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

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>,

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`.

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"

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)]

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};

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,

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 {

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)]

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};