update NLL after refactorings

Author: mark-i-m

src/borrow_check.md

@@ -11,13 +11,8 @@ enforcing a number of properties:
 - That you can't mutate a place while it is immutably borrowed.
 - etc
 
-At the time of this writing, the code is in a state of transition. The
-"main" borrow checker still works by processing [the HIR](hir.html),
-but that is being phased out in favor of the MIR-based borrow checker.
-Accordingly, this documentation focuses on the new, MIR-based borrow
-checker.
-
-Doing borrow checking on MIR has several advantages:
+The borrow checker operates on the MIR. An older implementation operated on the
+HIR. Doing borrow checking on MIR has several advantages:
 
 - The MIR is *far* less complex than the HIR; the radical desugaring
   helps prevent bugs in the borrow checker. (If you're curious, you
@@ -42,15 +37,15 @@ the [`mir_borrowck`] query.
   we will modify this copy in place to modify the types and things to
   include references to the new regions that we are computing.
 - We then invoke [`replace_regions_in_mir`] to modify our local MIR.
-  Among other things, this function will replace all of the [regions](./appendix/glossary.html) in
-  the MIR with fresh [inference variables](./appendix/glossary.html).
+  Among other things, this function will replace all of the [regions](./appendix/glossary.md) in
+  the MIR with fresh [inference variables](./appendix/glossary.md).
 - Next, we perform a number of
-  [dataflow analyses](./appendix/background.html#dataflow) that
+  [dataflow analyses](./appendix/background.md#dataflow) that
   compute what data is moved and when.
-- We then do a [second type check](borrow_check/type_check.html) across the MIR:
+- We then do a [second type check](borrow_check/type_check.md) across the MIR:
   the purpose of this type check is to determine all of the constraints between
   different regions.
-- Next, we do [region inference](borrow_check/region_inference.html), which computes
+- Next, we do [region inference](borrow_check/region_inference.md), which computes
   the values of each region — basically, the points in the control-flow graph where
   each lifetime must be valid according to the constraints we collected.
 - At this point, we can compute the "borrows in scope" at each point.

src/borrow_check/region_inference.md

@@ -1,11 +1,9 @@
 # Region inference (NLL)
 
-The MIR-based region checking code is located in
-[the `rustc_mir::borrow_check::nll` module][nll]. (NLL, of course,
-stands for "non-lexical lifetimes", a term that will hopefully be
-deprecated once they become the standard kind of lifetime.)
+The MIR-based region checking code is located in [the `rustc_mir::borrow_check`
+module][nll].
 
-[nll]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/index.html
+[nll]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/index.html
 
 The MIR-based region analysis consists of two major functions:
 
@@ -36,12 +34,12 @@ The MIR-based region analysis consists of two major functions:
   - The [NLL RFC] also includes fairly thorough (and hopefully readable)
     coverage.
 
-[cp]: ./region_inference/constraint_propagation.html
-[fvb]: ../appendix/background.html#free-vs-bound
+[cp]: ./region_inference/constraint_propagation.md
+[fvb]: ../appendix/background.md#free-vs-bound
 [`replace_regions_in_mir`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/fn.replace_regions_in_mir.html
 [`compute_regions`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/fn.compute_regions.html
-[`RegionInferenceContext`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/struct.RegionInferenceContext.html
-[`solve`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/struct.RegionInferenceContext.html#method.solve
+[`RegionInferenceContext`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/struct.RegionInferenceContext.html
+[`solve`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/struct.RegionInferenceContext.html#method.solve
 [NLL RFC]: https://rust-lang.github.io/rfcs/2094-nll.html
 [MIR type checker]: ./type_check.md
 
@@ -68,7 +66,7 @@ the moment.
 
 TODO: write about _how_ these regions are computed.
 
-[`UniversalRegions`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/universal_regions/struct.UniversalRegions.html
+[`UniversalRegions`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/universal_regions/struct.UniversalRegions.html
 
 <a name="region-variables"></a>
 
@@ -84,7 +82,7 @@ maintain a set storing what elements are present in its value (to make this
 efficient, we give each kind of element an index, the `RegionElementIndex`, and
 use sparse bitsets).
 
-[ri]: https://github.com/rust-lang/rust/tree/master/src/librustc_mir/borrow_check/nll/region_infer/
+[ri]: https://github.com/rust-lang/rust/tree/master/src/librustc_mir/borrow_check/region_infer/
 
 The kinds of region elements are as follows:
 
@@ -115,7 +113,7 @@ common sorts of constraints are:
 2. Liveness constraints. Each region needs to be live at points where it can be
    used. These constraints are collected by [`generate_constraints`].
 
-[`generate_constraints`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/constraint_generation/fn.generate_constraints.html
+[`generate_constraints`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/constraint_generation/fn.generate_constraints.html
 
 ## Inference Overview
 
@@ -219,12 +217,12 @@ Here are some of the fields of the struct:
 - [`closure_bounds_mapping`]: used for propagating region constraints from
   closures back out to the creator of the closure.
 
-[`constraints`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/struct.RegionInferenceContext.html#structfield.constraints
-[`liveness_constraints`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/struct.RegionInferenceContext.html#structfield.liveness_constraints
-[`universal_regions`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/struct.RegionInferenceContext.html#structfield.universal_regions
-[`universal_region_relations`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/struct.RegionInferenceContext.html#structfield.universal_region_relations
-[`type_tests`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/struct.RegionInferenceContext.html#structfield.type_tests
-[`closure_bounds_mapping`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/struct.RegionInferenceContext.html#structfield.closure_bounds_mapping
+[`constraints`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/struct.RegionInferenceContext.html#structfield.constraints
+[`liveness_constraints`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/struct.RegionInferenceContext.html#structfield.liveness_constraints
+[`universal_regions`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/struct.RegionInferenceContext.html#structfield.universal_regions
+[`universal_region_relations`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/struct.RegionInferenceContext.html#structfield.universal_region_relations
+[`type_tests`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/struct.RegionInferenceContext.html#structfield.type_tests
+[`closure_bounds_mapping`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/struct.RegionInferenceContext.html#structfield.closure_bounds_mapping
 
 TODO: should we discuss any of the others fields? What about the SCCs?
 
@@ -233,6 +231,6 @@ inference. This is done by calling the [`solve`] method on the context. This
 is where we call [`propagate_constraints`] and then check the resulting type
 tests and universal regions, as discussed above.
 
-[`propagate_constraints`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/struct.RegionInferenceContext.html#method.propagate_constraints
-[`check_type_tests`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/struct.RegionInferenceContext.html#method.check_type_tests
-[`check_universal_regions`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/struct.RegionInferenceContext.html#method.check_universal_regions
+[`propagate_constraints`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/struct.RegionInferenceContext.html#method.propagate_constraints
+[`check_type_tests`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/struct.RegionInferenceContext.html#method.check_type_tests
+[`check_universal_regions`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/struct.RegionInferenceContext.html#method.check_universal_regions

src/borrow_check/region_inference/constraint_propagation.md

@@ -10,7 +10,7 @@ on one at a time (each of them is fairly independent from the others):
 - outlives constraints (`R1: R2`), which arise from subtyping;
 - [member constraints][m_c] (`member R_m of [R_c...]`), which arise from impl Trait.
 
-[`propagate_constraints`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/struct.RegionInferenceContext.html#method.propagate_constraints
+[`propagate_constraints`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/struct.RegionInferenceContext.html#method.propagate_constraints
 [m_c]: ./member_constraints.md
 
 In this chapter, we'll explain the "heart" of constraint propagation,
@@ -68,8 +68,8 @@ though; instead, we store a (sparse) bitset per region variable (of
 type [`LivenessValues`]). This way we only need a single bit for each
 liveness constraint.
 
-[`liveness_constraints`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/struct.RegionInferenceContext.html#structfield.liveness_constraints
-[`LivenessValues`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/values/struct.LivenessValues.html
+[`liveness_constraints`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/struct.RegionInferenceContext.html#structfield.liveness_constraints
+[`LivenessValues`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/values/struct.LivenessValues.html
 
 One thing that is worth mentioning: All lifetime parameters are always
 considered to be live over the entire function body. This is because
@@ -112,9 +112,9 @@ induces an edge `'a -> 'b`. This conversion happens in the
 [`RegionInferenceContext::new`] function that creates the inference
 context.
 
-[`ConstraintSet`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/constraints/struct.OutlivesConstraintSet.html
-[graph-fn]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/constraints/struct.OutlivesConstraintSet.html#method.graph
-[`RegionInferenceContext::new`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/struct.RegionInferenceContext.html#method.new
+[`ConstraintSet`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/constraints/struct.OutlivesConstraintSet.html
+[graph-fn]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/constraints/struct.OutlivesConstraintSet.html#method.graph
+[`RegionInferenceContext::new`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/struct.RegionInferenceContext.html#method.new
 
 When using a graph representation, we can detect regions that must be equal
 by looking for cycles. That is, if you have a constraint like
@@ -146,8 +146,8 @@ of fields are defined in terms of SCCs. For example, the
 of a specific region `'a` then, we first figure out the SCC that the
 region is a part of, and then find the value of that SCC.
 
-[`constraint_sccs`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/struct.RegionInferenceContext.html#structfield.constraint_sccs
-[`scc_values`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/struct.RegionInferenceContext.html#structfield.scc_values
+[`constraint_sccs`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/struct.RegionInferenceContext.html#structfield.constraint_sccs
+[`scc_values`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/struct.RegionInferenceContext.html#structfield.scc_values
 
 When we compute SCCs, we not only figure out which regions are a
 member of each SCC, we also figure out the edges between them. So for example

src/borrow_check/region_inference/lifetime_parameters.md

@@ -29,9 +29,9 @@ relationships to one another. So if you have e.g. `where 'a: 'b`, then
 the [`UniversalRegionRelations`] struct would track that `'a: 'b` is
 known to hold (which could be tested with the [`outlives`] function.
 
-[`UniversalRegions`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/universal_regions/struct.UniversalRegions.html
-[`UniversalRegionRelations`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/type_check/free_region_relations/struct.UniversalRegionRelations.html
-[`outlives`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/type_check/free_region_relations/struct.UniversalRegionRelations.html#method.outlives
+[`UniversalRegions`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/universal_regions/struct.UniversalRegions.html
+[`UniversalRegionRelations`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/type_check/free_region_relations/struct.UniversalRegionRelations.html
+[`outlives`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/type_check/free_region_relations/struct.UniversalRegionRelations.html#method.outlives
 
 ## Everything is a region variable
 
@@ -56,7 +56,7 @@ type). These subdivisions are not important for the topics discussed
 here, but become important when we consider [closure constraint
 propagation](./closure_constraints.html), so we discuss them there.
 
-[`RegionClassification`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/universal_regions/enum.RegionClassification.html#variant.Local
+[`RegionClassification`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/universal_regions/enum.RegionClassification.html#variant.Local
 
 ## Universal lifetimes as the elements of a region's value
 
@@ -86,7 +86,7 @@ liveness constraint (i.e., `'a` must extend until the end of
 itself). In the code, these liveness constraints are setup in
 [`init_free_and_bound_regions`].
 
-[`init_free_and_bound_regions`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/struct.RegionInferenceContext.html#method.init_free_and_bound_regions
+[`init_free_and_bound_regions`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/struct.RegionInferenceContext.html#method.init_free_and_bound_regions
 
 ## Propagating outlives constraints for universal regions
 
@@ -122,4 +122,4 @@ not, as in our example, that is an error. This check is done in the
 universal regions, inspects their final value, and tests against the
 declared [`UniversalRegionRelations`].
 
-[`check_universal_regions`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/region_infer/struct.RegionInferenceContext.html#method.check_universal_regions
+[`check_universal_regions`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/region_infer/struct.RegionInferenceContext.html#method.check_universal_regions

src/borrow_check/type_check.md

@@ -1,7 +1,7 @@
 # The MIR type-check
 
 A key component of the borrow check is the
-[MIR type-check](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/nll/type_check/index.html).
+[MIR type-check](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/borrow_check/type_check/index.html).
 This check walks the MIR and does a complete "type check" -- the same
 kind you might find in any other language. In the process of doing
 this type-check, we also uncover the region constraints that apply to