Remove BorrowckAnalyses.

This results in two non-generic types being used: `BorrowckResults` and
`BorrowckFlowState`. It's a net reduction in lines of code, and a little
easier to read.

Author: nnethercote

compiler/rustc_borrowck/src/dataflow.rs

@@ -11,43 +11,33 @@ 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 rustc_mir_dataflow::{Analysis, AnalysisDomain, Results};
 use std::fmt;
 
 use crate::{places_conflict, BorrowSet, PlaceConflictBias, PlaceExt, RegionInferenceContext};
 
-/// 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>>,
->;
+pub struct BorrowckResults<'mir, 'tcx> {
+    pub(crate) borrows: Results<'tcx, Borrows<'mir, 'tcx>>,
+    pub(crate) uninits: Results<'tcx, MaybeUninitializedPlaces<'mir, 'tcx>>,
+    pub(crate) ever_inits: 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;
-
-impl<'tcx, B, U, E, D: Direction> ResultsVisitable<'tcx>
-    for BorrowckAnalyses<Results<'tcx, B>, Results<'tcx, U>, Results<'tcx, E>>
-where
-    B: Analysis<'tcx, Direction = D>,
-    U: Analysis<'tcx, Direction = D>,
-    E: Analysis<'tcx, Direction = D>,
-{
-    type Direction = D;
-    type FlowState = BorrowckAnalyses<B::Domain, U::Domain, E::Domain>;
+#[derive(Debug)]
+pub struct BorrowckFlowState<'mir, 'tcx> {
+    pub(crate) borrows: <Borrows<'mir, 'tcx> as AnalysisDomain<'tcx>>::Domain,
+    pub(crate) uninits: <MaybeUninitializedPlaces<'mir, 'tcx> as AnalysisDomain<'tcx>>::Domain,
+    pub(crate) ever_inits: <EverInitializedPlaces<'mir, 'tcx> as AnalysisDomain<'tcx>>::Domain,
+}
+
+impl<'mir, 'tcx> ResultsVisitable<'tcx> for BorrowckResults<'mir, 'tcx> {
+    // All three analyses are forward, but we have to use just one here.
+    type Direction = <Borrows<'mir, 'tcx> as AnalysisDomain<'tcx>>::Direction;
+    type FlowState = BorrowckFlowState<'mir, 'tcx>;
 
     fn new_flow_state(&self, body: &mir::Body<'tcx>) -> Self::FlowState {
-        BorrowckAnalyses {
+        BorrowckFlowState {
             borrows: self.borrows.analysis.bottom_value(body),
             uninits: self.uninits.analysis.bottom_value(body),
             ever_inits: self.ever_inits.analysis.bottom_value(body),