convert type-check constraints into NLL constraints on the fly

We used to accumulate a vector of type-check constraints, but now we
generate them as we go, and just store the NLL-style
`OutlivesConstraint` and `TypeTest` information.

7 files changed, 339 insertions, 266 deletions

diff --git a/src/librustc_data_structures/indexed_vec.rs b/src/librustc_data_structures/indexed_vec.rs
index 1fb63afc72f..ad3710e9536 100644
--- a/src/librustc_data_structures/indexed_vec.rs
+++ b/src/librustc_data_structures/indexed_vec.rs
@@ -368,6 +368,11 @@ impl<I: Idx, T> IndexVec<I, T> {
     }
 
     #[inline]
+    pub fn from_raw(raw: Vec<T>) -> Self {
+        IndexVec { raw, _marker: PhantomData }
+    }
+
+    #[inline]
     pub fn with_capacity(capacity: usize) -> Self {
         IndexVec { raw: Vec::with_capacity(capacity), _marker: PhantomData }
     }
diff --git a/src/librustc_mir/borrow_check/nll/constraint_generation.rs b/src/librustc_mir/borrow_check/nll/constraint_generation.rs
index 4f87a2b30ae..72db9f8da98 100644
--- a/src/librustc_mir/borrow_check/nll/constraint_generation.rs
+++ b/src/librustc_mir/borrow_check/nll/constraint_generation.rs
@@ -11,6 +11,8 @@
 use borrow_check::borrow_set::BorrowSet;
 use borrow_check::location::LocationTable;
 use borrow_check::nll::facts::AllFacts;
+use borrow_check::nll::region_infer::{Cause, RegionInferenceContext};
+use borrow_check::nll::ToRegionVid;
 use rustc::hir;
 use rustc::infer::InferCtxt;
 use rustc::mir::visit::TyContext;
@@ -21,9 +23,7 @@ use rustc::mir::{Local, PlaceProjection, ProjectionElem, Statement, Terminator};
 use rustc::ty::fold::TypeFoldable;
 use rustc::ty::subst::Substs;
 use rustc::ty::{self, CanonicalTy, ClosureSubsts, GeneratorSubsts};
-
-use super::region_infer::{Cause, RegionInferenceContext};
-use super::ToRegionVid;
+use std::iter;
 
 pub(super) fn generate_constraints<'cx, 'gcx, 'tcx>(
     infcx: &InferCtxt<'cx, 'gcx, 'tcx>,
@@ -32,6 +32,7 @@ pub(super) fn generate_constraints<'cx, 'gcx, 'tcx>(
     location_table: &LocationTable,
     mir: &Mir<'tcx>,
     borrow_set: &BorrowSet<'tcx>,
+    liveness_set_from_typeck: &[(ty::Region<'tcx>, Location, Cause)],
 ) {
     let mut cg = ConstraintGeneration {
         borrow_set,
@@ -42,6 +43,8 @@ pub(super) fn generate_constraints<'cx, 'gcx, 'tcx>(
         mir,
     };
 
+    cg.add_region_liveness_constraints_from_type_check(liveness_set_from_typeck);
+
     for (bb, data) in mir.basic_blocks().iter_enumerated() {
         cg.visit_basic_block_data(bb, data);
     }
@@ -209,7 +212,7 @@ impl<'cg, 'cx, 'gcx, 'tcx> Visitor<'tcx> for ConstraintGeneration<'cg, 'cx, 'gcx
                 self.add_reborrow_constraint(location, region, borrowed_place);
             }
 
-            _ => { }
+            _ => {}
         }
 
         self.super_rvalue(rvalue, location);
@@ -225,6 +228,42 @@ impl<'cg, 'cx, 'gcx, 'tcx> Visitor<'tcx> for ConstraintGeneration<'cg, 'cx, 'gcx
 }
 
 impl<'cx, 'cg, 'gcx, 'tcx> ConstraintGeneration<'cx, 'cg, 'gcx, 'tcx> {
+    /// The MIR type checker generates region liveness constraints
+    /// that we also have to respect.
+    fn add_region_liveness_constraints_from_type_check(
+        &mut self,
+        liveness_set: &[(ty::Region<'tcx>, Location, Cause)],
+    ) {
+        debug!(
+            "add_region_liveness_constraints_from_type_check(liveness_set={} items)",
+            liveness_set.len(),
+        );
+
+        let ConstraintGeneration {
+            regioncx,
+            location_table,
+            all_facts,
+            ..
+        } = self;
+
+        for (region, location, cause) in liveness_set {
+            debug!("generate: {:#?} is live at {:#?}", region, location);
+            let region_vid = regioncx.to_region_vid(region);
+            regioncx.add_live_point(region_vid, *location, &cause);
+        }
+
+        if let Some(all_facts) = all_facts {
+            all_facts
+                .region_live_at
+                .extend(liveness_set.into_iter().flat_map(|(region, location, _)| {
+                    let r = regioncx.to_region_vid(region);
+                    let p1 = location_table.start_index(*location);
+                    let p2 = location_table.mid_index(*location);
+                    iter::once((r, p1)).chain(iter::once((r, p2)))
+                }));
+        }
+    }
+
     /// Some variable with type `live_ty` is "regular live" at
     /// `location` -- i.e., it may be used later. This means that all
     /// regions appearing in the type `live_ty` must be live at
diff --git a/src/librustc_mir/borrow_check/nll/mod.rs b/src/librustc_mir/borrow_check/nll/mod.rs
index c3d9dd8378d..dcb52a3b18a 100644
--- a/src/librustc_mir/borrow_check/nll/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/mod.rs
@@ -11,6 +11,7 @@
 use borrow_check::borrow_set::BorrowSet;
 use borrow_check::location::{LocationIndex, LocationTable};
 use borrow_check::nll::facts::AllFactsExt;
+use borrow_check::nll::type_check::MirTypeckRegionConstraints;
 use dataflow::indexes::BorrowIndex;
 use dataflow::move_paths::MoveData;
 use dataflow::FlowAtLocation;
@@ -41,7 +42,6 @@ mod facts;
 mod invalidation;
 crate mod region_infer;
 mod renumber;
-mod subtype_constraint_generation;
 crate mod type_check;
 mod universal_regions;
 
@@ -91,46 +91,53 @@ pub(in borrow_check) fn compute_regions<'cx, 'gcx, 'tcx>(
     Option<Rc<Output<RegionVid, BorrowIndex, LocationIndex>>>,
     Option<ClosureRegionRequirements<'gcx>>,
 ) {
+    let mut all_facts = if infcx.tcx.sess.opts.debugging_opts.nll_facts
+        || infcx.tcx.sess.opts.debugging_opts.polonius
+    {
+        Some(AllFacts::default())
+    } else {
+        None
+    };
+
     // Run the MIR type-checker.
     let liveness = &LivenessResults::compute(mir);
-    let constraint_sets = &type_check::type_check(
+    let constraint_sets = type_check::type_check(
         infcx,
         param_env,
         mir,
         def_id,
         &universal_regions,
+        location_table,
         &liveness,
+        &mut all_facts,
         flow_inits,
         move_data,
     );
 
-    let mut all_facts = if infcx.tcx.sess.opts.debugging_opts.nll_facts
-        || infcx.tcx.sess.opts.debugging_opts.polonius
-    {
-        Some(AllFacts::default())
-    } else {
-        None
-    };
-
     if let Some(all_facts) = &mut all_facts {
         all_facts
             .universal_region
             .extend(universal_regions.universal_regions());
     }
 
-    // Create the region inference context, taking ownership of the region inference
-    // data that was contained in `infcx`.
+    // Create the region inference context, taking ownership of the
+    // region inference data that was contained in `infcx`, and the
+    // base constraints generated by the type-check.
     let var_origins = infcx.take_region_var_origins();
-    let mut regioncx = RegionInferenceContext::new(var_origins, universal_regions, mir);
-
-    // Generate various constraints.
-    subtype_constraint_generation::generate(
-        &mut regioncx,
-        &mut all_facts,
-        location_table,
+    let MirTypeckRegionConstraints {
+        liveness_set,
+        outlives_constraints,
+        type_tests,
+    } = constraint_sets;
+    let mut regioncx = RegionInferenceContext::new(
+        var_origins,
+        universal_regions,
         mir,
-        constraint_sets,
+        outlives_constraints,
+        type_tests,
     );
+
+    // Generate various additional constraints.
     constraint_generation::generate_constraints(
         infcx,
         &mut regioncx,
@@ -138,6 +145,7 @@ pub(in borrow_check) fn compute_regions<'cx, 'gcx, 'tcx>(
         location_table,
         &mir,
         borrow_set,
+        &liveness_set,
     );
     invalidation::generate_invalidates(
         infcx,
diff --git a/src/librustc_mir/borrow_check/nll/region_infer/mod.rs b/src/librustc_mir/borrow_check/nll/region_infer/mod.rs
index d974a60c15c..f123d421700 100644
--- a/src/librustc_mir/borrow_check/nll/region_infer/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/region_infer/mod.rs
@@ -123,15 +123,14 @@ pub struct OutlivesConstraint {
     // it is for convenience. Before we dump the constraints in the
     // debugging logs, we sort them, and we'd like the "super region"
     // to be first, etc. (In particular, span should remain last.)
-
     /// The region SUP must outlive SUB...
-    sup: RegionVid,
+    pub sup: RegionVid,
 
     /// Region that must be outlived.
-    sub: RegionVid,
+    pub sub: RegionVid,
 
     /// At this location.
-    point: Location,
+    pub point: Location,
 
     /// Later on, we thread the constraints onto a linked list
     /// grouped by their `sub` field. So if you had:
@@ -141,10 +140,10 @@ pub struct OutlivesConstraint {
     /// 0     | `'a: 'b`   | Some(2)
     /// 1     | `'b: 'c`   | None
     /// 2     | `'c: 'b`   | None
-    next: Option<ConstraintIndex>,
+    pub next: Option<ConstraintIndex>,
 
     /// Where did this constraint arise?
-    span: Span,
+    pub span: Span,
 }
 
 newtype_index!(ConstraintIndex { DEBUG_FORMAT = "ConstraintIndex({})" });
@@ -240,11 +239,19 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     /// `num_region_variables` valid inference variables; the first N
     /// of those will be constant regions representing the free
     /// regions defined in `universal_regions`.
+    ///
+    /// The `outlives_constraints` and `type_tests` are an initial set
+    /// of constraints produced by the MIR type check.
     pub(crate) fn new(
         var_infos: VarInfos,
         universal_regions: UniversalRegions<'tcx>,
         mir: &Mir<'tcx>,
+        outlives_constraints: Vec<OutlivesConstraint>,
+        type_tests: Vec<TypeTest<'tcx>>,
     ) -> Self {
+        // The `next` field should not yet have been initialized:
+        debug_assert!(outlives_constraints.iter().all(|c| c.next.is_none()));
+
         let num_region_variables = var_infos.len();
         let num_universal_regions = universal_regions.len();
 
@@ -262,8 +269,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
             liveness_constraints: RegionValues::new(elements, num_region_variables),
             inferred_values: None,
             dependency_map: None,
-            constraints: IndexVec::new(),
-            type_tests: Vec::new(),
+            constraints: IndexVec::from_raw(outlives_constraints),
+            type_tests,
             universal_regions,
         };
 
@@ -346,7 +353,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     where
         R: ToRegionVid,
     {
-        let inferred_values = self.inferred_values
+        let inferred_values = self
+            .inferred_values
             .as_ref()
             .expect("region values not yet inferred");
         inferred_values.contains(r.to_region_vid(), p)
@@ -354,7 +362,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
 
     /// Returns access to the value of `r` for debugging purposes.
     crate fn region_value_str(&self, r: RegionVid) -> String {
-        let inferred_values = self.inferred_values
+        let inferred_values = self
+            .inferred_values
             .as_ref()
             .expect("region values not yet inferred");
 
@@ -397,11 +406,6 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         });
     }
 
-    /// Add a "type test" that must be satisfied.
-    pub(super) fn add_type_test(&mut self, type_test: TypeTest<'tcx>) {
-        self.type_tests.push(type_test);
-    }
-
     /// Perform region inference and report errors if we see any
     /// unsatisfiable constraints. If this is a closure, returns the
     /// region requirements to propagate to our creator, if any.
@@ -596,7 +600,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         if self.universal_regions.is_universal_region(r) {
             return self.definitions[r].external_name;
         } else {
-            let inferred_values = self.inferred_values
+            let inferred_values = self
+                .inferred_values
                 .as_ref()
                 .expect("region values not yet inferred");
             let upper_bound = self.universal_upper_bound(r);
@@ -635,8 +640,11 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         // region, which ensures it can be encoded in a `ClosureOutlivesRequirement`.
         let lower_bound_plus = self.non_local_universal_upper_bound(*lower_bound);
         assert!(self.universal_regions.is_universal_region(lower_bound_plus));
-        assert!(!self.universal_regions
-            .is_local_free_region(lower_bound_plus));
+        assert!(
+            !self
+                .universal_regions
+                .is_local_free_region(lower_bound_plus)
+        );
 
         propagated_outlives_requirements.push(ClosureOutlivesRequirement {
             subject,
@@ -664,7 +672,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     ) -> Option<ClosureOutlivesSubject<'gcx>> {
         let tcx = infcx.tcx;
         let gcx = tcx.global_tcx();
-        let inferred_values = self.inferred_values
+        let inferred_values = self
+            .inferred_values
             .as_ref()
             .expect("region values not yet inferred");
 
@@ -845,7 +854,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
             sup_region, sub_region, point
         );
 
-        let inferred_values = self.inferred_values
+        let inferred_values = self
+            .inferred_values
             .as_ref()
             .expect("values for regions not yet inferred");
 
@@ -912,7 +922,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     ) {
         // The universal regions are always found in a prefix of the
         // full list.
-        let universal_definitions = self.definitions
+        let universal_definitions = self
+            .definitions
             .iter_enumerated()
             .take_while(|(_, fr_definition)| fr_definition.is_universal);
 
diff --git a/src/librustc_mir/borrow_check/nll/subtype_constraint_generation.rs b/src/librustc_mir/borrow_check/nll/subtype_constraint_generation.rs
deleted file mode 100644
index fd445c62e4e..00000000000
--- a/src/librustc_mir/borrow_check/nll/subtype_constraint_generation.rs
+++ /dev/null
@@ -1,199 +0,0 @@
-// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-use borrow_check::location::LocationTable;
-use borrow_check::nll::facts::AllFacts;
-use rustc::infer::region_constraints::Constraint;
-use rustc::infer::region_constraints::RegionConstraintData;
-use rustc::infer::region_constraints::{Verify, VerifyBound};
-use rustc::mir::{Location, Mir};
-use rustc::ty;
-use std::iter;
-use syntax::codemap::Span;
-
-use super::region_infer::{RegionInferenceContext, RegionTest, TypeTest};
-use super::type_check::Locations;
-use super::type_check::MirTypeckRegionConstraints;
-use super::type_check::OutlivesSet;
-
-/// When the MIR type-checker executes, it validates all the types in
-/// the MIR, and in the process generates a set of constraints that
-/// must hold regarding the regions in the MIR, along with locations
-/// *where* they must hold. This code takes those constriants and adds
-/// them into the NLL `RegionInferenceContext`.
-pub(super) fn generate<'tcx>(
-    regioncx: &mut RegionInferenceContext<'tcx>,
-    all_facts: &mut Option<AllFacts>,
-    location_table: &LocationTable,
-    mir: &Mir<'tcx>,
-    constraints: &MirTypeckRegionConstraints<'tcx>,
-) {
-    SubtypeConstraintGenerator {
-        regioncx,
-        location_table,
-        mir,
-    }.generate(constraints, all_facts);
-}
-
-struct SubtypeConstraintGenerator<'cx, 'tcx: 'cx> {
-    regioncx: &'cx mut RegionInferenceContext<'tcx>,
-    location_table: &'cx LocationTable,
-    mir: &'cx Mir<'tcx>,
-}
-
-impl<'cx, 'tcx> SubtypeConstraintGenerator<'cx, 'tcx> {
-    fn generate(
-        &mut self,
-        constraints: &MirTypeckRegionConstraints<'tcx>,
-        all_facts: &mut Option<AllFacts>,
-    ) {
-        let MirTypeckRegionConstraints {
-            liveness_set,
-            outlives_sets,
-        } = constraints;
-
-        debug!(
-            "generate(liveness_set={} items, outlives_sets={} items)",
-            liveness_set.len(),
-            outlives_sets.len()
-        );
-
-        for (region, location, cause) in liveness_set {
-            debug!("generate: {:#?} is live at {:#?}", region, location);
-            let region_vid = self.to_region_vid(region);
-            self.regioncx.add_live_point(region_vid, *location, &cause);
-        }
-
-        if let Some(all_facts) = all_facts {
-            all_facts
-                .region_live_at
-                .extend(liveness_set.into_iter().flat_map(|(region, location, _)| {
-                    let r = self.to_region_vid(region);
-                    let p1 = self.location_table.start_index(*location);
-                    let p2 = self.location_table.mid_index(*location);
-                    iter::once((r, p1)).chain(iter::once((r, p2)))
-                }));
-        }
-
-        for OutlivesSet { locations, data } in outlives_sets {
-            debug!("generate: constraints at: {:#?}", locations);
-            let RegionConstraintData {
-                constraints,
-                verifys,
-                givens,
-            } = &**data;
-
-            let span = self.mir
-                .source_info(locations.from_location().unwrap_or(Location::START))
-                .span;
-
-            let at_location = locations.at_location().unwrap_or(Location::START);
-
-            for constraint in constraints.keys() {
-                debug!("generate: constraint: {:?}", constraint);
-                let (a_vid, b_vid) = match constraint {
-                    Constraint::VarSubVar(a_vid, b_vid) => (*a_vid, *b_vid),
-                    Constraint::RegSubVar(a_r, b_vid) => (self.to_region_vid(a_r), *b_vid),
-                    Constraint::VarSubReg(a_vid, b_r) => (*a_vid, self.to_region_vid(b_r)),
-                    Constraint::RegSubReg(a_r, b_r) => {
-                        (self.to_region_vid(a_r), self.to_region_vid(b_r))
-                    }
-                };
-
-                // We have the constraint that `a_vid <= b_vid`. Add
-                // `b_vid: a_vid` to our region checker. Note that we
-                // reverse direction, because `regioncx` talks about
-                // "outlives" (`>=`) whereas the region constraints
-                // talk about `<=`.
-                self.regioncx.add_outlives(span, b_vid, a_vid, at_location);
-
-                // In the new analysis, all outlives relations etc
-                // "take effect" at the mid point of the statement
-                // that requires them, so ignore the `at_location`.
-                if let Some(all_facts) = all_facts {
-                    if let Some(from_location) = locations.from_location() {
-                        all_facts.outlives.push((
-                            b_vid,
-                            a_vid,
-                            self.location_table.mid_index(from_location),
-                        ));
-                    } else {
-                        for location in self.location_table.all_points() {
-                            all_facts.outlives.push((b_vid, a_vid, location));
-                        }
-                    }
-                }
-            }
-
-            for verify in verifys {
-                let type_test = self.verify_to_type_test(verify, span, locations);
-                self.regioncx.add_type_test(type_test);
-            }
-
-            assert!(
-                givens.is_empty(),
-                "MIR type-checker does not use givens (thank goodness)"
-            );
-        }
-    }
-
-    fn verify_to_type_test(
-        &self,
-        verify: &Verify<'tcx>,
-        span: Span,
-        locations: &Locations,
-    ) -> TypeTest<'tcx> {
-        let generic_kind = verify.kind;
-
-        let lower_bound = self.to_region_vid(verify.region);
-
-        let point = locations.at_location().unwrap_or(Location::START);
-
-        let test = self.verify_bound_to_region_test(&verify.bound);
-
-        TypeTest {
-            generic_kind,
-            lower_bound,
-            point,
-            span,
-            test,
-        }
-    }
-
-    fn verify_bound_to_region_test(&self, verify_bound: &VerifyBound<'tcx>) -> RegionTest {
-        match verify_bound {
-            VerifyBound::AnyRegion(regions) => RegionTest::IsOutlivedByAnyRegionIn(
-                regions.iter().map(|r| self.to_region_vid(r)).collect(),
-            ),
-
-            VerifyBound::AllRegions(regions) => RegionTest::IsOutlivedByAllRegionsIn(
-                regions.iter().map(|r| self.to_region_vid(r)).collect(),
-            ),
-
-            VerifyBound::AnyBound(bounds) => RegionTest::Any(
-                bounds
-                    .iter()
-                    .map(|b| self.verify_bound_to_region_test(b))
-                    .collect(),
-            ),
-
-            VerifyBound::AllBounds(bounds) => RegionTest::All(
-                bounds
-                    .iter()
-                    .map(|b| self.verify_bound_to_region_test(b))
-                    .collect(),
-            ),
-        }
-    }
-
-    fn to_region_vid(&self, r: ty::Region<'tcx>) -> ty::RegionVid {
-        self.regioncx.to_region_vid(r)
-    }
-}
diff --git a/src/librustc_mir/borrow_check/nll/type_check/constraint_conversion.rs b/src/librustc_mir/borrow_check/nll/type_check/constraint_conversion.rs
new file mode 100644
index 00000000000..06aaf6810fa
--- /dev/null
+++ b/src/librustc_mir/borrow_check/nll/type_check/constraint_conversion.rs
@@ -0,0 +1,190 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use borrow_check::location::LocationTable;
+use borrow_check::nll::facts::AllFacts;
+use borrow_check::nll::region_infer::{OutlivesConstraint, RegionTest, TypeTest};
+use borrow_check::nll::type_check::Locations;
+use borrow_check::nll::universal_regions::UniversalRegions;
+use rustc::infer::region_constraints::Constraint;
+use rustc::infer::region_constraints::RegionConstraintData;
+use rustc::infer::region_constraints::{Verify, VerifyBound};
+use rustc::mir::{Location, Mir};
+use rustc::ty;
+use syntax::codemap::Span;
+
+crate struct ConstraintConversion<'a, 'tcx: 'a> {
+    mir: &'a Mir<'tcx>,
+    universal_regions: &'a UniversalRegions<'tcx>,
+    location_table: &'a LocationTable,
+    outlives_constraints: &'a mut Vec<OutlivesConstraint>,
+    type_tests: &'a mut Vec<TypeTest<'tcx>>,
+    all_facts: &'a mut Option<AllFacts>,
+
+}
+
+impl<'a, 'tcx> ConstraintConversion<'a, 'tcx> {
+    crate fn new(
+        mir: &'a Mir<'tcx>,
+        universal_regions: &'a UniversalRegions<'tcx>,
+        location_table: &'a LocationTable,
+        outlives_constraints: &'a mut Vec<OutlivesConstraint>,
+        type_tests: &'a mut Vec<TypeTest<'tcx>>,
+        all_facts: &'a mut Option<AllFacts>,
+    ) -> Self {
+        Self {
+            mir,
+            universal_regions,
+            location_table,
+            outlives_constraints,
+            type_tests,
+            all_facts,
+        }
+    }
+
+    crate fn convert(
+        &mut self,
+        locations: Locations,
+        data: &RegionConstraintData<'tcx>,
+    ) {
+        debug!("generate: constraints at: {:#?}", locations);
+        let RegionConstraintData {
+            constraints,
+            verifys,
+            givens,
+        } = data;
+
+        let span = self
+            .mir
+            .source_info(locations.from_location().unwrap_or(Location::START))
+            .span;
+
+        let at_location = locations.at_location().unwrap_or(Location::START);
+
+        for constraint in constraints.keys() {
+            debug!("generate: constraint: {:?}", constraint);
+            let (a_vid, b_vid) = match constraint {
+                Constraint::VarSubVar(a_vid, b_vid) => (*a_vid, *b_vid),
+                Constraint::RegSubVar(a_r, b_vid) => (self.to_region_vid(a_r), *b_vid),
+                Constraint::VarSubReg(a_vid, b_r) => (*a_vid, self.to_region_vid(b_r)),
+                Constraint::RegSubReg(a_r, b_r) => {
+                    (self.to_region_vid(a_r), self.to_region_vid(b_r))
+                }
+            };
+
+            // We have the constraint that `a_vid <= b_vid`. Add
+            // `b_vid: a_vid` to our region checker. Note that we
+            // reverse direction, because `regioncx` talks about
+            // "outlives" (`>=`) whereas the region constraints
+            // talk about `<=`.
+            self.add_outlives(span, b_vid, a_vid, at_location);
+
+            // In the new analysis, all outlives relations etc
+            // "take effect" at the mid point of the statement
+            // that requires them, so ignore the `at_location`.
+            if let Some(all_facts) = &mut self.all_facts {
+                if let Some(from_location) = locations.from_location() {
+                    all_facts.outlives.push((
+                        b_vid,
+                        a_vid,
+                        self.location_table.mid_index(from_location),
+                    ));
+                } else {
+                    for location in self.location_table.all_points() {
+                        all_facts.outlives.push((b_vid, a_vid, location));
+                    }
+                }
+            }
+        }
+
+        for verify in verifys {
+            let type_test = self.verify_to_type_test(verify, span, locations);
+            self.add_type_test(type_test);
+        }
+
+        assert!(
+            givens.is_empty(),
+            "MIR type-checker does not use givens (thank goodness)"
+        );
+    }
+
+    fn verify_to_type_test(
+        &self,
+        verify: &Verify<'tcx>,
+        span: Span,
+        locations: Locations,
+    ) -> TypeTest<'tcx> {
+        let generic_kind = verify.kind;
+
+        let lower_bound = self.to_region_vid(verify.region);
+
+        let point = locations.at_location().unwrap_or(Location::START);
+
+        let test = self.verify_bound_to_region_test(&verify.bound);
+
+        TypeTest {
+            generic_kind,
+            lower_bound,
+            point,
+            span,
+            test,
+        }
+    }
+
+    fn verify_bound_to_region_test(&self, verify_bound: &VerifyBound<'tcx>) -> RegionTest {
+        match verify_bound {
+            VerifyBound::AnyRegion(regions) => RegionTest::IsOutlivedByAnyRegionIn(
+                regions.iter().map(|r| self.to_region_vid(r)).collect(),
+            ),
+
+            VerifyBound::AllRegions(regions) => RegionTest::IsOutlivedByAllRegionsIn(
+                regions.iter().map(|r| self.to_region_vid(r)).collect(),
+            ),
+
+            VerifyBound::AnyBound(bounds) => RegionTest::Any(
+                bounds
+                    .iter()
+                    .map(|b| self.verify_bound_to_region_test(b))
+                    .collect(),
+            ),
+
+            VerifyBound::AllBounds(bounds) => RegionTest::All(
+                bounds
+                    .iter()
+                    .map(|b| self.verify_bound_to_region_test(b))
+                    .collect(),
+            ),
+        }
+    }
+
+    fn to_region_vid(&self, r: ty::Region<'tcx>) -> ty::RegionVid {
+        self.universal_regions.to_region_vid(r)
+    }
+
+    fn add_outlives(
+        &mut self,
+        span: Span,
+        sup: ty::RegionVid,
+        sub: ty::RegionVid,
+        point: Location,
+    ) {
+        self.outlives_constraints.push(OutlivesConstraint {
+            span,
+            sub,
+            sup,
+            point,
+            next: None,
+        });
+    }
+
+    fn add_type_test(&mut self, type_test: TypeTest<'tcx>) {
+        self.type_tests.push(type_test);
+    }
+}
diff --git a/src/librustc_mir/borrow_check/nll/type_check/mod.rs b/src/librustc_mir/borrow_check/nll/type_check/mod.rs
index a8ae614d619..bed0fec4d4d 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/mod.rs
@@ -11,8 +11,10 @@
 //! This pass type-checks the MIR to ensure it is not broken.
 #![allow(unreachable_code)]
 
+use borrow_check::location::LocationTable;
+use borrow_check::nll::facts::AllFacts;
 use borrow_check::nll::region_infer::Cause;
-use borrow_check::nll::region_infer::ClosureRegionRequirementsExt;
+use borrow_check::nll::region_infer::{ClosureRegionRequirementsExt, OutlivesConstraint, TypeTest};
 use borrow_check::nll::universal_regions::UniversalRegions;
 use dataflow::move_paths::MoveData;
 use dataflow::FlowAtLocation;
@@ -63,6 +65,7 @@ macro_rules! span_mirbug_and_err {
     })
 }
 
+mod constraint_conversion;
 mod input_output;
 mod liveness;
 
@@ -101,7 +104,9 @@ pub(crate) fn type_check<'gcx, 'tcx>(
     mir: &Mir<'tcx>,
     mir_def_id: DefId,
     universal_regions: &UniversalRegions<'tcx>,
+    location_table: &LocationTable,
     liveness: &LivenessResults,
+    all_facts: &mut Option<AllFacts>,
     flow_inits: &mut FlowAtLocation<MaybeInitializedPlaces<'_, 'gcx, 'tcx>>,
     move_data: &MoveData<'tcx>,
 ) -> MirTypeckRegionConstraints<'tcx> {
@@ -114,6 +119,11 @@ pub(crate) fn type_check<'gcx, 'tcx>(
         mir,
         &universal_regions.region_bound_pairs,
         Some(implicit_region_bound),
+        Some(BorrowCheckContext {
+            universal_regions,
+            location_table,
+            all_facts,
+        }),
         &mut |cx| {
             liveness::generate(cx, mir, liveness, flow_inits, move_data);
 
@@ -129,6 +139,7 @@ fn type_check_internal<'gcx, 'tcx>(
     mir: &Mir<'tcx>,
     region_bound_pairs: &[(ty::Region<'tcx>, GenericKind<'tcx>)],
     implicit_region_bound: Option<ty::Region<'tcx>>,
+    borrowck_context: Option<BorrowCheckContext<'_, 'tcx>>,
     extra: &mut dyn FnMut(&mut TypeChecker<'_, 'gcx, 'tcx>),
 ) -> MirTypeckRegionConstraints<'tcx> {
     let mut checker = TypeChecker::new(
@@ -137,6 +148,8 @@ fn type_check_internal<'gcx, 'tcx>(
         param_env,
         region_bound_pairs,
         implicit_region_bound,
+        borrowck_context,
+        mir,
     );
     let errors_reported = {
         let mut verifier = TypeVerifier::new(&mut checker, mir);
@@ -587,12 +600,20 @@ struct TypeChecker<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
     implicit_region_bound: Option<ty::Region<'tcx>>,
     reported_errors: FxHashSet<(Ty<'tcx>, Span)>,
     constraints: MirTypeckRegionConstraints<'tcx>,
+    borrowck_context: Option<BorrowCheckContext<'a, 'tcx>>,
+    mir: &'a Mir<'tcx>,
+}
+
+struct BorrowCheckContext<'a, 'tcx: 'a> {
+    universal_regions: &'a UniversalRegions<'tcx>,
+    location_table: &'a LocationTable,
+    all_facts: &'a mut Option<AllFacts>,
 }
 
 /// A collection of region constraints that must be satisfied for the
 /// program to be considered well-typed.
 #[derive(Default)]
-pub(crate) struct MirTypeckRegionConstraints<'tcx> {
+crate struct MirTypeckRegionConstraints<'tcx> {
     /// In general, the type-checker is not responsible for enforcing
     /// liveness constraints; this job falls to the region inferencer,
     /// which performs a liveness analysis. However, in some limited
@@ -600,24 +621,11 @@ pub(crate) struct MirTypeckRegionConstraints<'tcx> {
     /// not otherwise appear in the MIR -- in particular, the
     /// late-bound regions that it instantiates at call-sites -- and
     /// hence it must report on their liveness constraints.
-    pub liveness_set: Vec<(ty::Region<'tcx>, Location, Cause)>,
+    crate liveness_set: Vec<(ty::Region<'tcx>, Location, Cause)>,
 
-    /// During the course of type-checking, we will accumulate region
-    /// constraints due to performing subtyping operations or solving
-    /// traits. These are accumulated into this vector for later use.
-    pub outlives_sets: Vec<OutlivesSet<'tcx>>,
-}
-
-/// Outlives relationships between regions and types created at a
-/// particular point within the control-flow graph.
-pub struct OutlivesSet<'tcx> {
-    /// The locations associated with these constraints.
-    pub locations: Locations,
+    crate outlives_constraints: Vec<OutlivesConstraint>,
 
-    /// Constraints generated. In terms of the NLL RFC, when you have
-    /// a constraint `R1: R2 @ P`, the data in there specifies things
-    /// like `R1: R2`.
-    pub data: Rc<RegionConstraintData<'tcx>>,
+    crate type_tests: Vec<TypeTest<'tcx>>,
 }
 
 /// The `Locations` type summarizes *where* region constraints are
@@ -695,6 +703,8 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
         param_env: ty::ParamEnv<'gcx>,
         region_bound_pairs: &'a [(ty::Region<'tcx>, GenericKind<'tcx>)],
         implicit_region_bound: Option<ty::Region<'tcx>>,
+        borrowck_context: Option<BorrowCheckContext<'a, 'tcx>>,
+        mir: &'a Mir<'tcx>,
     ) -> Self {
         TypeChecker {
             infcx,
@@ -703,6 +713,8 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
             param_env,
             region_bound_pairs,
             implicit_region_bound,
+            borrowck_context,
+            mir,
             reported_errors: FxHashSet(),
             constraints: MirTypeckRegionConstraints::default(),
         }
@@ -750,9 +762,16 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
             locations, data
         );
 
-        self.constraints
-            .outlives_sets
-            .push(OutlivesSet { locations, data });
+        if let Some(borrowck_context) = &mut self.borrowck_context {
+            constraint_conversion::ConstraintConversion::new(
+                self.mir,
+                borrowck_context.universal_regions,
+                borrowck_context.location_table,
+                &mut self.constraints.outlives_constraints,
+                &mut self.constraints.type_tests,
+                &mut borrowck_context.all_facts,
+            ).convert(locations, &data);
+        }
     }
 
     /// Helper for `fully_perform_op`, but also used on its own
@@ -1712,7 +1731,7 @@ impl MirPass for TypeckMir {
         }
         let param_env = tcx.param_env(def_id);
         tcx.infer_ctxt().enter(|infcx| {
-            let _ = type_check_internal(&infcx, id, param_env, mir, &[], None, &mut |_| ());
+            let _ = type_check_internal(&infcx, id, param_env, mir, &[], None, None, &mut |_| ());
 
             // For verification purposes, we just ignore the resulting
             // region constraint sets. Not our problem. =)