Rename some Analysis and ResultsVisitor methods.

The words "before" and "after" have an obvious temporal meaning, e.g.
`seek_before_primary_effect`,
`visit_statement_{before,after}_primary_effect`. But "before" is also
used to name the effect that occurs before the primary effect of a
statement/terminator; this is `Effect::Before`. This leads to the
confusing possibility of talking about things happening "before/after
the before event".

This commit removes this awkward overloading of "before" by renaming
`Effect::Before` as `Effect::Early`. It also renames some of the
`Analysis` and `ResultsVisitor` methods to be more consistent.

Here are the before and after names:

- `Effect::{Before,Primary}`              -> `Effect::{Early,Primary}`
- `apply_before_statement_effect`         -> `apply_early_statement_effect`
- `apply_statement_effect`                -> `apply_primary_statement_effect`
- `visit_statement_before_primary_effect` -> `visit_after_early_statement_effect`
- `visit_statement_after_primary_effect`  -> `visit_after_primary_statement_effect`

(And s/statement/terminator/ for all the terminator events.)

compiler/rustc_mir_transform/src/coroutine.rs

@@ -878,7 +878,7 @@ struct StorageConflictVisitor<'a, 'tcx> {
 impl<'a, 'tcx> ResultsVisitor<'a, 'tcx, MaybeRequiresStorage<'a, 'tcx>>
     for StorageConflictVisitor<'a, 'tcx>
 {
-    fn visit_statement_before_primary_effect(
+    fn visit_after_early_statement_effect(
         &mut self,
         _results: &mut Results<'tcx, MaybeRequiresStorage<'a, 'tcx>>,
         state: &BitSet<Local>,
@@ -888,7 +888,7 @@ impl<'a, 'tcx> ResultsVisitor<'a, 'tcx, MaybeRequiresStorage<'a, 'tcx>>
         self.apply_state(state, loc);
     }
 
-    fn visit_terminator_before_primary_effect(
+    fn visit_after_early_terminator_effect(
         &mut self,
         _results: &mut Results<'tcx, MaybeRequiresStorage<'a, 'tcx>>,
         state: &BitSet<Local>,

compiler/rustc_mir_transform/src/dataflow_const_prop.rs

@@ -106,7 +106,7 @@ impl<'tcx> Analysis<'tcx> for ConstAnalysis<'_, 'tcx> {
         }
     }
 
-    fn apply_statement_effect(
+    fn apply_primary_statement_effect(
         &mut self,
         state: &mut Self::Domain,
         statement: &Statement<'tcx>,
@@ -117,7 +117,7 @@ impl<'tcx> Analysis<'tcx> for ConstAnalysis<'_, 'tcx> {
         }
     }
 
-    fn apply_terminator_effect<'mir>(
+    fn apply_primary_terminator_effect<'mir>(
         &mut self,
         state: &mut Self::Domain,
         terminator: &'mir Terminator<'tcx>,
@@ -224,7 +224,7 @@ impl<'a, 'tcx> ConstAnalysis<'a, 'tcx> {
     }
 
     /// The effect of a successful function call return should not be
-    /// applied here, see [`Analysis::apply_terminator_effect`].
+    /// applied here, see [`Analysis::apply_primary_terminator_effect`].
     fn handle_terminator<'mir>(
         &self,
         terminator: &'mir Terminator<'tcx>,
@@ -949,7 +949,7 @@ fn try_write_constant<'tcx>(
 
 impl<'mir, 'tcx> ResultsVisitor<'mir, 'tcx, ConstAnalysis<'_, 'tcx>> for Collector<'_, 'tcx> {
     #[instrument(level = "trace", skip(self, results, statement))]
-    fn visit_statement_before_primary_effect(
+    fn visit_after_early_statement_effect(
         &mut self,
         results: &mut Results<'tcx, ConstAnalysis<'_, 'tcx>>,
         state: &State<FlatSet<Scalar>>,
@@ -971,7 +971,7 @@ impl<'mir, 'tcx> ResultsVisitor<'mir, 'tcx, ConstAnalysis<'_, 'tcx>> for Collect
     }
 
     #[instrument(level = "trace", skip(self, results, statement))]
-    fn visit_statement_after_primary_effect(
+    fn visit_after_primary_statement_effect(
         &mut self,
         results: &mut Results<'tcx, ConstAnalysis<'_, 'tcx>>,
         state: &State<FlatSet<Scalar>>,
@@ -996,7 +996,7 @@ impl<'mir, 'tcx> ResultsVisitor<'mir, 'tcx, ConstAnalysis<'_, 'tcx>> for Collect
         }
     }
 
-    fn visit_terminator_before_primary_effect(
+    fn visit_after_early_terminator_effect(
         &mut self,
         results: &mut Results<'tcx, ConstAnalysis<'_, 'tcx>>,
         state: &State<FlatSet<Scalar>>,