Auto merge of rust-lang#66886 - mark-i-m:simplify-borrow_check-2, r=matthewjasper

Remove the borrow check::nll submodule

NLL is the only borrow checker now, so no need to have a separate submodule.

@rustbot modify labels: +S-blocked

Waiting on rust-lang#66815

Author: bors

Diff for: src/librustc_mir/borrow_check/nll/constraint_generation.rs renamed to src/librustc_mir/borrow_check/constraint_generation.rs

@@ -1,9 +1,3 @@
-use crate::borrow_check::borrow_set::BorrowSet;
-use crate::borrow_check::location::LocationTable;
-use crate::borrow_check::nll::ToRegionVid;
-use crate::borrow_check::nll::facts::AllFacts;
-use crate::borrow_check::nll::region_infer::values::LivenessValues;
-use crate::borrow_check::places_conflict;
 use rustc::infer::InferCtxt;
 use rustc::mir::visit::TyContext;
 use rustc::mir::visit::Visitor;
@@ -15,6 +9,15 @@ use rustc::ty::fold::TypeFoldable;
 use rustc::ty::{self, RegionVid, Ty};
 use rustc::ty::subst::SubstsRef;
 
+use crate::borrow_check::{
+    borrow_set::BorrowSet,
+    location::LocationTable,
+    nll::ToRegionVid,
+    facts::AllFacts,
+    region_infer::values::LivenessValues,
+    places_conflict,
+};
+
 pub(super) fn generate_constraints<'cx, 'tcx>(
     infcx: &InferCtxt<'cx, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,

Diff for: src/librustc_mir/borrow_check/nll/constraints/graph.rs renamed to src/librustc_mir/borrow_check/constraints/graph.rs

@@ -1,12 +1,15 @@
-use crate::borrow_check::nll::type_check::Locations;
-use crate::borrow_check::nll::constraints::OutlivesConstraintIndex;
-use crate::borrow_check::nll::constraints::{OutlivesConstraintSet, OutlivesConstraint};
 use rustc::mir::ConstraintCategory;
 use rustc::ty::RegionVid;
 use rustc_data_structures::graph;
 use rustc_index::vec::IndexVec;
 use syntax_pos::DUMMY_SP;
 
+use crate::borrow_check::{
+    type_check::Locations,
+    constraints::OutlivesConstraintIndex,
+    constraints::{OutlivesConstraintSet, OutlivesConstraint},
+};
+
 /// The construct graph organizes the constraints by their end-points.
 /// It can be used to view a `R1: R2` constraint as either an edge `R1
 /// -> R2` or `R2 -> R1` depending on the direction type `D`.

Diff for: src/librustc_mir/borrow_check/nll/constraints/mod.rs renamed to src/librustc_mir/borrow_check/constraints/mod.rs

@@ -1,11 +1,12 @@
-use crate::borrow_check::nll::type_check::Locations;
 use rustc::mir::ConstraintCategory;
 use rustc::ty::RegionVid;
 use rustc_data_structures::graph::scc::Sccs;
 use rustc_index::vec::{Idx, IndexVec};
 use std::fmt;
 use std::ops::Index;
 
+use crate::borrow_check::type_check::Locations;
+
 crate mod graph;
 
 /// A set of NLL region constraints. These include "outlives"

Diff for: src/librustc_mir/borrow_check/diagnostics/explain_borrow.rs

@@ -1,9 +1,7 @@
+//! Print diagnostics to explain why values are borrowed.
+
 use std::collections::VecDeque;
 
-use crate::borrow_check::borrow_set::BorrowData;
-use crate::borrow_check::nll::region_infer::Cause;
-use crate::borrow_check::nll::ConstraintDescription;
-use crate::borrow_check::{MirBorrowckCtxt, WriteKind};
 use rustc::mir::{
     CastKind, ConstraintCategory, FakeReadCause, Local, Location, Body, Operand, Place, Rvalue,
     Statement, StatementKind, TerminatorKind,
@@ -16,6 +14,13 @@ use rustc_errors::DiagnosticBuilder;
 use syntax_pos::Span;
 use syntax_pos::symbol::Symbol;
 
+use crate::borrow_check::{
+    borrow_set::BorrowData,
+    region_infer::Cause,
+    nll::ConstraintDescription,
+    MirBorrowckCtxt, WriteKind,
+};
+
 use super::{UseSpans, find_use, RegionName};
 
 #[derive(Debug)]

Diff for: src/librustc_mir/borrow_check/diagnostics/find_use.rs

@@ -1,8 +1,7 @@
 use std::collections::VecDeque;
 use std::rc::Rc;
 
-use crate::borrow_check::nll::region_infer::{Cause, RegionInferenceContext};
-use crate::borrow_check::nll::ToRegionVid;
+use crate::borrow_check::{nll::ToRegionVid, region_infer::{Cause, RegionInferenceContext}};
 use crate::util::liveness::{self, DefUse};
 use rustc::mir::visit::{MirVisitable, PlaceContext, Visitor};
 use rustc::mir::{Local, Location, Body};

Diff for: src/librustc_mir/borrow_check/diagnostics/outlives_suggestion.rs

@@ -13,7 +13,7 @@ use syntax_pos::symbol::Symbol;
 
 use smallvec::SmallVec;
 
-use crate::borrow_check::nll::region_infer::RegionInferenceContext;
+use crate::borrow_check::region_infer::RegionInferenceContext;
 
 use super::{
     RegionName, RegionNameSource, ErrorConstraintInfo, ErrorReportingCtx, RegionErrorNamingCtx,

Diff for: src/librustc_mir/borrow_check/diagnostics/region_errors.rs

@@ -1,10 +1,5 @@
-use crate::borrow_check::nll::constraints::OutlivesConstraint;
-use crate::borrow_check::nll::region_infer::RegionInferenceContext;
-use crate::borrow_check::nll::type_check::Locations;
-use crate::borrow_check::nll::universal_regions::DefiningTy;
-use crate::borrow_check::nll::ConstraintDescription;
-use crate::borrow_check::Upvar;
-use crate::util::borrowck_errors;
+//! Error reporting machinery for lifetime errors.
+
 use rustc::hir::def_id::DefId;
 use rustc::infer::error_reporting::nice_region_error::NiceRegionError;
 use rustc::infer::InferCtxt;
@@ -19,6 +14,17 @@ use syntax::symbol::kw;
 use syntax_pos::Span;
 use syntax_pos::symbol::Symbol;
 
+use crate::util::borrowck_errors;
+
+use crate::borrow_check::{
+    constraints::OutlivesConstraint,
+    region_infer::RegionInferenceContext,
+    type_check::Locations,
+    universal_regions::DefiningTy,
+    nll::ConstraintDescription,
+    Upvar,
+};
+
 use super::{OutlivesSuggestionBuilder, RegionName, RegionNameSource, RegionErrorNamingCtx};
 
 impl ConstraintDescription for ConstraintCategory {

Diff for: src/librustc_mir/borrow_check/diagnostics/region_name.rs

@@ -15,14 +15,13 @@ use rustc_data_structures::fx::FxHashMap;
 use syntax_pos::{Span, symbol::Symbol, DUMMY_SP};
 
 use crate::borrow_check::{
-    nll::region_infer::RegionInferenceContext,
-    nll::universal_regions::DefiningTy,
+    diagnostics::region_errors::ErrorReportingCtx,
+    region_infer::RegionInferenceContext,
+    universal_regions::DefiningTy,
     nll::ToRegionVid,
     Upvar,
 };
 
-use super::region_errors::ErrorReportingCtx;
-
 /// A name for a particular region used in emitting diagnostics. This name could be a generated
 /// name like `'1`, a name used by the user like `'a`, or a name like `'static`.
 #[derive(Debug, Clone)]

Diff for: src/librustc_mir/borrow_check/diagnostics/var_name.rs

@@ -1,5 +1,4 @@
-use crate::borrow_check::nll::region_infer::RegionInferenceContext;
-use crate::borrow_check::nll::ToRegionVid;
+use crate::borrow_check::{nll::ToRegionVid, region_infer::RegionInferenceContext};
 use crate::borrow_check::Upvar;
 use rustc::mir::{Local, Body};
 use rustc::ty::{RegionVid, TyCtxt};

Diff for: src/librustc_mir/borrow_check/nll/facts.rs renamed to src/librustc_mir/borrow_check/facts.rs

@@ -1,14 +1,3 @@
-use crate::borrow_check::borrow_set::BorrowSet;
-use crate::borrow_check::location::LocationTable;
-use crate::borrow_check::{JustWrite, WriteAndRead};
-use crate::borrow_check::{AccessDepth, Deep, Shallow};
-use crate::borrow_check::{ReadOrWrite, Activation, Read, Reservation, Write};
-use crate::borrow_check::{LocalMutationIsAllowed, MutateMode};
-use crate::borrow_check::ArtificialField;
-use crate::borrow_check::{ReadKind, WriteKind};
-use crate::borrow_check::nll::facts::AllFacts;
-use crate::borrow_check::path_utils::*;
-use crate::dataflow::indexes::BorrowIndex;
 use rustc::ty::{self, TyCtxt};
 use rustc::mir::visit::Visitor;
 use rustc::mir::{BasicBlock, Location, Body, Place, ReadOnlyBodyAndCache, Rvalue};
@@ -17,6 +6,17 @@ use rustc::mir::TerminatorKind;
 use rustc::mir::{Operand, BorrowKind};
 use rustc_data_structures::graph::dominators::Dominators;
 
+use crate::dataflow::indexes::BorrowIndex;
+
+use crate::borrow_check::{
+    borrow_set::BorrowSet,
+    location::LocationTable,
+    facts::AllFacts,
+    path_utils::*,
+    JustWrite, WriteAndRead, AccessDepth, Deep, Shallow, ReadOrWrite, Activation, Read,
+    Reservation, Write, LocalMutationIsAllowed, MutateMode, ArtificialField, ReadKind, WriteKind,
+};
+
 pub(super) fn generate_invalidates<'tcx>(
     tcx: TyCtxt<'tcx>,
     param_env: ty::ParamEnv<'tcx>,

Diff for: src/librustc_mir/borrow_check/nll/invalidation.rs renamed to src/librustc_mir/borrow_check/invalidation.rs

@@ -1,6 +1,5 @@
 //! This query borrow-checks the MIR to (further) ensure it is not broken.
 
-use crate::borrow_check::nll::region_infer::RegionInferenceContext;
 use rustc::hir::{self, HirId};
 use rustc::hir::Node;
 use rustc::hir::def_id::DefId;
@@ -41,7 +40,6 @@ use crate::dataflow::{do_dataflow, DebugFormatted};
 use crate::dataflow::EverInitializedPlaces;
 use crate::dataflow::{MaybeInitializedPlaces, MaybeUninitializedPlaces};
 
-use self::borrow_set::{BorrowData, BorrowSet};
 use self::flows::Flows;
 use self::location::LocationTable;
 use self::prefixes::PrefixSet;
@@ -50,17 +48,31 @@ use self::diagnostics::AccessKind;
 
 use self::path_utils::*;
 
-crate mod borrow_set;
 mod diagnostics;
 mod flows;
 mod location;
 mod path_utils;
-crate mod place_ext;
-crate mod places_conflict;
 mod prefixes;
 mod used_muts;
-
-pub(crate) mod nll;
+mod constraint_generation;
+mod facts;
+mod invalidation;
+mod renumber;
+mod member_constraints;
+mod constraints;
+mod universal_regions;
+mod type_check;
+mod region_infer;
+mod borrow_set;
+mod place_ext;
+mod places_conflict;
+mod nll;
+
+crate use region_infer::RegionInferenceContext;
+crate use borrow_set::{BorrowSet, BorrowData};
+crate use places_conflict::{places_conflict, PlaceConflictBias};
+crate use place_ext::PlaceExt;
+crate use nll::ToRegionVid;
 
 // FIXME(eddyb) perhaps move this somewhere more centrally.
 #[derive(Debug)]

Diff for: src/librustc_mir/borrow_check/nll/member_constraints.rs renamed to src/librustc_mir/borrow_check/member_constraints.rs

@@ -1,13 +1,5 @@
-use crate::borrow_check::borrow_set::BorrowSet;
-use crate::borrow_check::location::LocationTable;
-use crate::borrow_check::nll::facts::AllFactsExt;
-use crate::borrow_check::nll::type_check::{MirTypeckResults, MirTypeckRegionConstraints};
-use crate::borrow_check::nll::region_infer::values::RegionValueElements;
-use crate::dataflow::move_paths::{InitLocation, MoveData, InitKind};
-use crate::dataflow::FlowAtLocation;
-use crate::dataflow::MaybeInitializedPlaces;
-use crate::transform::MirSource;
-use crate::borrow_check::Upvar;
+//! The entry point of the NLL borrow checker.
+
 use rustc::hir::def_id::DefId;
 use rustc::infer::InferCtxt;
 use rustc::mir::{ClosureOutlivesSubject, ClosureRegionRequirements,
@@ -27,24 +19,23 @@ use syntax::symbol::sym;
 
 use self::mir_util::PassWhere;
 use polonius_engine::{Algorithm, Output};
+
 use crate::util as mir_util;
 use crate::util::pretty;
+use crate::dataflow::move_paths::{InitLocation, MoveData, InitKind};
+use crate::dataflow::FlowAtLocation;
+use crate::dataflow::MaybeInitializedPlaces;
+use crate::transform::MirSource;
 
-mod constraint_generation;
-mod facts;
-mod invalidation;
-mod renumber;
-
-mod member_constraints;
-
-crate mod constraints;
-crate mod universal_regions;
-crate mod type_check;
-crate mod region_infer;
-
-use self::facts::{AllFacts, RustcFacts};
-use self::region_infer::RegionInferenceContext;
-use self::universal_regions::UniversalRegions;
+use crate::borrow_check::{
+    borrow_set::BorrowSet,
+    location::LocationTable,
+    facts::{AllFacts, AllFactsExt, RustcFacts},
+    region_infer::{RegionInferenceContext, values::RegionValueElements},
+    universal_regions::UniversalRegions,
+    type_check::{self, MirTypeckResults, MirTypeckRegionConstraints},
+    Upvar, renumber, constraint_generation, invalidation,
+};
 
 crate type PoloniusOutput = Output<RustcFacts>;
 

Diff for: src/librustc_mir/borrow_check/mod.rs

@@ -2,11 +2,12 @@
 //! libgraphviz traits, specialized to attaching borrowck analysis
 //! data to rendered labels.
 
-use super::*;
-use crate::borrow_check::nll::constraints::OutlivesConstraint;
 use std::borrow::Cow;
 use std::io::{self, Write};
 
+use super::*;
+use crate::borrow_check::constraints::OutlivesConstraint;
+
 impl<'tcx> RegionInferenceContext<'tcx> {
     /// Write out the region constraint graph.
     crate fn dump_graphviz_raw_constraints(&self, mut w: &mut dyn Write) -> io::Result<()> {

Diff for: src/librustc_mir/borrow_check/nll/mod.rs renamed to src/librustc_mir/borrow_check/nll.rs

@@ -23,29 +23,26 @@ use syntax_pos::Span;
 use syntax_pos::symbol::Symbol;
 
 use crate::borrow_check::{
-    nll::{
-        constraints::{
-            graph::NormalConstraintGraph,
-            ConstraintSccIndex,
-            OutlivesConstraint,
-            OutlivesConstraintSet,
-        },
-        member_constraints::{MemberConstraintSet, NllMemberConstraintIndex},
-        region_infer::values::{
-            PlaceholderIndices, RegionElement, ToElementIndex
-        },
-        type_check::{free_region_relations::UniversalRegionRelations, Locations},
+    constraints::{
+        graph::NormalConstraintGraph,
+        ConstraintSccIndex,
+        OutlivesConstraint,
+        OutlivesConstraintSet,
     },
+    member_constraints::{MemberConstraintSet, NllMemberConstraintIndex},
+    region_infer::values::{
+        PlaceholderIndices, RegionElement, ToElementIndex, LivenessValues, RegionValueElements,
+        RegionValues,
+    },
+    type_check::{free_region_relations::UniversalRegionRelations, Locations},
     diagnostics::{
         OutlivesSuggestionBuilder, RegionErrorNamingCtx,
     },
+    nll::{ToRegionVid, PoloniusOutput},
+    universal_regions::UniversalRegions,
     Upvar,
 };
 
-use self::values::{LivenessValues, RegionValueElements, RegionValues};
-use super::universal_regions::UniversalRegions;
-use super::{PoloniusOutput, ToRegionVid};
-
 mod dump_mir;
 mod graphviz;
 

Diff for: src/librustc_mir/borrow_check/nll/region_infer/dump_mir.rs renamed to src/librustc_mir/borrow_check/region_infer/dump_mir.rs

@@ -1,8 +1,3 @@
-use crate::borrow_check::nll::constraints::OutlivesConstraint;
-use crate::borrow_check::nll::region_infer::TypeTest;
-use crate::borrow_check::nll::type_check::{Locations, MirTypeckRegionConstraints};
-use crate::borrow_check::nll::universal_regions::UniversalRegions;
-use crate::borrow_check::nll::ToRegionVid;
 use rustc::infer::canonical::QueryRegionConstraints;
 use rustc::infer::canonical::QueryOutlivesConstraint;
 use rustc::infer::outlives::env::RegionBoundPairs;
@@ -14,6 +9,14 @@ use rustc::ty::subst::GenericArgKind;
 use rustc::ty::{self, TyCtxt};
 use syntax_pos::DUMMY_SP;
 
+use crate::borrow_check::{
+    constraints::OutlivesConstraint,
+    region_infer::TypeTest,
+    type_check::{Locations, MirTypeckRegionConstraints},
+    universal_regions::UniversalRegions,
+    nll::ToRegionVid,
+};
+
 crate struct ConstraintConversion<'a, 'tcx> {
     infcx: &'a InferCtxt<'a, 'tcx>,
     tcx: TyCtxt<'tcx>,