Remove SwitchIntTarget.

It's only passed to `Analysis::apply_switch_int_edge_effect`, and the
existing impls of that method only use the `value` field. So pass that
instead.

Author: nnethercote

compiler/rustc_mir_dataflow/src/framework/direction.rs

@@ -5,7 +5,7 @@ use rustc_middle::mir::{
 };
 
 use super::visitor::ResultsVisitor;
-use super::{Analysis, Effect, EffectIndex, Results, SwitchIntTarget};
+use super::{Analysis, Effect, EffectIndex, Results};
 
 pub trait Direction {
     const IS_FORWARD: bool;
@@ -117,8 +117,7 @@ impl Direction for Backward {
                         let mut tmp = analysis.bottom_value(body);
                         for &value in &body.basic_blocks.switch_sources()[&(block, pred)] {
                             tmp.clone_from(exit_state);
-                            let si_target = SwitchIntTarget { value, target: block };
-                            analysis.apply_switch_int_edge_effect(&mut data, &mut tmp, si_target);
+                            analysis.apply_switch_int_edge_effect(&mut data, &mut tmp, value);
                             propagate(pred, &tmp);
                         }
                     } else {
@@ -292,9 +291,8 @@ impl Direction for Forward {
                     let mut tmp = analysis.bottom_value(body);
                     for (value, target) in targets.iter() {
                         tmp.clone_from(exit_state);
-                        let si_target =
-                            SwitchIntTarget { value: SwitchTargetValue::Normal(value), target };
-                        analysis.apply_switch_int_edge_effect(&mut data, &mut tmp, si_target);
+                        let value = SwitchTargetValue::Normal(value);
+                        analysis.apply_switch_int_edge_effect(&mut data, &mut tmp, value);
                         propagate(target, &tmp);
                     }
 
@@ -305,7 +303,7 @@ impl Direction for Forward {
                     analysis.apply_switch_int_edge_effect(
                         &mut data,
                         exit_state,
-                        SwitchIntTarget { value: SwitchTargetValue::Otherwise, target: otherwise },
+                        SwitchTargetValue::Otherwise,
                     );
                     propagate(otherwise, exit_state);
                 } else {

compiler/rustc_mir_dataflow/src/framework/mod.rs

@@ -222,7 +222,7 @@ pub trait Analysis<'tcx> {
         &mut self,
         _data: &mut Self::SwitchIntData,
         _state: &mut Self::Domain,
-        _edge: SwitchIntTarget,
+        _value: SwitchTargetValue,
     ) {
         unreachable!();
     }
@@ -432,10 +432,5 @@ impl EffectIndex {
     }
 }
 
-pub struct SwitchIntTarget {
-    pub value: SwitchTargetValue,
-    pub target: BasicBlock,
-}
-
 #[cfg(test)]
 mod tests;

compiler/rustc_mir_dataflow/src/impls/initialized.rs

@@ -12,7 +12,6 @@ use rustc_middle::ty::{self, TyCtxt};
 use tracing::{debug, instrument};
 
 use crate::drop_flag_effects::DropFlagState;
-use crate::framework::SwitchIntTarget;
 use crate::move_paths::{HasMoveData, InitIndex, InitKind, LookupResult, MoveData, MovePathIndex};
 use crate::{
     Analysis, GenKill, MaybeReachable, drop_flag_effects, drop_flag_effects_for_function_entry,
@@ -424,9 +423,9 @@ impl<'tcx> Analysis<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
         &mut self,
         data: &mut Self::SwitchIntData,
         state: &mut Self::Domain,
-        edge: SwitchIntTarget,
+        value: SwitchTargetValue,
     ) {
-        if let SwitchTargetValue::Normal(value) = edge.value {
+        if let SwitchTargetValue::Normal(value) = value {
             // Kill all move paths that correspond to variants we know to be inactive along this
             // particular outgoing edge of a `SwitchInt`.
             drop_flag_effects::on_all_inactive_variants(
@@ -537,9 +536,9 @@ impl<'tcx> Analysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
         &mut self,
         data: &mut Self::SwitchIntData,
         state: &mut Self::Domain,
-        edge: SwitchIntTarget,
+        value: SwitchTargetValue,
     ) {
-        if let SwitchTargetValue::Normal(value) = edge.value {
+        if let SwitchTargetValue::Normal(value) = value {
             // Mark all move paths that correspond to variants other than this one as maybe
             // uninitialized (in reality, they are *definitely* uninitialized).
             drop_flag_effects::on_all_inactive_variants(