( - &cause, self_ty, potential_self_ty) { - err.emit(); - } - break + if fcx.infcx.can_eq(fcx.param_env, self_ty, potential_self_ty).is_ok() { + autoderef.finalize(); + if let Some(mut err) = fcx.demand_eqtype_with_origin( + &cause, self_ty, potential_self_ty) { + err.emit(); } - } else { - fcx.tcx.sess.diagnostic().mut_span_err( - span, &format!("invalid `self` type: {:?}", self_arg_ty)) - .note(&format!("type must be `{:?}` or a type that dereferences to it", self_ty)) - .help("consider changing to `self`, `&self`, `&mut self`, or `self: Box`") - .code(DiagnosticId::Error("E0307".into())) - .emit(); - return + break } + } else { + fcx.tcx.sess.diagnostic().mut_span_err( + span, &format!("invalid `self` type: {:?}", self_arg_ty)) + .note(&format!("type must be `{:?}` or a type that dereferences to it", self_ty)) + .help("consider changing to `self`, `&self`, `&mut self`, or `self: Box`") + .code(DiagnosticId::Error("E0307".into())) + .emit(); + return } + } - let is_self_ty = |ty| fcx.infcx.can_eq(fcx.param_env, self_ty, ty).is_ok(); - let self_kind = ExplicitSelf::determine(self_arg_ty, is_self_ty); - - if !fcx.tcx.features().arbitrary_self_types { - match self_kind { - ExplicitSelf::ByValue | - ExplicitSelf::ByReference(_, _) | - ExplicitSelf::ByBox => (), - - ExplicitSelf::ByRawPointer(_) => { - feature_gate::feature_err( - &fcx.tcx.sess.parse_sess, - "arbitrary_self_types", - span, - GateIssue::Language, - "raw pointer `self` is unstable") - .help("consider changing to `self`, `&self`, `&mut self`, or `self: Box`") - .emit(); - } + let is_self_ty = |ty| fcx.infcx.can_eq(fcx.param_env, self_ty, ty).is_ok(); + let self_kind = ExplicitSelf::determine(self_arg_ty, is_self_ty); + + if !fcx.tcx.features().arbitrary_self_types { + match self_kind { + ExplicitSelf::ByValue | + ExplicitSelf::ByReference(_, _) | + ExplicitSelf::ByBox => (), + + ExplicitSelf::ByRawPointer(_) => { + feature_gate::feature_err( + &fcx.tcx.sess.parse_sess, + "arbitrary_self_types", + span, + GateIssue::Language, + "raw pointer `self` is unstable") + .help("consider changing to `self`, `&self`, `&mut self`, or `self: Box`") + .emit(); + } - ExplicitSelf::Other => { - feature_gate::feature_err( - &fcx.tcx.sess.parse_sess, - "arbitrary_self_types", - span, - GateIssue::Language,"arbitrary `self` types are unstable") - .help("consider changing to `self`, `&self`, `&mut self`, or `self: Box`") - .emit(); - } + ExplicitSelf::Other => { + feature_gate::feature_err( + &fcx.tcx.sess.parse_sess, + "arbitrary_self_types", + span, + GateIssue::Language,"arbitrary `self` types are unstable") + .help("consider changing to `self`, `&self`, `&mut self`, or `self: Box`") + .emit(); } } } +} - fn check_variances_for_type_defn(&self, - item: &hir::Item, - ast_generics: &hir::Generics) - { - let item_def_id = self.tcx.hir.local_def_id(item.id); - let ty = self.tcx.type_of(item_def_id); - if self.tcx.has_error_field(ty) { - return; - } - - let ty_predicates = self.tcx.predicates_of(item_def_id); - assert_eq!(ty_predicates.parent, None); - let variances = self.tcx.variances_of(item_def_id); +fn check_variances_for_type_defn<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, + item: &hir::Item, + ast_generics: &hir::Generics) +{ + let item_def_id = tcx.hir.local_def_id(item.id); + let ty = tcx.type_of(item_def_id); + if tcx.has_error_field(ty) { + return; + } - let mut constrained_parameters: FxHashSet<_> = - variances.iter().enumerate() - .filter(|&(_, &variance)| variance != ty::Bivariant) - .map(|(index, _)| Parameter(index as u32)) - .collect(); + let ty_predicates = tcx.predicates_of(item_def_id); + assert_eq!(ty_predicates.parent, None); + let variances = tcx.variances_of(item_def_id); - identify_constrained_type_params(self.tcx, - ty_predicates.predicates.as_slice(), - None, - &mut constrained_parameters); + let mut constrained_parameters: FxHashSet<_> = + variances.iter().enumerate() + .filter(|&(_, &variance)| variance != ty::Bivariant) + .map(|(index, _)| Parameter(index as u32)) + .collect(); - for (index, _) in variances.iter().enumerate() { - if constrained_parameters.contains(&Parameter(index as u32)) { - continue; - } + identify_constrained_type_params(tcx, + ty_predicates.predicates.as_slice(), + None, + &mut constrained_parameters); - let (span, name) = match ast_generics.params[index] { - hir::GenericParam::Lifetime(ref ld) => (ld.lifetime.span, ld.lifetime.name.name()), - hir::GenericParam::Type(ref tp) => (tp.span, tp.name), - }; - self.report_bivariance(span, name); + for (index, _) in variances.iter().enumerate() { + if constrained_parameters.contains(&Parameter(index as u32)) { + continue; } + + let (span, name) = match ast_generics.params[index] { + hir::GenericParam::Lifetime(ref ld) => (ld.lifetime.span, ld.lifetime.name.name()), + hir::GenericParam::Type(ref tp) => (tp.span, tp.name), + }; + report_bivariance(tcx, span, name); } +} - fn report_bivariance(&self, - span: Span, - param_name: ast::Name) - { - let mut err = error_392(self.tcx, span, param_name); - - let suggested_marker_id = self.tcx.lang_items().phantom_data(); - match suggested_marker_id { - Some(def_id) => { - err.help( - &format!("consider removing `{}` or using a marker such as `{}`", - param_name, - self.tcx.item_path_str(def_id))); - } - None => { - // no lang items, no help! - } +fn report_bivariance<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, + span: Span, + param_name: ast::Name) +{ + let mut err = error_392(tcx, span, param_name); + + let suggested_marker_id = tcx.lang_items().phantom_data(); + match suggested_marker_id { + Some(def_id) => { + err.help( + &format!("consider removing `{}` or using a marker such as `{}`", + param_name, + tcx.item_path_str(def_id))); + } + None => { + // no lang items, no help! } - err.emit(); } + err.emit(); } fn reject_shadowing_type_parameters(tcx: TyCtxt, def_id: DefId) { @@ -648,6 +654,19 @@ fn reject_shadowing_type_parameters(tcx: TyCtxt, def_id: DefId) { } } +pub struct CheckTypeWellFormedVisitor<'a, 'tcx: 'a> { + tcx: TyCtxt<'a, 'tcx, 'tcx>, +} + +impl<'a, 'gcx> CheckTypeWellFormedVisitor<'a, 'gcx> { + pub fn new(tcx: TyCtxt<'a, 'gcx, 'gcx>) + -> CheckTypeWellFormedVisitor<'a, 'gcx> { + CheckTypeWellFormedVisitor { + tcx, + } + } +} + impl<'a, 'tcx, 'v> Visitor<'v> for CheckTypeWellFormedVisitor<'a, 'tcx> { fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'v> { NestedVisitorMap::None @@ -655,27 +674,22 @@ impl<'a, 'tcx, 'v> Visitor<'v> for CheckTypeWellFormedVisitor<'a, 'tcx> { fn visit_item(&mut self, i: &hir::Item) { debug!("visit_item: {:?}", i); - self.check_item_well_formed(i); + let def_id = self.tcx.hir.local_def_id(i.id); + ty::maps::queries::check_item_well_formed::ensure(self.tcx, def_id); intravisit::walk_item(self, i); } fn visit_trait_item(&mut self, trait_item: &'v hir::TraitItem) { debug!("visit_trait_item: {:?}", trait_item); - let method_sig = match trait_item.node { - hir::TraitItemKind::Method(ref sig, _) => Some(sig), - _ => None - }; - self.check_associated_item(trait_item.id, trait_item.span, method_sig); + let def_id = self.tcx.hir.local_def_id(trait_item.id); + ty::maps::queries::check_trait_item_well_formed::ensure(self.tcx, def_id); intravisit::walk_trait_item(self, trait_item) } fn visit_impl_item(&mut self, impl_item: &'v hir::ImplItem) { debug!("visit_impl_item: {:?}", impl_item); - let method_sig = match impl_item.node { - hir::ImplItemKind::Method(ref sig, _) => Some(sig), - _ => None - }; - self.check_associated_item(impl_item.id, impl_item.span, method_sig); + let def_id = self.tcx.hir.local_def_id(impl_item.id); + ty::maps::queries::check_impl_item_well_formed::ensure(self.tcx, def_id); intravisit::walk_impl_item(self, impl_item) } }