diff --git a/compiler/rustc_mir_transform/src/abort_unwinding_calls.rs b/compiler/rustc_mir_transform/src/abort_unwinding_calls.rs
index e4bc6b3efe422..8291df9be5349 100644
--- a/compiler/rustc_mir_transform/src/abort_unwinding_calls.rs
+++ b/compiler/rustc_mir_transform/src/abort_unwinding_calls.rs
@@ -20,7 +20,7 @@ use rustc_target::spec::PanicStrategy;
 /// This forces all unwinds, in panic=abort mode happening in foreign code, to
 /// trigger a process abort.
 #[derive(PartialEq)]
-pub struct AbortUnwindingCalls;
+pub(super) struct AbortUnwindingCalls;
 
 impl<'tcx> crate::MirPass<'tcx> for AbortUnwindingCalls {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
@@ -50,9 +50,7 @@ impl<'tcx> crate::MirPass<'tcx> for AbortUnwindingCalls {
         // with a function call, and whose function we're calling may unwind.
         // This will filter to functions with `extern "C-unwind"` ABIs, for
         // example.
-        let mut calls_to_terminate = Vec::new();
-        let mut cleanups_to_remove = Vec::new();
-        for (id, block) in body.basic_blocks.iter_enumerated() {
+        for block in body.basic_blocks.as_mut() {
             if block.is_cleanup {
                 continue;
             }
@@ -61,7 +59,7 @@ impl<'tcx> crate::MirPass<'tcx> for AbortUnwindingCalls {
 
             let call_can_unwind = match &terminator.kind {
                 TerminatorKind::Call { func, .. } => {
-                    let ty = func.ty(body, tcx);
+                    let ty = func.ty(&body.local_decls, tcx);
                     let sig = ty.fn_sig(tcx);
                     let fn_def_id = match ty.kind() {
                         ty::FnPtr(..) => None,
@@ -86,33 +84,22 @@ impl<'tcx> crate::MirPass<'tcx> for AbortUnwindingCalls {
                 _ => continue,
             };
 
-            // If this function call can't unwind, then there's no need for it
-            // to have a landing pad. This means that we can remove any cleanup
-            // registered for it.
             if !call_can_unwind {
-                cleanups_to_remove.push(id);
-                continue;
-            }
-
-            // Otherwise if this function can unwind, then if the outer function
-            // can also unwind there's nothing to do. If the outer function
-            // can't unwind, however, we need to change the landing pad for this
-            // function call to one that aborts.
-            if !body_can_unwind {
-                calls_to_terminate.push(id);
+                // If this function call can't unwind, then there's no need for it
+                // to have a landing pad. This means that we can remove any cleanup
+                // registered for it.
+                let cleanup = block.terminator_mut().unwind_mut().unwrap();
+                *cleanup = UnwindAction::Unreachable;
+            } else if !body_can_unwind {
+                // Otherwise if this function can unwind, then if the outer function
+                // can also unwind there's nothing to do. If the outer function
+                // can't unwind, however, we need to change the landing pad for this
+                // function call to one that aborts.
+                let cleanup = block.terminator_mut().unwind_mut().unwrap();
+                *cleanup = UnwindAction::Terminate(UnwindTerminateReason::Abi);
             }
         }
 
-        for id in calls_to_terminate {
-            let cleanup = body.basic_blocks_mut()[id].terminator_mut().unwind_mut().unwrap();
-            *cleanup = UnwindAction::Terminate(UnwindTerminateReason::Abi);
-        }
-
-        for id in cleanups_to_remove {
-            let cleanup = body.basic_blocks_mut()[id].terminator_mut().unwind_mut().unwrap();
-            *cleanup = UnwindAction::Unreachable;
-        }
-
         // We may have invalidated some `cleanup` blocks so clean those up now.
         super::simplify::remove_dead_blocks(body);
     }
diff --git a/compiler/rustc_mir_transform/src/add_call_guards.rs b/compiler/rustc_mir_transform/src/add_call_guards.rs
index 78e850de3c772..18a0746f54f08 100644
--- a/compiler/rustc_mir_transform/src/add_call_guards.rs
+++ b/compiler/rustc_mir_transform/src/add_call_guards.rs
@@ -4,11 +4,11 @@ use rustc_middle::ty::TyCtxt;
 use tracing::debug;
 
 #[derive(PartialEq)]
-pub enum AddCallGuards {
+pub(super) enum AddCallGuards {
     AllCallEdges,
     CriticalCallEdges,
 }
-pub use self::AddCallGuards::*;
+pub(super) use self::AddCallGuards::*;
 
 /**
  * Breaks outgoing critical edges for call terminators in the MIR.
@@ -37,7 +37,7 @@ impl<'tcx> crate::MirPass<'tcx> for AddCallGuards {
 }
 
 impl AddCallGuards {
-    pub fn add_call_guards(&self, body: &mut Body<'_>) {
+    pub(super) fn add_call_guards(&self, body: &mut Body<'_>) {
         let mut pred_count: IndexVec<_, _> =
             body.basic_blocks.predecessors().iter().map(|ps| ps.len()).collect();
         pred_count[START_BLOCK] += 1;
diff --git a/compiler/rustc_mir_transform/src/add_moves_for_packed_drops.rs b/compiler/rustc_mir_transform/src/add_moves_for_packed_drops.rs
index 4a8196aeff5b0..47572d8d3b22b 100644
--- a/compiler/rustc_mir_transform/src/add_moves_for_packed_drops.rs
+++ b/compiler/rustc_mir_transform/src/add_moves_for_packed_drops.rs
@@ -35,7 +35,7 @@ use crate::util;
 ///
 /// The storage instructions are required to avoid stack space
 /// blowup.
-pub struct AddMovesForPackedDrops;
+pub(super) struct AddMovesForPackedDrops;
 
 impl<'tcx> crate::MirPass<'tcx> for AddMovesForPackedDrops {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
@@ -44,7 +44,7 @@ impl<'tcx> crate::MirPass<'tcx> for AddMovesForPackedDrops {
     }
 }
 
-pub fn add_moves_for_packed_drops<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
+fn add_moves_for_packed_drops<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     let patch = add_moves_for_packed_drops_patch(tcx, body);
     patch.apply(body);
 }
diff --git a/compiler/rustc_mir_transform/src/add_retag.rs b/compiler/rustc_mir_transform/src/add_retag.rs
index 2e12064fe7351..794e85fbfedfb 100644
--- a/compiler/rustc_mir_transform/src/add_retag.rs
+++ b/compiler/rustc_mir_transform/src/add_retag.rs
@@ -8,7 +8,7 @@ use rustc_hir::LangItem;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 
-pub struct AddRetag;
+pub(super) struct AddRetag;
 
 /// Determine whether this type may contain a reference (or box), and thus needs retagging.
 /// We will only recurse `depth` times into Tuples/ADTs to bound the cost of this.
diff --git a/compiler/rustc_mir_transform/src/add_subtyping_projections.rs b/compiler/rustc_mir_transform/src/add_subtyping_projections.rs
index 369f6c6008440..ab6bf18b30cb3 100644
--- a/compiler/rustc_mir_transform/src/add_subtyping_projections.rs
+++ b/compiler/rustc_mir_transform/src/add_subtyping_projections.rs
@@ -1,15 +1,14 @@
-use rustc_index::IndexVec;
 use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::visit::MutVisitor;
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 
-pub struct Subtyper;
+pub(super) struct Subtyper;
 
-pub struct SubTypeChecker<'a, 'tcx> {
+struct SubTypeChecker<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
     patcher: MirPatch<'tcx>,
-    local_decls: &'a IndexVec<Local, LocalDecl<'tcx>>,
+    local_decls: &'a LocalDecls<'tcx>,
 }
 
 impl<'a, 'tcx> MutVisitor<'tcx> for SubTypeChecker<'a, 'tcx> {
@@ -52,7 +51,7 @@ impl<'a, 'tcx> MutVisitor<'tcx> for SubTypeChecker<'a, 'tcx> {
 // // gets transformed to
 // let temp: rval_ty = rval;
 // let place: place_ty = temp as place_ty;
-pub fn subtype_finder<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
+fn subtype_finder<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     let patch = MirPatch::new(body);
     let mut checker = SubTypeChecker { tcx, patcher: patch, local_decls: &body.local_decls };
 
diff --git a/compiler/rustc_mir_transform/src/check_alignment.rs b/compiler/rustc_mir_transform/src/check_alignment.rs
index 2e072aa262aac..e1d5152ae5150 100644
--- a/compiler/rustc_mir_transform/src/check_alignment.rs
+++ b/compiler/rustc_mir_transform/src/check_alignment.rs
@@ -7,7 +7,7 @@ use rustc_middle::ty::{self, ParamEnv, Ty, TyCtxt};
 use rustc_session::Session;
 use tracing::{debug, trace};
 
-pub struct CheckAlignment;
+pub(super) struct CheckAlignment;
 
 impl<'tcx> crate::MirPass<'tcx> for CheckAlignment {
     fn is_enabled(&self, sess: &Session) -> bool {
diff --git a/compiler/rustc_mir_transform/src/check_const_item_mutation.rs b/compiler/rustc_mir_transform/src/check_const_item_mutation.rs
index fb03323e37e6e..234ed8206f5d5 100644
--- a/compiler/rustc_mir_transform/src/check_const_item_mutation.rs
+++ b/compiler/rustc_mir_transform/src/check_const_item_mutation.rs
@@ -8,7 +8,7 @@ use rustc_span::Span;
 
 use crate::errors;
 
-pub struct CheckConstItemMutation;
+pub(super) struct CheckConstItemMutation;
 
 impl<'tcx> crate::MirLint<'tcx> for CheckConstItemMutation {
     fn run_lint(&self, tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
diff --git a/compiler/rustc_mir_transform/src/check_packed_ref.rs b/compiler/rustc_mir_transform/src/check_packed_ref.rs
index 2f957de7e78d8..1922d4fef25de 100644
--- a/compiler/rustc_mir_transform/src/check_packed_ref.rs
+++ b/compiler/rustc_mir_transform/src/check_packed_ref.rs
@@ -5,7 +5,7 @@ use rustc_middle::ty::{self, TyCtxt};
 
 use crate::{errors, util};
 
-pub struct CheckPackedRef;
+pub(super) struct CheckPackedRef;
 
 impl<'tcx> crate::MirLint<'tcx> for CheckPackedRef {
     fn run_lint(&self, tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
diff --git a/compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs b/compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs
index 2f3be1e425d8d..97ce16c06616f 100644
--- a/compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs
+++ b/compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs
@@ -21,7 +21,7 @@ use rustc_middle::mir::{Body, BorrowKind, CastKind, Rvalue, StatementKind, Termi
 use rustc_middle::ty::adjustment::PointerCoercion;
 use rustc_middle::ty::TyCtxt;
 
-pub struct CleanupPostBorrowck;
+pub(super) struct CleanupPostBorrowck;
 
 impl<'tcx> crate::MirPass<'tcx> for CleanupPostBorrowck {
     fn run_pass(&self, _tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
diff --git a/compiler/rustc_mir_transform/src/copy_prop.rs b/compiler/rustc_mir_transform/src/copy_prop.rs
index 85d25ca22318d..dc4ee58ea83e3 100644
--- a/compiler/rustc_mir_transform/src/copy_prop.rs
+++ b/compiler/rustc_mir_transform/src/copy_prop.rs
@@ -17,7 +17,7 @@ use crate::ssa::SsaLocals;
 /// where each of the locals is only assigned once.
 ///
 /// We want to replace all those locals by `_a`, either copied or moved.
-pub struct CopyProp;
+pub(super) struct CopyProp;
 
 impl<'tcx> crate::MirPass<'tcx> for CopyProp {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
diff --git a/compiler/rustc_mir_transform/src/coroutine.rs b/compiler/rustc_mir_transform/src/coroutine.rs
index eefb748e49d51..a9c56174206f1 100644
--- a/compiler/rustc_mir_transform/src/coroutine.rs
+++ b/compiler/rustc_mir_transform/src/coroutine.rs
@@ -53,7 +53,7 @@
 mod by_move_body;
 use std::{iter, ops};
 
-pub use by_move_body::coroutine_by_move_body_def_id;
+pub(super) use by_move_body::coroutine_by_move_body_def_id;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::pluralize;
 use rustc_hir as hir;
@@ -85,7 +85,7 @@ use tracing::{debug, instrument, trace};
 use crate::deref_separator::deref_finder;
 use crate::{abort_unwinding_calls, errors, pass_manager as pm, simplify};
 
-pub struct StateTransform;
+pub(super) struct StateTransform;
 
 struct RenameLocalVisitor<'tcx> {
     from: Local,
@@ -1199,7 +1199,7 @@ fn insert_panic_block<'tcx>(
     message: AssertMessage<'tcx>,
 ) -> BasicBlock {
     let assert_block = BasicBlock::new(body.basic_blocks.len());
-    let term = TerminatorKind::Assert {
+    let kind = TerminatorKind::Assert {
         cond: Operand::Constant(Box::new(ConstOperand {
             span: body.span,
             user_ty: None,
@@ -1211,14 +1211,7 @@ fn insert_panic_block<'tcx>(
         unwind: UnwindAction::Continue,
     };
 
-    let source_info = SourceInfo::outermost(body.span);
-    body.basic_blocks_mut().push(BasicBlockData {
-        statements: Vec::new(),
-        terminator: Some(Terminator { source_info, kind: term }),
-        is_cleanup: false,
-    });
-
-    assert_block
+    insert_term_block(body, kind)
 }
 
 fn can_return<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>, param_env: ty::ParamEnv<'tcx>) -> bool {
diff --git a/compiler/rustc_mir_transform/src/coroutine/by_move_body.rs b/compiler/rustc_mir_transform/src/coroutine/by_move_body.rs
index 9e35dfed0ee8d..6476f3c623841 100644
--- a/compiler/rustc_mir_transform/src/coroutine/by_move_body.rs
+++ b/compiler/rustc_mir_transform/src/coroutine/by_move_body.rs
@@ -82,7 +82,7 @@ use rustc_middle::ty::{self, InstanceKind, Ty, TyCtxt, TypeVisitableExt};
 use rustc_span::symbol::kw;
 use rustc_target::abi::{FieldIdx, VariantIdx};
 
-pub fn coroutine_by_move_body_def_id<'tcx>(
+pub(crate) fn coroutine_by_move_body_def_id<'tcx>(
     tcx: TyCtxt<'tcx>,
     coroutine_def_id: LocalDefId,
 ) -> DefId {
diff --git a/compiler/rustc_mir_transform/src/cost_checker.rs b/compiler/rustc_mir_transform/src/cost_checker.rs
index a1c1422912ee3..59b403538a33d 100644
--- a/compiler/rustc_mir_transform/src/cost_checker.rs
+++ b/compiler/rustc_mir_transform/src/cost_checker.rs
@@ -12,7 +12,7 @@ const CONST_SWITCH_BONUS: usize = 10;
 
 /// Verify that the callee body is compatible with the caller.
 #[derive(Clone)]
-pub(crate) struct CostChecker<'b, 'tcx> {
+pub(super) struct CostChecker<'b, 'tcx> {
     tcx: TyCtxt<'tcx>,
     param_env: ParamEnv<'tcx>,
     penalty: usize,
@@ -22,7 +22,7 @@ pub(crate) struct CostChecker<'b, 'tcx> {
 }
 
 impl<'b, 'tcx> CostChecker<'b, 'tcx> {
-    pub fn new(
+    pub(super) fn new(
         tcx: TyCtxt<'tcx>,
         param_env: ParamEnv<'tcx>,
         instance: Option<ty::Instance<'tcx>>,
@@ -36,7 +36,7 @@ impl<'b, 'tcx> CostChecker<'b, 'tcx> {
     /// Needed because the `CostChecker` is used sometimes for just blocks,
     /// and even the full `Inline` doesn't call `visit_body`, so there's nowhere
     /// to put this logic in the visitor.
-    pub fn add_function_level_costs(&mut self) {
+    pub(super) fn add_function_level_costs(&mut self) {
         fn is_call_like(bbd: &BasicBlockData<'_>) -> bool {
             use TerminatorKind::*;
             match bbd.terminator().kind {
@@ -64,7 +64,7 @@ impl<'b, 'tcx> CostChecker<'b, 'tcx> {
         }
     }
 
-    pub fn cost(&self) -> usize {
+    pub(super) fn cost(&self) -> usize {
         usize::saturating_sub(self.penalty, self.bonus)
     }
 
diff --git a/compiler/rustc_mir_transform/src/coverage/mod.rs b/compiler/rustc_mir_transform/src/coverage/mod.rs
index 4edba61fdec9e..042f589768a99 100644
--- a/compiler/rustc_mir_transform/src/coverage/mod.rs
+++ b/compiler/rustc_mir_transform/src/coverage/mod.rs
@@ -1,4 +1,4 @@
-pub mod query;
+pub(super) mod query;
 
 mod counters;
 mod graph;
@@ -32,7 +32,7 @@ use crate::coverage::mappings::ExtractedMappings;
 /// Inserts `StatementKind::Coverage` statements that either instrument the binary with injected
 /// counters, via intrinsic `llvm.instrprof.increment`, and/or inject metadata used during codegen
 /// to construct the coverage map.
-pub struct InstrumentCoverage;
+pub(super) struct InstrumentCoverage;
 
 impl<'tcx> crate::MirPass<'tcx> for InstrumentCoverage {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
diff --git a/compiler/rustc_mir_transform/src/cross_crate_inline.rs b/compiler/rustc_mir_transform/src/cross_crate_inline.rs
index 50aaed090f6b8..ce109ef7674f0 100644
--- a/compiler/rustc_mir_transform/src/cross_crate_inline.rs
+++ b/compiler/rustc_mir_transform/src/cross_crate_inline.rs
@@ -10,7 +10,7 @@ use rustc_span::sym;
 
 use crate::{inline, pass_manager as pm};
 
-pub fn provide(providers: &mut Providers) {
+pub(super) fn provide(providers: &mut Providers) {
     providers.cross_crate_inlinable = cross_crate_inlinable;
 }
 
diff --git a/compiler/rustc_mir_transform/src/ctfe_limit.rs b/compiler/rustc_mir_transform/src/ctfe_limit.rs
index ea473b64ce540..bd58b1b668997 100644
--- a/compiler/rustc_mir_transform/src/ctfe_limit.rs
+++ b/compiler/rustc_mir_transform/src/ctfe_limit.rs
@@ -8,7 +8,7 @@ use rustc_middle::mir::{
 use rustc_middle::ty::TyCtxt;
 use tracing::instrument;
 
-pub struct CtfeLimit;
+pub(super) struct CtfeLimit;
 
 impl<'tcx> crate::MirPass<'tcx> for CtfeLimit {
     #[instrument(skip(self, _tcx, body))]
diff --git a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
index 46f7408ef8064..d365989c8df20 100644
--- a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
+++ b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
@@ -26,7 +26,7 @@ use tracing::{debug, debug_span, instrument};
 const BLOCK_LIMIT: usize = 100;
 const PLACE_LIMIT: usize = 100;
 
-pub struct DataflowConstProp;
+pub(super) struct DataflowConstProp;
 
 impl<'tcx> crate::MirPass<'tcx> for DataflowConstProp {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
@@ -332,7 +332,7 @@ impl<'tcx> ValueAnalysis<'tcx> for ConstAnalysis<'_, 'tcx> {
 }
 
 impl<'a, 'tcx> ConstAnalysis<'a, 'tcx> {
-    pub fn new(tcx: TyCtxt<'tcx>, body: &'a Body<'tcx>, map: Map<'tcx>) -> Self {
+    fn new(tcx: TyCtxt<'tcx>, body: &'a Body<'tcx>, map: Map<'tcx>) -> Self {
         let param_env = tcx.param_env_reveal_all_normalized(body.source.def_id());
         Self {
             map,
diff --git a/compiler/rustc_mir_transform/src/dead_store_elimination.rs b/compiler/rustc_mir_transform/src/dead_store_elimination.rs
index 9081a2e2e3028..65c037559c595 100644
--- a/compiler/rustc_mir_transform/src/dead_store_elimination.rs
+++ b/compiler/rustc_mir_transform/src/dead_store_elimination.rs
@@ -28,7 +28,7 @@ use crate::util::is_within_packed;
 ///
 /// The `borrowed` set must be a `BitSet` of all the locals that are ever borrowed in this body. It
 /// can be generated via the [`borrowed_locals`] function.
-pub fn eliminate<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
+fn eliminate<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     let borrowed_locals = borrowed_locals(body);
 
     // If the user requests complete debuginfo, mark the locals that appear in it as live, so
@@ -127,7 +127,7 @@ pub fn eliminate<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     }
 }
 
-pub enum DeadStoreElimination {
+pub(super) enum DeadStoreElimination {
     Initial,
     Final,
 }
diff --git a/compiler/rustc_mir_transform/src/deduce_param_attrs.rs b/compiler/rustc_mir_transform/src/deduce_param_attrs.rs
index 71af099199ea9..e870a71b05aa7 100644
--- a/compiler/rustc_mir_transform/src/deduce_param_attrs.rs
+++ b/compiler/rustc_mir_transform/src/deduce_param_attrs.rs
@@ -150,7 +150,7 @@ fn type_will_always_be_passed_directly(ty: Ty<'_>) -> bool {
 /// body of the function instead of just the signature. These can be useful for optimization
 /// purposes on a best-effort basis. We compute them here and store them into the crate metadata so
 /// dependent crates can use them.
-pub fn deduced_param_attrs<'tcx>(
+pub(super) fn deduced_param_attrs<'tcx>(
     tcx: TyCtxt<'tcx>,
     def_id: LocalDefId,
 ) -> &'tcx [DeducedParamAttrs] {
diff --git a/compiler/rustc_mir_transform/src/deduplicate_blocks.rs b/compiler/rustc_mir_transform/src/deduplicate_blocks.rs
index be50c1da8a438..c8179d513c7ce 100644
--- a/compiler/rustc_mir_transform/src/deduplicate_blocks.rs
+++ b/compiler/rustc_mir_transform/src/deduplicate_blocks.rs
@@ -13,7 +13,7 @@ use tracing::debug;
 
 use super::simplify::simplify_cfg;
 
-pub struct DeduplicateBlocks;
+pub(super) struct DeduplicateBlocks;
 
 impl<'tcx> crate::MirPass<'tcx> for DeduplicateBlocks {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
diff --git a/compiler/rustc_mir_transform/src/deref_separator.rs b/compiler/rustc_mir_transform/src/deref_separator.rs
index a878f777448f5..ad7ccef4976aa 100644
--- a/compiler/rustc_mir_transform/src/deref_separator.rs
+++ b/compiler/rustc_mir_transform/src/deref_separator.rs
@@ -1,16 +1,15 @@
-use rustc_index::IndexVec;
 use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::visit::NonUseContext::VarDebugInfo;
 use rustc_middle::mir::visit::{MutVisitor, PlaceContext};
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 
-pub struct Derefer;
+pub(super) struct Derefer;
 
-pub struct DerefChecker<'a, 'tcx> {
+struct DerefChecker<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
     patcher: MirPatch<'tcx>,
-    local_decls: &'a IndexVec<Local, LocalDecl<'tcx>>,
+    local_decls: &'a LocalDecls<'tcx>,
 }
 
 impl<'a, 'tcx> MutVisitor<'tcx> for DerefChecker<'a, 'tcx> {
@@ -67,7 +66,7 @@ impl<'a, 'tcx> MutVisitor<'tcx> for DerefChecker<'a, 'tcx> {
     }
 }
 
-pub fn deref_finder<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
+pub(super) fn deref_finder<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     let patch = MirPatch::new(body);
     let mut checker = DerefChecker { tcx, patcher: patch, local_decls: &body.local_decls };
 
diff --git a/compiler/rustc_mir_transform/src/dest_prop.rs b/compiler/rustc_mir_transform/src/dest_prop.rs
index 67bee36b8a5e2..175097e30ee30 100644
--- a/compiler/rustc_mir_transform/src/dest_prop.rs
+++ b/compiler/rustc_mir_transform/src/dest_prop.rs
@@ -146,7 +146,7 @@ use rustc_mir_dataflow::points::{save_as_intervals, DenseLocationMap, PointIndex
 use rustc_mir_dataflow::Analysis;
 use tracing::{debug, trace};
 
-pub struct DestinationPropagation;
+pub(super) struct DestinationPropagation;
 
 impl<'tcx> crate::MirPass<'tcx> for DestinationPropagation {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
diff --git a/compiler/rustc_mir_transform/src/dump_mir.rs b/compiler/rustc_mir_transform/src/dump_mir.rs
index 06ae1b490d75c..1640d34d6c8ee 100644
--- a/compiler/rustc_mir_transform/src/dump_mir.rs
+++ b/compiler/rustc_mir_transform/src/dump_mir.rs
@@ -7,7 +7,7 @@ use rustc_middle::mir::{write_mir_pretty, Body};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::config::{OutFileName, OutputType};
 
-pub struct Marker(pub &'static str);
+pub(super) struct Marker(pub &'static str);
 
 impl<'tcx> crate::MirPass<'tcx> for Marker {
     fn name(&self) -> &'static str {
diff --git a/compiler/rustc_mir_transform/src/early_otherwise_branch.rs b/compiler/rustc_mir_transform/src/early_otherwise_branch.rs
index 1c54cd70023d6..3884321df2a2c 100644
--- a/compiler/rustc_mir_transform/src/early_otherwise_branch.rs
+++ b/compiler/rustc_mir_transform/src/early_otherwise_branch.rs
@@ -90,7 +90,7 @@ use super::simplify::simplify_cfg;
 ///     |      ...      |
 ///     =================
 /// ```
-pub struct EarlyOtherwiseBranch;
+pub(super) struct EarlyOtherwiseBranch;
 
 impl<'tcx> crate::MirPass<'tcx> for EarlyOtherwiseBranch {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
@@ -310,42 +310,28 @@ fn verify_candidate_branch<'tcx>(
 ) -> bool {
     // In order for the optimization to be correct, the branch must...
     // ...have exactly one statement
-    let [statement] = branch.statements.as_slice() else {
-        return false;
-    };
-    // ...assign the discriminant of `place` in that statement
-    let StatementKind::Assign(boxed) = &statement.kind else { return false };
-    let (discr_place, Rvalue::Discriminant(from_place)) = &**boxed else { return false };
-    if *from_place != place {
-        return false;
-    }
-    // ...make that assignment to a local
-    if discr_place.projection.len() != 0 {
-        return false;
-    }
-    // ...terminate on a `SwitchInt` that invalidates that local
-    let TerminatorKind::SwitchInt { discr: switch_op, targets, .. } = &branch.terminator().kind
-    else {
-        return false;
-    };
-    if *switch_op != Operand::Move(*discr_place) {
-        return false;
-    }
-    // ...fall through to `destination` if the switch misses
-    if destination != targets.otherwise() {
-        return false;
-    }
-    // ...have a branch for value `value`
-    let mut iter = targets.iter();
-    let Some((target_value, _)) = iter.next() else {
-        return false;
-    };
-    if target_value != value {
-        return false;
-    }
-    // ...and have no more branches
-    if let Some(_) = iter.next() {
-        return false;
+    if let [statement] = branch.statements.as_slice()
+        // ...assign the discriminant of `place` in that statement
+        && let StatementKind::Assign(boxed) = &statement.kind
+        && let (discr_place, Rvalue::Discriminant(from_place)) = &**boxed
+        && *from_place == place
+        // ...make that assignment to a local
+        && discr_place.projection.is_empty()
+        // ...terminate on a `SwitchInt` that invalidates that local
+        && let TerminatorKind::SwitchInt { discr: switch_op, targets, .. } =
+            &branch.terminator().kind
+        && *switch_op == Operand::Move(*discr_place)
+        // ...fall through to `destination` if the switch misses
+        && destination == targets.otherwise()
+        // ...have a branch for value `value`
+        && let mut iter = targets.iter()
+        && let Some((target_value, _)) = iter.next()
+        && target_value == value
+        // ...and have no more branches
+        && iter.next().is_none()
+    {
+        true
+    } else {
+        false
     }
-    true
 }
diff --git a/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs b/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs
index 66e49d556e23c..367a8c0759315 100644
--- a/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs
+++ b/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs
@@ -11,7 +11,7 @@ use rustc_middle::ty::{Ty, TyCtxt};
 use rustc_target::abi::FieldIdx;
 
 /// Constructs the types used when accessing a Box's pointer
-pub fn build_ptr_tys<'tcx>(
+fn build_ptr_tys<'tcx>(
     tcx: TyCtxt<'tcx>,
     pointee: Ty<'tcx>,
     unique_did: DefId,
@@ -26,7 +26,7 @@ pub fn build_ptr_tys<'tcx>(
 }
 
 /// Constructs the projection needed to access a Box's pointer
-pub fn build_projection<'tcx>(
+pub(super) fn build_projection<'tcx>(
     unique_ty: Ty<'tcx>,
     nonnull_ty: Ty<'tcx>,
     ptr_ty: Ty<'tcx>,
@@ -88,68 +88,65 @@ impl<'tcx, 'a> MutVisitor<'tcx> for ElaborateBoxDerefVisitor<'tcx, 'a> {
     }
 }
 
-pub struct ElaborateBoxDerefs;
+pub(super) struct ElaborateBoxDerefs;
 
 impl<'tcx> crate::MirPass<'tcx> for ElaborateBoxDerefs {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        if let Some(def_id) = tcx.lang_items().owned_box() {
-            let unique_did = tcx.adt_def(def_id).non_enum_variant().fields[FieldIdx::ZERO].did;
+        // If box is not present, this pass doesn't need to do anything.
+        let Some(def_id) = tcx.lang_items().owned_box() else { return };
 
-            let Some(nonnull_def) = tcx.type_of(unique_did).instantiate_identity().ty_adt_def()
-            else {
-                span_bug!(tcx.def_span(unique_did), "expected Box to contain Unique")
-            };
+        let unique_did = tcx.adt_def(def_id).non_enum_variant().fields[FieldIdx::ZERO].did;
 
-            let nonnull_did = nonnull_def.non_enum_variant().fields[FieldIdx::ZERO].did;
+        let Some(nonnull_def) = tcx.type_of(unique_did).instantiate_identity().ty_adt_def() else {
+            span_bug!(tcx.def_span(unique_did), "expected Box to contain Unique")
+        };
 
-            let patch = MirPatch::new(body);
+        let nonnull_did = nonnull_def.non_enum_variant().fields[FieldIdx::ZERO].did;
 
-            let local_decls = &mut body.local_decls;
+        let patch = MirPatch::new(body);
 
-            let mut visitor =
-                ElaborateBoxDerefVisitor { tcx, unique_did, nonnull_did, local_decls, patch };
+        let local_decls = &mut body.local_decls;
 
-            for (block, data) in body.basic_blocks.as_mut_preserves_cfg().iter_enumerated_mut() {
-                visitor.visit_basic_block_data(block, data);
-            }
+        let mut visitor =
+            ElaborateBoxDerefVisitor { tcx, unique_did, nonnull_did, local_decls, patch };
 
-            visitor.patch.apply(body);
-
-            for debug_info in body.var_debug_info.iter_mut() {
-                if let VarDebugInfoContents::Place(place) = &mut debug_info.value {
-                    let mut new_projections: Option<Vec<_>> = None;
-
-                    for (base, elem) in place.iter_projections() {
-                        let base_ty = base.ty(&body.local_decls, tcx).ty;
-
-                        if let PlaceElem::Deref = elem
-                            && let Some(boxed_ty) = base_ty.boxed_ty()
-                        {
-                            // Clone the projections before us, since now we need to mutate them.
-                            let new_projections =
-                                new_projections.get_or_insert_with(|| base.projection.to_vec());
-
-                            let (unique_ty, nonnull_ty, ptr_ty) =
-                                build_ptr_tys(tcx, boxed_ty, unique_did, nonnull_did);
-
-                            new_projections.extend_from_slice(&build_projection(
-                                unique_ty, nonnull_ty, ptr_ty,
-                            ));
-                            new_projections.push(PlaceElem::Deref);
-                        } else if let Some(new_projections) = new_projections.as_mut() {
-                            // Keep building up our projections list once we've started it.
-                            new_projections.push(elem);
-                        }
-                    }
+        for (block, data) in body.basic_blocks.as_mut_preserves_cfg().iter_enumerated_mut() {
+            visitor.visit_basic_block_data(block, data);
+        }
+
+        visitor.patch.apply(body);
+
+        for debug_info in body.var_debug_info.iter_mut() {
+            if let VarDebugInfoContents::Place(place) = &mut debug_info.value {
+                let mut new_projections: Option<Vec<_>> = None;
 
-                    // Store the mutated projections if we actually changed something.
-                    if let Some(new_projections) = new_projections {
-                        place.projection = tcx.mk_place_elems(&new_projections);
+                for (base, elem) in place.iter_projections() {
+                    let base_ty = base.ty(&body.local_decls, tcx).ty;
+
+                    if let PlaceElem::Deref = elem
+                        && let Some(boxed_ty) = base_ty.boxed_ty()
+                    {
+                        // Clone the projections before us, since now we need to mutate them.
+                        let new_projections =
+                            new_projections.get_or_insert_with(|| base.projection.to_vec());
+
+                        let (unique_ty, nonnull_ty, ptr_ty) =
+                            build_ptr_tys(tcx, boxed_ty, unique_did, nonnull_did);
+
+                        new_projections
+                            .extend_from_slice(&build_projection(unique_ty, nonnull_ty, ptr_ty));
+                        new_projections.push(PlaceElem::Deref);
+                    } else if let Some(new_projections) = new_projections.as_mut() {
+                        // Keep building up our projections list once we've started it.
+                        new_projections.push(elem);
                     }
                 }
+
+                // Store the mutated projections if we actually changed something.
+                if let Some(new_projections) = new_projections {
+                    place.projection = tcx.mk_place_elems(&new_projections);
+                }
             }
-        } else {
-            // box is not present, this pass doesn't need to do anything
         }
     }
 }
diff --git a/compiler/rustc_mir_transform/src/elaborate_drops.rs b/compiler/rustc_mir_transform/src/elaborate_drops.rs
index f4a951ebde600..fba4320fb5dc5 100644
--- a/compiler/rustc_mir_transform/src/elaborate_drops.rs
+++ b/compiler/rustc_mir_transform/src/elaborate_drops.rs
@@ -47,7 +47,7 @@ use crate::deref_separator::deref_finder;
 ///     }
 /// }
 /// ```
-pub struct ElaborateDrops;
+pub(super) struct ElaborateDrops;
 
 impl<'tcx> crate::MirPass<'tcx> for ElaborateDrops {
     #[instrument(level = "trace", skip(self, tcx, body))]
diff --git a/compiler/rustc_mir_transform/src/errors.rs b/compiler/rustc_mir_transform/src/errors.rs
index 2703dc57cdad9..9a93c3a72b1c9 100644
--- a/compiler/rustc_mir_transform/src/errors.rs
+++ b/compiler/rustc_mir_transform/src/errors.rs
@@ -64,7 +64,7 @@ impl<'a, P: std::fmt::Debug> LintDiagnostic<'a, ()> for AssertLint<P> {
 }
 
 impl AssertLintKind {
-    pub fn lint(&self) -> &'static Lint {
+    pub(crate) fn lint(&self) -> &'static Lint {
         match self {
             AssertLintKind::ArithmeticOverflow => lint::builtin::ARITHMETIC_OVERFLOW,
             AssertLintKind::UnconditionalPanic => lint::builtin::UNCONDITIONAL_PANIC,
diff --git a/compiler/rustc_mir_transform/src/function_item_references.rs b/compiler/rustc_mir_transform/src/function_item_references.rs
index 199fd0f10ee2c..0efaa172e0c6f 100644
--- a/compiler/rustc_mir_transform/src/function_item_references.rs
+++ b/compiler/rustc_mir_transform/src/function_item_references.rs
@@ -11,7 +11,7 @@ use rustc_target::spec::abi::Abi;
 
 use crate::errors;
 
-pub struct FunctionItemReferences;
+pub(super) struct FunctionItemReferences;
 
 impl<'tcx> crate::MirLint<'tcx> for FunctionItemReferences {
     fn run_lint(&self, tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
diff --git a/compiler/rustc_mir_transform/src/gvn.rs b/compiler/rustc_mir_transform/src/gvn.rs
index df0fcc42e5926..e5d2b13efd8fe 100644
--- a/compiler/rustc_mir_transform/src/gvn.rs
+++ b/compiler/rustc_mir_transform/src/gvn.rs
@@ -109,7 +109,7 @@ use tracing::{debug, instrument, trace};
 
 use crate::ssa::{AssignedValue, SsaLocals};
 
-pub struct GVN;
+pub(super) struct GVN;
 
 impl<'tcx> crate::MirPass<'tcx> for GVN {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
diff --git a/compiler/rustc_mir_transform/src/inline.rs b/compiler/rustc_mir_transform/src/inline.rs
index 6cc7e0ee1e4bc..03ef808efecb6 100644
--- a/compiler/rustc_mir_transform/src/inline.rs
+++ b/compiler/rustc_mir_transform/src/inline.rs
@@ -32,9 +32,11 @@ pub(crate) mod cycle;
 
 const TOP_DOWN_DEPTH_LIMIT: usize = 5;
 
+// Made public so that `mir_drops_elaborated_and_const_checked` can be overridden
+// by custom rustc drivers, running all the steps by themselves. See #114628.
 pub struct Inline;
 
-#[derive(Copy, Clone, Debug)]
+#[derive(Clone, Debug)]
 struct CallSite<'tcx> {
     callee: Instance<'tcx>,
     fn_sig: ty::PolyFnSig<'tcx>,
@@ -156,7 +158,6 @@ impl<'tcx> Inliner<'tcx> {
             match self.try_inlining(caller_body, &callsite) {
                 Err(reason) => {
                     debug!("not-inlined {} [{}]", callsite.callee, reason);
-                    continue;
                 }
                 Ok(new_blocks) => {
                     debug!("inlined {}", callsite.callee);
@@ -638,7 +639,7 @@ impl<'tcx> Inliner<'tcx> {
             );
             let dest_ty = dest.ty(caller_body, self.tcx);
             let temp =
-                Place::from(self.new_call_temp(caller_body, &callsite, dest_ty, return_block));
+                Place::from(self.new_call_temp(caller_body, callsite, dest_ty, return_block));
             caller_body[callsite.block].statements.push(Statement {
                 source_info: callsite.source_info,
                 kind: StatementKind::Assign(Box::new((temp, dest))),
@@ -657,7 +658,7 @@ impl<'tcx> Inliner<'tcx> {
                 true,
                 self.new_call_temp(
                     caller_body,
-                    &callsite,
+                    callsite,
                     destination.ty(caller_body, self.tcx).ty,
                     return_block,
                 ),
@@ -665,7 +666,7 @@ impl<'tcx> Inliner<'tcx> {
         };
 
         // Copy the arguments if needed.
-        let args = self.make_call_args(args, &callsite, caller_body, &callee_body, return_block);
+        let args = self.make_call_args(args, callsite, caller_body, &callee_body, return_block);
 
         let mut integrator = Integrator {
             args: &args,
diff --git a/compiler/rustc_mir_transform/src/instsimplify.rs b/compiler/rustc_mir_transform/src/instsimplify.rs
index 4fbfa744e6733..a9591bf39848f 100644
--- a/compiler/rustc_mir_transform/src/instsimplify.rs
+++ b/compiler/rustc_mir_transform/src/instsimplify.rs
@@ -13,13 +13,13 @@ use rustc_target::spec::abi::Abi;
 use crate::simplify::simplify_duplicate_switch_targets;
 use crate::take_array;
 
-pub enum InstSimplify {
+pub(super) enum InstSimplify {
     BeforeInline,
     AfterSimplifyCfg,
 }
 
 impl InstSimplify {
-    pub fn name(&self) -> &'static str {
+    fn name(&self) -> &'static str {
         match self {
             InstSimplify::BeforeInline => "InstSimplify-before-inline",
             InstSimplify::AfterSimplifyCfg => "InstSimplify-after-simplifycfg",
diff --git a/compiler/rustc_mir_transform/src/jump_threading.rs b/compiler/rustc_mir_transform/src/jump_threading.rs
index 02dd56e1b4fdb..e950c2cb72ab8 100644
--- a/compiler/rustc_mir_transform/src/jump_threading.rs
+++ b/compiler/rustc_mir_transform/src/jump_threading.rs
@@ -55,7 +55,7 @@ use tracing::{debug, instrument, trace};
 
 use crate::cost_checker::CostChecker;
 
-pub struct JumpThreading;
+pub(super) struct JumpThreading;
 
 const MAX_BACKTRACK: usize = 5;
 const MAX_COST: usize = 100;
diff --git a/compiler/rustc_mir_transform/src/known_panics_lint.rs b/compiler/rustc_mir_transform/src/known_panics_lint.rs
index 61405fb25c6f2..e964310c5429e 100644
--- a/compiler/rustc_mir_transform/src/known_panics_lint.rs
+++ b/compiler/rustc_mir_transform/src/known_panics_lint.rs
@@ -26,7 +26,7 @@ use tracing::{debug, instrument, trace};
 
 use crate::errors::{AssertLint, AssertLintKind};
 
-pub struct KnownPanicsLint;
+pub(super) struct KnownPanicsLint;
 
 impl<'tcx> crate::MirLint<'tcx> for KnownPanicsLint {
     fn run_lint(&self, tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
@@ -852,7 +852,7 @@ const MAX_ALLOC_LIMIT: u64 = 1024;
 
 /// The mode that `ConstProp` is allowed to run in for a given `Local`.
 #[derive(Clone, Copy, Debug, PartialEq)]
-pub enum ConstPropMode {
+enum ConstPropMode {
     /// The `Local` can be propagated into and reads of this `Local` can also be propagated.
     FullConstProp,
     /// The `Local` can only be propagated into and from its own block.
@@ -864,7 +864,7 @@ pub enum ConstPropMode {
 
 /// A visitor that determines locals in a MIR body
 /// that can be const propagated
-pub struct CanConstProp {
+struct CanConstProp {
     can_const_prop: IndexVec<Local, ConstPropMode>,
     // False at the beginning. Once set, no more assignments are allowed to that local.
     found_assignment: BitSet<Local>,
@@ -872,7 +872,7 @@ pub struct CanConstProp {
 
 impl CanConstProp {
     /// Returns true if `local` can be propagated
-    pub fn check<'tcx>(
+    fn check<'tcx>(
         tcx: TyCtxt<'tcx>,
         param_env: ParamEnv<'tcx>,
         body: &Body<'tcx>,
diff --git a/compiler/rustc_mir_transform/src/large_enums.rs b/compiler/rustc_mir_transform/src/large_enums.rs
index f02ba71ddc64c..f61cf236f77cc 100644
--- a/compiler/rustc_mir_transform/src/large_enums.rs
+++ b/compiler/rustc_mir_transform/src/large_enums.rs
@@ -23,7 +23,7 @@ use rustc_target::abi::{HasDataLayout, Size, TagEncoding, Variants};
 /// In summary, what this does is at runtime determine which enum variant is active,
 /// and instead of copying all the bytes of the largest possible variant,
 /// copy only the bytes for the currently active variant.
-pub struct EnumSizeOpt {
+pub(super) struct EnumSizeOpt {
     pub(crate) discrepancy: u64,
 }
 
diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs
index 62e73ba2c8e24..0bbbf047f634c 100644
--- a/compiler/rustc_mir_transform/src/lib.rs
+++ b/compiler/rustc_mir_transform/src/lib.rs
@@ -11,6 +11,7 @@
 #![feature(round_char_boundary)]
 #![feature(try_blocks)]
 #![feature(yeet_expr)]
+#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use hir::ConstContext;
@@ -72,6 +73,8 @@ mod errors;
 mod ffi_unwind_calls;
 mod function_item_references;
 mod gvn;
+// Made public so that `mir_drops_elaborated_and_const_checked` can be overridden
+// by custom rustc drivers, running all the steps by themselves. See #114628.
 pub mod inline;
 mod instsimplify;
 mod jump_threading;
@@ -459,8 +462,8 @@ fn mir_drops_elaborated_and_const_checked(tcx: TyCtxt<'_>, def: LocalDefId) -> &
     tcx.alloc_steal_mir(body)
 }
 
-// Made public such that `mir_drops_elaborated_and_const_checked` can be overridden
-// by custom rustc drivers, running all the steps by themselves.
+// Made public so that `mir_drops_elaborated_and_const_checked` can be overridden
+// by custom rustc drivers, running all the steps by themselves. See #114628.
 pub fn run_analysis_to_runtime_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     assert!(body.phase == MirPhase::Analysis(AnalysisPhase::Initial));
     let did = body.source.def_id();
diff --git a/compiler/rustc_mir_transform/src/lint.rs b/compiler/rustc_mir_transform/src/lint.rs
index 746068064b8fb..23733994a8b4a 100644
--- a/compiler/rustc_mir_transform/src/lint.rs
+++ b/compiler/rustc_mir_transform/src/lint.rs
@@ -13,7 +13,7 @@ use rustc_mir_dataflow::impls::{MaybeStorageDead, MaybeStorageLive};
 use rustc_mir_dataflow::storage::always_storage_live_locals;
 use rustc_mir_dataflow::{Analysis, ResultsCursor};
 
-pub fn lint_body<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>, when: String) {
+pub(super) fn lint_body<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>, when: String) {
     let always_live_locals = &always_storage_live_locals(body);
 
     let maybe_storage_live = MaybeStorageLive::new(Cow::Borrowed(always_live_locals))
diff --git a/compiler/rustc_mir_transform/src/lower_intrinsics.rs b/compiler/rustc_mir_transform/src/lower_intrinsics.rs
index 55eec33230615..6d635606687a9 100644
--- a/compiler/rustc_mir_transform/src/lower_intrinsics.rs
+++ b/compiler/rustc_mir_transform/src/lower_intrinsics.rs
@@ -7,7 +7,7 @@ use rustc_span::symbol::sym;
 
 use crate::take_array;
 
-pub struct LowerIntrinsics;
+pub(super) struct LowerIntrinsics;
 
 impl<'tcx> crate::MirPass<'tcx> for LowerIntrinsics {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
@@ -35,20 +35,19 @@ impl<'tcx> crate::MirPass<'tcx> for LowerIntrinsics {
                         terminator.kind = TerminatorKind::Goto { target };
                     }
                     sym::forget => {
-                        if let Some(target) = *target {
-                            block.statements.push(Statement {
-                                source_info: terminator.source_info,
-                                kind: StatementKind::Assign(Box::new((
-                                    *destination,
-                                    Rvalue::Use(Operand::Constant(Box::new(ConstOperand {
-                                        span: terminator.source_info.span,
-                                        user_ty: None,
-                                        const_: Const::zero_sized(tcx.types.unit),
-                                    }))),
-                                ))),
-                            });
-                            terminator.kind = TerminatorKind::Goto { target };
-                        }
+                        let target = target.unwrap();
+                        block.statements.push(Statement {
+                            source_info: terminator.source_info,
+                            kind: StatementKind::Assign(Box::new((
+                                *destination,
+                                Rvalue::Use(Operand::Constant(Box::new(ConstOperand {
+                                    span: terminator.source_info.span,
+                                    user_ty: None,
+                                    const_: Const::zero_sized(tcx.types.unit),
+                                }))),
+                            ))),
+                        });
+                        terminator.kind = TerminatorKind::Goto { target };
                     }
                     sym::copy_nonoverlapping => {
                         let target = target.unwrap();
@@ -121,43 +120,41 @@ impl<'tcx> crate::MirPass<'tcx> for LowerIntrinsics {
                         terminator.kind = TerminatorKind::Goto { target };
                     }
                     sym::add_with_overflow | sym::sub_with_overflow | sym::mul_with_overflow => {
-                        if let Some(target) = *target {
-                            let Ok([lhs, rhs]) = take_array(args) else {
-                                bug!("Wrong arguments for {} intrinsic", intrinsic.name);
-                            };
-                            let bin_op = match intrinsic.name {
-                                sym::add_with_overflow => BinOp::AddWithOverflow,
-                                sym::sub_with_overflow => BinOp::SubWithOverflow,
-                                sym::mul_with_overflow => BinOp::MulWithOverflow,
-                                _ => bug!("unexpected intrinsic"),
-                            };
-                            block.statements.push(Statement {
-                                source_info: terminator.source_info,
-                                kind: StatementKind::Assign(Box::new((
-                                    *destination,
-                                    Rvalue::BinaryOp(bin_op, Box::new((lhs.node, rhs.node))),
-                                ))),
-                            });
-                            terminator.kind = TerminatorKind::Goto { target };
-                        }
+                        let target = target.unwrap();
+                        let Ok([lhs, rhs]) = take_array(args) else {
+                            bug!("Wrong arguments for {} intrinsic", intrinsic.name);
+                        };
+                        let bin_op = match intrinsic.name {
+                            sym::add_with_overflow => BinOp::AddWithOverflow,
+                            sym::sub_with_overflow => BinOp::SubWithOverflow,
+                            sym::mul_with_overflow => BinOp::MulWithOverflow,
+                            _ => bug!("unexpected intrinsic"),
+                        };
+                        block.statements.push(Statement {
+                            source_info: terminator.source_info,
+                            kind: StatementKind::Assign(Box::new((
+                                *destination,
+                                Rvalue::BinaryOp(bin_op, Box::new((lhs.node, rhs.node))),
+                            ))),
+                        });
+                        terminator.kind = TerminatorKind::Goto { target };
                     }
                     sym::size_of | sym::min_align_of => {
-                        if let Some(target) = *target {
-                            let tp_ty = generic_args.type_at(0);
-                            let null_op = match intrinsic.name {
-                                sym::size_of => NullOp::SizeOf,
-                                sym::min_align_of => NullOp::AlignOf,
-                                _ => bug!("unexpected intrinsic"),
-                            };
-                            block.statements.push(Statement {
-                                source_info: terminator.source_info,
-                                kind: StatementKind::Assign(Box::new((
-                                    *destination,
-                                    Rvalue::NullaryOp(null_op, tp_ty),
-                                ))),
-                            });
-                            terminator.kind = TerminatorKind::Goto { target };
-                        }
+                        let target = target.unwrap();
+                        let tp_ty = generic_args.type_at(0);
+                        let null_op = match intrinsic.name {
+                            sym::size_of => NullOp::SizeOf,
+                            sym::min_align_of => NullOp::AlignOf,
+                            _ => bug!("unexpected intrinsic"),
+                        };
+                        block.statements.push(Statement {
+                            source_info: terminator.source_info,
+                            kind: StatementKind::Assign(Box::new((
+                                *destination,
+                                Rvalue::NullaryOp(null_op, tp_ty),
+                            ))),
+                        });
+                        terminator.kind = TerminatorKind::Goto { target };
                     }
                     sym::read_via_copy => {
                         let Ok([arg]) = take_array(args) else {
@@ -219,17 +216,23 @@ impl<'tcx> crate::MirPass<'tcx> for LowerIntrinsics {
                         terminator.kind = TerminatorKind::Goto { target };
                     }
                     sym::discriminant_value => {
-                        if let (Some(target), Some(arg)) = (*target, args[0].node.place()) {
-                            let arg = tcx.mk_place_deref(arg);
-                            block.statements.push(Statement {
-                                source_info: terminator.source_info,
-                                kind: StatementKind::Assign(Box::new((
-                                    *destination,
-                                    Rvalue::Discriminant(arg),
-                                ))),
-                            });
-                            terminator.kind = TerminatorKind::Goto { target };
-                        }
+                        let target = target.unwrap();
+                        let Ok([arg]) = take_array(args) else {
+                            span_bug!(
+                                terminator.source_info.span,
+                                "Wrong arguments for discriminant_value intrinsic"
+                            );
+                        };
+                        let arg = arg.node.place().unwrap();
+                        let arg = tcx.mk_place_deref(arg);
+                        block.statements.push(Statement {
+                            source_info: terminator.source_info,
+                            kind: StatementKind::Assign(Box::new((
+                                *destination,
+                                Rvalue::Discriminant(arg),
+                            ))),
+                        });
+                        terminator.kind = TerminatorKind::Goto { target };
                     }
                     sym::offset => {
                         let target = target.unwrap();
@@ -267,7 +270,6 @@ impl<'tcx> crate::MirPass<'tcx> for LowerIntrinsics {
                                 Rvalue::Cast(CastKind::Transmute, arg.node, dst_ty),
                             ))),
                         });
-
                         if let Some(target) = *target {
                             terminator.kind = TerminatorKind::Goto { target };
                         } else {
@@ -299,7 +301,6 @@ impl<'tcx> crate::MirPass<'tcx> for LowerIntrinsics {
                                 Rvalue::Aggregate(Box::new(kind), fields.into()),
                             ))),
                         });
-
                         terminator.kind = TerminatorKind::Goto { target };
                     }
                     sym::ptr_metadata => {
diff --git a/compiler/rustc_mir_transform/src/lower_slice_len.rs b/compiler/rustc_mir_transform/src/lower_slice_len.rs
index 555309a775001..ca59d4d12acad 100644
--- a/compiler/rustc_mir_transform/src/lower_slice_len.rs
+++ b/compiler/rustc_mir_transform/src/lower_slice_len.rs
@@ -5,7 +5,7 @@ use rustc_hir::def_id::DefId;
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 
-pub struct LowerSliceLenCalls;
+pub(super) struct LowerSliceLenCalls;
 
 impl<'tcx> crate::MirPass<'tcx> for LowerSliceLenCalls {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
@@ -17,7 +17,7 @@ impl<'tcx> crate::MirPass<'tcx> for LowerSliceLenCalls {
     }
 }
 
-pub fn lower_slice_len_calls<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
+fn lower_slice_len_calls<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     let language_items = tcx.lang_items();
     let Some(slice_len_fn_item_def_id) = language_items.slice_len_fn() else {
         // there is no lang item to compare to :)
diff --git a/compiler/rustc_mir_transform/src/match_branches.rs b/compiler/rustc_mir_transform/src/match_branches.rs
index 233b39fb47a41..2a2616b20a6de 100644
--- a/compiler/rustc_mir_transform/src/match_branches.rs
+++ b/compiler/rustc_mir_transform/src/match_branches.rs
@@ -10,7 +10,7 @@ use rustc_type_ir::TyKind::*;
 
 use super::simplify::simplify_cfg;
 
-pub struct MatchBranchSimplification;
+pub(super) struct MatchBranchSimplification;
 
 impl<'tcx> crate::MirPass<'tcx> for MatchBranchSimplification {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
diff --git a/compiler/rustc_mir_transform/src/mentioned_items.rs b/compiler/rustc_mir_transform/src/mentioned_items.rs
index 41ce03caf0873..7f9d0a5b6985c 100644
--- a/compiler/rustc_mir_transform/src/mentioned_items.rs
+++ b/compiler/rustc_mir_transform/src/mentioned_items.rs
@@ -5,7 +5,7 @@ use rustc_middle::ty::{self, TyCtxt};
 use rustc_session::Session;
 use rustc_span::source_map::Spanned;
 
-pub struct MentionedItems;
+pub(super) struct MentionedItems;
 
 struct MentionedItemsVisitor<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
diff --git a/compiler/rustc_mir_transform/src/multiple_return_terminators.rs b/compiler/rustc_mir_transform/src/multiple_return_terminators.rs
index 1b4972d487eea..b6d6ef5de1da9 100644
--- a/compiler/rustc_mir_transform/src/multiple_return_terminators.rs
+++ b/compiler/rustc_mir_transform/src/multiple_return_terminators.rs
@@ -7,7 +7,7 @@ use rustc_middle::ty::TyCtxt;
 
 use crate::simplify;
 
-pub struct MultipleReturnTerminators;
+pub(super) struct MultipleReturnTerminators;
 
 impl<'tcx> crate::MirPass<'tcx> for MultipleReturnTerminators {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
diff --git a/compiler/rustc_mir_transform/src/nrvo.rs b/compiler/rustc_mir_transform/src/nrvo.rs
index 94573a9d89bfd..98fa149e2bc71 100644
--- a/compiler/rustc_mir_transform/src/nrvo.rs
+++ b/compiler/rustc_mir_transform/src/nrvo.rs
@@ -30,7 +30,7 @@ use tracing::{debug, trace};
 ///
 /// [#47954]: https://github.com/rust-lang/rust/pull/47954
 /// [#71003]: https://github.com/rust-lang/rust/pull/71003
-pub struct RenameReturnPlace;
+pub(super) struct RenameReturnPlace;
 
 impl<'tcx> crate::MirPass<'tcx> for RenameReturnPlace {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
diff --git a/compiler/rustc_mir_transform/src/pass_manager.rs b/compiler/rustc_mir_transform/src/pass_manager.rs
index 28d4e1a1c9184..60ece5e7db97d 100644
--- a/compiler/rustc_mir_transform/src/pass_manager.rs
+++ b/compiler/rustc_mir_transform/src/pass_manager.rs
@@ -269,12 +269,7 @@ pub(super) fn validate_body<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>, when
     validate::Validator { when, mir_phase: body.phase }.run_pass(tcx, body);
 }
 
-pub(super) fn dump_mir_for_pass<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    body: &Body<'tcx>,
-    pass_name: &str,
-    is_after: bool,
-) {
+fn dump_mir_for_pass<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>, pass_name: &str, is_after: bool) {
     mir::dump_mir(
         tcx,
         true,
diff --git a/compiler/rustc_mir_transform/src/prettify.rs b/compiler/rustc_mir_transform/src/prettify.rs
index ad71c6226601c..ef011d230c279 100644
--- a/compiler/rustc_mir_transform/src/prettify.rs
+++ b/compiler/rustc_mir_transform/src/prettify.rs
@@ -15,7 +15,7 @@ use rustc_session::Session;
 ///
 /// Thus after this pass, all the successors of a block are later than it in the
 /// `IndexVec`, unless that successor is a back-edge (such as from a loop).
-pub struct ReorderBasicBlocks;
+pub(super) struct ReorderBasicBlocks;
 
 impl<'tcx> crate::MirPass<'tcx> for ReorderBasicBlocks {
     fn is_enabled(&self, _session: &Session) -> bool {
@@ -43,7 +43,7 @@ impl<'tcx> crate::MirPass<'tcx> for ReorderBasicBlocks {
 /// assigned or referenced will have a smaller number.
 ///
 /// (Does not reorder arguments nor the [`RETURN_PLACE`].)
-pub struct ReorderLocals;
+pub(super) struct ReorderLocals;
 
 impl<'tcx> crate::MirPass<'tcx> for ReorderLocals {
     fn is_enabled(&self, _session: &Session) -> bool {
@@ -135,8 +135,8 @@ impl<'tcx> Visitor<'tcx> for LocalFinder {
 }
 
 struct LocalUpdater<'tcx> {
-    pub map: IndexVec<Local, Local>,
-    pub tcx: TyCtxt<'tcx>,
+    map: IndexVec<Local, Local>,
+    tcx: TyCtxt<'tcx>,
 }
 
 impl<'tcx> MutVisitor<'tcx> for LocalUpdater<'tcx> {
diff --git a/compiler/rustc_mir_transform/src/promote_consts.rs b/compiler/rustc_mir_transform/src/promote_consts.rs
index cf0a569ffa494..65309f63d5937 100644
--- a/compiler/rustc_mir_transform/src/promote_consts.rs
+++ b/compiler/rustc_mir_transform/src/promote_consts.rs
@@ -37,7 +37,7 @@ use tracing::{debug, instrument};
 /// After this pass is run, `promoted_fragments` will hold the MIR body corresponding to each
 /// newly created `Constant`.
 #[derive(Default)]
-pub struct PromoteTemps<'tcx> {
+pub(super) struct PromoteTemps<'tcx> {
     pub promoted_fragments: Cell<IndexVec<Promoted, Body<'tcx>>>,
 }
 
diff --git a/compiler/rustc_mir_transform/src/ref_prop.rs b/compiler/rustc_mir_transform/src/ref_prop.rs
index 4a447d24ccec7..25b98786c66b7 100644
--- a/compiler/rustc_mir_transform/src/ref_prop.rs
+++ b/compiler/rustc_mir_transform/src/ref_prop.rs
@@ -70,7 +70,7 @@ use crate::ssa::{SsaLocals, StorageLiveLocals};
 ///
 /// For immutable borrows, we do not need to preserve such uniqueness property,
 /// so we perform all the possible instantiations without removing the `_1 = &_2` statement.
-pub struct ReferencePropagation;
+pub(super) struct ReferencePropagation;
 
 impl<'tcx> crate::MirPass<'tcx> for ReferencePropagation {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
diff --git a/compiler/rustc_mir_transform/src/remove_noop_landing_pads.rs b/compiler/rustc_mir_transform/src/remove_noop_landing_pads.rs
index ccba8d015e3a6..37197c3f573d3 100644
--- a/compiler/rustc_mir_transform/src/remove_noop_landing_pads.rs
+++ b/compiler/rustc_mir_transform/src/remove_noop_landing_pads.rs
@@ -8,7 +8,7 @@ use tracing::debug;
 /// A pass that removes noop landing pads and replaces jumps to them with
 /// `UnwindAction::Continue`. This is important because otherwise LLVM generates
 /// terrible code for these.
-pub struct RemoveNoopLandingPads;
+pub(super) struct RemoveNoopLandingPads;
 
 impl<'tcx> crate::MirPass<'tcx> for RemoveNoopLandingPads {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
diff --git a/compiler/rustc_mir_transform/src/remove_place_mention.rs b/compiler/rustc_mir_transform/src/remove_place_mention.rs
index 5801fdedcebb2..71399eb72f004 100644
--- a/compiler/rustc_mir_transform/src/remove_place_mention.rs
+++ b/compiler/rustc_mir_transform/src/remove_place_mention.rs
@@ -4,7 +4,7 @@ use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 use tracing::trace;
 
-pub struct RemovePlaceMention;
+pub(super) struct RemovePlaceMention;
 
 impl<'tcx> crate::MirPass<'tcx> for RemovePlaceMention {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
diff --git a/compiler/rustc_mir_transform/src/remove_storage_markers.rs b/compiler/rustc_mir_transform/src/remove_storage_markers.rs
index 329b30d3890a3..3ecb4a8994f5f 100644
--- a/compiler/rustc_mir_transform/src/remove_storage_markers.rs
+++ b/compiler/rustc_mir_transform/src/remove_storage_markers.rs
@@ -4,7 +4,7 @@ use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 use tracing::trace;
 
-pub struct RemoveStorageMarkers;
+pub(super) struct RemoveStorageMarkers;
 
 impl<'tcx> crate::MirPass<'tcx> for RemoveStorageMarkers {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
diff --git a/compiler/rustc_mir_transform/src/remove_uninit_drops.rs b/compiler/rustc_mir_transform/src/remove_uninit_drops.rs
index aafe971311d31..c58f492655a84 100644
--- a/compiler/rustc_mir_transform/src/remove_uninit_drops.rs
+++ b/compiler/rustc_mir_transform/src/remove_uninit_drops.rs
@@ -14,7 +14,7 @@ use rustc_target::abi::FieldIdx;
 /// like [#90770].
 ///
 /// [#90770]: https://github.com/rust-lang/rust/issues/90770
-pub struct RemoveUninitDrops;
+pub(super) struct RemoveUninitDrops;
 
 impl<'tcx> crate::MirPass<'tcx> for RemoveUninitDrops {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
diff --git a/compiler/rustc_mir_transform/src/remove_unneeded_drops.rs b/compiler/rustc_mir_transform/src/remove_unneeded_drops.rs
index 43109aae0fb6c..28925ba1beb13 100644
--- a/compiler/rustc_mir_transform/src/remove_unneeded_drops.rs
+++ b/compiler/rustc_mir_transform/src/remove_unneeded_drops.rs
@@ -10,7 +10,7 @@ use tracing::{debug, trace};
 
 use super::simplify::simplify_cfg;
 
-pub struct RemoveUnneededDrops;
+pub(super) struct RemoveUnneededDrops;
 
 impl<'tcx> crate::MirPass<'tcx> for RemoveUnneededDrops {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
diff --git a/compiler/rustc_mir_transform/src/remove_zsts.rs b/compiler/rustc_mir_transform/src/remove_zsts.rs
index 9aa46bd4fbae6..f13bb1c5993d5 100644
--- a/compiler/rustc_mir_transform/src/remove_zsts.rs
+++ b/compiler/rustc_mir_transform/src/remove_zsts.rs
@@ -4,7 +4,7 @@ use rustc_middle::mir::visit::*;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 
-pub struct RemoveZsts;
+pub(super) struct RemoveZsts;
 
 impl<'tcx> crate::MirPass<'tcx> for RemoveZsts {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
diff --git a/compiler/rustc_mir_transform/src/required_consts.rs b/compiler/rustc_mir_transform/src/required_consts.rs
index 50637e2ac03bb..ebcf5b5d27b84 100644
--- a/compiler/rustc_mir_transform/src/required_consts.rs
+++ b/compiler/rustc_mir_transform/src/required_consts.rs
@@ -1,7 +1,7 @@
 use rustc_middle::mir::visit::Visitor;
 use rustc_middle::mir::{traversal, Body, ConstOperand, Location};
 
-pub struct RequiredConstsVisitor<'a, 'tcx> {
+pub(super) struct RequiredConstsVisitor<'a, 'tcx> {
     required_consts: &'a mut Vec<ConstOperand<'tcx>>,
 }
 
@@ -10,7 +10,7 @@ impl<'a, 'tcx> RequiredConstsVisitor<'a, 'tcx> {
         RequiredConstsVisitor { required_consts }
     }
 
-    pub fn compute_required_consts(body: &mut Body<'tcx>) {
+    pub(super) fn compute_required_consts(body: &mut Body<'tcx>) {
         let mut required_consts = Vec::new();
         let mut required_consts_visitor = RequiredConstsVisitor::new(&mut required_consts);
         for (bb, bb_data) in traversal::reverse_postorder(&body) {
diff --git a/compiler/rustc_mir_transform/src/reveal_all.rs b/compiler/rustc_mir_transform/src/reveal_all.rs
index 29312a99cbc01..3db962bd94aee 100644
--- a/compiler/rustc_mir_transform/src/reveal_all.rs
+++ b/compiler/rustc_mir_transform/src/reveal_all.rs
@@ -4,7 +4,7 @@ use rustc_middle::mir::visit::*;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 
-pub struct RevealAll;
+pub(super) struct RevealAll;
 
 impl<'tcx> crate::MirPass<'tcx> for RevealAll {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
diff --git a/compiler/rustc_mir_transform/src/shim.rs b/compiler/rustc_mir_transform/src/shim.rs
index 8c70e4291185d..cf8ef580b2720 100644
--- a/compiler/rustc_mir_transform/src/shim.rs
+++ b/compiler/rustc_mir_transform/src/shim.rs
@@ -26,7 +26,7 @@ use crate::{
 
 mod async_destructor_ctor;
 
-pub fn provide(providers: &mut Providers) {
+pub(super) fn provide(providers: &mut Providers) {
     providers.mir_shims = make_shim;
 }
 
@@ -331,7 +331,7 @@ fn new_body<'tcx>(
     body
 }
 
-pub struct DropShimElaborator<'a, 'tcx> {
+pub(super) struct DropShimElaborator<'a, 'tcx> {
     pub body: &'a Body<'tcx>,
     pub patch: MirPatch<'tcx>,
     pub tcx: TyCtxt<'tcx>,
@@ -913,7 +913,7 @@ fn build_call_shim<'tcx>(
     body
 }
 
-pub fn build_adt_ctor(tcx: TyCtxt<'_>, ctor_id: DefId) -> Body<'_> {
+pub(super) fn build_adt_ctor(tcx: TyCtxt<'_>, ctor_id: DefId) -> Body<'_> {
     debug_assert!(tcx.is_constructor(ctor_id));
 
     let param_env = tcx.param_env_reveal_all_normalized(ctor_id);
diff --git a/compiler/rustc_mir_transform/src/shim/async_destructor_ctor.rs b/compiler/rustc_mir_transform/src/shim/async_destructor_ctor.rs
index 50810f23113f3..c88953a1d1a20 100644
--- a/compiler/rustc_mir_transform/src/shim/async_destructor_ctor.rs
+++ b/compiler/rustc_mir_transform/src/shim/async_destructor_ctor.rs
@@ -23,7 +23,7 @@ use tracing::debug;
 
 use super::{local_decls_for_sig, new_body};
 
-pub fn build_async_destructor_ctor_shim<'tcx>(
+pub(super) fn build_async_destructor_ctor_shim<'tcx>(
     tcx: TyCtxt<'tcx>,
     def_id: DefId,
     ty: Option<Ty<'tcx>>,
diff --git a/compiler/rustc_mir_transform/src/simplify.rs b/compiler/rustc_mir_transform/src/simplify.rs
index 1478b86d3c765..cb8e1dfda98ba 100644
--- a/compiler/rustc_mir_transform/src/simplify.rs
+++ b/compiler/rustc_mir_transform/src/simplify.rs
@@ -35,7 +35,7 @@ use rustc_span::DUMMY_SP;
 use smallvec::SmallVec;
 use tracing::{debug, trace};
 
-pub enum SimplifyCfg {
+pub(super) enum SimplifyCfg {
     Initial,
     PromoteConsts,
     RemoveFalseEdges,
@@ -50,7 +50,7 @@ pub enum SimplifyCfg {
 }
 
 impl SimplifyCfg {
-    pub fn name(&self) -> &'static str {
+    fn name(&self) -> &'static str {
         match self {
             SimplifyCfg::Initial => "SimplifyCfg-initial",
             SimplifyCfg::PromoteConsts => "SimplifyCfg-promote-consts",
@@ -66,7 +66,7 @@ impl SimplifyCfg {
     }
 }
 
-pub(crate) fn simplify_cfg(body: &mut Body<'_>) {
+pub(super) fn simplify_cfg(body: &mut Body<'_>) {
     CfgSimplifier::new(body).simplify();
     remove_dead_blocks(body);
 
@@ -85,13 +85,13 @@ impl<'tcx> crate::MirPass<'tcx> for SimplifyCfg {
     }
 }
 
-pub struct CfgSimplifier<'a, 'tcx> {
+struct CfgSimplifier<'a, 'tcx> {
     basic_blocks: &'a mut IndexSlice<BasicBlock, BasicBlockData<'tcx>>,
     pred_count: IndexVec<BasicBlock, u32>,
 }
 
 impl<'a, 'tcx> CfgSimplifier<'a, 'tcx> {
-    pub fn new(body: &'a mut Body<'tcx>) -> Self {
+    fn new(body: &'a mut Body<'tcx>) -> Self {
         let mut pred_count = IndexVec::from_elem(0u32, &body.basic_blocks);
 
         // we can't use mir.predecessors() here because that counts
@@ -111,7 +111,7 @@ impl<'a, 'tcx> CfgSimplifier<'a, 'tcx> {
         CfgSimplifier { basic_blocks, pred_count }
     }
 
-    pub fn simplify(mut self) {
+    fn simplify(mut self) {
         self.strip_nops();
 
         // Vec of the blocks that should be merged. We store the indices here, instead of the
@@ -280,7 +280,7 @@ impl<'a, 'tcx> CfgSimplifier<'a, 'tcx> {
     }
 }
 
-pub fn simplify_duplicate_switch_targets(terminator: &mut Terminator<'_>) {
+pub(super) fn simplify_duplicate_switch_targets(terminator: &mut Terminator<'_>) {
     if let TerminatorKind::SwitchInt { targets, .. } = &mut terminator.kind {
         let otherwise = targets.otherwise();
         if targets.iter().any(|t| t.1 == otherwise) {
@@ -292,7 +292,7 @@ pub fn simplify_duplicate_switch_targets(terminator: &mut Terminator<'_>) {
     }
 }
 
-pub(crate) fn remove_dead_blocks(body: &mut Body<'_>) {
+pub(super) fn remove_dead_blocks(body: &mut Body<'_>) {
     let should_deduplicate_unreachable = |bbdata: &BasicBlockData<'_>| {
         // CfgSimplifier::simplify leaves behind some unreachable basic blocks without a
         // terminator. Those blocks will be deleted by remove_dead_blocks, but we run just
@@ -360,7 +360,7 @@ pub(crate) fn remove_dead_blocks(body: &mut Body<'_>) {
     }
 }
 
-pub enum SimplifyLocals {
+pub(super) enum SimplifyLocals {
     BeforeConstProp,
     AfterGVN,
     Final,
@@ -385,7 +385,7 @@ impl<'tcx> crate::MirPass<'tcx> for SimplifyLocals {
     }
 }
 
-pub fn remove_unused_definitions<'tcx>(body: &mut Body<'tcx>) {
+pub(super) fn remove_unused_definitions<'tcx>(body: &mut Body<'tcx>) {
     // First, we're going to get a count of *actual* uses for every `Local`.
     let mut used_locals = UsedLocals::new(body);
 
@@ -397,7 +397,7 @@ pub fn remove_unused_definitions<'tcx>(body: &mut Body<'tcx>) {
     remove_unused_definitions_helper(&mut used_locals, body);
 }
 
-pub fn simplify_locals<'tcx>(body: &mut Body<'tcx>, tcx: TyCtxt<'tcx>) {
+fn simplify_locals<'tcx>(body: &mut Body<'tcx>, tcx: TyCtxt<'tcx>) {
     // First, we're going to get a count of *actual* uses for every `Local`.
     let mut used_locals = UsedLocals::new(body);
 
diff --git a/compiler/rustc_mir_transform/src/simplify_branches.rs b/compiler/rustc_mir_transform/src/simplify_branches.rs
index 5a014bb734683..e83b4727c4856 100644
--- a/compiler/rustc_mir_transform/src/simplify_branches.rs
+++ b/compiler/rustc_mir_transform/src/simplify_branches.rs
@@ -2,10 +2,11 @@ use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 use tracing::trace;
 
-pub enum SimplifyConstCondition {
+pub(super) enum SimplifyConstCondition {
     AfterConstProp,
     Final,
 }
+
 /// A pass that replaces a branch with a goto when its condition is known.
 impl<'tcx> crate::MirPass<'tcx> for SimplifyConstCondition {
     fn name(&self) -> &'static str {
diff --git a/compiler/rustc_mir_transform/src/simplify_comparison_integral.rs b/compiler/rustc_mir_transform/src/simplify_comparison_integral.rs
index bd30ecc59b3d7..644bcb58d567d 100644
--- a/compiler/rustc_mir_transform/src/simplify_comparison_integral.rs
+++ b/compiler/rustc_mir_transform/src/simplify_comparison_integral.rs
@@ -23,7 +23,7 @@ use tracing::trace;
 /// ```ignore (MIR)
 /// switchInt(_4) -> [43i32: bb3, otherwise: bb2];
 /// ```
-pub struct SimplifyComparisonIntegral;
+pub(super) struct SimplifyComparisonIntegral;
 
 impl<'tcx> crate::MirPass<'tcx> for SimplifyComparisonIntegral {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
diff --git a/compiler/rustc_mir_transform/src/single_use_consts.rs b/compiler/rustc_mir_transform/src/single_use_consts.rs
index 64a928728307b..26059268c37d4 100644
--- a/compiler/rustc_mir_transform/src/single_use_consts.rs
+++ b/compiler/rustc_mir_transform/src/single_use_consts.rs
@@ -19,7 +19,7 @@ use rustc_middle::ty::TyCtxt;
 ///
 /// It also removes *never*-used constants, since it had all the information
 /// needed to do that too, including updating the debug info.
-pub struct SingleUseConsts;
+pub(super) struct SingleUseConsts;
 
 impl<'tcx> crate::MirPass<'tcx> for SingleUseConsts {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
diff --git a/compiler/rustc_mir_transform/src/sroa.rs b/compiler/rustc_mir_transform/src/sroa.rs
index 3c5ccc0c99a8a..e6dd2cfd862d8 100644
--- a/compiler/rustc_mir_transform/src/sroa.rs
+++ b/compiler/rustc_mir_transform/src/sroa.rs
@@ -11,7 +11,7 @@ use rustc_mir_dataflow::value_analysis::{excluded_locals, iter_fields};
 use rustc_target::abi::{FieldIdx, FIRST_VARIANT};
 use tracing::{debug, instrument};
 
-pub struct ScalarReplacementOfAggregates;
+pub(super) struct ScalarReplacementOfAggregates;
 
 impl<'tcx> crate::MirPass<'tcx> for ScalarReplacementOfAggregates {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
diff --git a/compiler/rustc_mir_transform/src/ssa.rs b/compiler/rustc_mir_transform/src/ssa.rs
index c1254766f0a97..cf8622cadd1ff 100644
--- a/compiler/rustc_mir_transform/src/ssa.rs
+++ b/compiler/rustc_mir_transform/src/ssa.rs
@@ -16,7 +16,7 @@ use rustc_middle::mir::*;
 use rustc_middle::ty::{ParamEnv, TyCtxt};
 use tracing::{debug, instrument, trace};
 
-pub struct SsaLocals {
+pub(super) struct SsaLocals {
     /// Assignments to each local. This defines whether the local is SSA.
     assignments: IndexVec<Local, Set1<DefLocation>>,
     /// We visit the body in reverse postorder, to ensure each local is assigned before it is used.
@@ -32,14 +32,18 @@ pub struct SsaLocals {
     borrowed_locals: BitSet<Local>,
 }
 
-pub enum AssignedValue<'a, 'tcx> {
+pub(super) enum AssignedValue<'a, 'tcx> {
     Arg,
     Rvalue(&'a mut Rvalue<'tcx>),
     Terminator,
 }
 
 impl SsaLocals {
-    pub fn new<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>, param_env: ParamEnv<'tcx>) -> SsaLocals {
+    pub(super) fn new<'tcx>(
+        tcx: TyCtxt<'tcx>,
+        body: &Body<'tcx>,
+        param_env: ParamEnv<'tcx>,
+    ) -> SsaLocals {
         let assignment_order = Vec::with_capacity(body.local_decls.len());
 
         let assignments = IndexVec::from_elem(Set1::Empty, &body.local_decls);
@@ -101,25 +105,25 @@ impl SsaLocals {
         ssa
     }
 
-    pub fn num_locals(&self) -> usize {
+    pub(super) fn num_locals(&self) -> usize {
         self.assignments.len()
     }
 
-    pub fn locals(&self) -> impl Iterator<Item = Local> {
+    pub(super) fn locals(&self) -> impl Iterator<Item = Local> {
         self.assignments.indices()
     }
 
-    pub fn is_ssa(&self, local: Local) -> bool {
+    pub(super) fn is_ssa(&self, local: Local) -> bool {
         matches!(self.assignments[local], Set1::One(_))
     }
 
     /// Return the number of uses if a local that are not "Deref".
-    pub fn num_direct_uses(&self, local: Local) -> u32 {
+    pub(super) fn num_direct_uses(&self, local: Local) -> u32 {
         self.direct_uses[local]
     }
 
     #[inline]
-    pub fn assignment_dominates(
+    pub(super) fn assignment_dominates(
         &self,
         dominators: &Dominators<BasicBlock>,
         local: Local,
@@ -131,7 +135,7 @@ impl SsaLocals {
         }
     }
 
-    pub fn assignments<'a, 'tcx>(
+    pub(super) fn assignments<'a, 'tcx>(
         &'a self,
         body: &'a Body<'tcx>,
     ) -> impl Iterator<Item = (Local, &'a Rvalue<'tcx>, Location)> + 'a {
@@ -148,7 +152,7 @@ impl SsaLocals {
         })
     }
 
-    pub fn for_each_assignment_mut<'tcx>(
+    pub(super) fn for_each_assignment_mut<'tcx>(
         &self,
         basic_blocks: &mut IndexSlice<BasicBlock, BasicBlockData<'tcx>>,
         mut f: impl FnMut(Local, AssignedValue<'_, 'tcx>, Location),
@@ -194,17 +198,17 @@ impl SsaLocals {
     ///   _d => _a // transitively through _c
     ///
     /// Exception: we do not see through the return place, as it cannot be instantiated.
-    pub fn copy_classes(&self) -> &IndexSlice<Local, Local> {
+    pub(super) fn copy_classes(&self) -> &IndexSlice<Local, Local> {
         &self.copy_classes
     }
 
     /// Set of SSA locals that are immutably borrowed.
-    pub fn borrowed_locals(&self) -> &BitSet<Local> {
+    pub(super) fn borrowed_locals(&self) -> &BitSet<Local> {
         &self.borrowed_locals
     }
 
     /// Make a property uniform on a copy equivalence class by removing elements.
-    pub fn meet_copy_equivalence(&self, property: &mut BitSet<Local>) {
+    pub(super) fn meet_copy_equivalence(&self, property: &mut BitSet<Local>) {
         // Consolidate to have a local iff all its copies are.
         //
         // `copy_classes` defines equivalence classes between locals. The `local`s that recursively
diff --git a/compiler/rustc_mir_transform/src/unreachable_enum_branching.rs b/compiler/rustc_mir_transform/src/unreachable_enum_branching.rs
index 51a322628ee69..6957394ed1044 100644
--- a/compiler/rustc_mir_transform/src/unreachable_enum_branching.rs
+++ b/compiler/rustc_mir_transform/src/unreachable_enum_branching.rs
@@ -12,7 +12,7 @@ use rustc_middle::ty::{Ty, TyCtxt};
 use rustc_target::abi::{Abi, Variants};
 use tracing::trace;
 
-pub struct UnreachableEnumBranching;
+pub(super) struct UnreachableEnumBranching;
 
 fn get_discriminant_local(terminator: &TerminatorKind<'_>) -> Option<Local> {
     if let TerminatorKind::SwitchInt { discr: Operand::Move(p), .. } = terminator {
diff --git a/compiler/rustc_mir_transform/src/unreachable_prop.rs b/compiler/rustc_mir_transform/src/unreachable_prop.rs
index b8da86f1a8dde..c60cbae21422c 100644
--- a/compiler/rustc_mir_transform/src/unreachable_prop.rs
+++ b/compiler/rustc_mir_transform/src/unreachable_prop.rs
@@ -10,7 +10,7 @@ use rustc_middle::mir::*;
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_target::abi::Size;
 
-pub struct UnreachablePropagation;
+pub(super) struct UnreachablePropagation;
 
 impl crate::MirPass<'_> for UnreachablePropagation {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
diff --git a/compiler/rustc_mir_transform/src/validate.rs b/compiler/rustc_mir_transform/src/validate.rs
index e515dfc5ea57f..18865c73f75b1 100644
--- a/compiler/rustc_mir_transform/src/validate.rs
+++ b/compiler/rustc_mir_transform/src/validate.rs
@@ -26,7 +26,7 @@ enum EdgeKind {
     Normal,
 }
 
-pub struct Validator {
+pub(super) struct Validator {
     /// Describes at which point in the pipeline this validation is happening.
     pub when: String,
     /// The phase for which we are upholding the dialect. If the given phase forbids a specific
@@ -531,7 +531,7 @@ impl<'a, 'tcx> Visitor<'tcx> for CfgChecker<'a, 'tcx> {
 ///
 /// `caller_body` is used to detect cycles in MIR inlining and MIR validation before
 /// `optimized_mir` is available.
-pub fn validate_types<'tcx>(
+pub(super) fn validate_types<'tcx>(
     tcx: TyCtxt<'tcx>,
     mir_phase: MirPhase,
     param_env: ty::ParamEnv<'tcx>,