diff --git a/compiler/rustc_borrowck/src/dataflow.rs b/compiler/rustc_borrowck/src/dataflow.rs
index 84d5ffb94791..813ceaeb8da9 100644
--- a/compiler/rustc_borrowck/src/dataflow.rs
+++ b/compiler/rustc_borrowck/src/dataflow.rs
@@ -44,7 +44,7 @@ impl<'a, 'tcx> Analysis<'tcx> for Borrowck<'a, 'tcx> {
     }
 
     fn apply_early_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         stmt: &mir::Statement<'tcx>,
         loc: Location,
@@ -55,7 +55,7 @@ impl<'a, 'tcx> Analysis<'tcx> for Borrowck<'a, 'tcx> {
     }
 
     fn apply_primary_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         stmt: &mir::Statement<'tcx>,
         loc: Location,
@@ -66,7 +66,7 @@ impl<'a, 'tcx> Analysis<'tcx> for Borrowck<'a, 'tcx> {
     }
 
     fn apply_early_terminator_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         term: &mir::Terminator<'tcx>,
         loc: Location,
@@ -77,7 +77,7 @@ impl<'a, 'tcx> Analysis<'tcx> for Borrowck<'a, 'tcx> {
     }
 
     fn apply_primary_terminator_effect<'mir>(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         term: &'mir mir::Terminator<'tcx>,
         loc: Location,
@@ -92,7 +92,7 @@ impl<'a, 'tcx> Analysis<'tcx> for Borrowck<'a, 'tcx> {
     }
 
     fn apply_call_return_effect(
-        &mut self,
+        &self,
         _state: &mut Self::Domain,
         _block: BasicBlock,
         _return_places: CallReturnPlaces<'_, 'tcx>,
@@ -533,7 +533,7 @@ impl<'tcx> rustc_mir_dataflow::Analysis<'tcx> for Borrows<'_, 'tcx> {
     }
 
     fn apply_early_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         _statement: &mir::Statement<'tcx>,
         location: Location,
@@ -542,7 +542,7 @@ impl<'tcx> rustc_mir_dataflow::Analysis<'tcx> for Borrows<'_, 'tcx> {
     }
 
     fn apply_primary_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         stmt: &mir::Statement<'tcx>,
         location: Location,
@@ -590,7 +590,7 @@ impl<'tcx> rustc_mir_dataflow::Analysis<'tcx> for Borrows<'_, 'tcx> {
     }
 
     fn apply_early_terminator_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         _terminator: &mir::Terminator<'tcx>,
         location: Location,
@@ -599,7 +599,7 @@ impl<'tcx> rustc_mir_dataflow::Analysis<'tcx> for Borrows<'_, 'tcx> {
     }
 
     fn apply_primary_terminator_effect<'mir>(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         terminator: &'mir mir::Terminator<'tcx>,
         _location: Location,
diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs
index 3fef76b1fc40..a33241ebe70a 100644
--- a/compiler/rustc_borrowck/src/lib.rs
+++ b/compiler/rustc_borrowck/src/lib.rs
@@ -537,13 +537,13 @@ fn borrowck_check_region_constraints<'tcx>(
         mbcx.report_region_errors(nll_errors);
     }
 
-    let (mut flow_analysis, flow_entry_states) =
+    let (flow_analysis, flow_results) =
         get_flow_results(tcx, body, &move_data, &borrow_set, &regioncx);
     visit_results(
         body,
         traversal::reverse_postorder(body).map(|(bb, _)| bb),
-        &mut flow_analysis,
-        &flow_entry_states,
+        &flow_analysis,
+        &flow_results,
         &mut mbcx,
     );
 
diff --git a/compiler/rustc_const_eval/src/check_consts/resolver.rs b/compiler/rustc_const_eval/src/check_consts/resolver.rs
index 664dda8701a6..e6e3948305af 100644
--- a/compiler/rustc_const_eval/src/check_consts/resolver.rs
+++ b/compiler/rustc_const_eval/src/check_consts/resolver.rs
@@ -332,7 +332,7 @@ where
     }
 
     fn apply_primary_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         statement: &mir::Statement<'tcx>,
         location: Location,
@@ -341,7 +341,7 @@ where
     }
 
     fn apply_primary_terminator_effect<'mir>(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         terminator: &'mir mir::Terminator<'tcx>,
         location: Location,
@@ -351,7 +351,7 @@ where
     }
 
     fn apply_call_return_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         block: BasicBlock,
         return_places: CallReturnPlaces<'_, 'tcx>,
diff --git a/compiler/rustc_mir_dataflow/src/framework/cursor.rs b/compiler/rustc_mir_dataflow/src/framework/cursor.rs
index 3f6e7a066192..8799caa3e28f 100644
--- a/compiler/rustc_mir_dataflow/src/framework/cursor.rs
+++ b/compiler/rustc_mir_dataflow/src/framework/cursor.rs
@@ -1,8 +1,7 @@
 //! Random access inspection of the results of a dataflow analysis.
 
-use std::borrow::Cow;
 use std::cmp::Ordering;
-use std::ops::{Deref, DerefMut};
+use std::ops::Deref;
 
 #[cfg(debug_assertions)]
 use rustc_index::bit_set::DenseBitSet;
@@ -10,30 +9,20 @@ use rustc_middle::mir::{self, BasicBlock, Location};
 
 use super::{Analysis, Direction, Effect, EffectIndex, Results};
 
-/// Some `ResultsCursor`s want to own an `Analysis`, and some want to borrow an `Analysis`, either
-/// mutable or immutably. This type allows all of the above. It's similar to `Cow`, but `Cow`
-/// doesn't allow mutable borrowing.
-enum CowMut<'a, T> {
-    BorrowedMut(&'a mut T),
+/// This is like `Cow`, but it lacks the `T: ToOwned` bound and doesn't support
+/// `to_owned`/`into_owned`.
+enum SimpleCow<'a, T> {
+    Borrowed(&'a T),
     Owned(T),
 }
 
-impl<T> Deref for CowMut<'_, T> {
+impl<T> Deref for SimpleCow<'_, T> {
     type Target = T;
 
     fn deref(&self) -> &T {
         match self {
-            CowMut::BorrowedMut(borrowed) => borrowed,
-            CowMut::Owned(owned) => owned,
-        }
-    }
-}
-
-impl<T> DerefMut for CowMut<'_, T> {
-    fn deref_mut(&mut self) -> &mut T {
-        match self {
-            CowMut::BorrowedMut(borrowed) => borrowed,
-            CowMut::Owned(owned) => owned,
+            SimpleCow::Borrowed(borrowed) => borrowed,
+            SimpleCow::Owned(owned) => owned,
         }
     }
 }
@@ -53,8 +42,8 @@ where
     A: Analysis<'tcx>,
 {
     body: &'mir mir::Body<'tcx>,
-    analysis: CowMut<'mir, A>,
-    results: Cow<'mir, Results<A::Domain>>,
+    analysis: SimpleCow<'mir, A>,
+    results: SimpleCow<'mir, Results<A::Domain>>,
     state: A::Domain,
 
     pos: CursorPosition,
@@ -84,8 +73,8 @@ where
 
     fn new(
         body: &'mir mir::Body<'tcx>,
-        analysis: CowMut<'mir, A>,
-        results: Cow<'mir, Results<A::Domain>>,
+        analysis: SimpleCow<'mir, A>,
+        results: SimpleCow<'mir, Results<A::Domain>>,
     ) -> Self {
         let bottom_value = analysis.bottom_value(body);
         ResultsCursor {
@@ -111,16 +100,16 @@ where
         analysis: A,
         results: Results<A::Domain>,
     ) -> Self {
-        Self::new(body, CowMut::Owned(analysis), Cow::Owned(results))
+        Self::new(body, SimpleCow::Owned(analysis), SimpleCow::Owned(results))
     }
 
     /// Returns a new cursor that borrows and inspects analysis results.
     pub fn new_borrowing(
         body: &'mir mir::Body<'tcx>,
-        analysis: &'mir mut A,
+        analysis: &'mir A,
         results: &'mir Results<A::Domain>,
     ) -> Self {
-        Self::new(body, CowMut::BorrowedMut(analysis), Cow::Borrowed(results))
+        Self::new(body, SimpleCow::Borrowed(analysis), SimpleCow::Borrowed(results))
     }
 
     /// Allows inspection of unreachable basic blocks even with `debug_assertions` enabled.
@@ -236,7 +225,7 @@ where
         let target_effect_index = effect.at_index(target.statement_index);
 
         A::Direction::apply_effects_in_range(
-            &mut *self.analysis,
+            &*self.analysis,
             &mut self.state,
             target.block,
             block_data,
@@ -251,8 +240,8 @@ where
     ///
     /// This can be used, e.g., to apply the call return effect directly to the cursor without
     /// creating an extra copy of the dataflow state.
-    pub fn apply_custom_effect(&mut self, f: impl FnOnce(&mut A, &mut A::Domain)) {
-        f(&mut self.analysis, &mut self.state);
+    pub fn apply_custom_effect(&mut self, f: impl FnOnce(&A, &mut A::Domain)) {
+        f(&self.analysis, &mut self.state);
         self.state_needs_reset = true;
     }
 }
diff --git a/compiler/rustc_mir_dataflow/src/framework/direction.rs b/compiler/rustc_mir_dataflow/src/framework/direction.rs
index 1dd8fc40006d..b15b5c07ce38 100644
--- a/compiler/rustc_mir_dataflow/src/framework/direction.rs
+++ b/compiler/rustc_mir_dataflow/src/framework/direction.rs
@@ -14,7 +14,7 @@ pub trait Direction {
 
     /// Called by `iterate_to_fixpoint` during initial analysis computation.
     fn apply_effects_in_block<'mir, 'tcx, A>(
-        analysis: &mut A,
+        analysis: &A,
         body: &mir::Body<'tcx>,
         state: &mut A::Domain,
         block: BasicBlock,
@@ -28,7 +28,7 @@ pub trait Direction {
     ///
     /// `effects.start()` must precede or equal `effects.end()` in this direction.
     fn apply_effects_in_range<'tcx, A>(
-        analysis: &mut A,
+        analysis: &A,
         state: &mut A::Domain,
         block: BasicBlock,
         block_data: &mir::BasicBlockData<'tcx>,
@@ -40,7 +40,7 @@ pub trait Direction {
     /// all locations in a basic block (starting from `entry_state` and to
     /// visit them with `vis`.
     fn visit_results_in_block<'mir, 'tcx, A>(
-        analysis: &mut A,
+        analysis: &A,
         state: &mut A::Domain,
         block: BasicBlock,
         block_data: &'mir mir::BasicBlockData<'tcx>,
@@ -56,7 +56,7 @@ impl Direction for Backward {
     const IS_FORWARD: bool = false;
 
     fn apply_effects_in_block<'mir, 'tcx, A>(
-        analysis: &mut A,
+        analysis: &A,
         body: &mir::Body<'tcx>,
         state: &mut A::Domain,
         block: BasicBlock,
@@ -129,7 +129,7 @@ impl Direction for Backward {
     }
 
     fn apply_effects_in_range<'tcx, A>(
-        analysis: &mut A,
+        analysis: &A,
         state: &mut A::Domain,
         block: BasicBlock,
         block_data: &mir::BasicBlockData<'tcx>,
@@ -206,7 +206,7 @@ impl Direction for Backward {
     }
 
     fn visit_results_in_block<'mir, 'tcx, A>(
-        analysis: &mut A,
+        analysis: &A,
         state: &mut A::Domain,
         block: BasicBlock,
         block_data: &'mir mir::BasicBlockData<'tcx>,
@@ -242,7 +242,7 @@ impl Direction for Forward {
     const IS_FORWARD: bool = true;
 
     fn apply_effects_in_block<'mir, 'tcx, A>(
-        analysis: &mut A,
+        analysis: &A,
         body: &mir::Body<'tcx>,
         state: &mut A::Domain,
         block: BasicBlock,
@@ -312,7 +312,7 @@ impl Direction for Forward {
     }
 
     fn apply_effects_in_range<'tcx, A>(
-        analysis: &mut A,
+        analysis: &A,
         state: &mut A::Domain,
         block: BasicBlock,
         block_data: &mir::BasicBlockData<'tcx>,
@@ -386,7 +386,7 @@ impl Direction for Forward {
     }
 
     fn visit_results_in_block<'mir, 'tcx, A>(
-        analysis: &mut A,
+        analysis: &A,
         state: &mut A::Domain,
         block: BasicBlock,
         block_data: &'mir mir::BasicBlockData<'tcx>,
diff --git a/compiler/rustc_mir_dataflow/src/framework/graphviz.rs b/compiler/rustc_mir_dataflow/src/framework/graphviz.rs
index a55b7a8f6733..f9d9106ba7af 100644
--- a/compiler/rustc_mir_dataflow/src/framework/graphviz.rs
+++ b/compiler/rustc_mir_dataflow/src/framework/graphviz.rs
@@ -1,7 +1,6 @@
 //! A helpful diagram for debugging dataflow problems.
 
 use std::borrow::Cow;
-use std::cell::RefCell;
 use std::ffi::OsString;
 use std::path::PathBuf;
 use std::sync::OnceLock;
@@ -33,7 +32,7 @@ use crate::errors::{
 pub(super) fn write_graphviz_results<'tcx, A>(
     tcx: TyCtxt<'tcx>,
     body: &Body<'tcx>,
-    analysis: &mut A,
+    analysis: &A,
     results: &Results<A::Domain>,
     pass_name: Option<&'static str>,
 ) -> std::io::Result<()>
@@ -206,11 +205,7 @@ where
     A: Analysis<'tcx>,
 {
     body: &'mir Body<'tcx>,
-    // The `RefCell` is used because `<Formatter as Labeller>::node_label`
-    // takes `&self`, but it needs to modify the analysis. This is also the
-    // reason for the `Formatter`/`BlockFormatter` split; `BlockFormatter` has
-    // the operations that involve the mutation, i.e. within the `borrow_mut`.
-    analysis: RefCell<&'mir mut A>,
+    analysis: &'mir A,
     results: &'mir Results<A::Domain>,
     style: OutputStyle,
     reachable: DenseBitSet<BasicBlock>,
@@ -222,12 +217,12 @@ where
 {
     fn new(
         body: &'mir Body<'tcx>,
-        analysis: &'mir mut A,
+        analysis: &'mir A,
         results: &'mir Results<A::Domain>,
         style: OutputStyle,
     ) -> Self {
         let reachable = traversal::reachable_as_bitset(body);
-        Formatter { body, analysis: analysis.into(), results, style, reachable }
+        Formatter { body, analysis, results, style, reachable }
     }
 }
 
@@ -265,12 +260,11 @@ where
     }
 
     fn node_label(&self, block: &Self::Node) -> dot::LabelText<'_> {
-        let analysis = &mut **self.analysis.borrow_mut();
-
-        let diffs = StateDiffCollector::run(self.body, *block, analysis, self.results, self.style);
+        let diffs =
+            StateDiffCollector::run(self.body, *block, self.analysis, self.results, self.style);
 
         let mut fmt = BlockFormatter {
-            cursor: ResultsCursor::new_borrowing(self.body, analysis, self.results),
+            cursor: ResultsCursor::new_borrowing(self.body, self.analysis, self.results),
             style: self.style,
             bg: Background::Light,
         };
@@ -698,7 +692,7 @@ impl<D> StateDiffCollector<D> {
     fn run<'tcx, A>(
         body: &Body<'tcx>,
         block: BasicBlock,
-        analysis: &mut A,
+        analysis: &A,
         results: &Results<A::Domain>,
         style: OutputStyle,
     ) -> Self
diff --git a/compiler/rustc_mir_dataflow/src/framework/mod.rs b/compiler/rustc_mir_dataflow/src/framework/mod.rs
index b6a560360195..9e1fc5a59fe3 100644
--- a/compiler/rustc_mir_dataflow/src/framework/mod.rs
+++ b/compiler/rustc_mir_dataflow/src/framework/mod.rs
@@ -136,7 +136,7 @@ pub trait Analysis<'tcx> {
     /// analyses should not implement this without also implementing
     /// `apply_primary_statement_effect`.
     fn apply_early_statement_effect(
-        &mut self,
+        &self,
         _state: &mut Self::Domain,
         _statement: &mir::Statement<'tcx>,
         _location: Location,
@@ -145,7 +145,7 @@ pub trait Analysis<'tcx> {
 
     /// Updates the current dataflow state with the effect of evaluating a statement.
     fn apply_primary_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         statement: &mir::Statement<'tcx>,
         location: Location,
@@ -159,7 +159,7 @@ pub trait Analysis<'tcx> {
     /// analyses should not implement this without also implementing
     /// `apply_primary_terminator_effect`.
     fn apply_early_terminator_effect(
-        &mut self,
+        &self,
         _state: &mut Self::Domain,
         _terminator: &mir::Terminator<'tcx>,
         _location: Location,
@@ -173,7 +173,7 @@ pub trait Analysis<'tcx> {
     /// `InitializedPlaces` analyses, the return place for a function call is not marked as
     /// initialized here.
     fn apply_primary_terminator_effect<'mir>(
-        &mut self,
+        &self,
         _state: &mut Self::Domain,
         terminator: &'mir mir::Terminator<'tcx>,
         _location: Location,
@@ -189,7 +189,7 @@ pub trait Analysis<'tcx> {
     /// This is separate from `apply_primary_terminator_effect` to properly track state across
     /// unwind edges.
     fn apply_call_return_effect(
-        &mut self,
+        &self,
         _state: &mut Self::Domain,
         _block: BasicBlock,
         _return_places: CallReturnPlaces<'_, 'tcx>,
@@ -211,7 +211,7 @@ pub trait Analysis<'tcx> {
     /// engine doesn't need to clone the exit state for a block unless
     /// `get_switch_int_data` is actually called.
     fn get_switch_int_data(
-        &mut self,
+        &self,
         _block: mir::BasicBlock,
         _discr: &mir::Operand<'tcx>,
     ) -> Option<Self::SwitchIntData> {
@@ -220,7 +220,7 @@ pub trait Analysis<'tcx> {
 
     /// See comments on `get_switch_int_data`.
     fn apply_switch_int_edge_effect(
-        &mut self,
+        &self,
         _data: &mut Self::SwitchIntData,
         _state: &mut Self::Domain,
         _value: SwitchTargetValue,
@@ -245,7 +245,7 @@ pub trait Analysis<'tcx> {
     /// Without a `pass_name` to differentiates them, only the results for the latest run will be
     /// saved.
     fn iterate_to_fixpoint<'mir>(
-        mut self,
+        self,
         tcx: TyCtxt<'tcx>,
         body: &'mir mir::Body<'tcx>,
         pass_name: Option<&'static str>,
@@ -285,7 +285,7 @@ pub trait Analysis<'tcx> {
             state.clone_from(&results[bb]);
 
             Self::Direction::apply_effects_in_block(
-                &mut self,
+                &self,
                 body,
                 &mut state,
                 bb,
@@ -300,7 +300,7 @@ pub trait Analysis<'tcx> {
         }
 
         if tcx.sess.opts.unstable_opts.dump_mir_dataflow {
-            let res = write_graphviz_results(tcx, body, &mut self, &results, pass_name);
+            let res = write_graphviz_results(tcx, body, &self, &results, pass_name);
             if let Err(e) = res {
                 error!("Failed to write graphviz dataflow results: {}", e);
             }
diff --git a/compiler/rustc_mir_dataflow/src/framework/tests.rs b/compiler/rustc_mir_dataflow/src/framework/tests.rs
index 23e28a11a452..36d0f3a947bc 100644
--- a/compiler/rustc_mir_dataflow/src/framework/tests.rs
+++ b/compiler/rustc_mir_dataflow/src/framework/tests.rs
@@ -175,7 +175,7 @@ impl<'tcx, D: Direction> Analysis<'tcx> for MockAnalysis<'tcx, D> {
     }
 
     fn apply_early_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         _statement: &mir::Statement<'tcx>,
         location: Location,
@@ -185,7 +185,7 @@ impl<'tcx, D: Direction> Analysis<'tcx> for MockAnalysis<'tcx, D> {
     }
 
     fn apply_primary_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         _statement: &mir::Statement<'tcx>,
         location: Location,
@@ -195,7 +195,7 @@ impl<'tcx, D: Direction> Analysis<'tcx> for MockAnalysis<'tcx, D> {
     }
 
     fn apply_early_terminator_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         _terminator: &mir::Terminator<'tcx>,
         location: Location,
@@ -205,7 +205,7 @@ impl<'tcx, D: Direction> Analysis<'tcx> for MockAnalysis<'tcx, D> {
     }
 
     fn apply_primary_terminator_effect<'mir>(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         terminator: &'mir mir::Terminator<'tcx>,
         location: Location,
diff --git a/compiler/rustc_mir_dataflow/src/framework/visitor.rs b/compiler/rustc_mir_dataflow/src/framework/visitor.rs
index 9ec59dff0548..28ae08d1e6b1 100644
--- a/compiler/rustc_mir_dataflow/src/framework/visitor.rs
+++ b/compiler/rustc_mir_dataflow/src/framework/visitor.rs
@@ -7,7 +7,7 @@ use super::{Analysis, Direction, Results};
 pub fn visit_results<'mir, 'tcx, A>(
     body: &'mir mir::Body<'tcx>,
     blocks: impl IntoIterator<Item = BasicBlock>,
-    analysis: &mut A,
+    analysis: &A,
     results: &Results<A::Domain>,
     vis: &mut impl ResultsVisitor<'tcx, A>,
 ) where
@@ -31,7 +31,7 @@ pub fn visit_results<'mir, 'tcx, A>(
 /// Like `visit_results`, but only for reachable blocks.
 pub fn visit_reachable_results<'mir, 'tcx, A>(
     body: &'mir mir::Body<'tcx>,
-    analysis: &mut A,
+    analysis: &A,
     results: &Results<A::Domain>,
     vis: &mut impl ResultsVisitor<'tcx, A>,
 ) where
diff --git a/compiler/rustc_mir_dataflow/src/impls/borrowed_locals.rs b/compiler/rustc_mir_dataflow/src/impls/borrowed_locals.rs
index a4e4e30a8bb6..331e41bd126b 100644
--- a/compiler/rustc_mir_dataflow/src/impls/borrowed_locals.rs
+++ b/compiler/rustc_mir_dataflow/src/impls/borrowed_locals.rs
@@ -11,7 +11,6 @@ use crate::{Analysis, GenKill};
 /// At present, this is used as a very limited form of alias analysis. For example,
 /// `MaybeBorrowedLocals` is used to compute which locals are live during a yield expression for
 /// immovable coroutines.
-#[derive(Clone)]
 pub struct MaybeBorrowedLocals;
 
 impl MaybeBorrowedLocals {
@@ -34,7 +33,7 @@ impl<'tcx> Analysis<'tcx> for MaybeBorrowedLocals {
     }
 
     fn apply_primary_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         statement: &Statement<'tcx>,
         location: Location,
@@ -43,7 +42,7 @@ impl<'tcx> Analysis<'tcx> for MaybeBorrowedLocals {
     }
 
     fn apply_primary_terminator_effect<'mir>(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         terminator: &'mir Terminator<'tcx>,
         location: Location,
diff --git a/compiler/rustc_mir_dataflow/src/impls/initialized.rs b/compiler/rustc_mir_dataflow/src/impls/initialized.rs
index 5937d68f389e..9216106b6edd 100644
--- a/compiler/rustc_mir_dataflow/src/impls/initialized.rs
+++ b/compiler/rustc_mir_dataflow/src/impls/initialized.rs
@@ -376,7 +376,7 @@ impl<'tcx> Analysis<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
     }
 
     fn apply_primary_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         statement: &mir::Statement<'tcx>,
         location: Location,
@@ -400,7 +400,7 @@ impl<'tcx> Analysis<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
     }
 
     fn apply_primary_terminator_effect<'mir>(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         terminator: &'mir mir::Terminator<'tcx>,
         location: Location,
@@ -429,7 +429,7 @@ impl<'tcx> Analysis<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
     }
 
     fn apply_call_return_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         _block: mir::BasicBlock,
         return_places: CallReturnPlaces<'_, 'tcx>,
@@ -448,7 +448,7 @@ impl<'tcx> Analysis<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
     }
 
     fn get_switch_int_data(
-        &mut self,
+        &self,
         block: mir::BasicBlock,
         discr: &mir::Operand<'tcx>,
     ) -> Option<Self::SwitchIntData> {
@@ -460,7 +460,7 @@ impl<'tcx> Analysis<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
     }
 
     fn apply_switch_int_edge_effect(
-        &mut self,
+        &self,
         data: &mut Self::SwitchIntData,
         state: &mut Self::Domain,
         value: SwitchTargetValue,
@@ -513,7 +513,7 @@ impl<'tcx> Analysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
     }
 
     fn apply_primary_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         _statement: &mir::Statement<'tcx>,
         location: Location,
@@ -527,7 +527,7 @@ impl<'tcx> Analysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
     }
 
     fn apply_primary_terminator_effect<'mir>(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         terminator: &'mir mir::Terminator<'tcx>,
         location: Location,
@@ -545,7 +545,7 @@ impl<'tcx> Analysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
     }
 
     fn apply_call_return_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         _block: mir::BasicBlock,
         return_places: CallReturnPlaces<'_, 'tcx>,
@@ -564,7 +564,7 @@ impl<'tcx> Analysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
     }
 
     fn get_switch_int_data(
-        &mut self,
+        &self,
         block: mir::BasicBlock,
         discr: &mir::Operand<'tcx>,
     ) -> Option<Self::SwitchIntData> {
@@ -580,7 +580,7 @@ impl<'tcx> Analysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
     }
 
     fn apply_switch_int_edge_effect(
-        &mut self,
+        &self,
         data: &mut Self::SwitchIntData,
         state: &mut Self::Domain,
         value: SwitchTargetValue,
@@ -627,7 +627,7 @@ impl<'tcx> Analysis<'tcx> for EverInitializedPlaces<'_, 'tcx> {
 
     #[instrument(skip(self, state), level = "debug")]
     fn apply_primary_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         stmt: &mir::Statement<'tcx>,
         location: Location,
@@ -652,7 +652,7 @@ impl<'tcx> Analysis<'tcx> for EverInitializedPlaces<'_, 'tcx> {
 
     #[instrument(skip(self, state, terminator), level = "debug")]
     fn apply_primary_terminator_effect<'mir>(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         terminator: &'mir mir::Terminator<'tcx>,
         location: Location,
@@ -674,7 +674,7 @@ impl<'tcx> Analysis<'tcx> for EverInitializedPlaces<'_, 'tcx> {
     }
 
     fn apply_call_return_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         block: mir::BasicBlock,
         _return_places: CallReturnPlaces<'_, 'tcx>,
diff --git a/compiler/rustc_mir_dataflow/src/impls/liveness.rs b/compiler/rustc_mir_dataflow/src/impls/liveness.rs
index 596da18e3d1b..e439f2e052fe 100644
--- a/compiler/rustc_mir_dataflow/src/impls/liveness.rs
+++ b/compiler/rustc_mir_dataflow/src/impls/liveness.rs
@@ -41,7 +41,7 @@ impl<'tcx> Analysis<'tcx> for MaybeLiveLocals {
     }
 
     fn apply_primary_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         statement: &mir::Statement<'tcx>,
         location: Location,
@@ -50,7 +50,7 @@ impl<'tcx> Analysis<'tcx> for MaybeLiveLocals {
     }
 
     fn apply_primary_terminator_effect<'mir>(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         terminator: &'mir mir::Terminator<'tcx>,
         location: Location,
@@ -60,7 +60,7 @@ impl<'tcx> Analysis<'tcx> for MaybeLiveLocals {
     }
 
     fn apply_call_return_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         _block: mir::BasicBlock,
         return_places: CallReturnPlaces<'_, 'tcx>,
@@ -278,7 +278,7 @@ impl<'a, 'tcx> Analysis<'tcx> for MaybeTransitiveLiveLocals<'a> {
     }
 
     fn apply_primary_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         statement: &mir::Statement<'tcx>,
         location: Location,
@@ -294,7 +294,7 @@ impl<'a, 'tcx> Analysis<'tcx> for MaybeTransitiveLiveLocals<'a> {
     }
 
     fn apply_primary_terminator_effect<'mir>(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         terminator: &'mir mir::Terminator<'tcx>,
         location: Location,
@@ -304,7 +304,7 @@ impl<'a, 'tcx> Analysis<'tcx> for MaybeTransitiveLiveLocals<'a> {
     }
 
     fn apply_call_return_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         _block: mir::BasicBlock,
         return_places: CallReturnPlaces<'_, 'tcx>,
diff --git a/compiler/rustc_mir_dataflow/src/impls/storage_liveness.rs b/compiler/rustc_mir_dataflow/src/impls/storage_liveness.rs
index a01db72ff7f7..3702f7c55a43 100644
--- a/compiler/rustc_mir_dataflow/src/impls/storage_liveness.rs
+++ b/compiler/rustc_mir_dataflow/src/impls/storage_liveness.rs
@@ -54,7 +54,7 @@ impl<'a, 'tcx> Analysis<'tcx> for MaybeStorageLive<'a> {
     }
 
     fn apply_primary_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         stmt: &Statement<'tcx>,
         _: Location,
@@ -98,7 +98,7 @@ impl<'a, 'tcx> Analysis<'tcx> for MaybeStorageDead<'a> {
     }
 
     fn apply_primary_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         stmt: &Statement<'tcx>,
         _: Location,
@@ -144,7 +144,7 @@ impl<'tcx> Analysis<'tcx> for MaybeRequiresStorage<'_, 'tcx> {
     }
 
     fn apply_early_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         stmt: &Statement<'tcx>,
         loc: Location,
@@ -177,7 +177,7 @@ impl<'tcx> Analysis<'tcx> for MaybeRequiresStorage<'_, 'tcx> {
     }
 
     fn apply_primary_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         _: &Statement<'tcx>,
         loc: Location,
@@ -188,7 +188,7 @@ impl<'tcx> Analysis<'tcx> for MaybeRequiresStorage<'_, 'tcx> {
     }
 
     fn apply_early_terminator_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         terminator: &Terminator<'tcx>,
         loc: Location,
@@ -243,7 +243,7 @@ impl<'tcx> Analysis<'tcx> for MaybeRequiresStorage<'_, 'tcx> {
     }
 
     fn apply_primary_terminator_effect<'t>(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         terminator: &'t Terminator<'tcx>,
         loc: Location,
@@ -284,7 +284,7 @@ impl<'tcx> Analysis<'tcx> for MaybeRequiresStorage<'_, 'tcx> {
     }
 
     fn apply_call_return_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         _block: BasicBlock,
         return_places: CallReturnPlaces<'_, 'tcx>,
diff --git a/compiler/rustc_mir_transform/src/coroutine.rs b/compiler/rustc_mir_transform/src/coroutine.rs
index fef93c5c5bdc..1fc109533ca2 100644
--- a/compiler/rustc_mir_transform/src/coroutine.rs
+++ b/compiler/rustc_mir_transform/src/coroutine.rs
@@ -720,27 +720,16 @@ fn locals_live_across_suspend_points<'tcx>(
 
     // Calculate the MIR locals that have been previously borrowed (even if they are still active).
     let borrowed_locals = MaybeBorrowedLocals.iterate_to_fixpoint(tcx, body, Some("coroutine"));
-    let mut borrowed_locals_analysis1 = borrowed_locals.analysis;
-    let mut borrowed_locals_analysis2 = borrowed_locals_analysis1.clone(); // trivial
-    let borrowed_locals_cursor1 = ResultsCursor::new_borrowing(
-        body,
-        &mut borrowed_locals_analysis1,
-        &borrowed_locals.results,
-    );
-    let mut borrowed_locals_cursor2 = ResultsCursor::new_borrowing(
-        body,
-        &mut borrowed_locals_analysis2,
-        &borrowed_locals.results,
-    );
+    let borrowed_locals_cursor1 =
+        ResultsCursor::new_borrowing(body, &MaybeBorrowedLocals, &borrowed_locals.results);
+    let mut borrowed_locals_cursor2 =
+        ResultsCursor::new_borrowing(body, &MaybeBorrowedLocals, &borrowed_locals.results);
 
     // Calculate the MIR locals that we need to keep storage around for.
-    let mut requires_storage =
+    let requires_storage =
         MaybeRequiresStorage::new(borrowed_locals_cursor1).iterate_to_fixpoint(tcx, body, None);
-    let mut requires_storage_cursor = ResultsCursor::new_borrowing(
-        body,
-        &mut requires_storage.analysis,
-        &requires_storage.results,
-    );
+    let mut requires_storage_cursor =
+        ResultsCursor::new_borrowing(body, &requires_storage.analysis, &requires_storage.results);
 
     // Calculate the liveness of MIR locals ignoring borrows.
     let mut liveness =
@@ -812,7 +801,7 @@ fn locals_live_across_suspend_points<'tcx>(
         body,
         &saved_locals,
         always_live_locals.clone(),
-        &mut requires_storage.analysis,
+        &requires_storage.analysis,
         &requires_storage.results,
     );
 
@@ -878,7 +867,7 @@ fn compute_storage_conflicts<'mir, 'tcx>(
     body: &'mir Body<'tcx>,
     saved_locals: &'mir CoroutineSavedLocals,
     always_live_locals: DenseBitSet<Local>,
-    analysis: &mut MaybeRequiresStorage<'mir, 'tcx>,
+    analysis: &MaybeRequiresStorage<'mir, 'tcx>,
     results: &Results<DenseBitSet<Local>>,
 ) -> BitMatrix<CoroutineSavedLocal, CoroutineSavedLocal> {
     assert_eq!(body.local_decls.len(), saved_locals.domain_size());
diff --git a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
index 433100ef95fb..f849a788c361 100644
--- a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
+++ b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
@@ -61,13 +61,13 @@ impl<'tcx> crate::MirPass<'tcx> for DataflowConstProp {
         let map = Map::new(tcx, body, place_limit);
 
         // Perform the actual dataflow analysis.
-        let mut const_ = debug_span!("analyze")
+        let const_ = debug_span!("analyze")
             .in_scope(|| ConstAnalysis::new(tcx, body, map).iterate_to_fixpoint(tcx, body, None));
 
         // Collect results and patch the body afterwards.
         let mut visitor = Collector::new(tcx, &body.local_decls);
         debug_span!("collect").in_scope(|| {
-            visit_reachable_results(body, &mut const_.analysis, &const_.results, &mut visitor)
+            visit_reachable_results(body, &const_.analysis, &const_.results, &mut visitor)
         });
         let mut patch = visitor.patch;
         debug_span!("patch").in_scope(|| patch.visit_body_preserves_cfg(body));
@@ -112,7 +112,7 @@ impl<'tcx> Analysis<'tcx> for ConstAnalysis<'_, 'tcx> {
     }
 
     fn apply_primary_statement_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         statement: &Statement<'tcx>,
         _location: Location,
@@ -123,7 +123,7 @@ impl<'tcx> Analysis<'tcx> for ConstAnalysis<'_, 'tcx> {
     }
 
     fn apply_primary_terminator_effect<'mir>(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         terminator: &'mir Terminator<'tcx>,
         _location: Location,
@@ -136,7 +136,7 @@ impl<'tcx> Analysis<'tcx> for ConstAnalysis<'_, 'tcx> {
     }
 
     fn apply_call_return_effect(
-        &mut self,
+        &self,
         state: &mut Self::Domain,
         _block: BasicBlock,
         return_places: CallReturnPlaces<'_, 'tcx>,
diff --git a/compiler/rustc_mir_transform/src/liveness.rs b/compiler/rustc_mir_transform/src/liveness.rs
index 82f9dfe4745d..840bb169a1fa 100644
--- a/compiler/rustc_mir_transform/src/liveness.rs
+++ b/compiler/rustc_mir_transform/src/liveness.rs
@@ -1160,7 +1160,7 @@ impl<'tcx> Analysis<'tcx> for MaybeLivePlaces<'_, 'tcx> {
     }
 
     fn apply_primary_statement_effect(
-        &mut self,
+        &self,
         trans: &mut Self::Domain,
         statement: &Statement<'tcx>,
         location: Location,
@@ -1169,7 +1169,7 @@ impl<'tcx> Analysis<'tcx> for MaybeLivePlaces<'_, 'tcx> {
     }
 
     fn apply_primary_terminator_effect<'mir>(
-        &mut self,
+        &self,
         trans: &mut Self::Domain,
         terminator: &'mir Terminator<'tcx>,
         location: Location,
@@ -1179,7 +1179,7 @@ impl<'tcx> Analysis<'tcx> for MaybeLivePlaces<'_, 'tcx> {
     }
 
     fn apply_call_return_effect(
-        &mut self,
+        &self,
         _trans: &mut Self::Domain,
         _block: BasicBlock,
         _return_places: CallReturnPlaces<'_, 'tcx>,