diff --git a/Cargo.lock b/Cargo.lock
index 6849c40a54f237b07c9ec9dbaf9b86c8fab535cf..81549bd1d2055c178e30554ad36f5050d98b60f4 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3598,6 +3598,32 @@ dependencies = [
  "rustc_span",
 ]
 
+[[package]]
+name = "rustc_borrowck"
+version = "0.0.0"
+dependencies = [
+ "either",
+ "itertools 0.9.0",
+ "polonius-engine",
+ "rustc_data_structures",
+ "rustc_errors",
+ "rustc_graphviz",
+ "rustc_hir",
+ "rustc_index",
+ "rustc_infer",
+ "rustc_lexer",
+ "rustc_middle",
+ "rustc_mir",
+ "rustc_serialize",
+ "rustc_session",
+ "rustc_span",
+ "rustc_target",
+ "rustc_trait_selection",
+ "rustc_traits",
+ "smallvec",
+ "tracing",
+]
+
 [[package]]
 name = "rustc_builtin_macros"
 version = "0.0.0"
@@ -3888,6 +3914,7 @@ dependencies = [
  "rustc_ast_lowering",
  "rustc_ast_passes",
  "rustc_attr",
+ "rustc_borrowck",
  "rustc_builtin_macros",
  "rustc_codegen_llvm",
  "rustc_codegen_ssa",
@@ -4059,7 +4086,6 @@ dependencies = [
  "rustc_hir",
  "rustc_index",
  "rustc_infer",
- "rustc_lexer",
  "rustc_macros",
  "rustc_middle",
  "rustc_serialize",
@@ -4067,7 +4093,6 @@ dependencies = [
  "rustc_span",
  "rustc_target",
  "rustc_trait_selection",
- "rustc_traits",
  "smallvec",
  "tracing",
 ]
diff --git a/compiler/rustc_borrowck/Cargo.toml b/compiler/rustc_borrowck/Cargo.toml
new file mode 100644
index 0000000000000000000000000000000000000000..e919c2cbc4f15523634bb4148005d2b306118216
--- /dev/null
+++ b/compiler/rustc_borrowck/Cargo.toml
@@ -0,0 +1,30 @@
+[package]
+authors = ["The Rust Project Developers"]
+name = "rustc_borrowck"
+version = "0.0.0"
+edition = "2018"
+
+[lib]
+doctest = false
+
+[dependencies]
+either = "1.5.0"
+itertools = "0.9"
+tracing = "0.1"
+polonius-engine = "0.13.0"
+smallvec = { version = "1.6.1", features = ["union", "may_dangle"] }
+rustc_data_structures = { path = "../rustc_data_structures" }
+rustc_errors = { path = "../rustc_errors" }
+rustc_graphviz = { path = "../rustc_graphviz" }
+rustc_hir = { path = "../rustc_hir" }
+rustc_index = { path = "../rustc_index" }
+rustc_infer = { path = "../rustc_infer" }
+rustc_lexer = { path = "../rustc_lexer" }
+rustc_middle = { path = "../rustc_middle" }
+rustc_mir = { path = "../rustc_mir" }
+rustc_serialize = { path = "../rustc_serialize" }
+rustc_session = { path = "../rustc_session" }
+rustc_target = { path = "../rustc_target" }
+rustc_trait_selection = { path = "../rustc_trait_selection" }
+rustc_traits = { path = "../rustc_traits" }
+rustc_span = { path = "../rustc_span" }
diff --git a/compiler/rustc_mir/src/borrow_check/borrow_set.rs b/compiler/rustc_borrowck/src/borrow_set.rs
similarity index 98%
rename from compiler/rustc_mir/src/borrow_check/borrow_set.rs
rename to compiler/rustc_borrowck/src/borrow_set.rs
index 288eda32e414e4a10968ccc6320058e0160bca61..eb4d815bfc3ca3947941f0d3b3d1720f763d78ed 100644
--- a/compiler/rustc_mir/src/borrow_check/borrow_set.rs
+++ b/compiler/rustc_borrowck/src/borrow_set.rs
@@ -1,14 +1,14 @@
-use crate::borrow_check::nll::ToRegionVid;
-use crate::borrow_check::path_utils::allow_two_phase_borrow;
-use crate::borrow_check::place_ext::PlaceExt;
-use crate::dataflow::indexes::BorrowIndex;
-use crate::dataflow::move_paths::MoveData;
+use crate::nll::ToRegionVid;
+use crate::path_utils::allow_two_phase_borrow;
+use crate::place_ext::PlaceExt;
+use crate::BorrowIndex;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
 use rustc_index::bit_set::BitSet;
 use rustc_middle::mir::traversal;
 use rustc_middle::mir::visit::{MutatingUseContext, NonUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::{self, Body, Local, Location};
 use rustc_middle::ty::{RegionVid, TyCtxt};
+use rustc_mir::dataflow::move_paths::MoveData;
 use std::fmt;
 use std::ops::Index;
 
diff --git a/compiler/rustc_mir/src/util/borrowck_errors.rs b/compiler/rustc_borrowck/src/borrowck_errors.rs
similarity index 99%
rename from compiler/rustc_mir/src/util/borrowck_errors.rs
rename to compiler/rustc_borrowck/src/borrowck_errors.rs
index 56d8045813c425c2d7cb67a8cbdf8eec88d6b549..5702203d7c4ffba938aea53c89e71a1dbf7ba9bf 100644
--- a/compiler/rustc_mir/src/util/borrowck_errors.rs
+++ b/compiler/rustc_borrowck/src/borrowck_errors.rs
@@ -2,7 +2,7 @@
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_span::{MultiSpan, Span};
 
-impl<'cx, 'tcx> crate::borrow_check::MirBorrowckCtxt<'cx, 'tcx> {
+impl<'cx, 'tcx> crate::MirBorrowckCtxt<'cx, 'tcx> {
     crate fn cannot_move_when_borrowed(&self, span: Span, desc: &str) -> DiagnosticBuilder<'cx> {
         struct_span_err!(self, span, E0505, "cannot move out of {} because it is borrowed", desc,)
     }
diff --git a/compiler/rustc_mir/src/borrow_check/constraint_generation.rs b/compiler/rustc_borrowck/src/constraint_generation.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/constraint_generation.rs
rename to compiler/rustc_borrowck/src/constraint_generation.rs
index c84928523d9d6106a997d3a44e23c2d1a23f458e..a40f148cdf88c02a32706c7aeac8080a0f53314b 100644
--- a/compiler/rustc_mir/src/borrow_check/constraint_generation.rs
+++ b/compiler/rustc_borrowck/src/constraint_generation.rs
@@ -9,7 +9,7 @@
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::{self, RegionVid, Ty};
 
-use crate::borrow_check::{
+use crate::{
     borrow_set::BorrowSet, facts::AllFacts, location::LocationTable, nll::ToRegionVid,
     places_conflict, region_infer::values::LivenessValues,
 };
diff --git a/compiler/rustc_mir/src/borrow_check/constraints/graph.rs b/compiler/rustc_borrowck/src/constraints/graph.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/constraints/graph.rs
rename to compiler/rustc_borrowck/src/constraints/graph.rs
index 9e4cfb2cc00fa0f541e51649c229d0c0f18da8fb..cb9e0234c49ffa5a5a7edc3e653817563f93ee5e 100644
--- a/compiler/rustc_mir/src/borrow_check/constraints/graph.rs
+++ b/compiler/rustc_borrowck/src/constraints/graph.rs
@@ -4,7 +4,7 @@
 use rustc_middle::ty::{RegionVid, VarianceDiagInfo};
 use rustc_span::DUMMY_SP;
 
-use crate::borrow_check::{
+use crate::{
     constraints::OutlivesConstraintIndex,
     constraints::{OutlivesConstraint, OutlivesConstraintSet},
     type_check::Locations,
diff --git a/compiler/rustc_mir/src/borrow_check/constraints/mod.rs b/compiler/rustc_borrowck/src/constraints/mod.rs
similarity index 98%
rename from compiler/rustc_mir/src/borrow_check/constraints/mod.rs
rename to compiler/rustc_borrowck/src/constraints/mod.rs
index b944479ca456b387fe7dd23c44e1be17a2840308..98378a98684e2f0ff2589631a42988a14bcc598a 100644
--- a/compiler/rustc_mir/src/borrow_check/constraints/mod.rs
+++ b/compiler/rustc_borrowck/src/constraints/mod.rs
@@ -5,7 +5,7 @@
 use std::fmt;
 use std::ops::Index;
 
-use crate::borrow_check::type_check::Locations;
+use crate::type_check::Locations;
 
 crate mod graph;
 
diff --git a/compiler/rustc_mir/src/borrow_check/consumers.rs b/compiler/rustc_borrowck/src/consumers.rs
similarity index 100%
rename from compiler/rustc_mir/src/borrow_check/consumers.rs
rename to compiler/rustc_borrowck/src/consumers.rs
diff --git a/compiler/rustc_mir/src/dataflow/impls/borrows.rs b/compiler/rustc_borrowck/src/dataflow.rs
similarity index 79%
rename from compiler/rustc_mir/src/dataflow/impls/borrows.rs
rename to compiler/rustc_borrowck/src/dataflow.rs
index c92cff1433f1a50ef520de7fb21089063fea738d..cb440b2cbb9f4ed582fad09018ffa3551ebb0d97 100644
--- a/compiler/rustc_mir/src/dataflow/impls/borrows.rs
+++ b/compiler/rustc_borrowck/src/dataflow.rs
@@ -1,17 +1,110 @@
-use rustc_middle::mir::{self, Body, Location, Place};
-use rustc_middle::ty::RegionVid;
-use rustc_middle::ty::TyCtxt;
-
 use rustc_data_structures::fx::FxHashMap;
 use rustc_index::bit_set::BitSet;
+use rustc_middle::mir::{self, BasicBlock, Body, Location, Place};
+use rustc_middle::ty::RegionVid;
+use rustc_middle::ty::TyCtxt;
+use rustc_mir::dataflow::impls::{EverInitializedPlaces, MaybeUninitializedPlaces};
+use rustc_mir::dataflow::ResultsVisitable;
+use rustc_mir::dataflow::{self, fmt::DebugWithContext, GenKill};
+use rustc_mir::dataflow::{Analysis, Direction, Results};
+use std::fmt;
+use std::iter;
 
-use crate::borrow_check::{
+use crate::{
     places_conflict, BorrowSet, PlaceConflictBias, PlaceExt, RegionInferenceContext, ToRegionVid,
 };
-use crate::dataflow::{self, fmt::DebugWithContext, GenKill};
 
-use std::fmt;
-use std::iter;
+/// A tuple with named fields that can hold either the results or the transient state of the
+/// dataflow analyses used by the borrow checker.
+#[derive(Debug)]
+pub struct BorrowckAnalyses<B, U, E> {
+    pub borrows: B,
+    pub uninits: U,
+    pub ever_inits: E,
+}
+
+/// The results of the dataflow analyses used by the borrow checker.
+pub type BorrowckResults<'mir, 'tcx> = BorrowckAnalyses<
+    Results<'tcx, Borrows<'mir, 'tcx>>,
+    Results<'tcx, MaybeUninitializedPlaces<'mir, 'tcx>>,
+    Results<'tcx, EverInitializedPlaces<'mir, 'tcx>>,
+>;
+
+/// The transient state of the dataflow analyses used by the borrow checker.
+pub type BorrowckFlowState<'mir, 'tcx> =
+    <BorrowckResults<'mir, 'tcx> as ResultsVisitable<'tcx>>::FlowState;
+
+macro_rules! impl_visitable {
+    ( $(
+        $T:ident { $( $field:ident : $A:ident ),* $(,)? }
+    )* ) => { $(
+        impl<'tcx, $($A),*, D: Direction> ResultsVisitable<'tcx> for $T<$( Results<'tcx, $A> ),*>
+        where
+            $( $A: Analysis<'tcx, Direction = D>, )*
+        {
+            type Direction = D;
+            type FlowState = $T<$( $A::Domain ),*>;
+
+            fn new_flow_state(&self, body: &mir::Body<'tcx>) -> Self::FlowState {
+                $T {
+                    $( $field: self.$field.analysis.bottom_value(body) ),*
+                }
+            }
+
+            fn reset_to_block_entry(
+                &self,
+                state: &mut Self::FlowState,
+                block: BasicBlock,
+            ) {
+                $( state.$field.clone_from(&self.$field.entry_set_for_block(block)); )*
+            }
+
+            fn reconstruct_before_statement_effect(
+                &self,
+                state: &mut Self::FlowState,
+                stmt: &mir::Statement<'tcx>,
+                loc: Location,
+            ) {
+                $( self.$field.analysis
+                    .apply_before_statement_effect(&mut state.$field, stmt, loc); )*
+            }
+
+            fn reconstruct_statement_effect(
+                &self,
+                state: &mut Self::FlowState,
+                stmt: &mir::Statement<'tcx>,
+                loc: Location,
+            ) {
+                $( self.$field.analysis
+                    .apply_statement_effect(&mut state.$field, stmt, loc); )*
+            }
+
+            fn reconstruct_before_terminator_effect(
+                &self,
+                state: &mut Self::FlowState,
+                term: &mir::Terminator<'tcx>,
+                loc: Location,
+            ) {
+                $( self.$field.analysis
+                    .apply_before_terminator_effect(&mut state.$field, term, loc); )*
+            }
+
+            fn reconstruct_terminator_effect(
+                &self,
+                state: &mut Self::FlowState,
+                term: &mir::Terminator<'tcx>,
+                loc: Location,
+            ) {
+                $( self.$field.analysis
+                    .apply_terminator_effect(&mut state.$field, term, loc); )*
+            }
+        }
+    )* }
+}
+
+impl_visitable! {
+    BorrowckAnalyses { borrows: B, uninits: U, ever_inits: E }
+}
 
 rustc_index::newtype_index! {
     pub struct BorrowIndex {
diff --git a/compiler/rustc_mir/src/borrow_check/def_use.rs b/compiler/rustc_borrowck/src/def_use.rs
similarity index 100%
rename from compiler/rustc_mir/src/borrow_check/def_use.rs
rename to compiler/rustc_borrowck/src/def_use.rs
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/bound_region_errors.rs b/compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/diagnostics/bound_region_errors.rs
rename to compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs
index ac30093ba826015fba0f9859172857b2f2d3861b..76e779bfec608d25279bd40f4912cedb0e530332 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/bound_region_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs
@@ -14,8 +14,8 @@
 use std::fmt;
 use std::rc::Rc;
 
-use crate::borrow_check::region_infer::values::RegionElement;
-use crate::borrow_check::MirBorrowckCtxt;
+use crate::region_infer::values::RegionElement;
+use crate::MirBorrowckCtxt;
 
 #[derive(Clone)]
 crate struct UniverseInfo<'tcx>(UniverseInfoInner<'tcx>);
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/diagnostics/conflict_errors.rs
rename to compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
index 6561fe37c1c475b00f7520417c9199fedacd221a..8f6181f410df46e2c255ee34f9c5a32628cdbca7 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/conflict_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
@@ -15,11 +15,11 @@
 use rustc_span::{BytePos, MultiSpan, Span, DUMMY_SP};
 use rustc_trait_selection::infer::InferCtxtExt;
 
-use crate::dataflow::drop_flag_effects;
-use crate::dataflow::indexes::{MoveOutIndex, MovePathIndex};
-use crate::util::borrowck_errors;
+use crate::borrowck_errors;
+use rustc_mir::dataflow::drop_flag_effects;
+use rustc_mir::dataflow::move_paths::{MoveOutIndex, MovePathIndex};
 
-use crate::borrow_check::{
+use crate::{
     borrow_set::BorrowData, diagnostics::Instance, prefixes::IsPrefixOf,
     InitializationRequiringAction, MirBorrowckCtxt, PrefixSet, WriteKind,
 };
@@ -49,7 +49,7 @@ enum StorageDeadOrDrop<'tcx> {
 }
 
 impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
-    pub(in crate::borrow_check) fn report_use_of_moved_or_uninitialized(
+    pub(crate) fn report_use_of_moved_or_uninitialized(
         &mut self,
         location: Location,
         desired_action: InitializationRequiringAction,
@@ -441,7 +441,7 @@ pub(in crate::borrow_check) fn report_use_of_moved_or_uninitialized(
         }
     }
 
-    pub(in crate::borrow_check) fn report_move_out_while_borrowed(
+    pub(crate) fn report_move_out_while_borrowed(
         &mut self,
         location: Location,
         (place, span): (Place<'tcx>, Span),
@@ -489,7 +489,7 @@ pub(in crate::borrow_check) fn report_move_out_while_borrowed(
         err.buffer(&mut self.errors_buffer);
     }
 
-    pub(in crate::borrow_check) fn report_use_while_mutably_borrowed(
+    pub(crate) fn report_use_while_mutably_borrowed(
         &mut self,
         location: Location,
         (place, _span): (Place<'tcx>, Span),
@@ -535,7 +535,7 @@ pub(in crate::borrow_check) fn report_use_while_mutably_borrowed(
         err
     }
 
-    pub(in crate::borrow_check) fn report_conflicting_borrow(
+    pub(crate) fn report_conflicting_borrow(
         &mut self,
         location: Location,
         (place, span): (Place<'tcx>, Span),
@@ -798,7 +798,7 @@ fn suggest_split_at_mut_if_applicable(
     /// cannot borrow `a.u` (via `a.u.z.c`) as immutable because it is also borrowed as
     /// mutable (via `a.u.s.b`) [E0502]
     /// ```
-    pub(in crate::borrow_check) fn describe_place_for_conflicting_borrow(
+    pub(crate) fn describe_place_for_conflicting_borrow(
         &self,
         first_borrowed_place: Place<'tcx>,
         second_borrowed_place: Place<'tcx>,
@@ -875,7 +875,7 @@ pub(in crate::borrow_check) fn describe_place_for_conflicting_borrow(
     /// short a lifetime. (But sometimes it is more useful to report
     /// it as a more direct conflict between the execution of a
     /// `Drop::drop` with an aliasing borrow.)
-    pub(in crate::borrow_check) fn report_borrowed_value_does_not_live_long_enough(
+    pub(crate) fn report_borrowed_value_does_not_live_long_enough(
         &mut self,
         location: Location,
         borrow: &BorrowData<'tcx>,
@@ -1634,7 +1634,7 @@ fn predecessor_locations(
         (result, reinits_reachable)
     }
 
-    pub(in crate::borrow_check) fn report_illegal_mutation_of_borrowed(
+    pub(crate) fn report_illegal_mutation_of_borrowed(
         &mut self,
         location: Location,
         (place, span): (Place<'tcx>, Span),
@@ -1695,7 +1695,7 @@ fn explain_deref_coercion(&mut self, loan: &BorrowData<'tcx>, err: &mut Diagnost
             Some((method_did, method_substs)),
         ) = (
             &self.body[loan.reserve_location.block].terminator,
-            crate::util::find_self_call(
+            rustc_mir::util::find_self_call(
                 tcx,
                 self.body,
                 loan.assigned_place.local,
@@ -1726,7 +1726,7 @@ fn explain_deref_coercion(&mut self, loan: &BorrowData<'tcx>, err: &mut Diagnost
     /// assigned; `err_place` is a place providing a reason why
     /// `place` is not mutable (e.g., the non-`mut` local `x` in an
     /// assignment to `x.f`).
-    pub(in crate::borrow_check) fn report_illegal_reassignment(
+    pub(crate) fn report_illegal_reassignment(
         &mut self,
         _location: Location,
         (place, span): (Place<'tcx>, Span),
@@ -2226,7 +2226,7 @@ enum AnnotatedBorrowFnSignature<'tcx> {
 impl<'tcx> AnnotatedBorrowFnSignature<'tcx> {
     /// Annotate the provided diagnostic with information about borrow from the fn signature that
     /// helps explain.
-    pub(in crate::borrow_check) fn emit(
+    pub(crate) fn emit(
         &self,
         cx: &mut MirBorrowckCtxt<'_, 'tcx>,
         diag: &mut DiagnosticBuilder<'_>,
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/explain_borrow.rs b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
similarity index 98%
rename from compiler/rustc_mir/src/borrow_check/diagnostics/explain_borrow.rs
rename to compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
index f40a2db330a97062321e7ab72b26da575ab8a33f..2d12a682e7ae6d9c5c598fa1834b4b4b75f6b2e4 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/explain_borrow.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
@@ -15,8 +15,8 @@
 use rustc_span::symbol::Symbol;
 use rustc_span::Span;
 
-use crate::borrow_check::region_infer::BlameConstraint;
-use crate::borrow_check::{
+use crate::region_infer::BlameConstraint;
+use crate::{
     borrow_set::BorrowData, nll::ConstraintDescription, region_infer::Cause, MirBorrowckCtxt,
     WriteKind,
 };
@@ -24,7 +24,7 @@
 use super::{find_use, RegionName, UseSpans};
 
 #[derive(Debug)]
-pub(in crate::borrow_check) enum BorrowExplanation {
+pub(crate) enum BorrowExplanation {
     UsedLater(LaterUseKind, Span, Option<Span>),
     UsedLaterInLoop(LaterUseKind, Span, Option<Span>),
     UsedLaterWhenDropped {
@@ -43,7 +43,7 @@ pub(in crate::borrow_check) enum BorrowExplanation {
 }
 
 #[derive(Clone, Copy, Debug)]
-pub(in crate::borrow_check) enum LaterUseKind {
+pub(crate) enum LaterUseKind {
     TraitCapture,
     ClosureCapture,
     Call,
@@ -52,13 +52,13 @@ pub(in crate::borrow_check) enum LaterUseKind {
 }
 
 impl BorrowExplanation {
-    pub(in crate::borrow_check) fn is_explained(&self) -> bool {
+    pub(crate) fn is_explained(&self) -> bool {
         match self {
             BorrowExplanation::Unexplained => false,
             _ => true,
         }
     }
-    pub(in crate::borrow_check) fn add_explanation_to_diagnostic<'tcx>(
+    pub(crate) fn add_explanation_to_diagnostic<'tcx>(
         &self,
         tcx: TyCtxt<'tcx>,
         body: &Body<'tcx>,
@@ -267,7 +267,7 @@ pub(in crate::borrow_check) fn add_explanation_to_diagnostic<'tcx>(
             _ => {}
         }
     }
-    pub(in crate::borrow_check) fn add_lifetime_bound_suggestion_to_diagnostic(
+    pub(crate) fn add_lifetime_bound_suggestion_to_diagnostic(
         &self,
         err: &mut DiagnosticBuilder<'_>,
         category: &ConstraintCategory,
@@ -326,7 +326,7 @@ fn free_region_constraint_info(
     ///   - second half is the place being accessed
     ///
     /// [d]: https://rust-lang.github.io/rfcs/2094-nll.html#leveraging-intuition-framing-errors-in-terms-of-points
-    pub(in crate::borrow_check) fn explain_why_borrow_contains_point(
+    pub(crate) fn explain_why_borrow_contains_point(
         &self,
         location: Location,
         borrow: &BorrowData<'tcx>,
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/find_use.rs b/compiler/rustc_borrowck/src/diagnostics/find_use.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/diagnostics/find_use.rs
rename to compiler/rustc_borrowck/src/diagnostics/find_use.rs
index 8d8cdfb52934c3502927d63926a6df09d56fade1..ab4536f00fc4289d702989625a8ff46b44b60b5c 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/find_use.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/find_use.rs
@@ -1,7 +1,7 @@
 use std::collections::VecDeque;
 use std::rc::Rc;
 
-use crate::borrow_check::{
+use crate::{
     def_use::{self, DefUse},
     nll::ToRegionVid,
     region_infer::{Cause, RegionInferenceContext},
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/mod.rs b/compiler/rustc_borrowck/src/diagnostics/mod.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/diagnostics/mod.rs
rename to compiler/rustc_borrowck/src/diagnostics/mod.rs
index 55c6410ed320497730f7e1f90ae03f61a682e139..980894d6b4d0f5ee26d79f605107e47324b6abbd 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/mod.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mod.rs
@@ -12,6 +12,7 @@
 };
 use rustc_middle::ty::print::Print;
 use rustc_middle::ty::{self, DefIdTree, Instance, Ty, TyCtxt};
+use rustc_mir::dataflow::move_paths::{InitLocation, LookupResult};
 use rustc_span::{
     hygiene::{DesugaringKind, ForLoopLoc},
     symbol::sym,
@@ -21,7 +22,6 @@
 
 use super::borrow_set::BorrowData;
 use super::MirBorrowckCtxt;
-use crate::dataflow::move_paths::{InitLocation, LookupResult};
 
 mod find_use;
 mod outlives_suggestion;
@@ -899,9 +899,12 @@ pub(super) fn move_spans(
             kind: TerminatorKind::Call { fn_span, from_hir_call, .. }, ..
         }) = &self.body[location.block].terminator
         {
-            let (method_did, method_substs) = if let Some(info) =
-                crate::util::find_self_call(self.infcx.tcx, &self.body, target_temp, location.block)
-            {
+            let (method_did, method_substs) = if let Some(info) = rustc_mir::util::find_self_call(
+                self.infcx.tcx,
+                &self.body,
+                target_temp,
+                location.block,
+            ) {
                 info
             } else {
                 return normal_ret;
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/move_errors.rs b/compiler/rustc_borrowck/src/diagnostics/move_errors.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/diagnostics/move_errors.rs
rename to compiler/rustc_borrowck/src/diagnostics/move_errors.rs
index 66e06325fa982df6d564fa048a2284c2a10343c3..dd4886312da37a85c5b4371d361743b9f02d9016 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/move_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/move_errors.rs
@@ -2,16 +2,16 @@
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::mir::*;
 use rustc_middle::ty;
+use rustc_mir::dataflow::move_paths::{
+    IllegalMoveOrigin, IllegalMoveOriginKind, LookupResult, MoveError, MovePathIndex,
+};
 use rustc_span::source_map::DesugaringKind;
 use rustc_span::{sym, Span, DUMMY_SP};
 use rustc_trait_selection::traits::type_known_to_meet_bound_modulo_regions;
 
-use crate::borrow_check::diagnostics::UseSpans;
-use crate::borrow_check::prefixes::PrefixSet;
-use crate::borrow_check::MirBorrowckCtxt;
-use crate::dataflow::move_paths::{
-    IllegalMoveOrigin, IllegalMoveOriginKind, LookupResult, MoveError, MovePathIndex,
-};
+use crate::diagnostics::UseSpans;
+use crate::prefixes::PrefixSet;
+use crate::MirBorrowckCtxt;
 
 // Often when desugaring a pattern match we may have many individual moves in
 // MIR that are all part of one operation from the user's point-of-view. For
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/mutability_errors.rs b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/diagnostics/mutability_errors.rs
rename to compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
index 4e079ed865ac31d4f29ecaea2285fd8d86407811..b3578afbbb6354dbc9573e471b76039ad8884c3d 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/mutability_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
@@ -14,10 +14,10 @@
 use rustc_span::symbol::{kw, Symbol};
 use rustc_span::{BytePos, Span};
 
-use crate::borrow_check::diagnostics::BorrowedContentSource;
-use crate::borrow_check::MirBorrowckCtxt;
-use crate::util::collect_writes::FindAssignments;
+use crate::diagnostics::BorrowedContentSource;
+use crate::MirBorrowckCtxt;
 use rustc_errors::{Applicability, DiagnosticBuilder};
+use rustc_mir::util::collect_writes::FindAssignments;
 
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
 pub(crate) enum AccessKind {
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/outlives_suggestion.rs b/compiler/rustc_borrowck/src/diagnostics/outlives_suggestion.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/diagnostics/outlives_suggestion.rs
rename to compiler/rustc_borrowck/src/diagnostics/outlives_suggestion.rs
index 7dc3434bf333867fd21707db468d8d7ed4869b79..9de0c62f186c0f70ebb64880577e7fb55d39091c 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/outlives_suggestion.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/outlives_suggestion.rs
@@ -1,16 +1,14 @@
 //! Contains utilities for generating suggestions for borrowck errors related to unsatisfied
 //! outlives constraints.
 
-use std::collections::BTreeMap;
-
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::DiagnosticBuilder;
 use rustc_middle::ty::RegionVid;
-use tracing::debug;
-
 use smallvec::SmallVec;
+use std::collections::BTreeMap;
+use tracing::debug;
 
-use crate::borrow_check::MirBorrowckCtxt;
+use crate::MirBorrowckCtxt;
 
 use super::{ErrorConstraintInfo, RegionName, RegionNameSource};
 
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/region_errors.rs b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/diagnostics/region_errors.rs
rename to compiler/rustc_borrowck/src/diagnostics/region_errors.rs
index cbb8f064bb81ae6132770ca6ce15e2225f2d8215..57d2a3c5ce91bba441d81ad723ddcc02f02788fb 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/region_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs
@@ -11,10 +11,10 @@
 use rustc_span::symbol::{kw, sym};
 use rustc_span::{BytePos, Span};
 
-use crate::util::borrowck_errors;
+use crate::borrowck_errors;
 
-use crate::borrow_check::region_infer::BlameConstraint;
-use crate::borrow_check::{
+use crate::region_infer::BlameConstraint;
+use crate::{
     nll::ConstraintDescription,
     region_infer::{values::RegionElement, TypeTest},
     universal_regions::DefiningTy,
@@ -152,7 +152,7 @@ fn is_closure_fn_mut(&self, fr: RegionVid) -> bool {
     }
 
     /// Produces nice borrowck error diagnostics for all the errors collected in `nll_errors`.
-    pub(in crate::borrow_check) fn report_region_errors(&mut self, nll_errors: RegionErrors<'tcx>) {
+    pub(crate) fn report_region_errors(&mut self, nll_errors: RegionErrors<'tcx>) {
         // Iterate through all the errors, producing a diagnostic for each one. The diagnostics are
         // buffered in the `MirBorrowckCtxt`.
 
@@ -265,7 +265,7 @@ pub(in crate::borrow_check) fn report_region_errors(&mut self, nll_errors: Regio
     /// ```
     ///
     /// Here we would be invoked with `fr = 'a` and `outlived_fr = `'b`.
-    pub(in crate::borrow_check) fn report_region_error(
+    pub(crate) fn report_region_error(
         &mut self,
         fr: RegionVid,
         fr_origin: NllRegionVariableOrigin,
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/region_name.rs b/compiler/rustc_borrowck/src/diagnostics/region_name.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/diagnostics/region_name.rs
rename to compiler/rustc_borrowck/src/diagnostics/region_name.rs
index 1f168c612f16726f78b3f98ded96658f6be6926e..5edb52b0b650dca370cbced4b8c34a86a2d9def3 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/region_name.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/region_name.rs
@@ -10,7 +10,7 @@
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
 
-use crate::borrow_check::{nll::ToRegionVid, universal_regions::DefiningTy, MirBorrowckCtxt};
+use crate::{nll::ToRegionVid, universal_regions::DefiningTy, MirBorrowckCtxt};
 
 /// 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`.
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/var_name.rs b/compiler/rustc_borrowck/src/diagnostics/var_name.rs
similarity index 97%
rename from compiler/rustc_mir/src/borrow_check/diagnostics/var_name.rs
rename to compiler/rustc_borrowck/src/diagnostics/var_name.rs
index 4abc623fc5f371f15a768b3958681a0861d379eb..00f62806753556f477aec00a6280a662d27ba28b 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/var_name.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/var_name.rs
@@ -1,5 +1,5 @@
-use crate::borrow_check::Upvar;
-use crate::borrow_check::{nll::ToRegionVid, region_infer::RegionInferenceContext};
+use crate::Upvar;
+use crate::{nll::ToRegionVid, region_infer::RegionInferenceContext};
 use rustc_index::vec::{Idx, IndexVec};
 use rustc_middle::mir::{Body, Local};
 use rustc_middle::ty::{RegionVid, TyCtxt};
diff --git a/compiler/rustc_mir/src/borrow_check/facts.rs b/compiler/rustc_borrowck/src/facts.rs
similarity index 95%
rename from compiler/rustc_mir/src/borrow_check/facts.rs
rename to compiler/rustc_borrowck/src/facts.rs
index 215dead5bd15e3ced92ee4d06ce3b6b4522aa12f..ed3f846e4adc9d5024c63435294783b8c5b06c24 100644
--- a/compiler/rustc_mir/src/borrow_check/facts.rs
+++ b/compiler/rustc_borrowck/src/facts.rs
@@ -1,10 +1,11 @@
-use crate::borrow_check::location::{LocationIndex, LocationTable};
-use crate::dataflow::indexes::{BorrowIndex, MovePathIndex};
+use crate::location::{LocationIndex, LocationTable};
+use crate::BorrowIndex;
 use polonius_engine::AllFacts as PoloniusFacts;
 use polonius_engine::Atom;
 use rustc_index::vec::Idx;
 use rustc_middle::mir::Local;
 use rustc_middle::ty::{RegionVid, TyCtxt};
+use rustc_mir::dataflow::move_paths::MovePathIndex;
 use std::error::Error;
 use std::fmt::Debug;
 use std::fs::{self, File};
@@ -100,12 +101,6 @@ fn index(self) -> usize {
     }
 }
 
-impl Atom for MovePathIndex {
-    fn index(self) -> usize {
-        Idx::index(self)
-    }
-}
-
 struct FactWriter<'w> {
     location_table: &'w LocationTable,
     dir: &'w Path,
diff --git a/compiler/rustc_mir/src/borrow_check/invalidation.rs b/compiler/rustc_borrowck/src/invalidation.rs
similarity index 98%
rename from compiler/rustc_mir/src/borrow_check/invalidation.rs
rename to compiler/rustc_borrowck/src/invalidation.rs
index b83a427f4757475e80d00ec88afc03d4983b21e0..016fe0bb6dedffbe9ff419991993903f2c5cbde4 100644
--- a/compiler/rustc_mir/src/borrow_check/invalidation.rs
+++ b/compiler/rustc_borrowck/src/invalidation.rs
@@ -7,12 +7,10 @@
 use rustc_middle::ty::TyCtxt;
 use std::iter;
 
-use crate::dataflow::indexes::BorrowIndex;
-
-use crate::borrow_check::{
+use crate::{
     borrow_set::BorrowSet, facts::AllFacts, location::LocationTable, path_utils::*, AccessDepth,
-    Activation, ArtificialField, Deep, JustWrite, LocalMutationIsAllowed, MutateMode, Read,
-    ReadKind, ReadOrWrite, Reservation, Shallow, Write, WriteAndRead, WriteKind,
+    Activation, ArtificialField, BorrowIndex, Deep, JustWrite, LocalMutationIsAllowed, MutateMode,
+    Read, ReadKind, ReadOrWrite, Reservation, Shallow, Write, WriteAndRead, WriteKind,
 };
 
 pub(super) fn generate_invalidates<'tcx>(
diff --git a/compiler/rustc_mir/src/borrow_check/mod.rs b/compiler/rustc_borrowck/src/lib.rs
similarity index 98%
rename from compiler/rustc_mir/src/borrow_check/mod.rs
rename to compiler/rustc_borrowck/src/lib.rs
index 1dcb06765625899768022a79e169f4dfef0a690c..9fe3d79e4ed09582f27a1045e4b050118112cffa 100644
--- a/compiler/rustc_mir/src/borrow_check/mod.rs
+++ b/compiler/rustc_borrowck/src/lib.rs
@@ -1,5 +1,22 @@
 //! This query borrow-checks the MIR to (further) ensure it is not broken.
 
+#![feature(bool_to_option)]
+#![feature(box_patterns)]
+#![feature(const_panic)]
+#![feature(crate_visibility_modifier)]
+#![feature(format_args_capture)]
+#![feature(in_band_lifetimes)]
+#![feature(iter_zip)]
+#![feature(min_specialization)]
+#![feature(stmt_expr_attributes)]
+#![feature(trusted_step)]
+#![feature(try_blocks)]
+
+#[macro_use]
+extern crate rustc_middle;
+#[macro_use]
+extern crate tracing;
+
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::graph::dominators::Dominators;
 use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, ErrorReported};
@@ -29,14 +46,13 @@
 use std::mem;
 use std::rc::Rc;
 
-use crate::dataflow;
-use crate::dataflow::impls::{
-    Borrows, EverInitializedPlaces, MaybeInitializedPlaces, MaybeUninitializedPlaces,
+use rustc_mir::dataflow::impls::{
+    EverInitializedPlaces, MaybeInitializedPlaces, MaybeUninitializedPlaces,
 };
-use crate::dataflow::indexes::{BorrowIndex, InitIndex, MoveOutIndex, MovePathIndex};
-use crate::dataflow::move_paths::{InitLocation, LookupResult, MoveData, MoveError};
-use crate::dataflow::MoveDataParamEnv;
-use crate::dataflow::{Analysis, BorrowckFlowState as Flows, BorrowckResults};
+use rustc_mir::dataflow::move_paths::{InitIndex, MoveOutIndex, MovePathIndex};
+use rustc_mir::dataflow::move_paths::{InitLocation, LookupResult, MoveData, MoveError};
+use rustc_mir::dataflow::Analysis;
+use rustc_mir::dataflow::MoveDataParamEnv;
 
 use self::diagnostics::{AccessKind, RegionName};
 use self::location::LocationTable;
@@ -47,9 +63,10 @@
 use self::path_utils::*;
 
 mod borrow_set;
+mod borrowck_errors;
 mod constraint_generation;
 mod constraints;
-pub mod consumers;
+mod dataflow;
 mod def_use;
 mod diagnostics;
 mod facts;
@@ -67,15 +84,19 @@
 mod universal_regions;
 mod used_muts;
 
-crate use borrow_set::{BorrowData, BorrowSet};
-crate use nll::{PoloniusOutput, ToRegionVid};
-crate use place_ext::PlaceExt;
-crate use places_conflict::{places_conflict, PlaceConflictBias};
-crate use region_infer::RegionInferenceContext;
+// A public API provided for the Rust compiler consumers.
+pub mod consumers;
+
+use borrow_set::{BorrowData, BorrowSet};
+use dataflow::{BorrowIndex, BorrowckFlowState as Flows, BorrowckResults, Borrows};
+use nll::{PoloniusOutput, ToRegionVid};
+use place_ext::PlaceExt;
+use places_conflict::{places_conflict, PlaceConflictBias};
+use region_infer::RegionInferenceContext;
 
 // FIXME(eddyb) perhaps move this somewhere more centrally.
 #[derive(Debug)]
-crate struct Upvar<'tcx> {
+struct Upvar<'tcx> {
     place: CapturedPlace<'tcx>,
 
     /// If true, the capture is behind a reference.
@@ -352,7 +373,7 @@ fn do_mir_borrowck<'a, 'tcx>(
 
     mbcx.report_move_errors(move_errors);
 
-    dataflow::visit_results(
+    rustc_mir::dataflow::visit_results(
         &body,
         traversal::reverse_postorder(&body).map(|(bb, _)| bb),
         &results,
@@ -495,8 +516,8 @@ pub struct BodyWithBorrowckFacts<'tcx> {
     pub location_table: LocationTable,
 }
 
-crate struct MirBorrowckCtxt<'cx, 'tcx> {
-    crate infcx: &'cx InferCtxt<'cx, 'tcx>,
+struct MirBorrowckCtxt<'cx, 'tcx> {
+    infcx: &'cx InferCtxt<'cx, 'tcx>,
     param_env: ParamEnv<'tcx>,
     body: &'cx Body<'tcx>,
     move_data: &'cx MoveData<'tcx>,
@@ -594,7 +615,7 @@ pub struct BodyWithBorrowckFacts<'tcx> {
 // 2. loans made in overlapping scopes do not conflict
 // 3. assignments do not affect things loaned out as immutable
 // 4. moves do not affect things loaned out in any way
-impl<'cx, 'tcx> dataflow::ResultsVisitor<'cx, 'tcx> for MirBorrowckCtxt<'cx, 'tcx> {
+impl<'cx, 'tcx> rustc_mir::dataflow::ResultsVisitor<'cx, 'tcx> for MirBorrowckCtxt<'cx, 'tcx> {
     type FlowState = Flows<'cx, 'tcx>;
 
     fn visit_statement_before_primary_effect(
@@ -2344,7 +2365,7 @@ fn is_mutable(
     /// then returns the index of the field being projected. Note that this closure will always
     /// be `self` in the current MIR, because that is the only time we directly access the fields
     /// of a closure type.
-    pub fn is_upvar_field_projection(&self, place_ref: PlaceRef<'tcx>) -> Option<Field> {
+    fn is_upvar_field_projection(&self, place_ref: PlaceRef<'tcx>) -> Option<Field> {
         path_utils::is_upvar_field_projection(self.infcx.tcx, &self.upvars, place_ref, self.body())
     }
 }
diff --git a/compiler/rustc_mir/src/borrow_check/location.rs b/compiler/rustc_borrowck/src/location.rs
similarity index 100%
rename from compiler/rustc_mir/src/borrow_check/location.rs
rename to compiler/rustc_borrowck/src/location.rs
diff --git a/compiler/rustc_mir/src/borrow_check/member_constraints.rs b/compiler/rustc_borrowck/src/member_constraints.rs
similarity index 100%
rename from compiler/rustc_mir/src/borrow_check/member_constraints.rs
rename to compiler/rustc_borrowck/src/member_constraints.rs
diff --git a/compiler/rustc_mir/src/borrow_check/nll.rs b/compiler/rustc_borrowck/src/nll.rs
similarity index 97%
rename from compiler/rustc_mir/src/borrow_check/nll.rs
rename to compiler/rustc_borrowck/src/nll.rs
index 66ca94d3b415d644800462abf385349c43f5982f..d40990d4676bcf4ad9e38ae8d1f0160cae1795a8 100644
--- a/compiler/rustc_mir/src/borrow_check/nll.rs
+++ b/compiler/rustc_borrowck/src/nll.rs
@@ -20,13 +20,13 @@
 use self::mir_util::PassWhere;
 use polonius_engine::{Algorithm, Output};
 
-use crate::dataflow::impls::MaybeInitializedPlaces;
-use crate::dataflow::move_paths::{InitKind, InitLocation, MoveData};
-use crate::dataflow::ResultsCursor;
-use crate::util as mir_util;
-use crate::util::pretty;
+use rustc_mir::dataflow::impls::MaybeInitializedPlaces;
+use rustc_mir::dataflow::move_paths::{InitKind, InitLocation, MoveData};
+use rustc_mir::dataflow::ResultsCursor;
+use rustc_mir::util as mir_util;
+use rustc_mir::util::pretty;
 
-use crate::borrow_check::{
+use crate::{
     borrow_set::BorrowSet,
     constraint_generation,
     diagnostics::RegionErrors,
@@ -56,7 +56,7 @@
 /// Rewrites the regions in the MIR to use NLL variables, also scraping out the set of universal
 /// regions (e.g., region parameters) declared on the function. That set will need to be given to
 /// `compute_regions`.
-pub(in crate::borrow_check) fn replace_regions_in_mir<'cx, 'tcx>(
+pub(crate) fn replace_regions_in_mir<'cx, 'tcx>(
     infcx: &InferCtxt<'cx, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     body: &mut Body<'tcx>,
@@ -155,7 +155,7 @@ fn populate_polonius_move_facts(
 /// Computes the (non-lexical) regions from the input MIR.
 ///
 /// This may result in errors being reported.
-pub(in crate::borrow_check) fn compute_regions<'cx, 'tcx>(
+pub(crate) fn compute_regions<'cx, 'tcx>(
     infcx: &InferCtxt<'cx, 'tcx>,
     universal_regions: UniversalRegions<'tcx>,
     body: &Body<'tcx>,
diff --git a/compiler/rustc_mir/src/borrow_check/path_utils.rs b/compiler/rustc_borrowck/src/path_utils.rs
similarity index 96%
rename from compiler/rustc_mir/src/borrow_check/path_utils.rs
rename to compiler/rustc_borrowck/src/path_utils.rs
index 80de3b4e363bfb369a40b701ff9cf944e43df84a..d5d00b467eeed2bab3184a8724821b470edd9902 100644
--- a/compiler/rustc_mir/src/borrow_check/path_utils.rs
+++ b/compiler/rustc_borrowck/src/path_utils.rs
@@ -1,8 +1,8 @@
-use crate::borrow_check::borrow_set::{BorrowData, BorrowSet, TwoPhaseActivation};
-use crate::borrow_check::places_conflict;
-use crate::borrow_check::AccessDepth;
-use crate::borrow_check::Upvar;
-use crate::dataflow::indexes::BorrowIndex;
+use crate::borrow_set::{BorrowData, BorrowSet, TwoPhaseActivation};
+use crate::places_conflict;
+use crate::AccessDepth;
+use crate::BorrowIndex;
+use crate::Upvar;
 use rustc_data_structures::graph::dominators::Dominators;
 use rustc_middle::mir::BorrowKind;
 use rustc_middle::mir::{BasicBlock, Body, Field, Location, Place, PlaceRef, ProjectionElem};
diff --git a/compiler/rustc_mir/src/borrow_check/place_ext.rs b/compiler/rustc_borrowck/src/place_ext.rs
similarity index 98%
rename from compiler/rustc_mir/src/borrow_check/place_ext.rs
rename to compiler/rustc_borrowck/src/place_ext.rs
index 52fac3e53ee659fc3be18978d66cbd410be9fea1..83ff1595b0be44031dd044b5c2ba6d50dc372a22 100644
--- a/compiler/rustc_mir/src/borrow_check/place_ext.rs
+++ b/compiler/rustc_borrowck/src/place_ext.rs
@@ -1,4 +1,4 @@
-use crate::borrow_check::borrow_set::LocalsStateAtExit;
+use crate::borrow_set::LocalsStateAtExit;
 use rustc_hir as hir;
 use rustc_middle::mir::ProjectionElem;
 use rustc_middle::mir::{Body, Mutability, Place};
diff --git a/compiler/rustc_mir/src/borrow_check/places_conflict.rs b/compiler/rustc_borrowck/src/places_conflict.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/places_conflict.rs
rename to compiler/rustc_borrowck/src/places_conflict.rs
index d21550a8e1af60b5bb0564eae081fedc315ea0b8..773e9e90b0c6be85cfeebb0a2f788c1c17b3c30d 100644
--- a/compiler/rustc_mir/src/borrow_check/places_conflict.rs
+++ b/compiler/rustc_borrowck/src/places_conflict.rs
@@ -1,6 +1,6 @@
-use crate::borrow_check::ArtificialField;
-use crate::borrow_check::Overlap;
-use crate::borrow_check::{AccessDepth, Deep, Shallow};
+use crate::ArtificialField;
+use crate::Overlap;
+use crate::{AccessDepth, Deep, Shallow};
 use rustc_hir as hir;
 use rustc_middle::mir::{Body, BorrowKind, Local, Place, PlaceElem, PlaceRef, ProjectionElem};
 use rustc_middle::ty::{self, TyCtxt};
diff --git a/compiler/rustc_mir/src/borrow_check/prefixes.rs b/compiler/rustc_borrowck/src/prefixes.rs
similarity index 100%
rename from compiler/rustc_mir/src/borrow_check/prefixes.rs
rename to compiler/rustc_borrowck/src/prefixes.rs
diff --git a/compiler/rustc_mir/src/borrow_check/region_infer/dump_mir.rs b/compiler/rustc_borrowck/src/region_infer/dump_mir.rs
similarity index 98%
rename from compiler/rustc_mir/src/borrow_check/region_infer/dump_mir.rs
rename to compiler/rustc_borrowck/src/region_infer/dump_mir.rs
index 213ebff12abc0b65940e94f9845232c3c83cfa95..cfd3acb6bdebdf78a5b875ad7f9443ce6d438a08 100644
--- a/compiler/rustc_mir/src/borrow_check/region_infer/dump_mir.rs
+++ b/compiler/rustc_borrowck/src/region_infer/dump_mir.rs
@@ -4,7 +4,7 @@
 //! context internal state.
 
 use super::{OutlivesConstraint, RegionInferenceContext};
-use crate::borrow_check::type_check::Locations;
+use crate::type_check::Locations;
 use rustc_infer::infer::NllRegionVariableOrigin;
 use rustc_middle::ty::TyCtxt;
 use std::io::{self, Write};
diff --git a/compiler/rustc_mir/src/borrow_check/region_infer/graphviz.rs b/compiler/rustc_borrowck/src/region_infer/graphviz.rs
similarity index 98%
rename from compiler/rustc_mir/src/borrow_check/region_infer/graphviz.rs
rename to compiler/rustc_borrowck/src/region_infer/graphviz.rs
index b944d74e6f23137b3040974955e291d9ce70e26d..95048d50f117f733e4072615efc1ca3e740cd13c 100644
--- a/compiler/rustc_mir/src/borrow_check/region_infer/graphviz.rs
+++ b/compiler/rustc_borrowck/src/region_infer/graphviz.rs
@@ -6,7 +6,7 @@
 use std::io::{self, Write};
 
 use super::*;
-use crate::borrow_check::constraints::OutlivesConstraint;
+use crate::constraints::OutlivesConstraint;
 use rustc_graphviz as dot;
 
 impl<'tcx> RegionInferenceContext<'tcx> {
diff --git a/compiler/rustc_mir/src/borrow_check/region_infer/mod.rs b/compiler/rustc_borrowck/src/region_infer/mod.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/region_infer/mod.rs
rename to compiler/rustc_borrowck/src/region_infer/mod.rs
index a96cdbc13f345a2891feb89bb0f55f1f9622de66..48e45a9b1ce72e7f1559df69e847f627d7bb4e0c 100644
--- a/compiler/rustc_mir/src/borrow_check/region_infer/mod.rs
+++ b/compiler/rustc_borrowck/src/region_infer/mod.rs
@@ -17,7 +17,7 @@
 use rustc_middle::ty::{self, subst::SubstsRef, RegionVid, Ty, TyCtxt, TypeFoldable};
 use rustc_span::Span;
 
-use crate::borrow_check::{
+use crate::{
     constraints::{
         graph::NormalConstraintGraph, ConstraintSccIndex, OutlivesConstraint, OutlivesConstraintSet,
     },
@@ -132,33 +132,33 @@ pub(crate) struct AppliedMemberConstraint {
     ///
     /// The vector if `AppliedMemberConstraint` elements is kept sorted
     /// by this field.
-    pub(in crate::borrow_check) member_region_scc: ConstraintSccIndex,
+    pub(crate) member_region_scc: ConstraintSccIndex,
 
     /// The "best option" that `apply_member_constraint` found -- this was
     /// added as an "ad-hoc" lower-bound to `member_region_scc`.
-    pub(in crate::borrow_check) min_choice: ty::RegionVid,
+    pub(crate) min_choice: ty::RegionVid,
 
     /// The "member constraint index" -- we can find out details about
     /// the constraint from
     /// `set.member_constraints[member_constraint_index]`.
-    pub(in crate::borrow_check) member_constraint_index: NllMemberConstraintIndex,
+    pub(crate) member_constraint_index: NllMemberConstraintIndex,
 }
 
 pub(crate) struct RegionDefinition<'tcx> {
     /// What kind of variable is this -- a free region? existential
     /// variable? etc. (See the `NllRegionVariableOrigin` for more
     /// info.)
-    pub(in crate::borrow_check) origin: NllRegionVariableOrigin,
+    pub(crate) origin: NllRegionVariableOrigin,
 
     /// Which universe is this region variable defined in? This is
     /// most often `ty::UniverseIndex::ROOT`, but when we encounter
     /// forall-quantifiers like `for<'a> { 'a = 'b }`, we would create
     /// the variable for `'a` in a fresh universe that extends ROOT.
-    pub(in crate::borrow_check) universe: ty::UniverseIndex,
+    pub(crate) universe: ty::UniverseIndex,
 
     /// If this is 'static or an early-bound region, then this is
     /// `Some(X)` where `X` is the name of the region.
-    pub(in crate::borrow_check) external_name: Option<ty::Region<'tcx>>,
+    pub(crate) external_name: Option<ty::Region<'tcx>>,
 }
 
 /// N.B., the variants in `Cause` are intentionally ordered. Lower
@@ -245,7 +245,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     ///
     /// The `outlives_constraints` and `type_tests` are an initial set
     /// of constraints produced by the MIR type check.
-    pub(in crate::borrow_check) fn new(
+    pub(crate) fn new(
         var_infos: VarInfos,
         universal_regions: Rc<UniversalRegions<'tcx>>,
         placeholder_indices: Rc<PlaceholderIndices>,
@@ -534,7 +534,7 @@ pub fn to_region_vid(&self, r: ty::Region<'tcx>) -> RegionVid {
     /// Once region solving has completed, this function will return
     /// the member constraints that were applied to the value of a given
     /// region `r`. See `AppliedMemberConstraint`.
-    pub(in crate::borrow_check) fn applied_member_constraints(
+    pub(crate) fn applied_member_constraints(
         &self,
         r: impl ToRegionVid,
     ) -> &[AppliedMemberConstraint] {
@@ -1088,7 +1088,7 @@ fn non_local_universal_upper_bound(&self, r: RegionVid) -> RegionVid {
     ///   include the CFG anyhow.
     /// - For each `end('x)` element in `'r`, compute the mutual LUB, yielding
     ///   a result `'y`.
-    pub(in crate::borrow_check) fn universal_upper_bound(&self, r: RegionVid) -> RegionVid {
+    pub(crate) fn universal_upper_bound(&self, r: RegionVid) -> RegionVid {
         debug!("universal_upper_bound(r={:?}={})", r, self.region_value_str(r));
 
         // Find the smallest universal region that contains all other
@@ -1115,7 +1115,7 @@ pub(in crate::borrow_check) fn universal_upper_bound(&self, r: RegionVid) -> Reg
     /// Therefore, this method should only be used in diagnostic code,
     /// where displaying *some* named universal region is better than
     /// falling back to 'static.
-    pub(in crate::borrow_check) fn approx_universal_upper_bound(&self, r: RegionVid) -> RegionVid {
+    pub(crate) fn approx_universal_upper_bound(&self, r: RegionVid) -> RegionVid {
         debug!("approx_universal_upper_bound(r={:?}={})", r, self.region_value_str(r));
 
         // Find the smallest universal region that contains all other
diff --git a/compiler/rustc_mir/src/borrow_check/region_infer/opaque_types.rs b/compiler/rustc_borrowck/src/region_infer/opaque_types.rs
similarity index 97%
rename from compiler/rustc_mir/src/borrow_check/region_infer/opaque_types.rs
rename to compiler/rustc_borrowck/src/region_infer/opaque_types.rs
index 12fceeff0884c92a8f4f8ada963004d36b86c8f8..39b83e5043101bbde09f54f02f7f1862dc3c7b43 100644
--- a/compiler/rustc_mir/src/borrow_check/region_infer/opaque_types.rs
+++ b/compiler/rustc_borrowck/src/region_infer/opaque_types.rs
@@ -47,7 +47,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     /// which has no `external_name` in which case we use `'empty` as the
     /// region to pass to `infer_opaque_definition_from_instantiation`.
     #[instrument(skip(self, infcx))]
-    pub(in crate::borrow_check) fn infer_opaque_types(
+    pub(crate) fn infer_opaque_types(
         &self,
         infcx: &InferCtxt<'_, 'tcx>,
         opaque_ty_decls: VecMap<OpaqueTypeKey<'tcx>, Ty<'tcx>>,
@@ -105,7 +105,7 @@ pub(in crate::borrow_check) fn infer_opaque_types(
     /// that the regions produced are in fact equal to the named region they are
     /// replaced with. This is fine because this function is only to improve the
     /// region names in error messages.
-    pub(in crate::borrow_check) fn name_regions<T>(&self, tcx: TyCtxt<'tcx>, ty: T) -> T
+    pub(crate) fn name_regions<T>(&self, tcx: TyCtxt<'tcx>, ty: T) -> T
     where
         T: TypeFoldable<'tcx>,
     {
diff --git a/compiler/rustc_mir/src/borrow_check/region_infer/reverse_sccs.rs b/compiler/rustc_borrowck/src/region_infer/reverse_sccs.rs
similarity index 95%
rename from compiler/rustc_mir/src/borrow_check/region_infer/reverse_sccs.rs
rename to compiler/rustc_borrowck/src/region_infer/reverse_sccs.rs
index 5d345a6e63d6b1c8394abd53452dfcfe03676742..056907dcb16563a5daf40ddffa64485e97d96a3d 100644
--- a/compiler/rustc_mir/src/borrow_check/region_infer/reverse_sccs.rs
+++ b/compiler/rustc_borrowck/src/region_infer/reverse_sccs.rs
@@ -1,5 +1,5 @@
-use crate::borrow_check::constraints::ConstraintSccIndex;
-use crate::borrow_check::RegionInferenceContext;
+use crate::constraints::ConstraintSccIndex;
+use crate::RegionInferenceContext;
 use itertools::Itertools;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::graph::vec_graph::VecGraph;
diff --git a/compiler/rustc_mir/src/borrow_check/region_infer/values.rs b/compiler/rustc_borrowck/src/region_infer/values.rs
similarity index 100%
rename from compiler/rustc_mir/src/borrow_check/region_infer/values.rs
rename to compiler/rustc_borrowck/src/region_infer/values.rs
diff --git a/compiler/rustc_mir/src/borrow_check/renumber.rs b/compiler/rustc_borrowck/src/renumber.rs
similarity index 100%
rename from compiler/rustc_mir/src/borrow_check/renumber.rs
rename to compiler/rustc_borrowck/src/renumber.rs
diff --git a/compiler/rustc_mir/src/borrow_check/type_check/canonical.rs b/compiler/rustc_borrowck/src/type_check/canonical.rs
similarity index 98%
rename from compiler/rustc_mir/src/borrow_check/type_check/canonical.rs
rename to compiler/rustc_borrowck/src/type_check/canonical.rs
index b501716a899752b41db2117da612e6ada703ff34..7a8c0a3da1f1f4854370e6982b9243463fe3a69a 100644
--- a/compiler/rustc_mir/src/borrow_check/type_check/canonical.rs
+++ b/compiler/rustc_borrowck/src/type_check/canonical.rs
@@ -8,7 +8,7 @@
 use rustc_trait_selection::traits::query::type_op::{self, TypeOpOutput};
 use rustc_trait_selection::traits::query::Fallible;
 
-use crate::borrow_check::diagnostics::{ToUniverseInfo, UniverseInfo};
+use crate::diagnostics::{ToUniverseInfo, UniverseInfo};
 
 use super::{Locations, NormalizeLocation, TypeChecker};
 
diff --git a/compiler/rustc_mir/src/borrow_check/type_check/constraint_conversion.rs b/compiler/rustc_borrowck/src/type_check/constraint_conversion.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/type_check/constraint_conversion.rs
rename to compiler/rustc_borrowck/src/type_check/constraint_conversion.rs
index 446a0f8e72fbd9bf1c869589879e099db7c7a94d..b020746848535899733852039c543ac07d71164c 100644
--- a/compiler/rustc_mir/src/borrow_check/type_check/constraint_conversion.rs
+++ b/compiler/rustc_borrowck/src/type_check/constraint_conversion.rs
@@ -9,7 +9,7 @@
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_span::DUMMY_SP;
 
-use crate::borrow_check::{
+use crate::{
     constraints::OutlivesConstraint,
     nll::ToRegionVid,
     region_infer::TypeTest,
diff --git a/compiler/rustc_mir/src/borrow_check/type_check/free_region_relations.rs b/compiler/rustc_borrowck/src/type_check/free_region_relations.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/type_check/free_region_relations.rs
rename to compiler/rustc_borrowck/src/type_check/free_region_relations.rs
index 6426098d843fe80fd2dd709de1a3dcd3b7fc7fab..e1e8f6a61adb817038607d3c103394d97c29e531 100644
--- a/compiler/rustc_mir/src/borrow_check/type_check/free_region_relations.rs
+++ b/compiler/rustc_borrowck/src/type_check/free_region_relations.rs
@@ -13,7 +13,7 @@
 use std::rc::Rc;
 use type_op::TypeOpOutput;
 
-use crate::borrow_check::{
+use crate::{
     nll::ToRegionVid,
     type_check::constraint_conversion,
     type_check::{Locations, MirTypeckRegionConstraints},
@@ -55,7 +55,7 @@
 type NormalizedInputsAndOutput<'tcx> = Vec<Ty<'tcx>>;
 
 crate struct CreateResult<'tcx> {
-    pub(in crate::borrow_check) universal_region_relations: Frozen<UniversalRegionRelations<'tcx>>,
+    crate universal_region_relations: Frozen<UniversalRegionRelations<'tcx>>,
     crate region_bound_pairs: RegionBoundPairs<'tcx>,
     crate normalized_inputs_and_output: NormalizedInputsAndOutput<'tcx>,
 }
diff --git a/compiler/rustc_mir/src/borrow_check/type_check/input_output.rs b/compiler/rustc_borrowck/src/type_check/input_output.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/type_check/input_output.rs
rename to compiler/rustc_borrowck/src/type_check/input_output.rs
index ba9b6926526be010208f568415a9602c2043c62f..9d6f6f60a94f91976edabb4f5c5174614750cb49 100644
--- a/compiler/rustc_mir/src/borrow_check/type_check/input_output.rs
+++ b/compiler/rustc_borrowck/src/type_check/input_output.rs
@@ -7,16 +7,15 @@
 //! `RETURN_PLACE` the MIR arguments) are always fully normalized (and
 //! contain revealed `impl Trait` values).
 
+use rustc_index::vec::Idx;
 use rustc_infer::infer::LateBoundRegionConversionTime;
 use rustc_middle::mir::*;
 use rustc_middle::traits::ObligationCause;
 use rustc_middle::ty::{self, Ty};
-use rustc_trait_selection::traits::query::normalize::AtExt;
-
-use rustc_index::vec::Idx;
 use rustc_span::Span;
+use rustc_trait_selection::traits::query::normalize::AtExt;
 
-use crate::borrow_check::universal_regions::UniversalRegions;
+use crate::universal_regions::UniversalRegions;
 
 use super::{Locations, TypeChecker};
 
diff --git a/compiler/rustc_mir/src/borrow_check/type_check/liveness/local_use_map.rs b/compiler/rustc_borrowck/src/type_check/liveness/local_use_map.rs
similarity index 97%
rename from compiler/rustc_mir/src/borrow_check/type_check/liveness/local_use_map.rs
rename to compiler/rustc_borrowck/src/type_check/liveness/local_use_map.rs
index 7e8a33efe114ef6fb6a275c5a1b2a1fb70c170a2..8b74abd94c07711ee3f6a541e8bb546a35ecd274 100644
--- a/compiler/rustc_mir/src/borrow_check/type_check/liveness/local_use_map.rs
+++ b/compiler/rustc_borrowck/src/type_check/liveness/local_use_map.rs
@@ -3,8 +3,8 @@
 use rustc_middle::mir::visit::{PlaceContext, Visitor};
 use rustc_middle::mir::{Body, Local, Location};
 
-use crate::borrow_check::def_use::{self, DefUse};
-use crate::borrow_check::region_infer::values::{PointIndex, RegionValueElements};
+use crate::def_use::{self, DefUse};
+use crate::region_infer::values::{PointIndex, RegionValueElements};
 
 /// A map that cross references each local with the locations where it
 /// is defined (assigned), used, or dropped. Used during liveness
diff --git a/compiler/rustc_mir/src/borrow_check/type_check/liveness/mod.rs b/compiler/rustc_borrowck/src/type_check/liveness/mod.rs
similarity index 96%
rename from compiler/rustc_mir/src/borrow_check/type_check/liveness/mod.rs
rename to compiler/rustc_borrowck/src/type_check/liveness/mod.rs
index a34ae281b70dfdd547ed652226264299e0f37a1f..265c14bb28676c961685e00811f33f0c4e475696 100644
--- a/compiler/rustc_mir/src/borrow_check/type_check/liveness/mod.rs
+++ b/compiler/rustc_borrowck/src/type_check/liveness/mod.rs
@@ -3,11 +3,11 @@
 use rustc_middle::ty::{RegionVid, TyCtxt};
 use std::rc::Rc;
 
-use crate::dataflow::impls::MaybeInitializedPlaces;
-use crate::dataflow::move_paths::MoveData;
-use crate::dataflow::ResultsCursor;
+use rustc_mir::dataflow::impls::MaybeInitializedPlaces;
+use rustc_mir::dataflow::move_paths::MoveData;
+use rustc_mir::dataflow::ResultsCursor;
 
-use crate::borrow_check::{
+use crate::{
     constraints::OutlivesConstraintSet,
     facts::{AllFacts, AllFactsExt},
     location::LocationTable,
diff --git a/compiler/rustc_mir/src/borrow_check/type_check/liveness/polonius.rs b/compiler/rustc_borrowck/src/type_check/liveness/polonius.rs
similarity index 96%
rename from compiler/rustc_mir/src/borrow_check/type_check/liveness/polonius.rs
rename to compiler/rustc_borrowck/src/type_check/liveness/polonius.rs
index d285098c52ad2097c9aca8d8296b61533b153a6d..7c087d38eb748d1095ad352383b17065fdc86d5e 100644
--- a/compiler/rustc_mir/src/borrow_check/type_check/liveness/polonius.rs
+++ b/compiler/rustc_borrowck/src/type_check/liveness/polonius.rs
@@ -1,10 +1,9 @@
-use crate::borrow_check::def_use::{self, DefUse};
-use crate::borrow_check::location::{LocationIndex, LocationTable};
-use crate::dataflow::indexes::MovePathIndex;
-use crate::dataflow::move_paths::{LookupResult, MoveData};
+use crate::def_use::{self, DefUse};
+use crate::location::{LocationIndex, LocationTable};
 use rustc_middle::mir::visit::{MutatingUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::{Body, Local, Location, Place};
 use rustc_middle::ty::subst::GenericArg;
+use rustc_mir::dataflow::move_paths::{LookupResult, MoveData, MovePathIndex};
 
 use super::TypeChecker;
 
diff --git a/compiler/rustc_mir/src/borrow_check/type_check/liveness/trace.rs b/compiler/rustc_borrowck/src/type_check/liveness/trace.rs
similarity index 98%
rename from compiler/rustc_mir/src/borrow_check/type_check/liveness/trace.rs
rename to compiler/rustc_borrowck/src/type_check/liveness/trace.rs
index 566c11811e6e1108267411a5d79c688ed0809946..c7d776bfde0d4b552eff940998580f4d76bc4317 100644
--- a/compiler/rustc_mir/src/borrow_check/type_check/liveness/trace.rs
+++ b/compiler/rustc_borrowck/src/type_check/liveness/trace.rs
@@ -8,12 +8,11 @@
 use rustc_trait_selection::traits::query::type_op::{TypeOp, TypeOpOutput};
 use std::rc::Rc;
 
-use crate::dataflow::impls::MaybeInitializedPlaces;
-use crate::dataflow::indexes::MovePathIndex;
-use crate::dataflow::move_paths::{HasMoveData, MoveData};
-use crate::dataflow::ResultsCursor;
+use rustc_mir::dataflow::impls::MaybeInitializedPlaces;
+use rustc_mir::dataflow::move_paths::{HasMoveData, MoveData, MovePathIndex};
+use rustc_mir::dataflow::ResultsCursor;
 
-use crate::borrow_check::{
+use crate::{
     region_infer::values::{self, PointIndex, RegionValueElements},
     type_check::liveness::local_use_map::LocalUseMap,
     type_check::liveness::polonius,
diff --git a/compiler/rustc_mir/src/borrow_check/type_check/mod.rs b/compiler/rustc_borrowck/src/type_check/mod.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/type_check/mod.rs
rename to compiler/rustc_borrowck/src/type_check/mod.rs
index 639bcb8fa94efb7f3768665349a0508e5b703efe..63075d066a6dc8718ef526e0dd8bbb98b152f26d 100644
--- a/compiler/rustc_mir/src/borrow_check/type_check/mod.rs
+++ b/compiler/rustc_borrowck/src/type_check/mod.rs
@@ -41,14 +41,14 @@
 use rustc_trait_selection::traits::query::Fallible;
 use rustc_trait_selection::traits::{self, ObligationCause, PredicateObligations};
 
-use crate::dataflow::impls::MaybeInitializedPlaces;
-use crate::dataflow::move_paths::MoveData;
-use crate::dataflow::ResultsCursor;
-use crate::transform::{
+use rustc_mir::dataflow::impls::MaybeInitializedPlaces;
+use rustc_mir::dataflow::move_paths::MoveData;
+use rustc_mir::dataflow::ResultsCursor;
+use rustc_mir::transform::{
     check_consts::ConstCx, promote_consts::is_const_fn_in_array_repeat_expression,
 };
 
-use crate::borrow_check::{
+use crate::{
     borrow_set::BorrowSet,
     constraints::{OutlivesConstraint, OutlivesConstraintSet},
     diagnostics::UniverseInfo,
@@ -68,7 +68,7 @@
 
 macro_rules! span_mirbug {
     ($context:expr, $elem:expr, $($message:tt)*) => ({
-        $crate::borrow_check::type_check::mirbug(
+        $crate::type_check::mirbug(
             $context.tcx(),
             $context.last_span,
             &format!(
@@ -887,7 +887,7 @@ struct BorrowCheckContext<'a, 'tcx> {
 
 crate struct MirTypeckResults<'tcx> {
     crate constraints: MirTypeckRegionConstraints<'tcx>,
-    pub(in crate::borrow_check) universal_region_relations: Frozen<UniversalRegionRelations<'tcx>>,
+    crate universal_region_relations: Frozen<UniversalRegionRelations<'tcx>>,
     crate opaque_type_values: VecMap<OpaqueTypeKey<'tcx>, Ty<'tcx>>,
 }
 
diff --git a/compiler/rustc_mir/src/borrow_check/type_check/relate_tys.rs b/compiler/rustc_borrowck/src/type_check/relate_tys.rs
similarity index 96%
rename from compiler/rustc_mir/src/borrow_check/type_check/relate_tys.rs
rename to compiler/rustc_borrowck/src/type_check/relate_tys.rs
index 971c4daa6b311ae49ce41629b202f1fba271d230..0b9c33ccb775a96ad7fe411259aaa6ba7bbd609e 100644
--- a/compiler/rustc_mir/src/borrow_check/type_check/relate_tys.rs
+++ b/compiler/rustc_borrowck/src/type_check/relate_tys.rs
@@ -5,9 +5,9 @@
 use rustc_middle::ty::{self, Const, Ty};
 use rustc_trait_selection::traits::query::Fallible;
 
-use crate::borrow_check::constraints::OutlivesConstraint;
-use crate::borrow_check::diagnostics::UniverseInfo;
-use crate::borrow_check::type_check::{BorrowCheckContext, Locations};
+use crate::constraints::OutlivesConstraint;
+use crate::diagnostics::UniverseInfo;
+use crate::type_check::{BorrowCheckContext, Locations};
 
 /// Adds sufficient constraints to ensure that `a R b` where `R` depends on `v`:
 ///
diff --git a/compiler/rustc_mir/src/borrow_check/universal_regions.rs b/compiler/rustc_borrowck/src/universal_regions.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/universal_regions.rs
rename to compiler/rustc_borrowck/src/universal_regions.rs
index 3c9b4272b36497dc3fe826d9986e2c182ba2c5b1..bebd19370299d00cdf360796c578638612f80312 100644
--- a/compiler/rustc_mir/src/borrow_check/universal_regions.rs
+++ b/compiler/rustc_borrowck/src/universal_regions.rs
@@ -26,7 +26,7 @@
 use rustc_middle::ty::{self, RegionVid, Ty, TyCtxt};
 use std::iter;
 
-use crate::borrow_check::nll::ToRegionVid;
+use crate::nll::ToRegionVid;
 
 #[derive(Debug)]
 pub struct UniversalRegions<'tcx> {
diff --git a/compiler/rustc_mir/src/borrow_check/used_muts.rs b/compiler/rustc_borrowck/src/used_muts.rs
similarity index 99%
rename from compiler/rustc_mir/src/borrow_check/used_muts.rs
rename to compiler/rustc_borrowck/src/used_muts.rs
index e027056842db97d20cf69c0109df7def59377a78..6022a9809502b2fc79b1e98f77f80884f657526c 100644
--- a/compiler/rustc_mir/src/borrow_check/used_muts.rs
+++ b/compiler/rustc_borrowck/src/used_muts.rs
@@ -1,11 +1,10 @@
+use rustc_data_structures::fx::FxHashSet;
 use rustc_middle::mir::visit::{PlaceContext, Visitor};
 use rustc_middle::mir::{
     Local, Location, Place, Statement, StatementKind, Terminator, TerminatorKind,
 };
 
-use rustc_data_structures::fx::FxHashSet;
-
-use crate::borrow_check::MirBorrowckCtxt;
+use crate::MirBorrowckCtxt;
 
 impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     /// Walks the MIR adding to the set of `used_mut` locals that will be ignored for the purposes
diff --git a/compiler/rustc_interface/Cargo.toml b/compiler/rustc_interface/Cargo.toml
index dad5b256e42ab84316fc659ce2d21538602e0ed1..970267d626cd82cca970e9f71be23c0b6ecd8cfc 100644
--- a/compiler/rustc_interface/Cargo.toml
+++ b/compiler/rustc_interface/Cargo.toml
@@ -14,6 +14,7 @@ rayon = { version = "0.3.1", package = "rustc-rayon" }
 smallvec = { version = "1.6.1", features = ["union", "may_dangle"] }
 rustc_ast = { path = "../rustc_ast" }
 rustc_attr = { path = "../rustc_attr" }
+rustc_borrowck = { path = "../rustc_borrowck" }
 rustc_builtin_macros = { path = "../rustc_builtin_macros" }
 rustc_expand = { path = "../rustc_expand" }
 rustc_parse = { path = "../rustc_parse" }
diff --git a/compiler/rustc_interface/src/passes.rs b/compiler/rustc_interface/src/passes.rs
index 1d542db9b69c3eef068d2f40b1707f3038a0f5d9..df03ff59f461ac2b129f489c5243a70f0c7c5c2c 100644
--- a/compiler/rustc_interface/src/passes.rs
+++ b/compiler/rustc_interface/src/passes.rs
@@ -4,6 +4,7 @@
 
 use rustc_ast::mut_visit::MutVisitor;
 use rustc_ast::{self as ast, visit};
+use rustc_borrowck as mir_borrowck;
 use rustc_codegen_ssa::back::link::emit_metadata;
 use rustc_codegen_ssa::traits::CodegenBackend;
 use rustc_data_structures::parallel;
@@ -739,6 +740,7 @@ pub fn prepare_outputs(
     proc_macro_decls::provide(providers);
     rustc_middle::hir::provide(providers);
     mir::provide(providers);
+    mir_borrowck::provide(providers);
     mir_build::provide(providers);
     rustc_privacy::provide(providers);
     typeck::provide(providers);
diff --git a/compiler/rustc_mir/Cargo.toml b/compiler/rustc_mir/Cargo.toml
index 3049fb3b383b30292f7438823c476758e9998206..43c7b681e05f2209b6d47a951ea9a70f4a77ccee 100644
--- a/compiler/rustc_mir/Cargo.toml
+++ b/compiler/rustc_mir/Cargo.toml
@@ -8,30 +8,28 @@ doctest = false
 
 [dependencies]
 either = "1.5.0"
-rustc_graphviz = { path = "../rustc_graphviz" }
 gsgdt = "0.1.2"
 itertools = "0.9"
-tracing = "0.1"
 polonius-engine = "0.13.0"
 regex = "1"
-rustc_middle = { path = "../rustc_middle" }
+smallvec = { version = "1.0", features = ["union", "may_dangle"] }
+tracing = "0.1"
+rustc_apfloat = { path = "../rustc_apfloat" }
+rustc_ast = { path = "../rustc_ast" }
 rustc_attr = { path = "../rustc_attr" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
+rustc_graphviz = { path = "../rustc_graphviz" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_index = { path = "../rustc_index" }
 rustc_infer = { path = "../rustc_infer" }
-rustc_lexer = { path = "../rustc_lexer" }
 rustc_macros = { path = "../rustc_macros" }
+rustc_middle = { path = "../rustc_middle" }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_session = { path = "../rustc_session" }
 rustc_target = { path = "../rustc_target" }
 rustc_trait_selection = { path = "../rustc_trait_selection" }
-rustc_traits = { path = "../rustc_traits" }
-rustc_ast = { path = "../rustc_ast" }
 rustc_span = { path = "../rustc_span" }
-rustc_apfloat = { path = "../rustc_apfloat" }
-smallvec = { version = "1.6.1", features = ["union", "may_dangle"] }
 
 [dev-dependencies]
 coverage_test_macros = { path = "src/transform/coverage/test_macros" }
diff --git a/compiler/rustc_mir/src/dataflow/drop_flag_effects.rs b/compiler/rustc_mir/src/dataflow/drop_flag_effects.rs
index d16366fded900fe343ccc8e0c24419a934a10551..d4f8f994ae90414eecd838c3270574e5b8ecebd0 100644
--- a/compiler/rustc_mir/src/dataflow/drop_flag_effects.rs
+++ b/compiler/rustc_mir/src/dataflow/drop_flag_effects.rs
@@ -204,7 +204,7 @@ pub(crate) fn drop_flag_effects_for_location<'tcx, F>(
     for_location_inits(tcx, body, move_data, loc, |mpi| callback(mpi, DropFlagState::Present));
 }
 
-pub(crate) fn for_location_inits<'tcx, F>(
+pub fn for_location_inits<'tcx, F>(
     tcx: TyCtxt<'tcx>,
     body: &Body<'tcx>,
     move_data: &MoveData<'tcx>,
diff --git a/compiler/rustc_mir/src/dataflow/framework/mod.rs b/compiler/rustc_mir/src/dataflow/framework/mod.rs
index a5badc07d1017518a42456588a323fba799f1793..0bf62db1adac9339af42840e17d841026b438356 100644
--- a/compiler/rustc_mir/src/dataflow/framework/mod.rs
+++ b/compiler/rustc_mir/src/dataflow/framework/mod.rs
@@ -50,8 +50,7 @@
 pub use self::direction::{Backward, Direction, Forward};
 pub use self::engine::{Engine, Results};
 pub use self::lattice::{JoinSemiLattice, MeetSemiLattice};
-pub use self::visitor::{visit_results, ResultsVisitor};
-pub use self::visitor::{BorrowckFlowState, BorrowckResults};
+pub use self::visitor::{visit_results, ResultsVisitable, ResultsVisitor};
 
 /// Define the domain of a dataflow problem.
 ///
diff --git a/compiler/rustc_mir/src/dataflow/framework/visitor.rs b/compiler/rustc_mir/src/dataflow/framework/visitor.rs
index 82eb734ed0699a2ae00f18635b59c9414cf552a3..84136c4d78cf1e495bd739b48b181a88936d6882 100644
--- a/compiler/rustc_mir/src/dataflow/framework/visitor.rs
+++ b/compiler/rustc_mir/src/dataflow/framework/visitor.rs
@@ -1,7 +1,6 @@
 use rustc_middle::mir::{self, BasicBlock, Location};
 
 use super::{Analysis, Direction, Results};
-use crate::dataflow::impls::{borrows::Borrows, EverInitializedPlaces, MaybeUninitializedPlaces};
 
 /// Calls the corresponding method in `ResultsVisitor` for every location in a `mir::Body` with the
 /// dataflow state at that location.
@@ -186,95 +185,3 @@ fn reconstruct_terminator_effect(
         self.analysis.apply_terminator_effect(state, term, loc);
     }
 }
-
-/// A tuple with named fields that can hold either the results or the transient state of the
-/// dataflow analyses used by the borrow checker.
-#[derive(Debug)]
-pub struct BorrowckAnalyses<B, U, E> {
-    pub borrows: B,
-    pub uninits: U,
-    pub ever_inits: E,
-}
-
-/// The results of the dataflow analyses used by the borrow checker.
-pub type BorrowckResults<'mir, 'tcx> = BorrowckAnalyses<
-    Results<'tcx, Borrows<'mir, 'tcx>>,
-    Results<'tcx, MaybeUninitializedPlaces<'mir, 'tcx>>,
-    Results<'tcx, EverInitializedPlaces<'mir, 'tcx>>,
->;
-
-/// The transient state of the dataflow analyses used by the borrow checker.
-pub type BorrowckFlowState<'mir, 'tcx> =
-    <BorrowckResults<'mir, 'tcx> as ResultsVisitable<'tcx>>::FlowState;
-
-macro_rules! impl_visitable {
-    ( $(
-        $T:ident { $( $field:ident : $A:ident ),* $(,)? }
-    )* ) => { $(
-        impl<'tcx, $($A),*, D: Direction> ResultsVisitable<'tcx> for $T<$( Results<'tcx, $A> ),*>
-        where
-            $( $A: Analysis<'tcx, Direction = D>, )*
-        {
-            type Direction = D;
-            type FlowState = $T<$( $A::Domain ),*>;
-
-            fn new_flow_state(&self, body: &mir::Body<'tcx>) -> Self::FlowState {
-                $T {
-                    $( $field: self.$field.analysis.bottom_value(body) ),*
-                }
-            }
-
-            fn reset_to_block_entry(
-                &self,
-                state: &mut Self::FlowState,
-                block: BasicBlock,
-            ) {
-                $( state.$field.clone_from(&self.$field.entry_set_for_block(block)); )*
-            }
-
-            fn reconstruct_before_statement_effect(
-                &self,
-                state: &mut Self::FlowState,
-                stmt: &mir::Statement<'tcx>,
-                loc: Location,
-            ) {
-                $( self.$field.analysis
-                    .apply_before_statement_effect(&mut state.$field, stmt, loc); )*
-            }
-
-            fn reconstruct_statement_effect(
-                &self,
-                state: &mut Self::FlowState,
-                stmt: &mir::Statement<'tcx>,
-                loc: Location,
-            ) {
-                $( self.$field.analysis
-                    .apply_statement_effect(&mut state.$field, stmt, loc); )*
-            }
-
-            fn reconstruct_before_terminator_effect(
-                &self,
-                state: &mut Self::FlowState,
-                term: &mir::Terminator<'tcx>,
-                loc: Location,
-            ) {
-                $( self.$field.analysis
-                    .apply_before_terminator_effect(&mut state.$field, term, loc); )*
-            }
-
-            fn reconstruct_terminator_effect(
-                &self,
-                state: &mut Self::FlowState,
-                term: &mir::Terminator<'tcx>,
-                loc: Location,
-            ) {
-                $( self.$field.analysis
-                    .apply_terminator_effect(&mut state.$field, term, loc); )*
-            }
-        }
-    )* }
-}
-
-impl_visitable! {
-    BorrowckAnalyses { borrows: B, uninits: U, ever_inits: E }
-}
diff --git a/compiler/rustc_mir/src/dataflow/impls/mod.rs b/compiler/rustc_mir/src/dataflow/impls/mod.rs
index 185f0edfeb6bcbeaf6aab1f17c8fb43104510b2d..020a7b188fd1339d64cd33388954ac4dd5ac8a77 100644
--- a/compiler/rustc_mir/src/dataflow/impls/mod.rs
+++ b/compiler/rustc_mir/src/dataflow/impls/mod.rs
@@ -21,13 +21,11 @@
 use crate::dataflow::framework::SwitchIntEdgeEffects;
 
 mod borrowed_locals;
-pub(super) mod borrows;
 mod init_locals;
 mod liveness;
 mod storage_liveness;
 
 pub use self::borrowed_locals::{MaybeBorrowedLocals, MaybeMutBorrowedLocals};
-pub use self::borrows::Borrows;
 pub use self::init_locals::MaybeInitializedLocals;
 pub use self::liveness::MaybeLiveLocals;
 pub use self::storage_liveness::{MaybeRequiresStorage, MaybeStorageLive};
diff --git a/compiler/rustc_mir/src/dataflow/mod.rs b/compiler/rustc_mir/src/dataflow/mod.rs
index 8a426cc1015ccbdd4ae0562156a611fba8400c64..bb38f90a3ba63557266b2e610dc3986fbdb0a18d 100644
--- a/compiler/rustc_mir/src/dataflow/mod.rs
+++ b/compiler/rustc_mir/src/dataflow/mod.rs
@@ -5,9 +5,9 @@
 
 pub(crate) use self::drop_flag_effects::*;
 pub use self::framework::{
-    fmt, graphviz, lattice, visit_results, Analysis, AnalysisDomain, Backward, BorrowckFlowState,
-    BorrowckResults, Engine, Forward, GenKill, GenKillAnalysis, JoinSemiLattice, Results,
-    ResultsCursor, ResultsRefCursor, ResultsVisitor, SwitchIntEdgeEffects,
+    fmt, lattice, visit_results, Analysis, AnalysisDomain, Backward, Direction, Engine, Forward,
+    GenKill, GenKillAnalysis, JoinSemiLattice, Results, ResultsCursor, ResultsRefCursor,
+    ResultsVisitable, ResultsVisitor,
 };
 
 use self::move_paths::MoveData;
@@ -18,15 +18,12 @@
 pub mod move_paths;
 
 pub(crate) mod indexes {
-    pub(crate) use super::{
-        impls::borrows::BorrowIndex,
-        move_paths::{InitIndex, MoveOutIndex, MovePathIndex},
-    };
+    pub(crate) use super::move_paths::MovePathIndex;
 }
 
 pub struct MoveDataParamEnv<'tcx> {
-    pub(crate) move_data: MoveData<'tcx>,
-    pub(crate) param_env: ty::ParamEnv<'tcx>,
+    pub move_data: MoveData<'tcx>,
+    pub param_env: ty::ParamEnv<'tcx>,
 }
 
 pub(crate) fn has_rustc_mir_with(
diff --git a/compiler/rustc_mir/src/dataflow/move_paths/mod.rs b/compiler/rustc_mir/src/dataflow/move_paths/mod.rs
index 7c630259186032e245999763c8184d41b68214ce..699ec4bbff80fa788ad305ada8cc0c4c4f25c9ca 100644
--- a/compiler/rustc_mir/src/dataflow/move_paths/mod.rs
+++ b/compiler/rustc_mir/src/dataflow/move_paths/mod.rs
@@ -19,6 +19,12 @@ pub struct MovePathIndex {
     }
 }
 
+impl polonius_engine::Atom for MovePathIndex {
+    fn index(self) -> usize {
+        rustc_index::vec::Idx::index(self)
+    }
+}
+
 rustc_index::newtype_index! {
     pub struct MoveOutIndex {
         DEBUG_FORMAT = "mo{}"
@@ -276,7 +282,7 @@ fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
 }
 
 impl Init {
-    crate fn span<'tcx>(&self, body: &Body<'tcx>) -> Span {
+    pub fn span<'tcx>(&self, body: &Body<'tcx>) -> Span {
         match self.location {
             InitLocation::Argument(local) => body.local_decls[local].source_info.span,
             InitLocation::Statement(location) => body.source_info(location).span,
@@ -338,12 +344,12 @@ pub fn iter_locals_enumerated(&self) -> Enumerated<Local, Iter<'_, MovePathIndex
 
 #[derive(Debug)]
 pub struct IllegalMoveOrigin<'tcx> {
-    pub(crate) location: Location,
-    pub(crate) kind: IllegalMoveOriginKind<'tcx>,
+    pub location: Location,
+    pub kind: IllegalMoveOriginKind<'tcx>,
 }
 
 #[derive(Debug)]
-pub(crate) enum IllegalMoveOriginKind<'tcx> {
+pub enum IllegalMoveOriginKind<'tcx> {
     /// Illegal move due to attempt to move from behind a reference.
     BorrowedContent {
         /// The place the reference refers to: if erroneous code was trying to
diff --git a/compiler/rustc_mir/src/lib.rs b/compiler/rustc_mir/src/lib.rs
index e439a247c7f6cbdd036dc0f66be9c4ca94f49b5a..16dddc949df31e971fb456f67fd90a8c6c7278a3 100644
--- a/compiler/rustc_mir/src/lib.rs
+++ b/compiler/rustc_mir/src/lib.rs
@@ -4,40 +4,35 @@
 
 */
 
-#![feature(nll)]
-#![feature(in_band_lifetimes)]
 #![feature(array_windows)]
 #![feature(assert_matches)]
 #![cfg_attr(bootstrap, feature(bindings_after_at))]
+#![feature(associated_type_defaults)]
 #![feature(bool_to_option)]
 #![feature(box_patterns)]
+#![feature(control_flow_enum)]
 #![feature(crate_visibility_modifier)]
 #![feature(decl_macro)]
 #![feature(exact_size_is_empty)]
-#![feature(format_args_capture)]
+#![feature(in_band_lifetimes)]
 #![feature(iter_zip)]
-#![feature(never_type)]
 #![feature(map_try_insert)]
 #![feature(min_specialization)]
 #![feature(slice_ptr_get)]
-#![feature(trusted_len)]
-#![feature(try_blocks)]
-#![feature(associated_type_defaults)]
-#![feature(stmt_expr_attributes)]
-#![feature(trait_alias)]
 #![feature(option_get_or_insert_default)]
 #![feature(once_cell)]
-#![feature(control_flow_enum)]
-#![feature(try_reserve)]
-#![feature(try_reserve_kind)]
-#![recursion_limit = "256"]
+#![feature(never_type)]
+#![feature(stmt_expr_attributes)]
+#![feature(trait_alias)]
+#![feature(trusted_len)]
+#![feature(trusted_step)]
+#![feature(try_blocks)]
 
 #[macro_use]
 extern crate tracing;
 #[macro_use]
 extern crate rustc_middle;
 
-mod borrow_check;
 pub mod const_eval;
 pub mod dataflow;
 pub mod interpret;
@@ -46,13 +41,9 @@
 pub mod transform;
 pub mod util;
 
-// A public API provided for the Rust compiler consumers.
-pub use self::borrow_check::consumers;
-
 use rustc_middle::ty::query::Providers;
 
 pub fn provide(providers: &mut Providers) {
-    borrow_check::provide(providers);
     const_eval::provide(providers);
     shim::provide(providers);
     transform::provide(providers);
diff --git a/compiler/rustc_mir/src/transform/promote_consts.rs b/compiler/rustc_mir/src/transform/promote_consts.rs
index 1b43670ba3ac103eaa3021f0b2e2a0c7c69545c7..6822ad2d7b5dd0d3e02f0f9a2029b407bd249839 100644
--- a/compiler/rustc_mir/src/transform/promote_consts.rs
+++ b/compiler/rustc_mir/src/transform/promote_consts.rs
@@ -1058,7 +1058,7 @@ pub fn promote_candidates<'tcx>(
 
 /// This function returns `true` if the function being called in the array
 /// repeat expression is a `const` function.
-crate fn is_const_fn_in_array_repeat_expression<'tcx>(
+pub fn is_const_fn_in_array_repeat_expression<'tcx>(
     ccx: &ConstCx<'_, 'tcx>,
     place: &Place<'tcx>,
     body: &Body<'tcx>,
diff --git a/compiler/rustc_mir/src/util/collect_writes.rs b/compiler/rustc_mir/src/util/collect_writes.rs
index ecf3b08a96eedd1573a99d7826975da8bb8416c2..9c56fd722bda619d9da2c54104acf74999b2949b 100644
--- a/compiler/rustc_mir/src/util/collect_writes.rs
+++ b/compiler/rustc_mir/src/util/collect_writes.rs
@@ -2,7 +2,7 @@
 use rustc_middle::mir::visit::Visitor;
 use rustc_middle::mir::{Body, Local, Location};
 
-crate trait FindAssignments {
+pub trait FindAssignments {
     // Finds all statements that assign directly to local (i.e., X = ...)
     // and returns their locations.
     fn find_assignments(&self, local: Local) -> Vec<Location>;
diff --git a/compiler/rustc_mir/src/util/mod.rs b/compiler/rustc_mir/src/util/mod.rs
index 3e466b5060febad46d9057bbf047054bad41eb37..8f9db6daba7336e0e161734d384f04e71d8954bc 100644
--- a/compiler/rustc_mir/src/util/mod.rs
+++ b/compiler/rustc_mir/src/util/mod.rs
@@ -1,5 +1,4 @@
 pub mod aggregate;
-pub mod borrowck_errors;
 pub mod elaborate_drops;
 pub mod patch;
 pub mod storage;
@@ -10,7 +9,7 @@
 mod generic_graph;
 pub(crate) mod generic_graphviz;
 mod graphviz;
-pub(crate) mod pretty;
+pub mod pretty;
 pub(crate) mod spanview;
 
 pub use self::aggregate::expand_aggregate;
diff --git a/compiler/rustc_mir/src/util/pretty.rs b/compiler/rustc_mir/src/util/pretty.rs
index 92591db668ce9b7a6f0e9b74ec0b8b48133f648c..ec1aa5b476bb7df8c8ca723f3befb991d42b8b0d 100644
--- a/compiler/rustc_mir/src/util/pretty.rs
+++ b/compiler/rustc_mir/src/util/pretty.rs
@@ -250,7 +250,7 @@ fn create_dump_file_with_basename(
 /// bit of MIR-related data. Used by `mir-dump`, but also by other
 /// bits of code (e.g., NLL inference) that dump graphviz data or
 /// other things, and hence takes the extension as an argument.
-pub(crate) fn create_dump_file(
+pub fn create_dump_file(
     tcx: TyCtxt<'_>,
     extension: &str,
     pass_num: Option<&dyn Display>,