diff options
Diffstat (limited to 'compiler/rustc_hir_analysis/src/check/check.rs')
| -rw-r--r-- | compiler/rustc_hir_analysis/src/check/check.rs | 155 |
1 files changed, 136 insertions, 19 deletions
diff --git a/compiler/rustc_hir_analysis/src/check/check.rs b/compiler/rustc_hir_analysis/src/check/check.rs index 50ea8018e76..3080d8b3510 100644 --- a/compiler/rustc_hir_analysis/src/check/check.rs +++ b/compiler/rustc_hir_analysis/src/check/check.rs @@ -5,13 +5,14 @@ use rustc_abi::FieldIdx; use rustc_data_structures::unord::{UnordMap, UnordSet}; use rustc_errors::MultiSpan; use rustc_errors::codes::*; -use rustc_hir::Node; use rustc_hir::def::{CtorKind, DefKind}; +use rustc_hir::{Node, intravisit}; use rustc_infer::infer::{RegionVariableOrigin, TyCtxtInferExt}; -use rustc_infer::traits::Obligation; +use rustc_infer::traits::{Obligation, ObligationCauseCode}; use rustc_lint_defs::builtin::{ REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS, UNSUPPORTED_FN_PTR_CALLING_CONVENTIONS, }; +use rustc_middle::hir::nested_filter; use rustc_middle::middle::resolve_bound_vars::ResolvedArg; use rustc_middle::middle::stability::EvalResult; use rustc_middle::span_bug; @@ -190,7 +191,7 @@ fn check_static_inhabited(tcx: TyCtxt<'_>, def_id: LocalDefId) { /// Checks that an opaque type does not contain cycles and does not use `Self` or `T::Foo` /// projections that would result in "inheriting lifetimes". fn check_opaque(tcx: TyCtxt<'_>, def_id: LocalDefId) { - let hir::OpaqueTy { origin, .. } = tcx.hir().expect_opaque_ty(def_id); + let hir::OpaqueTy { origin, .. } = *tcx.hir().expect_opaque_ty(def_id); // HACK(jynelson): trying to infer the type of `impl trait` breaks documenting // `async-std` (and `pub async fn` in general). @@ -200,23 +201,20 @@ fn check_opaque(tcx: TyCtxt<'_>, def_id: LocalDefId) { return; } - let span = tcx.def_span(def_id); - if tcx.type_of(def_id).instantiate_identity().references_error() { return; } - if check_opaque_for_cycles(tcx, def_id, span).is_err() { + if check_opaque_for_cycles(tcx, def_id).is_err() { return; } - let _ = check_opaque_meets_bounds(tcx, def_id, span, origin); + let _ = check_opaque_meets_bounds(tcx, def_id, origin); } /// Checks that an opaque type does not contain cycles. pub(super) fn check_opaque_for_cycles<'tcx>( tcx: TyCtxt<'tcx>, def_id: LocalDefId, - span: Span, ) -> Result<(), ErrorGuaranteed> { let args = GenericArgs::identity_for_item(tcx, def_id); @@ -233,7 +231,7 @@ pub(super) fn check_opaque_for_cycles<'tcx>( .try_expand_impl_trait_type(def_id.to_def_id(), args, InspectCoroutineFields::No) .is_err() { - let reported = opaque_type_cycle_error(tcx, def_id, span); + let reported = opaque_type_cycle_error(tcx, def_id); return Err(reported); } @@ -267,10 +265,16 @@ pub(super) fn check_opaque_for_cycles<'tcx>( fn check_opaque_meets_bounds<'tcx>( tcx: TyCtxt<'tcx>, def_id: LocalDefId, - span: Span, - origin: &hir::OpaqueTyOrigin<LocalDefId>, + origin: hir::OpaqueTyOrigin<LocalDefId>, ) -> Result<(), ErrorGuaranteed> { - let defining_use_anchor = match *origin { + let (span, definition_def_id) = + if let Some((span, def_id)) = best_definition_site_of_opaque(tcx, def_id, origin) { + (span, Some(def_id)) + } else { + (tcx.def_span(def_id), None) + }; + + let defining_use_anchor = match origin { hir::OpaqueTyOrigin::FnReturn { parent, .. } | hir::OpaqueTyOrigin::AsyncFn { parent, .. } | hir::OpaqueTyOrigin::TyAlias { parent, .. } => parent, @@ -281,7 +285,7 @@ fn check_opaque_meets_bounds<'tcx>( let infcx = tcx.infer_ctxt().build(TypingMode::analysis_in_body(tcx, defining_use_anchor)); let ocx = ObligationCtxt::new_with_diagnostics(&infcx); - let args = match *origin { + let args = match origin { hir::OpaqueTyOrigin::FnReturn { parent, .. } | hir::OpaqueTyOrigin::AsyncFn { parent, .. } | hir::OpaqueTyOrigin::TyAlias { parent, .. } => GenericArgs::identity_for_item( @@ -306,8 +310,33 @@ fn check_opaque_meets_bounds<'tcx>( _ => re, }); - let misc_cause = traits::ObligationCause::misc(span, def_id); + // HACK: We eagerly instantiate some bounds to report better errors for them... + // This isn't necessary for correctness, since we register these bounds when + // equating the opaque below, but we should clean this up in the new solver. + for (predicate, pred_span) in + tcx.explicit_item_bounds(def_id).iter_instantiated_copied(tcx, args) + { + let predicate = predicate.fold_with(&mut BottomUpFolder { + tcx, + ty_op: |ty| if ty == opaque_ty { hidden_ty } else { ty }, + lt_op: |lt| lt, + ct_op: |ct| ct, + }); + + ocx.register_obligation(Obligation::new( + tcx, + ObligationCause::new( + span, + def_id, + ObligationCauseCode::OpaqueTypeBound(pred_span, definition_def_id), + ), + param_env, + predicate, + )); + } + let misc_cause = ObligationCause::misc(span, def_id); + // FIXME: We should just register the item bounds here, rather than equating. match ocx.eq(&misc_cause, param_env, opaque_ty, hidden_ty) { Ok(()) => {} Err(ty_err) => { @@ -364,6 +393,97 @@ fn check_opaque_meets_bounds<'tcx>( } } +fn best_definition_site_of_opaque<'tcx>( + tcx: TyCtxt<'tcx>, + opaque_def_id: LocalDefId, + origin: hir::OpaqueTyOrigin<LocalDefId>, +) -> Option<(Span, LocalDefId)> { + struct TaitConstraintLocator<'tcx> { + opaque_def_id: LocalDefId, + tcx: TyCtxt<'tcx>, + } + impl<'tcx> TaitConstraintLocator<'tcx> { + fn check(&self, item_def_id: LocalDefId) -> ControlFlow<(Span, LocalDefId)> { + if !self.tcx.has_typeck_results(item_def_id) { + return ControlFlow::Continue(()); + } + + if let Some(hidden_ty) = + self.tcx.mir_borrowck(item_def_id).concrete_opaque_types.get(&self.opaque_def_id) + { + ControlFlow::Break((hidden_ty.span, item_def_id)) + } else { + ControlFlow::Continue(()) + } + } + } + impl<'tcx> intravisit::Visitor<'tcx> for TaitConstraintLocator<'tcx> { + type NestedFilter = nested_filter::All; + type Result = ControlFlow<(Span, LocalDefId)>; + fn nested_visit_map(&mut self) -> Self::Map { + self.tcx.hir() + } + fn visit_expr(&mut self, ex: &'tcx hir::Expr<'tcx>) -> Self::Result { + if let hir::ExprKind::Closure(closure) = ex.kind { + self.check(closure.def_id)?; + } + intravisit::walk_expr(self, ex) + } + fn visit_item(&mut self, it: &'tcx hir::Item<'tcx>) -> Self::Result { + self.check(it.owner_id.def_id)?; + intravisit::walk_item(self, it) + } + fn visit_impl_item(&mut self, it: &'tcx hir::ImplItem<'tcx>) -> Self::Result { + self.check(it.owner_id.def_id)?; + intravisit::walk_impl_item(self, it) + } + fn visit_trait_item(&mut self, it: &'tcx hir::TraitItem<'tcx>) -> Self::Result { + self.check(it.owner_id.def_id)?; + intravisit::walk_trait_item(self, it) + } + fn visit_foreign_item(&mut self, it: &'tcx hir::ForeignItem<'tcx>) -> Self::Result { + intravisit::walk_foreign_item(self, it) + } + } + + let mut locator = TaitConstraintLocator { tcx, opaque_def_id }; + match origin { + hir::OpaqueTyOrigin::FnReturn { parent, .. } + | hir::OpaqueTyOrigin::AsyncFn { parent, .. } => locator.check(parent).break_value(), + hir::OpaqueTyOrigin::TyAlias { parent, in_assoc_ty: true } => { + let impl_def_id = tcx.local_parent(parent); + for assoc in tcx.associated_items(impl_def_id).in_definition_order() { + match assoc.kind { + ty::AssocKind::Const | ty::AssocKind::Fn => { + if let ControlFlow::Break(span) = locator.check(assoc.def_id.expect_local()) + { + return Some(span); + } + } + ty::AssocKind::Type => {} + } + } + + None + } + hir::OpaqueTyOrigin::TyAlias { in_assoc_ty: false, .. } => { + let scope = tcx.hir().get_defining_scope(tcx.local_def_id_to_hir_id(opaque_def_id)); + let found = if scope == hir::CRATE_HIR_ID { + tcx.hir().walk_toplevel_module(&mut locator) + } else { + match tcx.hir_node(scope) { + Node::Item(it) => locator.visit_item(it), + Node::ImplItem(it) => locator.visit_impl_item(it), + Node::TraitItem(it) => locator.visit_trait_item(it), + Node::ForeignItem(it) => locator.visit_foreign_item(it), + other => bug!("{:?} is not a valid scope for an opaque type item", other), + } + }; + found.break_value() + } + } +} + fn sanity_check_found_hidden_type<'tcx>( tcx: TyCtxt<'tcx>, key: ty::OpaqueTypeKey<'tcx>, @@ -1535,11 +1655,8 @@ fn check_type_alias_type_params_are_used<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalD /// /// If all the return expressions evaluate to `!`, then we explain that the error will go away /// after changing it. This can happen when a user uses `panic!()` or similar as a placeholder. -fn opaque_type_cycle_error( - tcx: TyCtxt<'_>, - opaque_def_id: LocalDefId, - span: Span, -) -> ErrorGuaranteed { +fn opaque_type_cycle_error(tcx: TyCtxt<'_>, opaque_def_id: LocalDefId) -> ErrorGuaranteed { + let span = tcx.def_span(opaque_def_id); let mut err = struct_span_code_err!(tcx.dcx(), span, E0720, "cannot resolve opaque type"); let mut label = false; |