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.

compiler/rustc_ast/src/mut_visit.rs

@@ -7,10 +7,10 @@
 //! a `MutVisitor` renaming item names in a module will miss all of those
 //! that are created by the expansion of a macro.
 
+use crate::ast::*;
 use crate::ptr::P;
 use crate::token::{self, Token};
 use crate::tokenstream::*;
-use crate::{ast::*, StaticItem};
 
 use rustc_data_structures::flat_map_in_place::FlatMapInPlace;
 use rustc_data_structures::stack::ensure_sufficient_stack;

compiler/rustc_ast/src/token.rs

@@ -13,7 +13,7 @@ use rustc_macros::HashStable_Generic;
 use rustc_span::symbol::{kw, sym};
 #[allow(hidden_glob_reexports)]
 use rustc_span::symbol::{Ident, Symbol};
-use rustc_span::{self, edition::Edition, Span, DUMMY_SP};
+use rustc_span::{edition::Edition, Span, DUMMY_SP};
 use std::borrow::Cow;
 use std::fmt;
 

compiler/rustc_ast/src/visit.rs

@@ -13,7 +13,7 @@
 //! instance, a walker looking for item names in a module will miss all of
 //! those that are created by the expansion of a macro.
 
-use crate::{ast::*, StaticItem};
+use crate::ast::*;
 
 use rustc_span::symbol::Ident;
 use rustc_span::Span;

compiler/rustc_ast_lowering/src/expr.rs

@@ -7,7 +7,6 @@ use super::errors::{
 use super::ResolverAstLoweringExt;
 use super::{ImplTraitContext, LoweringContext, ParamMode, ParenthesizedGenericArgs};
 use crate::{FnDeclKind, ImplTraitPosition};
-use rustc_ast::attr;
 use rustc_ast::ptr::P as AstP;
 use rustc_ast::*;
 use rustc_data_structures::stack::ensure_sufficient_stack;

compiler/rustc_ast_lowering/src/format.rs

@@ -1,6 +1,6 @@
 use super::LoweringContext;
 use rustc_ast as ast;
-use rustc_ast::visit::{self, Visitor};
+use rustc_ast::visit::Visitor;
 use rustc_ast::*;
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_hir as hir;

compiler/rustc_ast_lowering/src/index.rs

@@ -2,7 +2,7 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sorted_map::SortedMap;
 use rustc_hir as hir;
 use rustc_hir::def_id::LocalDefId;
-use rustc_hir::intravisit::{self, Visitor};
+use rustc_hir::intravisit::Visitor;
 use rustc_hir::*;
 use rustc_index::{Idx, IndexVec};
 use rustc_middle::span_bug;

compiler/rustc_ast_lowering/src/lib.rs

@@ -45,7 +45,6 @@ extern crate tracing;
 use crate::errors::{AssocTyParentheses, AssocTyParenthesesSub, MisplacedImplTrait};
 
 use rustc_ast::ptr::P;
-use rustc_ast::visit;
 use rustc_ast::{self as ast, *};
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::captures::Captures;

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -8,9 +8,9 @@
 
 use itertools::{Either, Itertools};
 use rustc_ast::ptr::P;
-use rustc_ast::visit::{self, AssocCtxt, BoundKind, FnCtxt, FnKind, Visitor};
+use rustc_ast::visit::{AssocCtxt, BoundKind, FnCtxt, FnKind, Visitor};
+use rustc_ast::walk_list;
 use rustc_ast::*;
-use rustc_ast::{walk_list, StaticItem};
 use rustc_ast_pretty::pprust::{self, State};
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_feature::Features;

compiler/rustc_borrowck/src/dataflow.rs

@@ -10,7 +10,7 @@ use rustc_middle::ty::RegionVid;
 use rustc_middle::ty::TyCtxt;
 use rustc_mir_dataflow::impls::{EverInitializedPlaces, MaybeUninitializedPlaces};
 use rustc_mir_dataflow::ResultsVisitable;
-use rustc_mir_dataflow::{self, fmt::DebugWithContext, GenKill};
+use rustc_mir_dataflow::{fmt::DebugWithContext, GenKill};
 use rustc_mir_dataflow::{Analysis, Direction, Results};
 use std::fmt;
 

compiler/rustc_borrowck/src/region_infer/graphviz.rs

@@ -8,7 +8,6 @@ use std::borrow::Cow;
 use std::io::{self, Write};
 
 use super::*;
-use crate::constraints::OutlivesConstraint;
 use rustc_graphviz as dot;
 
 impl<'tcx> RegionInferenceContext<'tcx> {

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -24,7 +24,6 @@ use rustc_infer::infer::{
 };
 use rustc_middle::mir::tcx::PlaceTy;
 use rustc_middle::mir::visit::{NonMutatingUseContext, PlaceContext, Visitor};
-use rustc_middle::mir::AssertKind;
 use rustc_middle::mir::*;
 use rustc_middle::traits::query::NoSolution;
 use rustc_middle::traits::ObligationCause;

compiler/rustc_builtin_macros/src/source_util.rs

@@ -5,11 +5,11 @@ use rustc_ast::tokenstream::TokenStream;
 use rustc_ast_pretty::pprust;
 use rustc_expand::base::{self, *};
 use rustc_expand::module::DirOwnership;
+use rustc_parse::new_parser_from_file;
 use rustc_parse::parser::{ForceCollect, Parser};
-use rustc_parse::{self, new_parser_from_file};
 use rustc_session::lint::builtin::INCOMPLETE_INCLUDE;
 use rustc_span::symbol::Symbol;
-use rustc_span::{self, Pos, Span};
+use rustc_span::{Pos, Span};
 
 use smallvec::SmallVec;
 use std::rc::Rc;

compiler/rustc_builtin_macros/src/test_harness.rs

@@ -2,7 +2,7 @@
 
 use rustc_ast as ast;
 use rustc_ast::entry::EntryPointType;
-use rustc_ast::mut_visit::{ExpectOne, *};
+use rustc_ast::mut_visit::*;
 use rustc_ast::ptr::P;
 use rustc_ast::visit::{walk_item, Visitor};
 use rustc_ast::{attr, ModKind};

compiler/rustc_codegen_cranelift/src/abi/comments.rs

@@ -3,7 +3,6 @@
 
 use std::borrow::Cow;
 
-use rustc_middle::mir;
 use rustc_target::abi::call::PassMode;
 
 use crate::prelude::*;

compiler/rustc_codegen_cranelift/src/abi/mod.rs

@@ -6,7 +6,7 @@ mod returning;
 
 use std::borrow::Cow;
 
-use cranelift_codegen::ir::{AbiParam, SigRef};
+use cranelift_codegen::ir::SigRef;
 use cranelift_module::ModuleError;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::ty::layout::FnAbiOf;

compiler/rustc_codegen_cranelift/src/analyze.rs

@@ -2,7 +2,6 @@
 
 use rustc_index::IndexVec;
 use rustc_middle::mir::StatementKind::*;
-use rustc_middle::ty::Ty;
 
 use crate::prelude::*;
 

compiler/rustc_codegen_cranelift/src/constant.rs

@@ -3,10 +3,9 @@
 use std::cmp::Ordering;
 
 use cranelift_module::*;
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::fx::FxHashSet;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::mir::interpret::{read_target_uint, AllocId, GlobalAlloc, Scalar};
-use rustc_middle::mir::ConstValue;
 use rustc_middle::ty::ScalarInt;
 
 use crate::prelude::*;

compiler/rustc_codegen_cranelift/src/inline_asm.rs

@@ -3,7 +3,6 @@
 use std::fmt::Write;
 
 use rustc_ast::ast::{InlineAsmOptions, InlineAsmTemplatePiece};
-use rustc_middle::mir::InlineAsmOperand;
 use rustc_span::sym;
 use rustc_target::asm::*;
 use target_lexicon::BinaryFormat;

compiler/rustc_codegen_cranelift/src/intrinsics/llvm.rs

@@ -1,7 +1,5 @@
 //! Emulate LLVM intrinsics
 
-use rustc_middle::ty::GenericArgsRef;
-
 use crate::intrinsics::*;
 use crate::prelude::*;
 

compiler/rustc_codegen_cranelift/src/intrinsics/llvm_aarch64.rs

@@ -1,7 +1,5 @@
 //! Emulate AArch64 LLVM intrinsics
 
-use rustc_middle::ty::GenericArgsRef;
-
 use crate::intrinsics::*;
 use crate::prelude::*;
 

compiler/rustc_codegen_cranelift/src/intrinsics/llvm_x86.rs

@@ -1,7 +1,6 @@
 //! Emulate x86 LLVM intrinsics
 
 use rustc_ast::ast::{InlineAsmOptions, InlineAsmTemplatePiece};
-use rustc_middle::ty::GenericArgsRef;
 use rustc_target::asm::*;
 
 use crate::inline_asm::{codegen_inline_asm_inner, CInlineAsmOperand};

compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs

@@ -1,7 +1,5 @@
 //! Codegen `extern "platform-intrinsic"` intrinsics.
 
-use rustc_middle::ty::GenericArgsRef;
-use rustc_span::Symbol;
 use rustc_target::abi::Endian;
 
 use super::*;

compiler/rustc_codegen_llvm/src/abi.rs

@@ -15,7 +15,6 @@ use rustc_middle::ty::layout::LayoutOf;
 pub use rustc_middle::ty::layout::{FAT_PTR_ADDR, FAT_PTR_EXTRA};
 use rustc_middle::ty::Ty;
 use rustc_session::config;
-use rustc_target::abi::call::ArgAbi;
 pub use rustc_target::abi::call::*;
 use rustc_target::abi::{self, HasDataLayout, Int};
 pub use rustc_target::spec::abi::Abi;

compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs

@@ -35,7 +35,7 @@ use rustc_middle::ty::{
 use rustc_session::config::{self, DebugInfo, Lto};
 use rustc_span::symbol::Symbol;
 use rustc_span::FileName;
-use rustc_span::{self, FileNameDisplayPreference, SourceFile};
+use rustc_span::{FileNameDisplayPreference, SourceFile};
 use rustc_symbol_mangling::typeid_for_trait_ref;
 use rustc_target::abi::{Align, Size};
 use smallvec::smallvec;

compiler/rustc_codegen_llvm/src/debuginfo/mod.rs

@@ -32,7 +32,7 @@ use rustc_middle::ty::{self, Instance, ParamEnv, Ty, TypeVisitableExt};
 use rustc_session::config::{self, DebugInfo};
 use rustc_session::Session;
 use rustc_span::symbol::Symbol;
-use rustc_span::{self, BytePos, Pos, SourceFile, SourceFileAndLine, SourceFileHash, Span};
+use rustc_span::{BytePos, Pos, SourceFile, SourceFileAndLine, SourceFileHash, Span};
 use rustc_target::abi::Size;
 
 use libc::c_uint;

compiler/rustc_codegen_ssa/src/mir/statement.rs

@@ -3,7 +3,6 @@ use rustc_middle::mir::NonDivergingIntrinsic;
 
 use super::FunctionCx;
 use super::LocalRef;
-use crate::traits::BuilderMethods;
 use crate::traits::*;
 
 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {

compiler/rustc_const_eval/src/transform/check_consts/check.rs

@@ -12,7 +12,7 @@ use rustc_middle::traits::BuiltinImplSource;
 use rustc_middle::ty::GenericArgs;
 use rustc_middle::ty::{self, adjustment::PointerCoercion, Instance, InstanceDef, Ty, TyCtxt};
 use rustc_middle::ty::{TraitRef, TypeVisitableExt};
-use rustc_mir_dataflow::{self, Analysis};
+use rustc_mir_dataflow::Analysis;
 use rustc_span::{sym, Span, Symbol};
 use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt as _;
 use rustc_trait_selection::traits::{self, ObligationCauseCode, ObligationCtxt, SelectionContext};

compiler/rustc_data_structures/src/fingerprint/tests.rs

@@ -1,5 +1,4 @@
 use super::*;
-use crate::stable_hasher::Hash64;
 
 // Check that `combine_commutative` is order independent.
 #[test]

compiler/rustc_data_structures/src/graph/implementation/tests.rs

@@ -1,5 +1,4 @@
 use crate::graph::implementation::*;
-use std::fmt::Debug;
 
 type TestGraph = Graph<&'static str, &'static str>;
 

compiler/rustc_data_structures/src/intern/tests.rs

@@ -1,5 +1,4 @@
 use super::*;
-use std::cmp::Ordering;
 
 #[derive(Debug)]
 struct S(u32);

compiler/rustc_data_structures/src/obligation_forest/tests.rs

@@ -1,7 +1,6 @@
 use super::*;
 
 use std::fmt;
-use std::marker::PhantomData;
 
 impl<'a> super::ForestObligation for &'a str {
     type CacheKey = &'a str;

compiler/rustc_data_structures/src/owned_slice.rs

@@ -4,7 +4,12 @@ use crate::sync::Lrc;
 // Use our fake Send/Sync traits when on not parallel compiler,
 // so that `OwnedSlice` only implements/requires Send/Sync
 // for parallel compiler builds.
-use crate::sync::{Send, Sync};
+cfg_match! {
+    cfg(not(parallel_compiler)) => {
+        use crate::sync::{Send, Sync};
+    }
+    _ => {}
+}
 
 /// An owned slice.
 ///

compiler/rustc_data_structures/src/sip128/tests.rs

@@ -1,6 +1,6 @@
 use super::*;
 
-use std::hash::{Hash, Hasher};
+use std::hash::Hash;
 
 // Hash just the bytes of the slice, without length prefix
 struct Bytes<'a>(&'a [u8]);

compiler/rustc_errors/src/json/tests.rs

@@ -1,11 +1,8 @@
 use super::*;
 
-use crate::json::JsonEmitter;
-use rustc_span::source_map::{FilePathMapping, SourceMap};
-
-use crate::emitter::{ColorConfig, HumanReadableErrorType};
-use crate::{Handler, TerminalUrl};
-use rustc_span::{BytePos, Span};
+use crate::emitter::ColorConfig;
+use crate::Handler;
+use rustc_span::BytePos;
 
 use std::str;
 

compiler/rustc_errors/src/markdown/tests/term.rs

@@ -3,7 +3,6 @@ use std::path::PathBuf;
 use termcolor::{BufferWriter, ColorChoice};
 
 use super::*;
-use crate::markdown::MdStream;
 
 const INPUT: &str = include_str!("input.md");
 const OUTPUT_PATH: &[&str] = &[env!("CARGO_MANIFEST_DIR"), "src","markdown","tests","output.stdout"];

compiler/rustc_expand/src/base.rs

@@ -21,7 +21,7 @@ use rustc_errors::{
 use rustc_feature::Features;
 use rustc_lint_defs::builtin::PROC_MACRO_BACK_COMPAT;
 use rustc_lint_defs::{BufferedEarlyLint, BuiltinLintDiagnostics, RegisteredTools};
-use rustc_parse::{self, parser, MACRO_ARGUMENTS};
+use rustc_parse::{parser, MACRO_ARGUMENTS};
 use rustc_session::errors::report_lit_error;
 use rustc_session::{parse::ParseSess, Limit, Session};
 use rustc_span::def_id::{CrateNum, DefId, LocalDefId};

compiler/rustc_hir_analysis/src/check/check.rs

@@ -1,5 +1,5 @@
 use crate::check::intrinsicck::InlineAsmCtxt;
-use crate::errors::{self, LinkageType};
+use crate::errors::LinkageType;
 
 use super::compare_impl_item::check_type_bounds;
 use super::compare_impl_item::{compare_impl_method, compare_impl_ty};
@@ -8,9 +8,8 @@ use rustc_attr as attr;
 use rustc_errors::{ErrorGuaranteed, MultiSpan};
 use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, DefKind};
-use rustc_hir::def_id::{DefId, LocalDefId, LocalModDefId};
+use rustc_hir::def_id::LocalModDefId;
 use rustc_hir::Node;
-use rustc_infer::infer::outlives::env::OutlivesEnvironment;
 use rustc_infer::infer::{RegionVariableOrigin, TyCtxtInferExt};
 use rustc_infer::traits::{Obligation, TraitEngineExt as _};
 use rustc_lint_defs::builtin::REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS;
@@ -21,18 +20,15 @@ use rustc_middle::ty::layout::{LayoutError, MAX_SIMD_LANES};
 use rustc_middle::ty::util::{Discr, IntTypeExt};
 use rustc_middle::ty::GenericArgKind;
 use rustc_middle::ty::{
-    self, AdtDef, ParamEnv, RegionKind, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable,
-    TypeVisitableExt,
+    AdtDef, ParamEnv, RegionKind, TypeSuperVisitable, TypeVisitable, TypeVisitableExt,
 };
 use rustc_session::lint::builtin::{UNINHABITED_STATIC, UNSUPPORTED_CALLING_CONVENTIONS};
 use rustc_span::symbol::sym;
-use rustc_span::{self, Span};
 use rustc_target::abi::FieldIdx;
-use rustc_target::spec::abi::Abi;
 use rustc_trait_selection::traits::error_reporting::on_unimplemented::OnUnimplementedDirective;
 use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt as _;
 use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _;
-use rustc_trait_selection::traits::{self, ObligationCtxt, TraitEngine, TraitEngineExt as _};
+use rustc_trait_selection::traits::{self, TraitEngine, TraitEngineExt as _};
 use rustc_type_ir::fold::TypeFoldable;
 
 use std::ops::ControlFlow;

compiler/rustc_hir_pretty/src/lib.rs

@@ -16,7 +16,7 @@ use rustc_hir::{BindingAnnotation, ByRef, GenericArg, GenericParam, GenericParam
 use rustc_hir::{GenericBound, PatKind, RangeEnd, TraitBoundModifier};
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::{kw, Ident, Symbol};
-use rustc_span::{self, FileName};
+use rustc_span::FileName;
 use rustc_target::spec::abi::Abi;
 
 use std::cell::Cell;

compiler/rustc_hir_typeck/src/coercion.rs

@@ -58,7 +58,7 @@ use rustc_middle::ty::visit::TypeVisitableExt;
 use rustc_middle::ty::{self, GenericArgsRef, Ty, TyCtxt, TypeAndMut};
 use rustc_session::parse::feature_err;
 use rustc_span::symbol::sym;
-use rustc_span::{self, DesugaringKind};
+use rustc_span::DesugaringKind;
 use rustc_target::spec::abi::Abi;
 use rustc_trait_selection::infer::InferCtxtExt as _;
 use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt as _;

compiler/rustc_hir_typeck/src/diverges.rs

@@ -1,4 +1,4 @@
-use rustc_span::{self, Span, DUMMY_SP};
+use rustc_span::{Span, DUMMY_SP};
 use std::{cmp, ops};
 
 /// Tracks whether executing a node may exit normally (versus

compiler/rustc_hir_typeck/src/expectation.rs

@@ -1,6 +1,6 @@
 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use rustc_middle::ty::{self, Ty};
-use rustc_span::{self, Span};
+use rustc_span::Span;
 
 use super::Expectation::*;
 use super::FnCtxt;