diff --git a/src/librustc_infer/infer/error_reporting/mod.rs b/src/librustc_infer/infer/error_reporting/mod.rs index a544381f33da..ebbfcb28db2f 100644 --- a/src/librustc_infer/infer/error_reporting/mod.rs +++ b/src/librustc_infer/infer/error_reporting/mod.rs @@ -49,7 +49,7 @@ use super::lexical_region_resolve::RegionResolutionError; use super::region_constraints::GenericKind; use super::{InferCtxt, RegionVariableOrigin, SubregionOrigin, TypeTrace, ValuePairs}; -use crate::infer::{self, SuppressRegionErrors}; +use crate::infer; use crate::traits::error_reporting::report_object_safety_error; use crate::traits::{ IfExpressionCause, MatchExpressionArmCause, ObligationCause, ObligationCauseCode, @@ -372,17 +372,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> { &self, region_scope_tree: ®ion::ScopeTree, errors: &Vec>, - suppress: SuppressRegionErrors, ) { - debug!( - "report_region_errors(): {} errors to start, suppress = {:?}", - errors.len(), - suppress - ); - - if suppress.suppressed() { - return; - } + debug!("report_region_errors(): {} errors to start", errors.len()); // try to pre-process the errors, which will group some of them // together into a `ProcessedErrors` group: diff --git a/src/librustc_infer/infer/lexical_region_resolve/mod.rs b/src/librustc_infer/infer/lexical_region_resolve/mod.rs index b7278ecd5e40..3af10e850d53 100644 --- a/src/librustc_infer/infer/lexical_region_resolve/mod.rs +++ b/src/librustc_infer/infer/lexical_region_resolve/mod.rs @@ -7,6 +7,7 @@ use crate::infer::region_constraints::RegionConstraintData; use crate::infer::region_constraints::VarInfos; use crate::infer::region_constraints::VerifyBound; use crate::infer::RegionVariableOrigin; +use crate::infer::RegionckMode; use crate::infer::SubregionOrigin; use rustc::middle::free_region::RegionRelations; use rustc::ty::fold::TypeFoldable; @@ -33,12 +34,29 @@ pub fn resolve<'tcx>( region_rels: &RegionRelations<'_, 'tcx>, var_infos: VarInfos, data: RegionConstraintData<'tcx>, + mode: RegionckMode, ) -> (LexicalRegionResolutions<'tcx>, Vec>) { debug!("RegionConstraintData: resolve_regions()"); let mut errors = vec![]; let mut resolver = LexicalResolver { region_rels, var_infos, data }; - let values = resolver.infer_variable_values(&mut errors); - (values, errors) + match mode { + RegionckMode::Solve => { + let values = resolver.infer_variable_values(&mut errors); + (values, errors) + } + RegionckMode::Erase { suppress_errors: false } => { + // Do real inference to get errors, then erase the results. + let mut values = resolver.infer_variable_values(&mut errors); + let re_erased = region_rels.tcx.lifetimes.re_erased; + + values.values.iter_mut().for_each(|v| *v = VarValue::Value(re_erased)); + (values, errors) + } + RegionckMode::Erase { suppress_errors: true } => { + // Skip region inference entirely. + (resolver.erased_data(region_rels.tcx), Vec::new()) + } + } } /// Contains the result of lexical region resolution. Offers methods @@ -163,6 +181,19 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> { } } + /// An erased version of the lexical region resolutions. Used when we're + /// erasing regions and suppressing errors: in item bodies with + /// `-Zborrowck=mir`. + fn erased_data(&self, tcx: TyCtxt<'tcx>) -> LexicalRegionResolutions<'tcx> { + LexicalRegionResolutions { + error_region: tcx.lifetimes.re_static, + values: IndexVec::from_elem_n( + VarValue::Value(tcx.lifetimes.re_erased), + self.num_vars(), + ), + } + } + fn dump_constraints(&self, free_regions: &RegionRelations<'_, 'tcx>) { debug!("----() Start constraint listing (context={:?}) ()----", free_regions.context); for (idx, (constraint, _)) in self.data.constraints.iter().enumerate() { diff --git a/src/librustc_infer/infer/mod.rs b/src/librustc_infer/infer/mod.rs index 9ae131c568d0..c5f06d53b8f7 100644 --- a/src/librustc_infer/infer/mod.rs +++ b/src/librustc_infer/infer/mod.rs @@ -79,31 +79,50 @@ pub type Bound = Option; pub type UnitResult<'tcx> = RelateResult<'tcx, ()>; // "unify result" pub type FixupResult<'tcx, T> = Result>; // "fixup result" -/// A flag that is used to suppress region errors. This is normally -/// false, but sometimes -- when we are doing region checks that the -/// NLL borrow checker will also do -- it might be set to true. -#[derive(Copy, Clone, Default, Debug)] -pub struct SuppressRegionErrors { - suppressed: bool, +/// How we should handle region solving. +/// +/// This is used so that the region values inferred by HIR region solving are +/// not exposed, and so that we can avoid doing work in HIR typeck that MIR +/// typeck will also do. +#[derive(Copy, Clone, Debug)] +pub enum RegionckMode { + /// The default mode: report region errors, don't erase regions. + Solve, + /// Erase the results of region after solving. + Erase { + /// A flag that is used to suppress region errors, when we are doing + /// region checks that the NLL borrow checker will also do -- it might + /// be set to true. + suppress_errors: bool, + }, } -impl SuppressRegionErrors { +impl Default for RegionckMode { + fn default() -> Self { + RegionckMode::Solve + } +} + +impl RegionckMode { pub fn suppressed(self) -> bool { - self.suppressed + match self { + Self::Solve => false, + Self::Erase { suppress_errors } => suppress_errors, + } } /// Indicates that the MIR borrowck will repeat these region /// checks, so we should ignore errors if NLL is (unconditionally) /// enabled. - pub fn when_nll_is_enabled(tcx: TyCtxt<'_>) -> Self { + pub fn for_item_body(tcx: TyCtxt<'_>) -> Self { // FIXME(Centril): Once we actually remove `::Migrate` also make // this always `true` and then proceed to eliminate the dead code. match tcx.borrowck_mode() { // If we're on Migrate mode, report AST region errors - BorrowckMode::Migrate => SuppressRegionErrors { suppressed: false }, + BorrowckMode::Migrate => RegionckMode::Erase { suppress_errors: false }, // If we're on MIR, don't report AST region errors as they should be reported by NLL - BorrowckMode::Mir => SuppressRegionErrors { suppressed: true }, + BorrowckMode::Mir => RegionckMode::Erase { suppress_errors: true }, } } } @@ -1207,20 +1226,13 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> { region_context: DefId, region_map: ®ion::ScopeTree, outlives_env: &OutlivesEnvironment<'tcx>, - suppress: SuppressRegionErrors, + mode: RegionckMode, ) { assert!( self.is_tainted_by_errors() || self.inner.borrow().region_obligations.is_empty(), "region_obligations not empty: {:#?}", self.inner.borrow().region_obligations ); - - let region_rels = &RegionRelations::new( - self.tcx, - region_context, - region_map, - outlives_env.free_region_map(), - ); let (var_infos, data) = self .inner .borrow_mut() @@ -1228,8 +1240,16 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> { .take() .expect("regions already resolved") .into_infos_and_data(); + + let region_rels = &RegionRelations::new( + self.tcx, + region_context, + region_map, + outlives_env.free_region_map(), + ); + let (lexical_region_resolutions, errors) = - lexical_region_resolve::resolve(region_rels, var_infos, data); + lexical_region_resolve::resolve(region_rels, var_infos, data, mode); let old_value = self.lexical_region_resolutions.replace(Some(lexical_region_resolutions)); assert!(old_value.is_none()); @@ -1240,7 +1260,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> { // this infcx was in use. This is totally hokey but // otherwise we have a hard time separating legit region // errors from silly ones. - self.report_region_errors(region_map, &errors, suppress); + self.report_region_errors(region_map, &errors); } } diff --git a/src/librustc_trait_selection/traits/mod.rs b/src/librustc_trait_selection/traits/mod.rs index 7b93982db974..43a90c4a6c16 100644 --- a/src/librustc_trait_selection/traits/mod.rs +++ b/src/librustc_trait_selection/traits/mod.rs @@ -21,7 +21,7 @@ mod util; pub mod wf; use crate::infer::outlives::env::OutlivesEnvironment; -use crate::infer::{InferCtxt, SuppressRegionErrors, TyCtxtInferExt}; +use crate::infer::{InferCtxt, RegionckMode, TyCtxtInferExt}; use crate::traits::error_reporting::InferCtxtExt as _; use crate::traits::query::evaluate_obligation::InferCtxtExt as _; use rustc::middle::region; @@ -244,7 +244,7 @@ fn do_normalize_predicates<'tcx>( region_context, ®ion_scope_tree, &outlives_env, - SuppressRegionErrors::default(), + RegionckMode::default(), ); let predicates = match infcx.fully_resolve(&predicates) { diff --git a/src/librustc_typeck/check/dropck.rs b/src/librustc_typeck/check/dropck.rs index dca4f9e7cbe0..e48ebbbb2351 100644 --- a/src/librustc_typeck/check/dropck.rs +++ b/src/librustc_typeck/check/dropck.rs @@ -9,7 +9,7 @@ use rustc::ty::subst::{Subst, SubstsRef}; use rustc::ty::{self, Predicate, Ty, TyCtxt}; use rustc_errors::struct_span_err; use rustc_infer::infer::outlives::env::OutlivesEnvironment; -use rustc_infer::infer::{InferOk, SuppressRegionErrors, TyCtxtInferExt}; +use rustc_infer::infer::{InferOk, RegionckMode, TyCtxtInferExt}; use rustc_infer::traits::TraitEngineExt as _; use rustc_span::Span; use rustc_trait_selection::traits::error_reporting::InferCtxtExt; @@ -139,7 +139,7 @@ fn ensure_drop_params_and_item_params_correspond<'tcx>( drop_impl_did, ®ion_scope_tree, &outlives_env, - SuppressRegionErrors::default(), + RegionckMode::default(), ); Ok(()) }) diff --git a/src/librustc_typeck/check/regionck.rs b/src/librustc_typeck/check/regionck.rs index ecc9a423b910..b6d6d3a7a873 100644 --- a/src/librustc_typeck/check/regionck.rs +++ b/src/librustc_typeck/check/regionck.rs @@ -85,7 +85,7 @@ use rustc_hir::def_id::DefId; use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor}; use rustc_hir::PatKind; use rustc_infer::infer::outlives::env::OutlivesEnvironment; -use rustc_infer::infer::{self, RegionObligation, SuppressRegionErrors}; +use rustc_infer::infer::{self, RegionObligation, RegionckMode}; use rustc_span::Span; use rustc_trait_selection::infer::OutlivesEnvironmentExt; use rustc_trait_selection::opaque_types::InferCtxtExt; @@ -124,7 +124,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { rcx.visit_body(body); rcx.visit_region_obligations(id); } - rcx.resolve_regions_and_report_errors(SuppressRegionErrors::when_nll_is_enabled(self.tcx)); + rcx.resolve_regions_and_report_errors(RegionckMode::for_item_body(self.tcx)); } /// Region checking during the WF phase for items. `wf_tys` are the @@ -142,7 +142,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { rcx.outlives_environment.add_implied_bounds(self, wf_tys, item_id, span); rcx.outlives_environment.save_implied_bounds(item_id); rcx.visit_region_obligations(item_id); - rcx.resolve_regions_and_report_errors(SuppressRegionErrors::default()); + rcx.resolve_regions_and_report_errors(RegionckMode::default()); } /// Region check a function body. Not invoked on closures, but @@ -165,7 +165,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { rcx.visit_fn_body(fn_id, body, self.tcx.hir().span(fn_id)); } - rcx.resolve_regions_and_report_errors(SuppressRegionErrors::when_nll_is_enabled(self.tcx)); + rcx.resolve_regions_and_report_errors(RegionckMode::for_item_body(self.tcx)); } } @@ -346,7 +346,7 @@ impl<'a, 'tcx> RegionCtxt<'a, 'tcx> { self.select_all_obligations_or_error(); } - fn resolve_regions_and_report_errors(&self, suppress: SuppressRegionErrors) { + fn resolve_regions_and_report_errors(&self, mode: RegionckMode) { self.infcx.process_registered_region_obligations( self.outlives_environment.region_bound_pairs_map(), self.implicit_region_bound, @@ -357,7 +357,7 @@ impl<'a, 'tcx> RegionCtxt<'a, 'tcx> { self.subject_def_id, &self.region_scope_tree, &self.outlives_environment, - suppress, + mode, ); } diff --git a/src/librustc_typeck/check/writeback.rs b/src/librustc_typeck/check/writeback.rs index 21536503ef7e..8ed6cc3a9432 100644 --- a/src/librustc_typeck/check/writeback.rs +++ b/src/librustc_typeck/check/writeback.rs @@ -124,7 +124,7 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> { fn write_ty_to_tables(&mut self, hir_id: hir::HirId, ty: Ty<'tcx>) { debug!("write_ty_to_tables({:?}, {:?})", hir_id, ty); - assert!(!ty.needs_infer() && !ty.has_placeholders()); + assert!(!ty.needs_infer() && !ty.has_placeholders() && !ty.has_free_regions()); self.tables.node_types_mut().insert(hir_id, ty); } @@ -326,9 +326,10 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> { let new_upvar_capture = match *upvar_capture { ty::UpvarCapture::ByValue => ty::UpvarCapture::ByValue, ty::UpvarCapture::ByRef(ref upvar_borrow) => { - let r = upvar_borrow.region; - let r = self.resolve(&r, &upvar_id.var_path.hir_id); - ty::UpvarCapture::ByRef(ty::UpvarBorrow { kind: upvar_borrow.kind, region: r }) + ty::UpvarCapture::ByRef(ty::UpvarBorrow { + kind: upvar_borrow.kind, + region: self.tcx().lifetimes.re_erased, + }) } }; debug!("Upvar capture for {:?} resolved to {:?}", upvar_id, new_upvar_capture); @@ -421,8 +422,7 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> { fn visit_opaque_types(&mut self, span: Span) { for (&def_id, opaque_defn) in self.fcx.opaque_types.borrow().iter() { let hir_id = self.tcx().hir().as_local_hir_id(def_id).unwrap(); - let instantiated_ty = - self.tcx().erase_regions(&self.resolve(&opaque_defn.concrete_ty, &hir_id)); + let instantiated_ty = self.resolve(&opaque_defn.concrete_ty, &hir_id); debug_assert!(!instantiated_ty.has_escaping_bound_vars()); @@ -611,10 +611,8 @@ impl Locatable for hir::HirId { } } -/////////////////////////////////////////////////////////////////////////// -// The Resolver. This is the type folding engine that detects -// unresolved types and so forth. - +/// The Resolver. This is the type folding engine that detects +/// unresolved types and so forth. struct Resolver<'cx, 'tcx> { tcx: TyCtxt<'tcx>, infcx: &'cx InferCtxt<'cx, 'tcx>, @@ -647,7 +645,7 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for Resolver<'cx, 'tcx> { fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> { match self.infcx.fully_resolve(&t) { - Ok(t) => t, + Ok(t) => self.infcx.tcx.erase_regions(&t), Err(_) => { debug!("Resolver::fold_ty: input type `{:?}` not fully resolvable", t); self.report_error(t); @@ -656,15 +654,14 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for Resolver<'cx, 'tcx> { } } - // FIXME This should be carefully checked - // We could use `self.report_error` but it doesn't accept a ty::Region, right now. fn fold_region(&mut self, r: ty::Region<'tcx>) -> ty::Region<'tcx> { - self.infcx.fully_resolve(&r).unwrap_or(self.tcx.lifetimes.re_static) + debug_assert!(!r.is_late_bound(), "Should not be resolving bound region."); + self.tcx.lifetimes.re_erased } fn fold_const(&mut self, ct: &'tcx ty::Const<'tcx>) -> &'tcx ty::Const<'tcx> { match self.infcx.fully_resolve(&ct) { - Ok(ct) => ct, + Ok(ct) => self.infcx.tcx.erase_regions(&ct), Err(_) => { debug!("Resolver::fold_const: input const `{:?}` not fully resolvable", ct); // FIXME: we'd like to use `self.report_error`, but it doesn't yet diff --git a/src/librustc_typeck/coherence/builtin.rs b/src/librustc_typeck/coherence/builtin.rs index 2ea7601ae653..e24d9bebf657 100644 --- a/src/librustc_typeck/coherence/builtin.rs +++ b/src/librustc_typeck/coherence/builtin.rs @@ -12,7 +12,7 @@ use rustc_hir::def_id::DefId; use rustc_hir::ItemKind; use rustc_infer::infer; use rustc_infer::infer::outlives::env::OutlivesEnvironment; -use rustc_infer::infer::{SuppressRegionErrors, TyCtxtInferExt}; +use rustc_infer::infer::{RegionckMode, TyCtxtInferExt}; use rustc_trait_selection::traits::error_reporting::InferCtxtExt; use rustc_trait_selection::traits::misc::{can_type_implement_copy, CopyImplementationError}; use rustc_trait_selection::traits::predicate_for_trait_def; @@ -307,7 +307,7 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: DefId) { impl_did, ®ion_scope_tree, &outlives_env, - SuppressRegionErrors::default(), + RegionckMode::default(), ); } } @@ -568,7 +568,7 @@ pub fn coerce_unsized_info(tcx: TyCtxt<'tcx>, impl_did: DefId) -> CoerceUnsizedI impl_did, ®ion_scope_tree, &outlives_env, - SuppressRegionErrors::default(), + RegionckMode::default(), ); CoerceUnsizedInfo { custom_kind: kind } diff --git a/src/librustc_typeck/impl_wf_check/min_specialization.rs b/src/librustc_typeck/impl_wf_check/min_specialization.rs index e96a8c454b8c..cae883761184 100644 --- a/src/librustc_typeck/impl_wf_check/min_specialization.rs +++ b/src/librustc_typeck/impl_wf_check/min_specialization.rs @@ -75,7 +75,7 @@ use rustc_data_structures::fx::FxHashSet; use rustc_hir as hir; use rustc_hir::def_id::DefId; use rustc_infer::infer::outlives::env::OutlivesEnvironment; -use rustc_infer::infer::{InferCtxt, SuppressRegionErrors, TyCtxtInferExt}; +use rustc_infer::infer::{InferCtxt, RegionckMode, TyCtxtInferExt}; use rustc_infer::traits::specialization_graph::Node; use rustc_span::Span; use rustc_trait_selection::traits::{self, translate_substs, wf}; @@ -162,7 +162,7 @@ fn get_impl_substs<'tcx>( impl1_def_id, &ScopeTree::default(), &outlives_env, - SuppressRegionErrors::default(), + RegionckMode::default(), ); let impl2_substs = match infcx.fully_resolve(&impl2_substs) { Ok(s) => s,