remove redundant imports

detects redundant imports that can be eliminated.

for #117772 :

In order to facilitate review and modification, split the checking code and
removing redundant imports code into two PR.

41 files changed, 6 insertions, 48 deletions

diff --git a/compiler/rustc_mir_transform/src/abort_unwinding_calls.rs b/compiler/rustc_mir_transform/src/abort_unwinding_calls.rs
index 2b3d423ea61..dfc7a9891f9 100644
--- a/compiler/rustc_mir_transform/src/abort_unwinding_calls.rs
+++ b/compiler/rustc_mir_transform/src/abort_unwinding_calls.rs
@@ -1,4 +1,3 @@
-use crate::MirPass;
 use rustc_ast::InlineAsmOptions;
 use rustc_middle::mir::*;
 use rustc_middle::ty::layout;
diff --git a/compiler/rustc_mir_transform/src/add_call_guards.rs b/compiler/rustc_mir_transform/src/add_call_guards.rs
index b814fbf32b1..a47c8d94bba 100644
--- a/compiler/rustc_mir_transform/src/add_call_guards.rs
+++ b/compiler/rustc_mir_transform/src/add_call_guards.rs
@@ -1,4 +1,3 @@
-use crate::MirPass;
 use rustc_index::{Idx, IndexVec};
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
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 ef2a0c790e9..de6d20ae3e8 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
@@ -2,7 +2,6 @@ use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 
 use crate::util;
-use crate::MirPass;
 use rustc_middle::mir::patch::MirPatch;
 
 /// This pass moves values being dropped that are within a packed
diff --git a/compiler/rustc_mir_transform/src/add_retag.rs b/compiler/rustc_mir_transform/src/add_retag.rs
index 75473ca53fb..94077c63057 100644
--- a/compiler/rustc_mir_transform/src/add_retag.rs
+++ b/compiler/rustc_mir_transform/src/add_retag.rs
@@ -4,7 +4,6 @@
 //! of MIR building, and only after this pass we think of the program has having the
 //! normal MIR semantics.
 
-use crate::MirPass;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 
diff --git a/compiler/rustc_mir_transform/src/add_subtyping_projections.rs b/compiler/rustc_mir_transform/src/add_subtyping_projections.rs
index e5be7c0ca76..04204c68f7b 100644
--- a/compiler/rustc_mir_transform/src/add_subtyping_projections.rs
+++ b/compiler/rustc_mir_transform/src/add_subtyping_projections.rs
@@ -1,4 +1,3 @@
-use crate::MirPass;
 use rustc_index::IndexVec;
 use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::visit::MutVisitor;
diff --git a/compiler/rustc_mir_transform/src/check_alignment.rs b/compiler/rustc_mir_transform/src/check_alignment.rs
index 42b2f18869c..9eec724ef21 100644
--- a/compiler/rustc_mir_transform/src/check_alignment.rs
+++ b/compiler/rustc_mir_transform/src/check_alignment.rs
@@ -1,4 +1,3 @@
-use crate::MirPass;
 use rustc_hir::lang_items::LangItem;
 use rustc_index::IndexVec;
 use rustc_middle::mir::*;
diff --git a/compiler/rustc_mir_transform/src/const_goto.rs b/compiler/rustc_mir_transform/src/const_goto.rs
index fd2d37dbea5..3884346076e 100644
--- a/compiler/rustc_mir_transform/src/const_goto.rs
+++ b/compiler/rustc_mir_transform/src/const_goto.rs
@@ -17,7 +17,6 @@
 //! }
 //! ```
 
-use crate::MirPass;
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 use rustc_middle::{mir::visit::Visitor, ty::ParamEnv};
diff --git a/compiler/rustc_mir_transform/src/const_prop.rs b/compiler/rustc_mir_transform/src/const_prop.rs
index d88b33cc973..e66d5e0a9f9 100644
--- a/compiler/rustc_mir_transform/src/const_prop.rs
+++ b/compiler/rustc_mir_transform/src/const_prop.rs
@@ -19,7 +19,6 @@ use rustc_target::abi::{self, HasDataLayout, Size, TargetDataLayout};
 use rustc_target::spec::abi::Abi as CallAbi;
 
 use crate::dataflow_const_prop::Patch;
-use crate::MirPass;
 use rustc_const_eval::interpret::{
     self, compile_time_machine, AllocId, ConstAllocation, FnArg, Frame, ImmTy, Immediate, InterpCx,
     InterpResult, MemoryKind, OpTy, PlaceTy, Pointer, Scalar, StackPopCleanup,
diff --git a/compiler/rustc_mir_transform/src/copy_prop.rs b/compiler/rustc_mir_transform/src/copy_prop.rs
index 74009496e75..0119b95cced 100644
--- a/compiler/rustc_mir_transform/src/copy_prop.rs
+++ b/compiler/rustc_mir_transform/src/copy_prop.rs
@@ -6,7 +6,6 @@ use rustc_middle::ty::TyCtxt;
 use rustc_mir_dataflow::impls::borrowed_locals;
 
 use crate::ssa::SsaLocals;
-use crate::MirPass;
 
 /// Unify locals that copy each other.
 ///
diff --git a/compiler/rustc_mir_transform/src/coroutine.rs b/compiler/rustc_mir_transform/src/coroutine.rs
index 737fb6bf612..ed8b4ef3ba4 100644
--- a/compiler/rustc_mir_transform/src/coroutine.rs
+++ b/compiler/rustc_mir_transform/src/coroutine.rs
@@ -55,7 +55,6 @@ use crate::deref_separator::deref_finder;
 use crate::errors;
 use crate::pass_manager as pm;
 use crate::simplify;
-use crate::MirPass;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::pluralize;
 use rustc_hir as hir;
@@ -63,7 +62,6 @@ use rustc_hir::lang_items::LangItem;
 use rustc_hir::CoroutineKind;
 use rustc_index::bit_set::{BitMatrix, BitSet, GrowableBitSet};
 use rustc_index::{Idx, IndexVec};
-use rustc_middle::mir::dump_mir;
 use rustc_middle::mir::visit::{MutVisitor, PlaceContext, Visitor};
 use rustc_middle::mir::*;
 use rustc_middle::ty::CoroutineArgs;
@@ -73,7 +71,7 @@ use rustc_mir_dataflow::impls::{
     MaybeBorrowedLocals, MaybeLiveLocals, MaybeRequiresStorage, MaybeStorageLive,
 };
 use rustc_mir_dataflow::storage::always_storage_live_locals;
-use rustc_mir_dataflow::{self, Analysis};
+use rustc_mir_dataflow::Analysis;
 use rustc_span::def_id::{DefId, LocalDefId};
 use rustc_span::symbol::sym;
 use rustc_span::Span;
diff --git a/compiler/rustc_mir_transform/src/coverage/query.rs b/compiler/rustc_mir_transform/src/coverage/query.rs
index 809407f897d..dfc7c3a713b 100644
--- a/compiler/rustc_mir_transform/src/coverage/query.rs
+++ b/compiler/rustc_mir_transform/src/coverage/query.rs
@@ -2,9 +2,9 @@ use super::*;
 
 use rustc_data_structures::captures::Captures;
 use rustc_middle::mir::coverage::*;
-use rustc_middle::mir::{Body, Coverage, CoverageIdsInfo};
+use rustc_middle::mir::{Body, CoverageIdsInfo};
 use rustc_middle::query::Providers;
-use rustc_middle::ty::{self, TyCtxt};
+use rustc_middle::ty::{self};
 
 /// A `query` provider for retrieving coverage information injected into MIR.
 pub(crate) fn provide(providers: &mut Providers) {
diff --git a/compiler/rustc_mir_transform/src/coverage/tests.rs b/compiler/rustc_mir_transform/src/coverage/tests.rs
index 302cbf05d78..931bc8e58ff 100644
--- a/compiler/rustc_mir_transform/src/coverage/tests.rs
+++ b/compiler/rustc_mir_transform/src/coverage/tests.rs
@@ -33,7 +33,7 @@ use rustc_data_structures::graph::WithSuccessors;
 use rustc_index::{Idx, IndexVec};
 use rustc_middle::mir::*;
 use rustc_middle::ty;
-use rustc_span::{self, BytePos, Pos, Span, DUMMY_SP};
+use rustc_span::{BytePos, Pos, Span, DUMMY_SP};
 
 fn bcb(index: u32) -> BasicCoverageBlock {
     BasicCoverageBlock::from_u32(index)
diff --git a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
index e9949ebbc87..146cc33e8c6 100644
--- a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
+++ b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
@@ -20,7 +20,6 @@ use rustc_span::DUMMY_SP;
 use rustc_target::abi::{Abi, FieldIdx, Size, VariantIdx, FIRST_VARIANT};
 
 use crate::const_prop::throw_machine_stop_str;
-use crate::MirPass;
 
 // These constants are somewhat random guesses and have not been optimized.
 // If `tcx.sess.mir_opt_level() >= 4`, we ignore the limits (this can become very expensive).
diff --git a/compiler/rustc_mir_transform/src/deduplicate_blocks.rs b/compiler/rustc_mir_transform/src/deduplicate_blocks.rs
index 666293cbc30..b40b2ec8bfd 100644
--- a/compiler/rustc_mir_transform/src/deduplicate_blocks.rs
+++ b/compiler/rustc_mir_transform/src/deduplicate_blocks.rs
@@ -3,8 +3,6 @@
 
 use std::{collections::hash_map::Entry, hash::Hash, hash::Hasher, iter};
 
-use crate::MirPass;
-
 use rustc_data_structures::fx::FxHashMap;
 use rustc_middle::mir::visit::MutVisitor;
 use rustc_middle::mir::*;
diff --git a/compiler/rustc_mir_transform/src/deref_separator.rs b/compiler/rustc_mir_transform/src/deref_separator.rs
index 42be7457018..0e2fccc85da 100644
--- a/compiler/rustc_mir_transform/src/deref_separator.rs
+++ b/compiler/rustc_mir_transform/src/deref_separator.rs
@@ -1,4 +1,3 @@
-use crate::MirPass;
 use rustc_index::IndexVec;
 use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::visit::NonUseContext::VarDebugInfo;
diff --git a/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs b/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs
index 1c917a85c03..96943435bab 100644
--- a/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs
+++ b/compiler/rustc_mir_transform/src/elaborate_box_derefs.rs
@@ -2,7 +2,6 @@
 //!
 //! Box is not actually a pointer so it is incorrect to dereference it directly.
 
-use crate::MirPass;
 use rustc_hir::def_id::DefId;
 use rustc_index::Idx;
 use rustc_middle::mir::patch::MirPatch;
diff --git a/compiler/rustc_mir_transform/src/elaborate_drops.rs b/compiler/rustc_mir_transform/src/elaborate_drops.rs
index f7188ea83fc..c45badbc559 100644
--- a/compiler/rustc_mir_transform/src/elaborate_drops.rs
+++ b/compiler/rustc_mir_transform/src/elaborate_drops.rs
@@ -1,5 +1,4 @@
 use crate::deref_separator::deref_finder;
-use crate::MirPass;
 use rustc_index::bit_set::BitSet;
 use rustc_index::IndexVec;
 use rustc_middle::mir::patch::MirPatch;
diff --git a/compiler/rustc_mir_transform/src/gvn.rs b/compiler/rustc_mir_transform/src/gvn.rs
index 1a5979ef714..b21988e179d 100644
--- a/compiler/rustc_mir_transform/src/gvn.rs
+++ b/compiler/rustc_mir_transform/src/gvn.rs
@@ -103,7 +103,6 @@ use std::borrow::Cow;
 
 use crate::dataflow_const_prop::DummyMachine;
 use crate::ssa::{AssignedValue, SsaLocals};
-use crate::MirPass;
 use either::Either;
 
 pub struct GVN;
diff --git a/compiler/rustc_mir_transform/src/inline.rs b/compiler/rustc_mir_transform/src/inline.rs
index 8fa26713184..8ad804bf3e7 100644
--- a/compiler/rustc_mir_transform/src/inline.rs
+++ b/compiler/rustc_mir_transform/src/inline.rs
@@ -17,7 +17,6 @@ use rustc_target::spec::abi::Abi;
 use crate::cost_checker::CostChecker;
 use crate::simplify::{remove_dead_blocks, CfgSimplifier};
 use crate::util;
-use crate::MirPass;
 use std::iter;
 use std::ops::{Range, RangeFrom};
 
diff --git a/compiler/rustc_mir_transform/src/instsimplify.rs b/compiler/rustc_mir_transform/src/instsimplify.rs
index 7a844b01707..4f0f63d22a4 100644
--- a/compiler/rustc_mir_transform/src/instsimplify.rs
+++ b/compiler/rustc_mir_transform/src/instsimplify.rs
@@ -1,8 +1,6 @@
 //! Performs various peephole optimizations.
 
 use crate::simplify::simplify_duplicate_switch_targets;
-use crate::MirPass;
-use rustc_hir::Mutability;
 use rustc_middle::mir::*;
 use rustc_middle::ty::layout::ValidityRequirement;
 use rustc_middle::ty::{self, GenericArgsRef, ParamEnv, Ty, TyCtxt};
diff --git a/compiler/rustc_mir_transform/src/jump_threading.rs b/compiler/rustc_mir_transform/src/jump_threading.rs
index 5754dd08164..36a15f47276 100644
--- a/compiler/rustc_mir_transform/src/jump_threading.rs
+++ b/compiler/rustc_mir_transform/src/jump_threading.rs
@@ -45,7 +45,6 @@ use rustc_middle::ty::{self, ScalarInt, Ty, TyCtxt};
 use rustc_mir_dataflow::value_analysis::{Map, PlaceIndex, State, TrackElem};
 
 use crate::cost_checker::CostChecker;
-use crate::MirPass;
 
 pub struct JumpThreading;
 
diff --git a/compiler/rustc_mir_transform/src/large_enums.rs b/compiler/rustc_mir_transform/src/large_enums.rs
index 0a8b13d6677..1d788a55ff8 100644
--- a/compiler/rustc_mir_transform/src/large_enums.rs
+++ b/compiler/rustc_mir_transform/src/large_enums.rs
@@ -1,5 +1,4 @@
 use crate::rustc_middle::ty::util::IntTypeExt;
-use crate::MirPass;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_middle::mir::interpret::AllocId;
 use rustc_middle::mir::*;
diff --git a/compiler/rustc_mir_transform/src/lower_intrinsics.rs b/compiler/rustc_mir_transform/src/lower_intrinsics.rs
index 249e0fc633e..18f588dccf6 100644
--- a/compiler/rustc_mir_transform/src/lower_intrinsics.rs
+++ b/compiler/rustc_mir_transform/src/lower_intrinsics.rs
@@ -1,6 +1,5 @@
 //! Lowers intrinsic calls
 
-use crate::MirPass;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_span::symbol::sym;
diff --git a/compiler/rustc_mir_transform/src/lower_slice_len.rs b/compiler/rustc_mir_transform/src/lower_slice_len.rs
index ae487841179..daeb56666f4 100644
--- a/compiler/rustc_mir_transform/src/lower_slice_len.rs
+++ b/compiler/rustc_mir_transform/src/lower_slice_len.rs
@@ -1,7 +1,6 @@
 //! This pass lowers calls to core::slice::len to just Len op.
 //! It should run before inlining!
 
-use crate::MirPass;
 use rustc_hir::def_id::DefId;
 use rustc_index::IndexSlice;
 use rustc_middle::mir::*;
diff --git a/compiler/rustc_mir_transform/src/match_branches.rs b/compiler/rustc_mir_transform/src/match_branches.rs
index 3dc627b6146..1c4aa37d57f 100644
--- a/compiler/rustc_mir_transform/src/match_branches.rs
+++ b/compiler/rustc_mir_transform/src/match_branches.rs
@@ -1,4 +1,3 @@
-use crate::MirPass;
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 use std::iter;
diff --git a/compiler/rustc_mir_transform/src/multiple_return_terminators.rs b/compiler/rustc_mir_transform/src/multiple_return_terminators.rs
index c9b42e75cb2..64749a4b5b6 100644
--- a/compiler/rustc_mir_transform/src/multiple_return_terminators.rs
+++ b/compiler/rustc_mir_transform/src/multiple_return_terminators.rs
@@ -1,7 +1,7 @@
 //! This pass removes jumps to basic blocks containing only a return, and replaces them with a
 //! return instead.
 
-use crate::{simplify, MirPass};
+use crate::simplify;
 use rustc_index::bit_set::BitSet;
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
diff --git a/compiler/rustc_mir_transform/src/normalize_array_len.rs b/compiler/rustc_mir_transform/src/normalize_array_len.rs
index 206cdf9fe28..128634bd7f2 100644
--- a/compiler/rustc_mir_transform/src/normalize_array_len.rs
+++ b/compiler/rustc_mir_transform/src/normalize_array_len.rs
@@ -2,7 +2,6 @@
 //! is taken using `.len()` method. Handy to preserve information in MIR for const prop
 
 use crate::ssa::SsaLocals;
-use crate::MirPass;
 use rustc_index::IndexVec;
 use rustc_middle::mir::visit::*;
 use rustc_middle::mir::*;
diff --git a/compiler/rustc_mir_transform/src/prettify.rs b/compiler/rustc_mir_transform/src/prettify.rs
index 745fa30841c..7b77d032353 100644
--- a/compiler/rustc_mir_transform/src/prettify.rs
+++ b/compiler/rustc_mir_transform/src/prettify.rs
@@ -4,7 +4,6 @@
 //! (`-Zmir-enable-passes=+ReorderBasicBlocks,+ReorderLocals`)
 //! to make the MIR easier to read for humans.
 
-use crate::MirPass;
 use rustc_index::{bit_set::BitSet, IndexSlice, IndexVec};
 use rustc_middle::mir::visit::{MutVisitor, PlaceContext, Visitor};
 use rustc_middle::mir::*;
diff --git a/compiler/rustc_mir_transform/src/ref_prop.rs b/compiler/rustc_mir_transform/src/ref_prop.rs
index df39c819ba9..f13ab5b0f1f 100644
--- a/compiler/rustc_mir_transform/src/ref_prop.rs
+++ b/compiler/rustc_mir_transform/src/ref_prop.rs
@@ -9,7 +9,6 @@ use rustc_mir_dataflow::storage::always_storage_live_locals;
 use rustc_mir_dataflow::Analysis;
 
 use crate::ssa::{SsaLocals, StorageLiveLocals};
-use crate::MirPass;
 
 /// Propagate references using SSA analysis.
 ///
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 54892442c87..095119e2e3f 100644
--- a/compiler/rustc_mir_transform/src/remove_noop_landing_pads.rs
+++ b/compiler/rustc_mir_transform/src/remove_noop_landing_pads.rs
@@ -1,4 +1,3 @@
-use crate::MirPass;
 use rustc_index::bit_set::BitSet;
 use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::*;
diff --git a/compiler/rustc_mir_transform/src/remove_place_mention.rs b/compiler/rustc_mir_transform/src/remove_place_mention.rs
index 8be1c37572d..78335b3b5e0 100644
--- a/compiler/rustc_mir_transform/src/remove_place_mention.rs
+++ b/compiler/rustc_mir_transform/src/remove_place_mention.rs
@@ -1,6 +1,5 @@
 //! This pass removes `PlaceMention` statement, which has no effect at codegen.
 
-use crate::MirPass;
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 
diff --git a/compiler/rustc_mir_transform/src/remove_storage_markers.rs b/compiler/rustc_mir_transform/src/remove_storage_markers.rs
index dbe082e9093..795f5232ee3 100644
--- a/compiler/rustc_mir_transform/src/remove_storage_markers.rs
+++ b/compiler/rustc_mir_transform/src/remove_storage_markers.rs
@@ -1,6 +1,5 @@
 //! This pass removes storage markers if they won't be emitted during codegen.
 
-use crate::MirPass;
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 
diff --git a/compiler/rustc_mir_transform/src/remove_uninit_drops.rs b/compiler/rustc_mir_transform/src/remove_uninit_drops.rs
index 548879e2e39..7d12bcf2fa1 100644
--- a/compiler/rustc_mir_transform/src/remove_uninit_drops.rs
+++ b/compiler/rustc_mir_transform/src/remove_uninit_drops.rs
@@ -4,9 +4,7 @@ use rustc_middle::ty::GenericArgsRef;
 use rustc_middle::ty::{self, ParamEnv, Ty, TyCtxt, VariantDef};
 use rustc_mir_dataflow::impls::MaybeInitializedPlaces;
 use rustc_mir_dataflow::move_paths::{LookupResult, MoveData, MovePathIndex};
-use rustc_mir_dataflow::{
-    self, move_path_children_matching, Analysis, MaybeReachable, MoveDataParamEnv,
-};
+use rustc_mir_dataflow::{move_path_children_matching, Analysis, MaybeReachable, MoveDataParamEnv};
 use rustc_target::abi::FieldIdx;
 
 use crate::MirPass;
diff --git a/compiler/rustc_mir_transform/src/remove_unneeded_drops.rs b/compiler/rustc_mir_transform/src/remove_unneeded_drops.rs
index 08b2a6537e9..5d528bed356 100644
--- a/compiler/rustc_mir_transform/src/remove_unneeded_drops.rs
+++ b/compiler/rustc_mir_transform/src/remove_unneeded_drops.rs
@@ -4,7 +4,6 @@
 //! useful because (unlike MIR building) it runs after type checking, so it can make use of
 //! `Reveal::All` to provide more precise type information.
 
-use crate::MirPass;
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 
diff --git a/compiler/rustc_mir_transform/src/remove_zsts.rs b/compiler/rustc_mir_transform/src/remove_zsts.rs
index 9f59f9d1245..34d57a45301 100644
--- a/compiler/rustc_mir_transform/src/remove_zsts.rs
+++ b/compiler/rustc_mir_transform/src/remove_zsts.rs
@@ -1,6 +1,5 @@
 //! Removes operations on ZST places, and convert ZST operands to constants.
 
-use crate::MirPass;
 use rustc_middle::mir::visit::*;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, Ty, TyCtxt};
diff --git a/compiler/rustc_mir_transform/src/reveal_all.rs b/compiler/rustc_mir_transform/src/reveal_all.rs
index 1626cf3c035..4d2eca57840 100644
--- a/compiler/rustc_mir_transform/src/reveal_all.rs
+++ b/compiler/rustc_mir_transform/src/reveal_all.rs
@@ -1,6 +1,5 @@
 //! Normalizes MIR in RevealAll mode.
 
-use crate::MirPass;
 use rustc_middle::mir::visit::*;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, Ty, TyCtxt};
diff --git a/compiler/rustc_mir_transform/src/separate_const_switch.rs b/compiler/rustc_mir_transform/src/separate_const_switch.rs
index 907cfe7581a..6e22690d8da 100644
--- a/compiler/rustc_mir_transform/src/separate_const_switch.rs
+++ b/compiler/rustc_mir_transform/src/separate_const_switch.rs
@@ -37,7 +37,6 @@
 //! simplicity rather than completeness (it notably
 //! sometimes duplicates abusively).
 
-use crate::MirPass;
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 use smallvec::SmallVec;
diff --git a/compiler/rustc_mir_transform/src/simplify.rs b/compiler/rustc_mir_transform/src/simplify.rs
index 97d398fe5c9..856a0f22771 100644
--- a/compiler/rustc_mir_transform/src/simplify.rs
+++ b/compiler/rustc_mir_transform/src/simplify.rs
@@ -27,7 +27,6 @@
 //! naively generate still contains the `_a = ()` write in the unreachable block "after" the
 //! return.
 
-use crate::MirPass;
 use rustc_data_structures::fx::FxIndexSet;
 use rustc_index::{Idx, IndexSlice, IndexVec};
 use rustc_middle::mir::visit::{MutVisitor, MutatingUseContext, PlaceContext, Visitor};
diff --git a/compiler/rustc_mir_transform/src/simplify_branches.rs b/compiler/rustc_mir_transform/src/simplify_branches.rs
index 1f0e605c3b8..35a052166bd 100644
--- a/compiler/rustc_mir_transform/src/simplify_branches.rs
+++ b/compiler/rustc_mir_transform/src/simplify_branches.rs
@@ -1,4 +1,3 @@
-use crate::MirPass;
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 
diff --git a/compiler/rustc_mir_transform/src/sroa.rs b/compiler/rustc_mir_transform/src/sroa.rs
index a4ca2b91e82..06d5e17fdd6 100644
--- a/compiler/rustc_mir_transform/src/sroa.rs
+++ b/compiler/rustc_mir_transform/src/sroa.rs
@@ -1,4 +1,3 @@
-use crate::MirPass;
 use rustc_data_structures::flat_map_in_place::FlatMapInPlace;
 use rustc_index::bit_set::{BitSet, GrowableBitSet};
 use rustc_index::IndexVec;
diff --git a/compiler/rustc_mir_transform/src/unreachable_prop.rs b/compiler/rustc_mir_transform/src/unreachable_prop.rs
index 919e8d6a234..f12a6aa2429 100644
--- a/compiler/rustc_mir_transform/src/unreachable_prop.rs
+++ b/compiler/rustc_mir_transform/src/unreachable_prop.rs
@@ -2,7 +2,6 @@
 //! when all of their successors are unreachable. This is achieved through a
 //! post-order traversal of the blocks.
 
-use crate::MirPass;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_middle::mir::interpret::Scalar;
 use rustc_middle::mir::patch::MirPatch;