Rollup merge of #69920 - Centril:hir-cleanup, r=Zoxc

Remove some imports to the rustc crate

- When we have `NestedVisitorMap::None`, we use `type Map = dyn intravisit::Map<'v>;` instead of the actual map. This doesn't actually result in dynamic dispatch (in the future we may want to use an associated type default to simplify the code).

- Use `rustc_session::` imports instead of `rustc::{session, lint}`.

r? @Zoxc

143 files changed, 369 insertions, 385 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 3f7427f5940..99bcfd7c7cc 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3624,6 +3624,7 @@ dependencies = [
  "rustc_data_structures",
  "rustc_hir",
  "rustc_metadata",
+ "rustc_session",
  "rustc_span",
  "rustc_target",
 ]
@@ -3677,6 +3678,7 @@ dependencies = [
  "rustc_parse",
  "rustc_plugin_impl",
  "rustc_save_analysis",
+ "rustc_session",
  "rustc_span",
  "rustc_target",
  "serialize",
@@ -3791,6 +3793,7 @@ dependencies = [
  "rustc_hir",
  "rustc_index",
  "rustc_macros",
+ "rustc_session",
  "rustc_span",
  "rustc_target",
  "smallvec 1.0.0",
@@ -3903,6 +3906,7 @@ dependencies = [
  "rustc_expand",
  "rustc_hir",
  "rustc_index",
+ "rustc_session",
  "rustc_span",
  "rustc_target",
  "serialize",
@@ -3933,6 +3937,7 @@ dependencies = [
  "rustc_infer",
  "rustc_lexer",
  "rustc_macros",
+ "rustc_session",
  "rustc_span",
  "rustc_target",
  "rustc_trait_selection",
@@ -4013,6 +4018,7 @@ dependencies = [
  "rustc_hir",
  "rustc_lint",
  "rustc_metadata",
+ "rustc_session",
  "rustc_span",
 ]
 
@@ -4027,6 +4033,7 @@ dependencies = [
  "rustc_data_structures",
  "rustc_errors",
  "rustc_hir",
+ "rustc_session",
  "rustc_span",
  "rustc_typeck",
 ]
@@ -4068,6 +4075,7 @@ dependencies = [
  "rustc_data_structures",
  "rustc_hir",
  "rustc_parse",
+ "rustc_session",
  "rustc_span",
  "serde_json",
 ]
@@ -4174,6 +4182,7 @@ dependencies = [
  "rustc_data_structures",
  "rustc_hir",
  "rustc_infer",
+ "rustc_session",
  "rustc_span",
  "rustc_target",
  "rustc_trait_selection",
@@ -4193,6 +4202,7 @@ dependencies = [
  "rustc_hir",
  "rustc_index",
  "rustc_infer",
+ "rustc_session",
  "rustc_span",
  "rustc_target",
  "rustc_trait_selection",
diff --git a/src/librustc/ich/hcx.rs b/src/librustc/ich/hcx.rs
index c15d54745a1..8fd86b3232d 100644
--- a/src/librustc/ich/hcx.rs
+++ b/src/librustc/ich/hcx.rs
@@ -1,8 +1,6 @@
-use crate::hir::map::definitions::Definitions;
-use crate::hir::map::DefPathHash;
+use crate::hir::map::definitions::{DefPathHash, Definitions};
 use crate::ich::{self, CachingSourceMapView};
 use crate::middle::cstore::CrateStore;
-use crate::session::Session;
 use crate::ty::{fast_reject, TyCtxt};
 
 use rustc_ast::ast;
@@ -11,6 +9,7 @@ use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::sync::Lrc;
 use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, DefIndex};
+use rustc_session::Session;
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::Symbol;
 use rustc_span::{BytePos, SourceFile};
diff --git a/src/librustc/lib.rs b/src/librustc/lib.rs
index 555a85fbfb3..8d0f604de6d 100644
--- a/src/librustc/lib.rs
+++ b/src/librustc/lib.rs
@@ -83,7 +83,6 @@ pub mod infer;
 pub mod lint;
 pub mod middle;
 pub mod mir;
-pub use rustc_session as session;
 pub mod traits;
 pub mod ty;
 
diff --git a/src/librustc/lint.rs b/src/librustc/lint.rs
index dcc8dcbf219..d4d01a716db 100644
--- a/src/librustc/lint.rs
+++ b/src/librustc/lint.rs
@@ -5,7 +5,7 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_errors::{pluralize, Applicability, DiagnosticBuilder, DiagnosticId};
 use rustc_hir::HirId;
-pub use rustc_session::lint::{builtin, Level, Lint, LintId, LintPass};
+use rustc_session::lint::{builtin, Level, Lint, LintId};
 use rustc_session::{DiagnosticMessageId, Session};
 use rustc_span::hygiene::MacroKind;
 use rustc_span::source_map::{DesugaringKind, ExpnKind, MultiSpan};
diff --git a/src/librustc/middle/cstore.rs b/src/librustc/middle/cstore.rs
index 42d56c65462..9f5a56903aa 100644
--- a/src/librustc/middle/cstore.rs
+++ b/src/librustc/middle/cstore.rs
@@ -2,10 +2,9 @@
 //! are *mostly* used as a part of that interface, but these should
 //! probably get a better home if someone can find one.
 
-use crate::hir::map as hir_map;
-use crate::hir::map::definitions::{DefKey, DefPathTable};
-use crate::session::search_paths::PathKind;
-use crate::session::CrateDisambiguator;
+pub use self::NativeLibraryKind::*;
+
+use crate::hir::map::definitions::{DefKey, DefPath, DefPathHash, DefPathTable};
 use crate::ty::TyCtxt;
 
 use rustc_ast::ast;
@@ -14,15 +13,16 @@ use rustc_data_structures::svh::Svh;
 use rustc_data_structures::sync::{self, MetadataRef};
 use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
 use rustc_macros::HashStable;
+use rustc_session::search_paths::PathKind;
+pub use rustc_session::utils::NativeLibraryKind;
+use rustc_session::CrateDisambiguator;
 use rustc_span::symbol::Symbol;
 use rustc_span::Span;
 use rustc_target::spec::Target;
+
 use std::any::Any;
 use std::path::{Path, PathBuf};
 
-pub use self::NativeLibraryKind::*;
-pub use rustc_session::utils::NativeLibraryKind;
-
 // lonely orphan structs and enums looking for a better home
 
 /// Where a crate came from on the local filesystem. One of these three options
@@ -197,8 +197,8 @@ pub trait CrateStore {
 
     // resolve
     fn def_key(&self, def: DefId) -> DefKey;
-    fn def_path(&self, def: DefId) -> hir_map::DefPath;
-    fn def_path_hash(&self, def: DefId) -> hir_map::DefPathHash;
+    fn def_path(&self, def: DefId) -> DefPath;
+    fn def_path_hash(&self, def: DefId) -> DefPathHash;
     fn def_path_table(&self, cnum: CrateNum) -> &DefPathTable;
 
     // "queries" used in resolve that aren't tracked for incremental compilation
diff --git a/src/librustc/middle/dependency_format.rs b/src/librustc/middle/dependency_format.rs
index 6ece51fe866..ee5f822d313 100644
--- a/src/librustc/middle/dependency_format.rs
+++ b/src/librustc/middle/dependency_format.rs
@@ -4,7 +4,7 @@
 //! For all the gory details, see the provider of the `dependency_formats`
 //! query.
 
-use crate::session::config;
+use rustc_session::config;
 
 /// A list of dependencies for a certain crate type.
 ///
diff --git a/src/librustc/middle/limits.rs b/src/librustc/middle/limits.rs
index 22e4f5ea222..6de53c703e1 100644
--- a/src/librustc/middle/limits.rs
+++ b/src/librustc/middle/limits.rs
@@ -5,13 +5,13 @@
 //! this via an attribute on the crate like `#![recursion_limit="22"]`. This pass
 //! just peeks and looks for that attribute.
 
-use crate::session::Session;
-use core::num::IntErrorKind;
 use rustc::bug;
 use rustc_ast::ast;
+use rustc_data_structures::sync::Once;
+use rustc_session::Session;
 use rustc_span::symbol::{sym, Symbol};
 
-use rustc_data_structures::sync::Once;
+use std::num::IntErrorKind;
 
 pub fn update_limits(sess: &Session, krate: &ast::Crate) {
     update_limit(sess, krate, &sess.recursion_limit, sym::recursion_limit, 128);
diff --git a/src/librustc/middle/stability.rs b/src/librustc/middle/stability.rs
index 048e24ce3aa..46525bdedad 100644
--- a/src/librustc/middle/stability.rs
+++ b/src/librustc/middle/stability.rs
@@ -3,7 +3,6 @@
 
 pub use self::StabilityLevel::*;
 
-use crate::session::{DiagnosticMessageId, Session};
 use crate::ty::{self, TyCtxt};
 use rustc_ast::ast::CRATE_NODE_ID;
 use rustc_attr::{self as attr, ConstStability, Deprecation, RustcDeprecation, Stability};
@@ -17,6 +16,7 @@ use rustc_hir::{self, HirId};
 use rustc_session::lint::builtin::{DEPRECATED, DEPRECATED_IN_FUTURE, SOFT_UNSTABLE};
 use rustc_session::lint::{BuiltinLintDiagnostics, Lint, LintBuffer};
 use rustc_session::parse::feature_err_issue;
+use rustc_session::{DiagnosticMessageId, Session};
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::{MultiSpan, Span};
 
diff --git a/src/librustc/mir/mono.rs b/src/librustc/mir/mono.rs
index 4f8efc1607e..27d82d25803 100644
--- a/src/librustc/mir/mono.rs
+++ b/src/librustc/mir/mono.rs
@@ -1,6 +1,5 @@
 use crate::dep_graph::{DepConstructor, DepNode, WorkProduct, WorkProductId};
 use crate::ich::{Fingerprint, NodeIdHashingMode, StableHashingContext};
-use crate::session::config::OptLevel;
 use crate::ty::print::obsolete::DefPathBasedNames;
 use crate::ty::{subst::InternalSubsts, Instance, InstanceDef, SymbolName, TyCtxt};
 use rustc_attr::InlineAttr;
@@ -9,6 +8,7 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
 use rustc_hir::HirId;
+use rustc_session::config::OptLevel;
 use rustc_span::source_map::Span;
 use rustc_span::symbol::Symbol;
 use std::fmt;
diff --git a/src/librustc/ty/layout.rs b/src/librustc/ty/layout.rs
index f5ef9bda0ee..041dfc7d169 100644
--- a/src/librustc/ty/layout.rs
+++ b/src/librustc/ty/layout.rs
@@ -1,30 +1,28 @@
-use crate::session::{self, DataTypeKind};
+use crate::ich::StableHashingContext;
+use crate::mir::{GeneratorLayout, GeneratorSavedLocal};
+use crate::ty::subst::Subst;
 use crate::ty::{self, subst::SubstsRef, ReprOptions, Ty, TyCtxt, TypeFoldable};
 
 use rustc_ast::ast::{self, Ident, IntTy, UintTy};
 use rustc_attr as attr;
-use rustc_span::DUMMY_SP;
-
-use std::cmp;
-use std::fmt;
-use std::iter;
-use std::mem;
-use std::ops::Bound;
-
-use crate::ich::StableHashingContext;
-use crate::mir::{GeneratorLayout, GeneratorSavedLocal};
-use crate::ty::subst::Subst;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_hir as hir;
 use rustc_index::bit_set::BitSet;
 use rustc_index::vec::{Idx, IndexVec};
-
+use rustc_session::{DataTypeKind, FieldInfo, SizeKind, VariantInfo};
+use rustc_span::DUMMY_SP;
 use rustc_target::abi::call::{
     ArgAbi, ArgAttribute, ArgAttributes, Conv, FnAbi, PassMode, Reg, RegKind,
 };
 pub use rustc_target::abi::*;
 use rustc_target::spec::{abi::Abi as SpecAbi, HasTargetSpec};
 
+use std::cmp;
+use std::fmt;
+use std::iter;
+use std::mem;
+use std::ops::Bound;
+
 pub trait IntegerExt {
     fn to_ty<'tcx>(&self, tcx: TyCtxt<'tcx>, signed: bool) -> Ty<'tcx>;
     fn from_attr<C: HasDataLayout>(cx: &C, ity: attr::IntType) -> Integer;
@@ -1651,7 +1649,7 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
                         if min_size < field_end {
                             min_size = field_end;
                         }
-                        session::FieldInfo {
+                        FieldInfo {
                             name: name.to_string(),
                             offset: offset.bytes(),
                             size: field_layout.size.bytes(),
@@ -1661,13 +1659,9 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
                 })
                 .collect();
 
-            session::VariantInfo {
+            VariantInfo {
                 name: n.map(|n| n.to_string()),
-                kind: if layout.is_unsized() {
-                    session::SizeKind::Min
-                } else {
-                    session::SizeKind::Exact
-                },
+                kind: if layout.is_unsized() { SizeKind::Min } else { SizeKind::Exact },
                 align: layout.align.abi.bytes(),
                 size: if min_size.bytes() == 0 { layout.size.bytes() } else { min_size.bytes() },
                 fields: field_info,
diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index dd834d9109d..74d677298d3 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -9,7 +9,6 @@ pub use self::Variance::*;
 use crate::arena::Arena;
 use crate::hir::exports::ExportMap;
 use crate::hir::map as hir_map;
-
 use crate::ich::Fingerprint;
 use crate::ich::StableHashingContext;
 use crate::infer::canonical::Canonical;
@@ -19,7 +18,6 @@ use crate::middle::resolve_lifetime::ObjectLifetimeDefault;
 use crate::mir::interpret::ErrorHandled;
 use crate::mir::GeneratorLayout;
 use crate::mir::ReadOnlyBodyAndCache;
-use crate::session::DataTypeKind;
 use crate::traits::{self, Reveal};
 use crate::ty;
 use crate::ty::layout::VariantIdx;
@@ -42,6 +40,7 @@ use rustc_hir::{Constness, GlobMap, Node, TraitMap};
 use rustc_index::vec::{Idx, IndexVec};
 use rustc_macros::HashStable;
 use rustc_serialize::{self, Encodable, Encoder};
+use rustc_session::DataTypeKind;
 use rustc_span::hygiene::ExpnId;
 use rustc_span::symbol::{kw, sym, Symbol};
 use rustc_span::Span;
diff --git a/src/librustc/ty/query/mod.rs b/src/librustc/ty/query/mod.rs
index 3d17883fec3..e3859ed12a2 100644
--- a/src/librustc/ty/query/mod.rs
+++ b/src/librustc/ty/query/mod.rs
@@ -19,8 +19,6 @@ use crate::mir::interpret::GlobalId;
 use crate::mir::interpret::{ConstEvalRawResult, ConstEvalResult, ConstValue};
 use crate::mir::interpret::{LitToConstError, LitToConstInput};
 use crate::mir::mono::CodegenUnit;
-use crate::session::config::{EntryFnType, OptLevel, OutputFilenames, SymbolManglingVersion};
-use crate::session::CrateDisambiguator;
 use crate::traits::query::{
     CanonicalPredicateGoal, CanonicalProjectionGoal, CanonicalTyGoal,
     CanonicalTypeOpAscribeUserTypeGoal, CanonicalTypeOpEqGoal, CanonicalTypeOpNormalizeGoal,
@@ -49,6 +47,8 @@ use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, DefIdSet, DefIndex};
 use rustc_hir::{Crate, HirIdSet, ItemLocalId, TraitCandidate};
 use rustc_index::vec::IndexVec;
+use rustc_session::config::{EntryFnType, OptLevel, OutputFilenames, SymbolManglingVersion};
+use rustc_session::CrateDisambiguator;
 use rustc_target::spec::PanicStrategy;
 
 use rustc_ast::ast;
diff --git a/src/librustc/ty/query/on_disk_cache.rs b/src/librustc/ty/query/on_disk_cache.rs
index 9c1db7c5f2b..62c2bd801ee 100644
--- a/src/librustc/ty/query/on_disk_cache.rs
+++ b/src/librustc/ty/query/on_disk_cache.rs
@@ -3,7 +3,6 @@ use crate::hir::map::definitions::DefPathHash;
 use crate::ich::{CachingSourceMapView, Fingerprint};
 use crate::mir::interpret::{AllocDecodingSession, AllocDecodingState};
 use crate::mir::{self, interpret};
-use crate::session::{CrateDisambiguator, Session};
 use crate::ty::codec::{self as ty_codec, TyDecoder, TyEncoder};
 use crate::ty::context::TyCtxt;
 use crate::ty::{self, Ty};
@@ -19,6 +18,7 @@ use rustc_serialize::{
     opaque, Decodable, Decoder, Encodable, Encoder, SpecializedDecoder, SpecializedEncoder,
     UseSpecializedDecodable, UseSpecializedEncodable,
 };
+use rustc_session::{CrateDisambiguator, Session};
 use rustc_span::hygiene::{ExpnId, SyntaxContext};
 use rustc_span::source_map::{SourceMap, StableSourceFileId};
 use rustc_span::{BytePos, SourceFile, Span, DUMMY_SP};
diff --git a/src/librustc_ast_lowering/lib.rs b/src/librustc_ast_lowering/lib.rs
index 32b0f0db358..43a6b7ac04c 100644
--- a/src/librustc_ast_lowering/lib.rs
+++ b/src/librustc_ast_lowering/lib.rs
@@ -37,7 +37,6 @@
 use rustc::arena::Arena;
 use rustc::dep_graph::DepGraph;
 use rustc::hir::map::definitions::{DefKey, DefPathData, Definitions};
-use rustc::hir::map::Map;
 use rustc::{bug, span_bug};
 use rustc_ast::ast;
 use rustc_ast::ast::*;
@@ -1463,7 +1462,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         }
 
         impl<'r, 'a, 'v, 'hir> intravisit::Visitor<'v> for ImplTraitLifetimeCollector<'r, 'a, 'hir> {
-            type Map = Map<'v>;
+            type Map = intravisit::ErasedMap<'v>;
 
             fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> {
                 intravisit::NestedVisitorMap::None
diff --git a/src/librustc_ast_lowering/path.rs b/src/librustc_ast_lowering/path.rs
index db8517bfbf0..b5b0a3089ce 100644
--- a/src/librustc_ast_lowering/path.rs
+++ b/src/librustc_ast_lowering/path.rs
@@ -1,7 +1,6 @@
 use super::{AnonymousLifetimeMode, ImplTraitContext, LoweringContext, ParamMode};
 use super::{GenericArgsCtor, ParenthesizedGenericArgs};
 
-use rustc::lint::builtin::ELIDED_LIFETIMES_IN_PATHS;
 use rustc::span_bug;
 use rustc_ast::ast::{self, *};
 use rustc_errors::{struct_span_err, Applicability};
@@ -9,6 +8,7 @@ use rustc_hir as hir;
 use rustc_hir::def::{DefKind, PartialRes, Res};
 use rustc_hir::def_id::DefId;
 use rustc_hir::GenericArg;
+use rustc_session::lint::builtin::ELIDED_LIFETIMES_IN_PATHS;
 use rustc_session::lint::BuiltinLintDiagnostics;
 use rustc_span::Span;
 
diff --git a/src/librustc_codegen_llvm/attributes.rs b/src/librustc_codegen_llvm/attributes.rs
index a9e4fdba030..072607fff85 100644
--- a/src/librustc_codegen_llvm/attributes.rs
+++ b/src/librustc_codegen_llvm/attributes.rs
@@ -3,8 +3,6 @@
 use std::ffi::CString;
 
 use rustc::middle::codegen_fn_attrs::CodegenFnAttrFlags;
-use rustc::session::config::{OptLevel, Sanitizer};
-use rustc::session::Session;
 use rustc::ty::layout::HasTyCtxt;
 use rustc::ty::query::Providers;
 use rustc::ty::{self, Ty, TyCtxt};
@@ -13,6 +11,8 @@ use rustc_data_structures::const_cstr;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::small_c_str::SmallCStr;
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
+use rustc_session::config::{OptLevel, Sanitizer};
+use rustc_session::Session;
 use rustc_target::abi::call::Conv;
 use rustc_target::spec::PanicStrategy;
 
diff --git a/src/librustc_codegen_llvm/back/archive.rs b/src/librustc_codegen_llvm/back/archive.rs
index 455b7086212..239ca57ba41 100644
--- a/src/librustc_codegen_llvm/back/archive.rs
+++ b/src/librustc_codegen_llvm/back/archive.rs
@@ -9,9 +9,9 @@ use std::str;
 
 use crate::llvm::archive_ro::{ArchiveRO, Child};
 use crate::llvm::{self, ArchiveKind};
-use rustc::session::Session;
 use rustc_codegen_ssa::back::archive::{find_library, ArchiveBuilder};
 use rustc_codegen_ssa::{looks_like_rust_object_file, METADATA_FILENAME, RLIB_BYTECODE_EXTENSION};
+use rustc_session::Session;
 use rustc_span::symbol::Symbol;
 
 struct ArchiveConfig<'a> {
diff --git a/src/librustc_codegen_llvm/back/lto.rs b/src/librustc_codegen_llvm/back/lto.rs
index 310cae978bf..1b64750f51f 100644
--- a/src/librustc_codegen_llvm/back/lto.rs
+++ b/src/librustc_codegen_llvm/back/lto.rs
@@ -9,7 +9,6 @@ use log::{debug, info};
 use rustc::bug;
 use rustc::dep_graph::WorkProduct;
 use rustc::middle::exported_symbols::SymbolExportLevel;
-use rustc::session::config::{self, Lto};
 use rustc_codegen_ssa::back::lto::{LtoModuleCodegen, SerializedModule, ThinModule, ThinShared};
 use rustc_codegen_ssa::back::symbol_export;
 use rustc_codegen_ssa::back::write::{CodegenContext, FatLTOInput, ModuleConfig};
@@ -19,6 +18,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::{FatalError, Handler};
 use rustc_hir::def_id::LOCAL_CRATE;
 use rustc_session::cgu_reuse_tracker::CguReuse;
+use rustc_session::config::{self, Lto};
 
 use std::ffi::{CStr, CString};
 use std::fs::File;
diff --git a/src/librustc_codegen_llvm/back/write.rs b/src/librustc_codegen_llvm/back/write.rs
index 0c243128104..2327b96e26c 100644
--- a/src/librustc_codegen_llvm/back/write.rs
+++ b/src/librustc_codegen_llvm/back/write.rs
@@ -15,8 +15,6 @@ use crate::LlvmCodegenBackend;
 use crate::ModuleLlvm;
 use log::debug;
 use rustc::bug;
-use rustc::session::config::{self, Lto, OutputType, Passes, Sanitizer, SwitchWithOptPath};
-use rustc::session::Session;
 use rustc::ty::TyCtxt;
 use rustc_codegen_ssa::back::write::{run_assembler, CodegenContext, ModuleConfig};
 use rustc_codegen_ssa::traits::*;
@@ -25,6 +23,8 @@ use rustc_data_structures::small_c_str::SmallCStr;
 use rustc_errors::{FatalError, Handler};
 use rustc_fs_util::{link_or_copy, path_to_c_string};
 use rustc_hir::def_id::LOCAL_CRATE;
+use rustc_session::config::{self, Lto, OutputType, Passes, Sanitizer, SwitchWithOptPath};
+use rustc_session::Session;
 
 use libc::{c_char, c_int, c_uint, c_void, size_t};
 use std::ffi::CString;
diff --git a/src/librustc_codegen_llvm/base.rs b/src/librustc_codegen_llvm/base.rs
index 04c084e459e..0d063d82c69 100644
--- a/src/librustc_codegen_llvm/base.rs
+++ b/src/librustc_codegen_llvm/base.rs
@@ -28,13 +28,13 @@ use rustc::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
 use rustc::middle::cstore::EncodedMetadata;
 use rustc::middle::exported_symbols;
 use rustc::mir::mono::{Linkage, Visibility};
-use rustc::session::config::DebugInfo;
 use rustc::ty::TyCtxt;
 use rustc_codegen_ssa::base::maybe_create_entry_wrapper;
 use rustc_codegen_ssa::mono_item::MonoItemExt;
 use rustc_codegen_ssa::traits::*;
 use rustc_codegen_ssa::{ModuleCodegen, ModuleKind};
 use rustc_data_structures::small_c_str::SmallCStr;
+use rustc_session::config::DebugInfo;
 use rustc_span::symbol::Symbol;
 
 use std::ffi::CString;
diff --git a/src/librustc_codegen_llvm/builder.rs b/src/librustc_codegen_llvm/builder.rs
index 1c5987f26f1..b37d63fce65 100644
--- a/src/librustc_codegen_llvm/builder.rs
+++ b/src/librustc_codegen_llvm/builder.rs
@@ -7,7 +7,6 @@ use crate::type_of::LayoutLlvmExt;
 use crate::value::Value;
 use libc::{c_char, c_uint};
 use log::debug;
-use rustc::session::config::{self, Sanitizer};
 use rustc::ty::layout::{self, Align, Size, TyLayout};
 use rustc::ty::{self, Ty, TyCtxt};
 use rustc_codegen_ssa::base::to_immediate;
@@ -19,6 +18,7 @@ use rustc_codegen_ssa::MemFlags;
 use rustc_data_structures::const_cstr;
 use rustc_data_structures::small_c_str::SmallCStr;
 use rustc_hir::def_id::DefId;
+use rustc_session::config::{self, Sanitizer};
 use rustc_target::spec::{HasTargetSpec, Target};
 use std::borrow::Cow;
 use std::ffi::CStr;
diff --git a/src/librustc_codegen_llvm/context.rs b/src/librustc_codegen_llvm/context.rs
index d9c88951440..7b1526e9da1 100644
--- a/src/librustc_codegen_llvm/context.rs
+++ b/src/librustc_codegen_llvm/context.rs
@@ -1,31 +1,30 @@
 use crate::attributes;
+use crate::callee::get_fn;
 use crate::debuginfo;
 use crate::llvm;
 use crate::llvm_util;
-use crate::value::Value;
-use rustc::dep_graph::DepGraphSafe;
-
 use crate::type_::Type;
-use rustc_codegen_ssa::traits::*;
+use crate::value::Value;
 
-use crate::callee::get_fn;
 use rustc::bug;
+use rustc::dep_graph::DepGraphSafe;
 use rustc::mir::mono::CodegenUnit;
-use rustc::session::config::{self, CFGuard, DebugInfo};
-use rustc::session::Session;
 use rustc::ty::layout::{
     HasParamEnv, LayoutError, LayoutOf, PointeeInfo, Size, TyLayout, VariantIdx,
 };
 use rustc::ty::{self, Instance, Ty, TyCtxt};
 use rustc_codegen_ssa::base::wants_msvc_seh;
+use rustc_codegen_ssa::traits::*;
 use rustc_data_structures::base_n;
 use rustc_data_structures::const_cstr;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::small_c_str::SmallCStr;
-use rustc_target::spec::{HasTargetSpec, Target};
-
+use rustc_session::config::{self, CFGuard, DebugInfo};
+use rustc_session::Session;
 use rustc_span::source_map::{Span, DUMMY_SP};
 use rustc_span::symbol::Symbol;
+use rustc_target::spec::{HasTargetSpec, Target};
+
 use std::cell::{Cell, RefCell};
 use std::ffi::CStr;
 use std::str;
diff --git a/src/librustc_codegen_llvm/debuginfo/gdb.rs b/src/librustc_codegen_llvm/debuginfo/gdb.rs
index 753a4e18faf..e4cbffb6db3 100644
--- a/src/librustc_codegen_llvm/debuginfo/gdb.rs
+++ b/src/librustc_codegen_llvm/debuginfo/gdb.rs
@@ -6,8 +6,8 @@ use crate::builder::Builder;
 use crate::common::CodegenCx;
 use crate::value::Value;
 use rustc::bug;
-use rustc::session::config::DebugInfo;
 use rustc_codegen_ssa::traits::*;
+use rustc_session::config::DebugInfo;
 
 use rustc_ast::attr;
 use rustc_span::symbol::sym;
diff --git a/src/librustc_codegen_llvm/debuginfo/metadata.rs b/src/librustc_codegen_llvm/debuginfo/metadata.rs
index 55eee13d028..6a7ed4e1dc3 100644
--- a/src/librustc_codegen_llvm/debuginfo/metadata.rs
+++ b/src/librustc_codegen_llvm/debuginfo/metadata.rs
@@ -24,7 +24,6 @@ use rustc::ich::NodeIdHashingMode;
 use rustc::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc::mir::interpret::truncate;
 use rustc::mir::{self, Field, GeneratorLayout};
-use rustc::session::config::{self, DebugInfo};
 use rustc::ty::layout::{
     self, Align, Integer, IntegerExt, LayoutOf, PrimitiveExt, Size, TyLayout, VariantIdx,
 };
@@ -42,6 +41,7 @@ use rustc_fs_util::path_to_c_string;
 use rustc_hir::def::CtorKind;
 use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
 use rustc_index::vec::{Idx, IndexVec};
+use rustc_session::config::{self, DebugInfo};
 use rustc_span::symbol::{Interner, Symbol};
 use rustc_span::{self, FileName, Span};
 use rustc_target::abi::HasDataLayout;
diff --git a/src/librustc_codegen_llvm/debuginfo/mod.rs b/src/librustc_codegen_llvm/debuginfo/mod.rs
index bbde541c58f..85decff35b9 100644
--- a/src/librustc_codegen_llvm/debuginfo/mod.rs
+++ b/src/librustc_codegen_llvm/debuginfo/mod.rs
@@ -20,12 +20,12 @@ use crate::builder::Builder;
 use crate::common::CodegenCx;
 use crate::value::Value;
 use rustc::mir;
-use rustc::session::config::{self, DebugInfo};
 use rustc::ty::{self, Instance, ParamEnv, Ty};
 use rustc_codegen_ssa::debuginfo::type_names;
 use rustc_codegen_ssa::mir::debuginfo::{DebugScope, FunctionDebugContext, VariableKind};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_index::vec::IndexVec;
+use rustc_session::config::{self, DebugInfo};
 
 use libc::c_uint;
 use log::debug;
diff --git a/src/librustc_codegen_llvm/lib.rs b/src/librustc_codegen_llvm/lib.rs
index f3265754574..fa730d289b1 100644
--- a/src/librustc_codegen_llvm/lib.rs
+++ b/src/librustc_codegen_llvm/lib.rs
@@ -15,31 +15,30 @@
 #![recursion_limit = "256"]
 
 use back::write::{create_informational_target_machine, create_target_machine};
-use rustc_span::symbol::Symbol;
 
 pub use llvm_util::target_features;
-use rustc::dep_graph::WorkProduct;
+use rustc::dep_graph::{DepGraph, WorkProduct};
+use rustc::middle::cstore::{EncodedMetadata, MetadataLoaderDyn};
+use rustc::ty::{self, TyCtxt};
+use rustc::util::common::ErrorReported;
 use rustc_ast::expand::allocator::AllocatorKind;
 use rustc_codegen_ssa::back::lto::{LtoModuleCodegen, SerializedModule, ThinModule};
 use rustc_codegen_ssa::back::write::{CodegenContext, FatLTOInput, ModuleConfig};
 use rustc_codegen_ssa::traits::*;
+use rustc_codegen_ssa::ModuleCodegen;
 use rustc_codegen_ssa::{CodegenResults, CompiledModule};
+use rustc_codegen_utils::codegen_backend::CodegenBackend;
 use rustc_errors::{FatalError, Handler};
+use rustc_serialize::json;
+use rustc_session::config::{self, OptLevel, OutputFilenames, PrintRequest};
+use rustc_session::Session;
+use rustc_span::symbol::Symbol;
+
 use std::any::Any;
 use std::ffi::CStr;
 use std::fs;
 use std::sync::Arc;
 
-use rustc::dep_graph::DepGraph;
-use rustc::middle::cstore::{EncodedMetadata, MetadataLoaderDyn};
-use rustc::session::config::{self, OptLevel, OutputFilenames, PrintRequest};
-use rustc::session::Session;
-use rustc::ty::{self, TyCtxt};
-use rustc::util::common::ErrorReported;
-use rustc_codegen_ssa::ModuleCodegen;
-use rustc_codegen_utils::codegen_backend::CodegenBackend;
-use rustc_serialize::json;
-
 mod back {
     pub mod archive;
     pub mod bytecode;
diff --git a/src/librustc_codegen_llvm/llvm/ffi.rs b/src/librustc_codegen_llvm/llvm/ffi.rs
index 388b6c74839..c17c06718f5 100644
--- a/src/librustc_codegen_llvm/llvm/ffi.rs
+++ b/src/librustc_codegen_llvm/llvm/ffi.rs
@@ -694,8 +694,8 @@ pub mod debuginfo {
     }
 
     impl DebugEmissionKind {
-        pub fn from_generic(kind: rustc::session::config::DebugInfo) -> Self {
-            use rustc::session::config::DebugInfo;
+        pub fn from_generic(kind: rustc_session::config::DebugInfo) -> Self {
+            use rustc_session::config::DebugInfo;
             match kind {
                 DebugInfo::None => DebugEmissionKind::NoDebug,
                 DebugInfo::Limited => DebugEmissionKind::LineTablesOnly,
diff --git a/src/librustc_codegen_llvm/llvm_util.rs b/src/librustc_codegen_llvm/llvm_util.rs
index 0081a75a4da..5e924c9af84 100644
--- a/src/librustc_codegen_llvm/llvm_util.rs
+++ b/src/librustc_codegen_llvm/llvm_util.rs
@@ -2,10 +2,10 @@ use crate::back::write::create_informational_target_machine;
 use crate::llvm;
 use libc::c_int;
 use rustc::bug;
-use rustc::session::config::PrintRequest;
-use rustc::session::Session;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_feature::UnstableFeatures;
+use rustc_session::config::PrintRequest;
+use rustc_session::Session;
 use rustc_span::symbol::sym;
 use rustc_span::symbol::Symbol;
 use rustc_target::spec::{MergeFunctions, PanicStrategy};
diff --git a/src/librustc_codegen_ssa/back/archive.rs b/src/librustc_codegen_ssa/back/archive.rs
index a357c350287..f83b4b2b0c0 100644
--- a/src/librustc_codegen_ssa/back/archive.rs
+++ b/src/librustc_codegen_ssa/back/archive.rs
@@ -1,4 +1,4 @@
-use rustc::session::Session;
+use rustc_session::Session;
 use rustc_span::symbol::Symbol;
 
 use std::io;
diff --git a/src/librustc_codegen_ssa/back/link.rs b/src/librustc_codegen_ssa/back/link.rs
index a71fe443038..af413d3cdfe 100644
--- a/src/librustc_codegen_ssa/back/link.rs
+++ b/src/librustc_codegen_ssa/back/link.rs
@@ -1,15 +1,15 @@
 use rustc::middle::cstore::{EncodedMetadata, LibSource, NativeLibrary, NativeLibraryKind};
 use rustc::middle::dependency_format::Linkage;
-use rustc::session::config::{
+use rustc_data_structures::fx::FxHashSet;
+use rustc_fs_util::fix_windows_verbatim_for_gcc;
+use rustc_hir::def_id::CrateNum;
+use rustc_session::config::{
     self, CFGuard, DebugInfo, OutputFilenames, OutputType, PrintRequest, Sanitizer,
 };
-use rustc::session::search_paths::PathKind;
+use rustc_session::search_paths::PathKind;
 /// For all the linkers we support, and information they might
 /// need out of the shared crate context before we get rid of it.
-use rustc::session::{filesearch, Session};
-use rustc_data_structures::fx::FxHashSet;
-use rustc_fs_util::fix_windows_verbatim_for_gcc;
-use rustc_hir::def_id::CrateNum;
+use rustc_session::{filesearch, Session};
 use rustc_span::symbol::Symbol;
 use rustc_target::spec::{LinkerFlavor, PanicStrategy, RelroLevel};
 
diff --git a/src/librustc_codegen_ssa/back/linker.rs b/src/librustc_codegen_ssa/back/linker.rs
index 5aafb8a12d7..6b30ae8559d 100644
--- a/src/librustc_codegen_ssa/back/linker.rs
+++ b/src/librustc_codegen_ssa/back/linker.rs
@@ -2,7 +2,6 @@ use super::archive;
 use super::command::Command;
 use super::symbol_export;
 
-use rustc_data_structures::fx::FxHashMap;
 use std::ffi::{OsStr, OsString};
 use std::fs::{self, File};
 use std::io::prelude::*;
@@ -10,11 +9,12 @@ use std::io::{self, BufWriter};
 use std::path::{Path, PathBuf};
 
 use rustc::middle::dependency_format::Linkage;
-use rustc::session::config::{self, CrateType, DebugInfo, LinkerPluginLto, Lto, OptLevel};
-use rustc::session::Session;
 use rustc::ty::TyCtxt;
+use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
 use rustc_serialize::{json, Encoder};
+use rustc_session::config::{self, CrateType, DebugInfo, LinkerPluginLto, Lto, OptLevel};
+use rustc_session::Session;
 use rustc_span::symbol::Symbol;
 use rustc_target::spec::{LinkerFlavor, LldFlavor};
 
diff --git a/src/librustc_codegen_ssa/back/symbol_export.rs b/src/librustc_codegen_ssa/back/symbol_export.rs
index 178a74c791b..8368d98884a 100644
--- a/src/librustc_codegen_ssa/back/symbol_export.rs
+++ b/src/librustc_codegen_ssa/back/symbol_export.rs
@@ -3,7 +3,6 @@ use std::sync::Arc;
 
 use rustc::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc::middle::exported_symbols::{metadata_symbol_name, ExportedSymbol, SymbolExportLevel};
-use rustc::session::config::{self, Sanitizer};
 use rustc::ty::query::Providers;
 use rustc::ty::subst::{GenericArgKind, SubstsRef};
 use rustc::ty::Instance;
@@ -16,6 +15,7 @@ use rustc_hir as hir;
 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, CRATE_DEF_INDEX, LOCAL_CRATE};
 use rustc_hir::Node;
 use rustc_index::vec::IndexVec;
+use rustc_session::config::{self, Sanitizer};
 
 pub fn threshold(tcx: TyCtxt<'_>) -> SymbolExportLevel {
     crates_export_threshold(&tcx.sess.crate_types.borrow())
diff --git a/src/librustc_codegen_ssa/back/write.rs b/src/librustc_codegen_ssa/back/write.rs
index dbc2ef6f2b0..303ee385658 100644
--- a/src/librustc_codegen_ssa/back/write.rs
+++ b/src/librustc_codegen_ssa/back/write.rs
@@ -14,10 +14,6 @@ use jobserver::{Acquired, Client};
 use rustc::dep_graph::{WorkProduct, WorkProductFileKind, WorkProductId};
 use rustc::middle::cstore::EncodedMetadata;
 use rustc::middle::exported_symbols::SymbolExportLevel;
-use rustc::session::config::{
-    self, Lto, OutputFilenames, OutputType, Passes, Sanitizer, SwitchWithOptPath,
-};
-use rustc::session::Session;
 use rustc::ty::TyCtxt;
 use rustc_ast::attr;
 use rustc_data_structures::fx::FxHashMap;
@@ -34,6 +30,10 @@ use rustc_incremental::{
     copy_cgu_workproducts_to_incr_comp_cache_dir, in_incr_comp_dir, in_incr_comp_dir_sess,
 };
 use rustc_session::cgu_reuse_tracker::CguReuseTracker;
+use rustc_session::config::{
+    self, Lto, OutputFilenames, OutputType, Passes, Sanitizer, SwitchWithOptPath,
+};
+use rustc_session::Session;
 use rustc_span::hygiene::ExpnId;
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::{sym, Symbol};
diff --git a/src/librustc_codegen_ssa/base.rs b/src/librustc_codegen_ssa/base.rs
index d6e1ab8909c..e57cae30b77 100644
--- a/src/librustc_codegen_ssa/base.rs
+++ b/src/librustc_codegen_ssa/base.rs
@@ -31,8 +31,6 @@ use rustc::middle::cstore::{self, LinkagePreference};
 use rustc::middle::lang_items;
 use rustc::middle::lang_items::StartFnLangItem;
 use rustc::mir::mono::{CodegenUnit, CodegenUnitNameBuilder, MonoItem};
-use rustc::session::config::{self, EntryFnType, Lto};
-use rustc::session::Session;
 use rustc::ty::layout::{self, Align, HasTyCtxt, LayoutOf, TyLayout, VariantIdx};
 use rustc::ty::layout::{FAT_PTR_ADDR, FAT_PTR_EXTRA};
 use rustc::ty::query::Providers;
@@ -46,6 +44,8 @@ use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_index::vec::Idx;
 use rustc_session::cgu_reuse_tracker::CguReuse;
+use rustc_session::config::{self, EntryFnType, Lto};
+use rustc_session::Session;
 use rustc_span::Span;
 
 use std::cmp;
diff --git a/src/librustc_codegen_ssa/common.rs b/src/librustc_codegen_ssa/common.rs
index 28b61e0b36d..147b2399502 100644
--- a/src/librustc_codegen_ssa/common.rs
+++ b/src/librustc_codegen_ssa/common.rs
@@ -1,8 +1,8 @@
 #![allow(non_camel_case_types, non_snake_case)]
 
-use rustc::session::Session;
 use rustc::ty::{Ty, TyCtxt};
 use rustc_errors::struct_span_err;
+use rustc_session::Session;
 use rustc_span::Span;
 
 use crate::base;
diff --git a/src/librustc_codegen_ssa/lib.rs b/src/librustc_codegen_ssa/lib.rs
index a2bb39b9e40..d2afbdc23e1 100644
--- a/src/librustc_codegen_ssa/lib.rs
+++ b/src/librustc_codegen_ssa/lib.rs
@@ -21,12 +21,12 @@ use rustc::dep_graph::WorkProduct;
 use rustc::middle::cstore::{CrateSource, LibSource, NativeLibrary};
 use rustc::middle::dependency_format::Dependencies;
 use rustc::middle::lang_items::LangItem;
-use rustc::session::config::{OutputFilenames, OutputType, RUST_CGU_EXT};
 use rustc::ty::query::Providers;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::svh::Svh;
 use rustc_data_structures::sync::Lrc;
 use rustc_hir::def_id::CrateNum;
+use rustc_session::config::{OutputFilenames, OutputType, RUST_CGU_EXT};
 use rustc_span::symbol::Symbol;
 use std::path::{Path, PathBuf};
 
diff --git a/src/librustc_codegen_ssa/mir/debuginfo.rs b/src/librustc_codegen_ssa/mir/debuginfo.rs
index 2dc1405f4e4..cbe5f511152 100644
--- a/src/librustc_codegen_ssa/mir/debuginfo.rs
+++ b/src/librustc_codegen_ssa/mir/debuginfo.rs
@@ -1,10 +1,10 @@
 use crate::traits::*;
 use rustc::mir;
-use rustc::session::config::DebugInfo;
 use rustc::ty;
 use rustc::ty::layout::{LayoutOf, Size};
 use rustc_hir::def_id::CrateNum;
 use rustc_index::vec::IndexVec;
+use rustc_session::config::DebugInfo;
 
 use rustc_span::symbol::{kw, Symbol};
 use rustc_span::{BytePos, Span};
diff --git a/src/librustc_codegen_ssa/traits/backend.rs b/src/librustc_codegen_ssa/traits/backend.rs
index 5535841156a..7acae300a2f 100644
--- a/src/librustc_codegen_ssa/traits/backend.rs
+++ b/src/librustc_codegen_ssa/traits/backend.rs
@@ -3,12 +3,12 @@ use super::CodegenObject;
 use crate::ModuleCodegen;
 
 use rustc::middle::cstore::EncodedMetadata;
-use rustc::session::{config, Session};
 use rustc::ty::layout::{HasTyCtxt, LayoutOf, TyLayout};
 use rustc::ty::Ty;
 use rustc::ty::TyCtxt;
 use rustc_ast::expand::allocator::AllocatorKind;
 use rustc_codegen_utils::codegen_backend::CodegenBackend;
+use rustc_session::{config, Session};
 use rustc_span::symbol::Symbol;
 
 use std::sync::Arc;
diff --git a/src/librustc_codegen_ssa/traits/misc.rs b/src/librustc_codegen_ssa/traits/misc.rs
index d7587163ba0..6863b474cb6 100644
--- a/src/librustc_codegen_ssa/traits/misc.rs
+++ b/src/librustc_codegen_ssa/traits/misc.rs
@@ -1,8 +1,8 @@
 use super::BackendTypes;
 use rustc::mir::mono::CodegenUnit;
-use rustc::session::Session;
 use rustc::ty::{self, Instance, Ty};
 use rustc_data_structures::fx::FxHashMap;
+use rustc_session::Session;
 use std::cell::RefCell;
 use std::sync::Arc;
 
diff --git a/src/librustc_codegen_utils/Cargo.toml b/src/librustc_codegen_utils/Cargo.toml
index b5533a8307c..7ab59029bc8 100644
--- a/src/librustc_codegen_utils/Cargo.toml
+++ b/src/librustc_codegen_utils/Cargo.toml
@@ -21,3 +21,4 @@ rustc_hir = { path = "../librustc_hir" }
 rustc_target = { path = "../librustc_target" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_metadata = { path = "../librustc_metadata" }
+rustc_session = { path = "../librustc_session" }
diff --git a/src/librustc_codegen_utils/codegen_backend.rs b/src/librustc_codegen_utils/codegen_backend.rs
index 96166e04c2e..561692e7066 100644
--- a/src/librustc_codegen_utils/codegen_backend.rs
+++ b/src/librustc_codegen_utils/codegen_backend.rs
@@ -10,11 +10,11 @@ use std::any::Any;
 
 use rustc::dep_graph::DepGraph;
 use rustc::middle::cstore::{EncodedMetadata, MetadataLoaderDyn};
-use rustc::session::config::{OutputFilenames, PrintRequest};
-use rustc::session::Session;
 use rustc::ty::query::Providers;
 use rustc::ty::TyCtxt;
 use rustc::util::common::ErrorReported;
+use rustc_session::config::{OutputFilenames, PrintRequest};
+use rustc_session::Session;
 use rustc_span::symbol::Symbol;
 
 pub use rustc_data_structures::sync::MetadataRef;
diff --git a/src/librustc_codegen_utils/link.rs b/src/librustc_codegen_utils/link.rs
index 2850a29148e..1f53eec514b 100644
--- a/src/librustc_codegen_utils/link.rs
+++ b/src/librustc_codegen_utils/link.rs
@@ -1,6 +1,6 @@
-use rustc::session::config::{self, Input, OutputFilenames, OutputType};
-use rustc::session::Session;
 use rustc_ast::{ast, attr};
+use rustc_session::config::{self, Input, OutputFilenames, OutputType};
+use rustc_session::Session;
 use rustc_span::symbol::sym;
 use rustc_span::Span;
 use std::path::{Path, PathBuf};
diff --git a/src/librustc_codegen_utils/symbol_names.rs b/src/librustc_codegen_utils/symbol_names.rs
index cfde09fad62..eb3fe49a5e9 100644
--- a/src/librustc_codegen_utils/symbol_names.rs
+++ b/src/librustc_codegen_utils/symbol_names.rs
@@ -89,12 +89,12 @@
 
 use rustc::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc::mir::mono::{InstantiationMode, MonoItem};
-use rustc::session::config::SymbolManglingVersion;
 use rustc::ty::query::Providers;
 use rustc::ty::subst::SubstsRef;
 use rustc::ty::{self, Instance, TyCtxt};
 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
 use rustc_hir::Node;
+use rustc_session::config::SymbolManglingVersion;
 
 use rustc_span::symbol::Symbol;
 
diff --git a/src/librustc_driver/Cargo.toml b/src/librustc_driver/Cargo.toml
index 26f1741153c..3e644958231 100644
--- a/src/librustc_driver/Cargo.toml
+++ b/src/librustc_driver/Cargo.toml
@@ -33,6 +33,7 @@ rustc_interface = { path = "../librustc_interface" }
 rustc_serialize = { path = "../libserialize", package = "serialize" }
 rustc_ast = { path = "../librustc_ast" }
 rustc_span = { path = "../librustc_span" }
+rustc_session = { path = "../librustc_session" }
 
 [target.'cfg(windows)'.dependencies]
 winapi = { version = "0.3", features = ["consoleapi", "debugapi", "processenv"] }
diff --git a/src/librustc_driver/lib.rs b/src/librustc_driver/lib.rs
index 8acb2260cbe..34f0c182499 100644
--- a/src/librustc_driver/lib.rs
+++ b/src/librustc_driver/lib.rs
@@ -18,12 +18,7 @@ extern crate lazy_static;
 
 pub extern crate rustc_plugin_impl as plugin;
 
-use rustc::lint::{Lint, LintId};
 use rustc::middle::cstore::MetadataLoader;
-use rustc::session::config::nightly_options;
-use rustc::session::config::{ErrorOutputType, Input, OutputType, PrintRequest};
-use rustc::session::{config, DiagnosticOutput, Session};
-use rustc::session::{early_error, early_warn};
 use rustc::ty::TyCtxt;
 use rustc::util::common::ErrorReported;
 use rustc_codegen_ssa::CodegenResults;
@@ -43,6 +38,11 @@ use rustc_metadata::locator;
 use rustc_save_analysis as save;
 use rustc_save_analysis::DumpHandler;
 use rustc_serialize::json::{self, ToJson};
+use rustc_session::config::nightly_options;
+use rustc_session::config::{ErrorOutputType, Input, OutputType, PrintRequest};
+use rustc_session::lint::{Lint, LintId};
+use rustc_session::{config, DiagnosticOutput, Session};
+use rustc_session::{early_error, early_warn};
 
 use std::borrow::Cow;
 use std::cmp::max;
@@ -652,7 +652,7 @@ impl RustcDefaultCalls {
         odir: &Option<PathBuf>,
         ofile: &Option<PathBuf>,
     ) -> Compilation {
-        use rustc::session::config::PrintRequest::*;
+        use rustc_session::config::PrintRequest::*;
         // PrintRequest::NativeStaticLibs is special - printed during linking
         // (empty iterator returns true)
         if sess.opts.prints.iter().all(|&p| p == PrintRequest::NativeStaticLibs) {
diff --git a/src/librustc_driver/pretty.rs b/src/librustc_driver/pretty.rs
index 2361046c036..1e5cc55a828 100644
--- a/src/librustc_driver/pretty.rs
+++ b/src/librustc_driver/pretty.rs
@@ -1,8 +1,6 @@
 //! The various pretty-printing routines.
 
 use rustc::hir::map as hir_map;
-use rustc::session::config::{Input, PpMode, PpSourceMode};
-use rustc::session::Session;
 use rustc::ty::{self, TyCtxt};
 use rustc::util::common::ErrorReported;
 use rustc_ast::ast;
@@ -11,6 +9,8 @@ use rustc_hir as hir;
 use rustc_hir::def_id::LOCAL_CRATE;
 use rustc_hir::print as pprust_hir;
 use rustc_mir::util::{write_mir_graphviz, write_mir_pretty};
+use rustc_session::config::{Input, PpMode, PpSourceMode};
+use rustc_session::Session;
 use rustc_span::FileName;
 
 use std::cell::Cell;
diff --git a/src/librustc_errors/emitter.rs b/src/librustc_errors/emitter.rs
index 03f83e61636..26f1fa267f9 100644
--- a/src/librustc_errors/emitter.rs
+++ b/src/librustc_errors/emitter.rs
@@ -5,7 +5,7 @@
 //! There are various `Emitter` implementations that generate different output formats such as
 //! JSON and human readable output.
 //!
-//! The output types are defined in `librustc::session::config::ErrorOutputType`.
+//! The output types are defined in `rustc_session::config::ErrorOutputType`.
 
 use Destination::*;
 
diff --git a/src/librustc_hir/intravisit.rs b/src/librustc_hir/intravisit.rs
index b13f1a91b03..316b31f0698 100644
--- a/src/librustc_hir/intravisit.rs
+++ b/src/librustc_hir/intravisit.rs
@@ -127,6 +127,25 @@ pub trait Map<'hir> {
     fn impl_item(&self, id: ImplItemId) -> &'hir ImplItem<'hir>;
 }
 
+/// An erased version of `Map<'hir>`, using dynamic dispatch.
+/// NOTE: This type is effectively only usable with `NestedVisitorMap::None`.
+pub struct ErasedMap<'hir>(&'hir dyn Map<'hir>);
+
+impl<'hir> Map<'hir> for ErasedMap<'hir> {
+    fn body(&self, id: BodyId) -> &'hir Body<'hir> {
+        self.0.body(id)
+    }
+    fn item(&self, id: HirId) -> &'hir Item<'hir> {
+        self.0.item(id)
+    }
+    fn trait_item(&self, id: TraitItemId) -> &'hir TraitItem<'hir> {
+        self.0.trait_item(id)
+    }
+    fn impl_item(&self, id: ImplItemId) -> &'hir ImplItem<'hir> {
+        self.0.impl_item(id)
+    }
+}
+
 /// Specifies what nested things a visitor wants to visit. The most
 /// common choice is `OnlyBodies`, which will cause the visitor to
 /// visit fn bodies for fns that it encounters, but skip over nested
diff --git a/src/librustc_incremental/persist/file_format.rs b/src/librustc_incremental/persist/file_format.rs
index 5c72b049d97..048a81b81ba 100644
--- a/src/librustc_incremental/persist/file_format.rs
+++ b/src/librustc_incremental/persist/file_format.rs
@@ -14,8 +14,8 @@ use std::fs;
 use std::io::{self, Read};
 use std::path::Path;
 
-use rustc::session::config::nightly_options;
 use rustc_serialize::opaque::Encoder;
+use rustc_session::config::nightly_options;
 
 /// The first few bytes of files generated by incremental compilation.
 const FILE_MAGIC: &[u8] = b"RSIC";
diff --git a/src/librustc_incremental/persist/fs.rs b/src/librustc_incremental/persist/fs.rs
index 8548ad392d2..4926f726f35 100644
--- a/src/librustc_incremental/persist/fs.rs
+++ b/src/librustc_incremental/persist/fs.rs
@@ -103,11 +103,11 @@
 //! unsupported file system and emit a warning in that case. This is not yet
 //! implemented.
 
-use rustc::session::{CrateDisambiguator, Session};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::svh::Svh;
 use rustc_data_structures::{base_n, flock};
 use rustc_fs_util::{link_or_copy, LinkOrCopy};
+use rustc_session::{CrateDisambiguator, Session};
 
 use std::fs as std_fs;
 use std::io;
diff --git a/src/librustc_incremental/persist/load.rs b/src/librustc_incremental/persist/load.rs
index 6c57f79e1a7..8a11586250d 100644
--- a/src/librustc_incremental/persist/load.rs
+++ b/src/librustc_incremental/persist/load.rs
@@ -1,12 +1,12 @@
 //! Code to save/load the dep-graph from files.
 
 use rustc::dep_graph::{PreviousDepGraph, SerializedDepGraph, WorkProduct, WorkProductId};
-use rustc::session::Session;
 use rustc::ty::query::OnDiskCache;
 use rustc::ty::TyCtxt;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_serialize::opaque::Decoder;
 use rustc_serialize::Decodable as RustcDecodable;
+use rustc_session::Session;
 use std::path::Path;
 
 use super::data::*;
diff --git a/src/librustc_incremental/persist/save.rs b/src/librustc_incremental/persist/save.rs
index 87f39dedd02..b465a11c99c 100644
--- a/src/librustc_incremental/persist/save.rs
+++ b/src/librustc_incremental/persist/save.rs
@@ -1,10 +1,10 @@
 use rustc::dep_graph::{DepGraph, DepKind, WorkProduct, WorkProductId};
-use rustc::session::Session;
 use rustc::ty::TyCtxt;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::join;
 use rustc_serialize::opaque::Encoder;
 use rustc_serialize::Encodable as RustcEncodable;
+use rustc_session::Session;
 use std::fs;
 use std::path::PathBuf;
 
diff --git a/src/librustc_incremental/persist/work_product.rs b/src/librustc_incremental/persist/work_product.rs
index b1861acec04..aa3588b284b 100644
--- a/src/librustc_incremental/persist/work_product.rs
+++ b/src/librustc_incremental/persist/work_product.rs
@@ -2,8 +2,8 @@
 
 use crate::persist::fs::*;
 use rustc::dep_graph::{WorkProduct, WorkProductFileKind, WorkProductId};
-use rustc::session::Session;
 use rustc_fs_util::link_or_copy;
+use rustc_session::Session;
 use std::fs as std_fs;
 use std::path::PathBuf;
 
diff --git a/src/librustc_infer/Cargo.toml b/src/librustc_infer/Cargo.toml
index 4f97fd82874..9ecd056430c 100644
--- a/src/librustc_infer/Cargo.toml
+++ b/src/librustc_infer/Cargo.toml
@@ -18,6 +18,7 @@ rustc_errors = { path = "../librustc_errors" }
 rustc_hir = { path = "../librustc_hir" }
 rustc_index = { path = "../librustc_index" }
 rustc_macros = { path = "../librustc_macros" }
+rustc_session = { path = "../librustc_session" }
 rustc_span = { path = "../librustc_span" }
 rustc_target = { path = "../librustc_target" }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
diff --git a/src/librustc_infer/infer/mod.rs b/src/librustc_infer/infer/mod.rs
index c5f06d53b8f..391fce946bf 100644
--- a/src/librustc_infer/infer/mod.rs
+++ b/src/librustc_infer/infer/mod.rs
@@ -5,7 +5,6 @@ pub use self::LateBoundRegionConversionTime::*;
 pub use self::RegionVariableOrigin::*;
 pub use self::SubregionOrigin::*;
 pub use self::ValuePairs::*;
-pub use rustc::ty::IntVarValue;
 
 use crate::traits::{self, ObligationCause, PredicateObligations, TraitEngine};
 
@@ -16,15 +15,14 @@ use rustc::middle::free_region::RegionRelations;
 use rustc::middle::region;
 use rustc::mir;
 use rustc::mir::interpret::ConstEvalResult;
-use rustc::session::config::BorrowckMode;
 use rustc::traits::select;
 use rustc::ty::error::{ExpectedFound, TypeError, UnconstrainedNumeric};
 use rustc::ty::fold::{TypeFoldable, TypeFolder};
 use rustc::ty::relate::RelateResult;
 use rustc::ty::subst::{GenericArg, InternalSubsts, SubstsRef};
+pub use rustc::ty::IntVarValue;
 use rustc::ty::{self, GenericParamDefKind, InferConst, Ty, TyCtxt};
 use rustc::ty::{ConstVid, FloatVid, IntVid, TyVid};
-
 use rustc_ast::ast;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::sync::Lrc;
@@ -32,8 +30,10 @@ use rustc_data_structures::unify as ut;
 use rustc_errors::DiagnosticBuilder;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
+use rustc_session::config::BorrowckMode;
 use rustc_span::symbol::Symbol;
 use rustc_span::Span;
+
 use std::cell::{Cell, Ref, RefCell};
 use std::collections::BTreeMap;
 use std::fmt;
diff --git a/src/librustc_interface/interface.rs b/src/librustc_interface/interface.rs
index e15217dfa67..c5ebcf0696f 100644
--- a/src/librustc_interface/interface.rs
+++ b/src/librustc_interface/interface.rs
@@ -1,10 +1,6 @@
 pub use crate::passes::BoxedResolver;
 use crate::util;
 
-use rustc::lint;
-use rustc::session::config::{self, ErrorOutputType, Input, OutputFilenames};
-use rustc::session::early_error;
-use rustc::session::{DiagnosticOutput, Session};
 use rustc::ty;
 use rustc::util::common::ErrorReported;
 use rustc_ast::ast::{self, MetaItemKind};
@@ -16,7 +12,11 @@ use rustc_data_structures::OnDrop;
 use rustc_errors::registry::Registry;
 use rustc_lint::LintStore;
 use rustc_parse::new_parser_from_source_str;
+use rustc_session::config::{self, ErrorOutputType, Input, OutputFilenames};
+use rustc_session::early_error;
+use rustc_session::lint;
 use rustc_session::parse::{CrateConfig, ParseSess};
+use rustc_session::{DiagnosticOutput, Session};
 use rustc_span::edition;
 use rustc_span::source_map::{FileLoader, FileName, SourceMap};
 use std::path::PathBuf;
diff --git a/src/librustc_interface/passes.rs b/src/librustc_interface/passes.rs
index 93f0beaa48b..ee323b204b7 100644
--- a/src/librustc_interface/passes.rs
+++ b/src/librustc_interface/passes.rs
@@ -6,13 +6,8 @@ use log::{info, log_enabled, warn};
 use rustc::arena::Arena;
 use rustc::dep_graph::DepGraph;
 use rustc::hir::map::Definitions;
-use rustc::lint;
 use rustc::middle;
 use rustc::middle::cstore::{CrateStore, MetadataLoader, MetadataLoaderDyn};
-use rustc::session::config::{self, CrateType, Input, OutputFilenames, OutputType};
-use rustc::session::config::{PpMode, PpSourceMode};
-use rustc::session::search_paths::PathKind;
-use rustc::session::Session;
 use rustc::ty::steal::Steal;
 use rustc::ty::{self, GlobalCtxt, ResolverOutputs, TyCtxt};
 use rustc::util::common::ErrorReported;
@@ -34,6 +29,11 @@ use rustc_parse::{parse_crate_from_file, parse_crate_from_source_str};
 use rustc_passes::{self, hir_stats, layout_test};
 use rustc_plugin_impl as plugin;
 use rustc_resolve::{Resolver, ResolverArenas};
+use rustc_session::config::{self, CrateType, Input, OutputFilenames, OutputType};
+use rustc_session::config::{PpMode, PpSourceMode};
+use rustc_session::lint;
+use rustc_session::search_paths::PathKind;
+use rustc_session::Session;
 use rustc_span::symbol::Symbol;
 use rustc_span::FileName;
 use rustc_trait_selection::traits;
diff --git a/src/librustc_interface/queries.rs b/src/librustc_interface/queries.rs
index 426d97cc09b..3514829dca7 100644
--- a/src/librustc_interface/queries.rs
+++ b/src/librustc_interface/queries.rs
@@ -3,8 +3,6 @@ use crate::passes::{self, BoxedResolver, QueryContext};
 
 use rustc::arena::Arena;
 use rustc::dep_graph::DepGraph;
-use rustc::session::config::{OutputFilenames, OutputType};
-use rustc::session::Session;
 use rustc::ty::steal::Steal;
 use rustc::ty::{GlobalCtxt, ResolverOutputs};
 use rustc::util::common::ErrorReported;
@@ -15,6 +13,8 @@ use rustc_hir::def_id::LOCAL_CRATE;
 use rustc_hir::Crate;
 use rustc_incremental::DepGraphFuture;
 use rustc_lint::LintStore;
+use rustc_session::config::{OutputFilenames, OutputType};
+use rustc_session::Session;
 use std::any::Any;
 use std::cell::{Ref, RefCell, RefMut};
 use std::mem;
diff --git a/src/librustc_interface/tests.rs b/src/librustc_interface/tests.rs
index 1b80cf4e3db..db5ada92914 100644
--- a/src/librustc_interface/tests.rs
+++ b/src/librustc_interface/tests.rs
@@ -2,16 +2,16 @@ extern crate getopts;
 
 use crate::interface::parse_cfgspecs;
 
-use rustc::lint::Level;
 use rustc::middle::cstore;
-use rustc::session::config::{build_configuration, build_session_options, to_crate_config};
-use rustc::session::config::{rustc_optgroups, ErrorOutputType, ExternLocation, Options, Passes};
-use rustc::session::config::{ExternEntry, LinkerPluginLto, LtoCli, SwitchWithOptPath};
-use rustc::session::config::{Externs, OutputType, OutputTypes, SymbolManglingVersion};
-use rustc::session::search_paths::SearchPath;
-use rustc::session::{build_session, Session};
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::{emitter::HumanReadableErrorType, registry, ColorConfig};
+use rustc_session::config::{build_configuration, build_session_options, to_crate_config};
+use rustc_session::config::{rustc_optgroups, ErrorOutputType, ExternLocation, Options, Passes};
+use rustc_session::config::{ExternEntry, LinkerPluginLto, LtoCli, SwitchWithOptPath};
+use rustc_session::config::{Externs, OutputType, OutputTypes, SymbolManglingVersion};
+use rustc_session::lint::Level;
+use rustc_session::search_paths::SearchPath;
+use rustc_session::{build_session, Session};
 use rustc_span::edition::{Edition, DEFAULT_EDITION};
 use rustc_span::symbol::sym;
 use rustc_target::spec::{MergeFunctions, PanicStrategy, RelroLevel};
diff --git a/src/librustc_interface/util.rs b/src/librustc_interface/util.rs
index 9521195a1b6..5c4de9e7155 100644
--- a/src/librustc_interface/util.rs
+++ b/src/librustc_interface/util.rs
@@ -1,5 +1,4 @@
 use log::info;
-use rustc::lint;
 use rustc::ty;
 use rustc_ast::ast::{AttrVec, BlockCheckMode};
 use rustc_ast::mut_visit::{visit_clobber, MutVisitor, *};
@@ -18,7 +17,7 @@ use rustc_metadata::dynamic_lib::DynamicLibrary;
 use rustc_resolve::{self, Resolver};
 use rustc_session as session;
 use rustc_session::config::{ErrorOutputType, Input, OutputFilenames};
-use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
+use rustc_session::lint::{self, BuiltinLintDiagnostics, LintBuffer};
 use rustc_session::parse::CrateConfig;
 use rustc_session::CrateDisambiguator;
 use rustc_session::{config, early_error, filesearch, DiagnosticOutput, Session};
diff --git a/src/librustc_lint/builtin.rs b/src/librustc_lint/builtin.rs
index 54b8fad3930..408031028b1 100644
--- a/src/librustc_lint/builtin.rs
+++ b/src/librustc_lint/builtin.rs
@@ -22,7 +22,6 @@
 //! `late_lint_methods!` invocation in `lib.rs`.
 
 use crate::{EarlyContext, EarlyLintPass, LateContext, LateLintPass, LintContext};
-use rustc::hir::map::Map;
 use rustc::lint::LintDiagnosticBuilder;
 use rustc::ty::{self, layout::VariantIdx, Ty, TyCtxt};
 use rustc_ast::ast::{self, Expr};
@@ -1071,7 +1070,7 @@ impl TypeAliasBounds {
             err: &'a mut DiagnosticBuilder<'db>,
         }
         impl<'a, 'db, 'v> Visitor<'v> for WalkAssocTypes<'a, 'db> {
-            type Map = Map<'v>;
+            type Map = intravisit::ErasedMap<'v>;
 
             fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> {
                 intravisit::NestedVisitorMap::None
diff --git a/src/librustc_metadata/Cargo.toml b/src/librustc_metadata/Cargo.toml
index a8e308c5c9e..088cba83ef9 100644
--- a/src/librustc_metadata/Cargo.toml
+++ b/src/librustc_metadata/Cargo.toml
@@ -26,6 +26,7 @@ stable_deref_trait = "1.0.0"
 rustc_ast = { path = "../librustc_ast" }
 rustc_expand = { path = "../librustc_expand" }
 rustc_span = { path = "../librustc_span" }
+rustc_session = { path = "../librustc_session" }
 
 [target.'cfg(windows)'.dependencies]
 winapi = { version = "0.3", features = ["errhandlingapi", "libloaderapi"] }
diff --git a/src/librustc_metadata/creader.rs b/src/librustc_metadata/creader.rs
index 18b4c9ad504..9616e1249dc 100644
--- a/src/librustc_metadata/creader.rs
+++ b/src/librustc_metadata/creader.rs
@@ -6,19 +6,18 @@ use crate::rmeta::{CrateDep, CrateMetadata, CrateNumMap, CrateRoot, MetadataBlob
 use rustc::hir::map::Definitions;
 use rustc::middle::cstore::DepKind;
 use rustc::middle::cstore::{CrateSource, ExternCrate, ExternCrateSource, MetadataLoaderDyn};
-use rustc::session::config;
-use rustc::session::search_paths::PathKind;
-use rustc::session::{CrateDisambiguator, Session};
 use rustc::ty::TyCtxt;
-use rustc_ast::ast;
-use rustc_ast::attr;
 use rustc_ast::expand::allocator::{global_allocator_spans, AllocatorKind};
+use rustc_ast::{ast, attr};
 use rustc_data_structures::svh::Svh;
 use rustc_data_structures::sync::Lrc;
 use rustc_errors::struct_span_err;
 use rustc_expand::base::SyntaxExtension;
 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
 use rustc_index::vec::IndexVec;
+use rustc_session::config;
+use rustc_session::search_paths::PathKind;
+use rustc_session::{CrateDisambiguator, Session};
 use rustc_span::edition::Edition;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::{Span, DUMMY_SP};
diff --git a/src/librustc_metadata/dependency_format.rs b/src/librustc_metadata/dependency_format.rs
index 4a9a9ddc4bd..4cfaf03b7a5 100644
--- a/src/librustc_metadata/dependency_format.rs
+++ b/src/librustc_metadata/dependency_format.rs
@@ -56,10 +56,10 @@ use crate::creader::CStore;
 use rustc::middle::cstore::LinkagePreference::{self, RequireDynamic, RequireStatic};
 use rustc::middle::cstore::{self, DepKind};
 use rustc::middle::dependency_format::{Dependencies, DependencyList, Linkage};
-use rustc::session::config;
 use rustc::ty::TyCtxt;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def_id::CrateNum;
+use rustc_session::config;
 use rustc_target::spec::PanicStrategy;
 
 crate fn calculate(tcx: TyCtxt<'_>) -> Dependencies {
diff --git a/src/librustc_metadata/lib.rs b/src/librustc_metadata/lib.rs
index d4cc3c32616..e401dc0f6e7 100644
--- a/src/librustc_metadata/lib.rs
+++ b/src/librustc_metadata/lib.rs
@@ -31,7 +31,7 @@ pub mod dynamic_lib;
 pub mod locator;
 
 pub fn validate_crate_name(
-    sess: Option<&rustc::session::Session>,
+    sess: Option<&rustc_session::Session>,
     s: &str,
     sp: Option<rustc_span::Span>,
 ) {
diff --git a/src/librustc_metadata/locator.rs b/src/librustc_metadata/locator.rs
index efa259d0c4e..1ede629e7ef 100644
--- a/src/librustc_metadata/locator.rs
+++ b/src/librustc_metadata/locator.rs
@@ -216,13 +216,13 @@ use crate::creader::Library;
 use crate::rmeta::{rustc_version, MetadataBlob, METADATA_HEADER};
 
 use rustc::middle::cstore::{CrateSource, MetadataLoader};
-use rustc::session::filesearch::{FileDoesntMatch, FileMatches, FileSearch};
-use rustc::session::search_paths::PathKind;
-use rustc::session::{config, CrateDisambiguator, Session};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::svh::Svh;
 use rustc_data_structures::sync::MetadataRef;
 use rustc_errors::{struct_span_err, DiagnosticBuilder};
+use rustc_session::filesearch::{FileDoesntMatch, FileMatches, FileSearch};
+use rustc_session::search_paths::PathKind;
+use rustc_session::{config, CrateDisambiguator, Session};
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::Span;
 use rustc_target::spec::{Target, TargetTriple};
diff --git a/src/librustc_metadata/native_libs.rs b/src/librustc_metadata/native_libs.rs
index 2fa9cb099dd..64bbf393ba0 100644
--- a/src/librustc_metadata/native_libs.rs
+++ b/src/librustc_metadata/native_libs.rs
@@ -1,12 +1,12 @@
 use rustc::middle::cstore::{self, NativeLibrary};
-use rustc::session::parse::feature_err;
-use rustc::session::Session;
 use rustc::ty::TyCtxt;
 use rustc_attr as attr;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
+use rustc_session::parse::feature_err;
+use rustc_session::Session;
 use rustc_span::source_map::Span;
 use rustc_span::symbol::{kw, sym, Symbol};
 use rustc_target::spec::abi::Abi;
diff --git a/src/librustc_metadata/rmeta/decoder.rs b/src/librustc_metadata/rmeta/decoder.rs
index 5b7d89243c3..cf0f8816058 100644
--- a/src/librustc_metadata/rmeta/decoder.rs
+++ b/src/librustc_metadata/rmeta/decoder.rs
@@ -14,36 +14,35 @@ use rustc::middle::exported_symbols::{ExportedSymbol, SymbolExportLevel};
 use rustc::middle::lang_items;
 use rustc::mir::interpret::{AllocDecodingSession, AllocDecodingState};
 use rustc::mir::{self, interpret, BodyAndCache, Promoted};
-use rustc::session::Session;
 use rustc::ty::codec::TyDecoder;
 use rustc::ty::{self, Ty, TyCtxt};
 use rustc::util::common::record_time;
+use rustc_ast::ast::{self, Ident};
+use rustc_attr as attr;
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::svh::Svh;
 use rustc_data_structures::sync::{AtomicCell, Lock, LockGuard, Lrc, Once};
+use rustc_expand::base::{SyntaxExtension, SyntaxExtensionKind};
+use rustc_expand::proc_macro::{AttrProcMacro, BangProcMacro, ProcMacroDerive};
 use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, CtorOf, DefKind, Res};
 use rustc_hir::def_id::{CrateNum, DefId, DefIndex, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
 use rustc_index::vec::{Idx, IndexVec};
+use rustc_serialize::{opaque, Decodable, Decoder, SpecializedDecoder};
+use rustc_session::Session;
+use rustc_span::source_map::{self, respan, Spanned};
+use rustc_span::symbol::{sym, Symbol};
+use rustc_span::{self, hygiene::MacroKind, BytePos, Pos, Span, DUMMY_SP};
 
+use log::debug;
+use proc_macro::bridge::client::ProcMacro;
 use std::io;
 use std::mem;
 use std::num::NonZeroUsize;
 use std::u32;
 
-use log::debug;
-use proc_macro::bridge::client::ProcMacro;
-use rustc_ast::ast::{self, Ident};
-use rustc_attr as attr;
-use rustc_expand::base::{SyntaxExtension, SyntaxExtensionKind};
-use rustc_expand::proc_macro::{AttrProcMacro, BangProcMacro, ProcMacroDerive};
-use rustc_serialize::{opaque, Decodable, Decoder, SpecializedDecoder};
-use rustc_span::source_map::{self, respan, Spanned};
-use rustc_span::symbol::{sym, Symbol};
-use rustc_span::{self, hygiene::MacroKind, BytePos, Pos, Span, DUMMY_SP};
-
 pub use cstore_impl::{provide, provide_extern};
 
 mod cstore_impl;
diff --git a/src/librustc_metadata/rmeta/decoder/cstore_impl.rs b/src/librustc_metadata/rmeta/decoder/cstore_impl.rs
index d87e24eeed1..cc2bd51f92f 100644
--- a/src/librustc_metadata/rmeta/decoder/cstore_impl.rs
+++ b/src/librustc_metadata/rmeta/decoder/cstore_impl.rs
@@ -10,7 +10,6 @@ use rustc::hir::map::{DefKey, DefPath, DefPathHash};
 use rustc::middle::cstore::{CrateSource, CrateStore, EncodedMetadata, NativeLibraryKind};
 use rustc::middle::exported_symbols::ExportedSymbol;
 use rustc::middle::stability::DeprecationEntry;
-use rustc::session::{CrateDisambiguator, Session};
 use rustc::ty::query::Providers;
 use rustc::ty::query::QueryConfig;
 use rustc::ty::{self, TyCtxt};
@@ -20,6 +19,7 @@ use rustc_ast::expand::allocator::AllocatorKind;
 use rustc_data_structures::svh::Svh;
 use rustc_hir as hir;
 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, CRATE_DEF_INDEX, LOCAL_CRATE};
+use rustc_session::{CrateDisambiguator, Session};
 use rustc_span::source_map::{self, Span, Spanned};
 use rustc_span::symbol::Symbol;
 
diff --git a/src/librustc_metadata/rmeta/encoder.rs b/src/librustc_metadata/rmeta/encoder.rs
index 4c8e07c223b..90179520a62 100644
--- a/src/librustc_metadata/rmeta/encoder.rs
+++ b/src/librustc_metadata/rmeta/encoder.rs
@@ -12,33 +12,31 @@ use rustc::traits::specialization_graph;
 use rustc::ty::codec::{self as ty_codec, TyEncoder};
 use rustc::ty::layout::VariantIdx;
 use rustc::ty::{self, SymbolName, Ty, TyCtxt};
+use rustc_ast::ast;
+use rustc_ast::attr;
 use rustc_data_structures::fingerprint::Fingerprint;
+use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::stable_hasher::StableHasher;
+use rustc_data_structures::sync::Lrc;
+use rustc_hir as hir;
 use rustc_hir::def::CtorKind;
 use rustc_hir::def_id::{CrateNum, DefId, DefIndex, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
+use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
+use rustc_hir::itemlikevisit::ItemLikeVisitor;
 use rustc_hir::{AnonConst, GenericParamKind};
 use rustc_index::vec::Idx;
-
-use rustc::session::config::{self, CrateType};
-use rustc_data_structures::fx::FxHashMap;
-use rustc_data_structures::stable_hasher::StableHasher;
-use rustc_data_structures::sync::Lrc;
 use rustc_serialize::{opaque, Encodable, Encoder, SpecializedEncoder};
-
-use log::{debug, trace};
-use rustc_ast::ast;
-use rustc_ast::attr;
+use rustc_session::config::{self, CrateType};
 use rustc_span::source_map::Spanned;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{self, FileName, SourceFile, Span};
+
+use log::{debug, trace};
 use std::hash::Hash;
 use std::num::NonZeroUsize;
 use std::path::Path;
 use std::u32;
 
-use rustc_hir as hir;
-use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
-use rustc_hir::itemlikevisit::ItemLikeVisitor;
-
 struct EncodeContext<'tcx> {
     opaque: opaque::Encoder,
     tcx: TyCtxt<'tcx>,
diff --git a/src/librustc_metadata/rmeta/mod.rs b/src/librustc_metadata/rmeta/mod.rs
index e2d8d5466bd..defa306b6d6 100644
--- a/src/librustc_metadata/rmeta/mod.rs
+++ b/src/librustc_metadata/rmeta/mod.rs
@@ -7,8 +7,6 @@ use rustc::middle::cstore::{DepKind, ForeignModule, LinkagePreference, NativeLib
 use rustc::middle::exported_symbols::{ExportedSymbol, SymbolExportLevel};
 use rustc::middle::lang_items;
 use rustc::mir;
-use rustc::session::config::SymbolManglingVersion;
-use rustc::session::CrateDisambiguator;
 use rustc::ty::{self, ReprOptions, Ty};
 use rustc_ast::ast::{self, MacroDef};
 use rustc_attr as attr;
@@ -19,6 +17,8 @@ use rustc_hir::def::CtorKind;
 use rustc_hir::def_id::{DefId, DefIndex};
 use rustc_index::vec::IndexVec;
 use rustc_serialize::opaque::Encoder;
+use rustc_session::config::SymbolManglingVersion;
+use rustc_session::CrateDisambiguator;
 use rustc_span::edition::Edition;
 use rustc_span::symbol::Symbol;
 use rustc_span::{self, Span};
diff --git a/src/librustc_mir/Cargo.toml b/src/librustc_mir/Cargo.toml
index cad50d50f3c..256a80076b9 100644
--- a/src/librustc_mir/Cargo.toml
+++ b/src/librustc_mir/Cargo.toml
@@ -27,6 +27,7 @@ rustc_infer = { path = "../librustc_infer" }
 rustc_lexer = { path = "../librustc_lexer" }
 rustc_macros = { path = "../librustc_macros" }
 rustc_serialize = { path = "../libserialize", package = "serialize" }
+rustc_session = { path = "../librustc_session" }
 rustc_target = { path = "../librustc_target" }
 rustc_trait_selection = { path = "../librustc_trait_selection" }
 rustc_ast = { path = "../librustc_ast" }
diff --git a/src/librustc_mir/borrow_check/mod.rs b/src/librustc_mir/borrow_check/mod.rs
index a61d00b0120..6c1901455fd 100644
--- a/src/librustc_mir/borrow_check/mod.rs
+++ b/src/librustc_mir/borrow_check/mod.rs
@@ -1,7 +1,5 @@
 //! This query borrow-checks the MIR to (further) ensure it is not broken.
 
-use rustc::lint::builtin::MUTABLE_BORROW_RESERVATION_CONFLICT;
-use rustc::lint::builtin::UNUSED_MUT;
 use rustc::mir::{
     read_only, traversal, Body, BodyAndCache, ClearCrossCrate, Local, Location, Mutability,
     Operand, Place, PlaceElem, PlaceRef, ReadOnlyBodyAndCache,
@@ -11,7 +9,7 @@ use rustc::mir::{Field, ProjectionElem, Promoted, Rvalue, Statement, StatementKi
 use rustc::mir::{Terminator, TerminatorKind};
 use rustc::ty::query::Providers;
 use rustc::ty::{self, RegionVid, TyCtxt};
-
+use rustc_ast::ast::Name;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::graph::dominators::Dominators;
 use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder};
@@ -20,6 +18,8 @@ use rustc_hir::{def_id::DefId, HirId, Node};
 use rustc_index::bit_set::BitSet;
 use rustc_index::vec::IndexVec;
 use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
+use rustc_session::lint::builtin::{MUTABLE_BORROW_RESERVATION_CONFLICT, UNUSED_MUT};
+use rustc_span::{Span, DUMMY_SP};
 
 use either::Either;
 use smallvec::SmallVec;
@@ -28,9 +28,6 @@ use std::collections::BTreeMap;
 use std::mem;
 use std::rc::Rc;
 
-use rustc_ast::ast::Name;
-use rustc_span::{Span, DUMMY_SP};
-
 use crate::dataflow;
 use crate::dataflow::generic::{Analysis, BorrowckFlowState as Flows, BorrowckResults};
 use crate::dataflow::indexes::{BorrowIndex, InitIndex, MoveOutIndex, MovePathIndex};
diff --git a/src/librustc_mir/dataflow/mod.rs b/src/librustc_mir/dataflow/mod.rs
index b4e33b9502e..dd0f9ff75b9 100644
--- a/src/librustc_mir/dataflow/mod.rs
+++ b/src/librustc_mir/dataflow/mod.rs
@@ -1,16 +1,14 @@
+use rustc::mir::traversal;
+use rustc::mir::{self, BasicBlock, BasicBlockData, Body, Location, Statement, Terminator};
+use rustc::ty::{self, TyCtxt};
 use rustc_ast::ast::{self, MetaItem};
 use rustc_ast_pretty::pprust;
-use rustc_span::symbol::{sym, Symbol};
-
 use rustc_data_structures::work_queue::WorkQueue;
+use rustc_hir::def_id::DefId;
 use rustc_index::bit_set::{BitSet, HybridBitSet};
 use rustc_index::vec::Idx;
-
-use rustc::mir::traversal;
-use rustc::mir::{self, BasicBlock, BasicBlockData, Body, Location, Statement, Terminator};
-use rustc::session::Session;
-use rustc::ty::{self, TyCtxt};
-use rustc_hir::def_id::DefId;
+use rustc_session::Session;
+use rustc_span::symbol::{sym, Symbol};
 
 use std::borrow::Borrow;
 use std::fmt;
diff --git a/src/librustc_mir/monomorphize/collector.rs b/src/librustc_mir/monomorphize/collector.rs
index f56bef031a7..51760500b03 100644
--- a/src/librustc_mir/monomorphize/collector.rs
+++ b/src/librustc_mir/monomorphize/collector.rs
@@ -183,7 +183,6 @@ use rustc::mir::interpret::{ErrorHandled, GlobalAlloc, Scalar};
 use rustc::mir::mono::{InstantiationMode, MonoItem};
 use rustc::mir::visit::Visitor as MirVisitor;
 use rustc::mir::{self, Local, Location};
-use rustc::session::config::EntryFnType;
 use rustc::ty::adjustment::{CustomCoerceUnsized, PointerCast};
 use rustc::ty::print::obsolete::DefPathBasedNames;
 use rustc::ty::subst::{InternalSubsts, SubstsRef};
@@ -194,6 +193,7 @@ use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, DefIdMap, LOCAL_CRATE};
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
 use rustc_index::bit_set::GrowableBitSet;
+use rustc_session::config::EntryFnType;
 use smallvec::SmallVec;
 use std::iter;
 
diff --git a/src/librustc_mir/transform/check_consts/ops.rs b/src/librustc_mir/transform/check_consts/ops.rs
index d06a2aa44f2..af7af7388bd 100644
--- a/src/librustc_mir/transform/check_consts/ops.rs
+++ b/src/librustc_mir/transform/check_consts/ops.rs
@@ -1,9 +1,9 @@
 //! Concrete error types for all operations which may be invalid in a certain const context.
 
-use rustc::session::config::nightly_options;
-use rustc::session::parse::feature_err;
 use rustc_errors::struct_span_err;
 use rustc_hir::def_id::DefId;
+use rustc_session::config::nightly_options;
+use rustc_session::parse::feature_err;
 use rustc_span::symbol::sym;
 use rustc_span::{Span, Symbol};
 
diff --git a/src/librustc_mir/transform/check_unsafety.rs b/src/librustc_mir/transform/check_unsafety.rs
index 21788593259..437a154a9b8 100644
--- a/src/librustc_mir/transform/check_unsafety.rs
+++ b/src/librustc_mir/transform/check_unsafety.rs
@@ -1,5 +1,3 @@
-use rustc::hir::map::Map;
-use rustc::lint::builtin::{SAFE_PACKED_BORROWS, UNUSED_UNSAFE};
 use rustc::mir::visit::{MutatingUseContext, PlaceContext, Visitor};
 use rustc::mir::*;
 use rustc::ty::cast::CastTy;
@@ -11,6 +9,7 @@ use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit;
 use rustc_hir::Node;
+use rustc_session::lint::builtin::{SAFE_PACKED_BORROWS, UNUSED_UNSAFE};
 use rustc_span::symbol::{sym, Symbol};
 
 use std::ops::Bound;
@@ -451,7 +450,7 @@ struct UnusedUnsafeVisitor<'a> {
 }
 
 impl<'a, 'tcx> intravisit::Visitor<'tcx> for UnusedUnsafeVisitor<'a> {
-    type Map = Map<'tcx>;
+    type Map = intravisit::ErasedMap<'tcx>;
 
     fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> {
         intravisit::NestedVisitorMap::None
diff --git a/src/librustc_mir/transform/const_prop.rs b/src/librustc_mir/transform/const_prop.rs
index 289b198d2c9..ca23c44f646 100644
--- a/src/librustc_mir/transform/const_prop.rs
+++ b/src/librustc_mir/transform/const_prop.rs
@@ -4,7 +4,6 @@
 use std::borrow::Cow;
 use std::cell::Cell;
 
-use rustc::lint;
 use rustc::mir::interpret::{InterpResult, Scalar};
 use rustc::mir::visit::{
     MutVisitor, MutatingUseContext, NonMutatingUseContext, PlaceContext, Visitor,
@@ -25,6 +24,7 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def::DefKind;
 use rustc_hir::HirId;
 use rustc_index::vec::IndexVec;
+use rustc_session::lint;
 use rustc_span::Span;
 use rustc_trait_selection::traits;
 
diff --git a/src/librustc_mir/transform/dump_mir.rs b/src/librustc_mir/transform/dump_mir.rs
index 5dec2c6df99..795bcb57d06 100644
--- a/src/librustc_mir/transform/dump_mir.rs
+++ b/src/librustc_mir/transform/dump_mir.rs
@@ -8,8 +8,8 @@ use std::io;
 use crate::transform::{MirPass, MirSource};
 use crate::util as mir_util;
 use rustc::mir::{Body, BodyAndCache};
-use rustc::session::config::{OutputFilenames, OutputType};
 use rustc::ty::TyCtxt;
+use rustc_session::config::{OutputFilenames, OutputType};
 
 pub struct Marker(pub &'static str);
 
diff --git a/src/librustc_mir/transform/inline.rs b/src/librustc_mir/transform/inline.rs
index b6802505df7..769f3fdcc01 100644
--- a/src/librustc_mir/transform/inline.rs
+++ b/src/librustc_mir/transform/inline.rs
@@ -1,25 +1,22 @@
 //! Inlining pass for MIR functions
 
-use rustc_hir::def_id::DefId;
-
-use rustc_index::bit_set::BitSet;
-use rustc_index::vec::{Idx, IndexVec};
-
 use rustc::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc::mir::visit::*;
 use rustc::mir::*;
-use rustc::session::config::Sanitizer;
 use rustc::ty::subst::{InternalSubsts, Subst, SubstsRef};
 use rustc::ty::{self, Instance, InstanceDef, ParamEnv, Ty, TyCtxt, TypeFoldable};
+use rustc_attr as attr;
+use rustc_hir::def_id::DefId;
+use rustc_index::bit_set::BitSet;
+use rustc_index::vec::{Idx, IndexVec};
+use rustc_session::config::Sanitizer;
+use rustc_target::spec::abi::Abi;
 
 use super::simplify::{remove_dead_blocks, CfgSimplifier};
 use crate::transform::{MirPass, MirSource};
 use std::collections::VecDeque;
 use std::iter;
 
-use rustc_attr as attr;
-use rustc_target::spec::abi::Abi;
-
 const DEFAULT_THRESHOLD: usize = 50;
 const HINT_THRESHOLD: usize = 100;
 
diff --git a/src/librustc_mir/transform/mod.rs b/src/librustc_mir/transform/mod.rs
index d4a5966af4a..3eb9d23a32a 100644
--- a/src/librustc_mir/transform/mod.rs
+++ b/src/librustc_mir/transform/mod.rs
@@ -1,5 +1,4 @@
 use crate::{shim, util};
-use rustc::hir::map::Map;
 use rustc::mir::{BodyAndCache, ConstQualifs, MirPhase, Promoted};
 use rustc::ty::query::Providers;
 use rustc::ty::steal::Steal;
@@ -86,7 +85,7 @@ fn mir_keys(tcx: TyCtxt<'_>, krate: CrateNum) -> &DefIdSet {
             }
             intravisit::walk_struct_def(self, v)
         }
-        type Map = Map<'tcx>;
+        type Map = intravisit::ErasedMap<'tcx>;
         fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
             NestedVisitorMap::None
         }
diff --git a/src/librustc_mir_build/hair/pattern/_match.rs b/src/librustc_mir_build/hair/pattern/_match.rs
index 486dd3579d2..82810f35675 100644
--- a/src/librustc_mir_build/hair/pattern/_match.rs
+++ b/src/librustc_mir_build/hair/pattern/_match.rs
@@ -235,17 +235,15 @@ use rustc_index::vec::Idx;
 use super::{compare_const_vals, PatternFoldable, PatternFolder};
 use super::{FieldPat, Pat, PatKind, PatRange};
 
-use rustc::ty::layout::{Integer, IntegerExt, Size, VariantIdx};
-use rustc::ty::{self, Const, Ty, TyCtxt, TypeFoldable, VariantDef};
-use rustc_hir::def_id::DefId;
-use rustc_hir::{HirId, RangeEnd};
-
-use rustc::lint;
 use rustc::mir::interpret::{truncate, AllocId, ConstValue, Pointer, Scalar};
 use rustc::mir::Field;
+use rustc::ty::layout::{Integer, IntegerExt, Size, VariantIdx};
+use rustc::ty::{self, Const, Ty, TyCtxt, TypeFoldable, VariantDef};
 use rustc::util::common::ErrorReported;
-
 use rustc_attr::{SignedInt, UnsignedInt};
+use rustc_hir::def_id::DefId;
+use rustc_hir::{HirId, RangeEnd};
+use rustc_session::lint;
 use rustc_span::{Span, DUMMY_SP};
 
 use arena::TypedArena;
diff --git a/src/librustc_mir_build/hair/pattern/check_match.rs b/src/librustc_mir_build/hair/pattern/check_match.rs
index 36913051813..f71ec5e9ac0 100644
--- a/src/librustc_mir_build/hair/pattern/check_match.rs
+++ b/src/librustc_mir_build/hair/pattern/check_match.rs
@@ -4,7 +4,6 @@ use super::_match::{expand_pattern, is_useful, MatchCheckCtxt, Matrix, PatStack}
 
 use super::{PatCtxt, PatKind, PatternError};
 
-use rustc::hir::map::Map;
 use rustc::ty::{self, Ty, TyCtxt};
 use rustc_ast::ast::Mutability;
 use rustc_errors::{error_code, struct_span_err, Applicability, DiagnosticBuilder};
@@ -43,7 +42,7 @@ struct MatchVisitor<'a, 'tcx> {
 }
 
 impl<'tcx> Visitor<'tcx> for MatchVisitor<'_, 'tcx> {
-    type Map = Map<'tcx>;
+    type Map = intravisit::ErasedMap<'tcx>;
 
     fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
         NestedVisitorMap::None
@@ -753,7 +752,7 @@ fn check_legality_of_bindings_in_at_patterns(cx: &MatchVisitor<'_, '_>, pat: &Pa
     }
 
     impl<'v> Visitor<'v> for AtBindingPatternVisitor<'_, '_, '_> {
-        type Map = Map<'v>;
+        type Map = intravisit::ErasedMap<'v>;
 
         fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
             NestedVisitorMap::None
diff --git a/src/librustc_mir_build/hair/pattern/const_to_pat.rs b/src/librustc_mir_build/hair/pattern/const_to_pat.rs
index 214e75fbdde..ae951e810e3 100644
--- a/src/librustc_mir_build/hair/pattern/const_to_pat.rs
+++ b/src/librustc_mir_build/hair/pattern/const_to_pat.rs
@@ -1,16 +1,14 @@
-use rustc::lint;
 use rustc::mir::Field;
 use rustc::ty::{self, Ty, TyCtxt};
 use rustc_hir as hir;
+use rustc_index::vec::Idx;
 use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
+use rustc_session::lint;
+use rustc_span::Span;
 use rustc_trait_selection::traits::predicate_for_trait_def;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt;
 use rustc_trait_selection::traits::{self, ObligationCause, PredicateObligation};
 
-use rustc_index::vec::Idx;
-
-use rustc_span::Span;
-
 use std::cell::Cell;
 
 use super::{FieldPat, Pat, PatCtxt, PatKind};
@@ -182,7 +180,7 @@ impl<'a, 'tcx> ConstToPat<'a, 'tcx> {
         let kind = match cv.ty.kind {
             ty::Float(_) => {
                 tcx.struct_span_lint_hir(
-                    ::rustc::lint::builtin::ILLEGAL_FLOATING_POINT_LITERAL_PATTERN,
+                    lint::builtin::ILLEGAL_FLOATING_POINT_LITERAL_PATTERN,
                     id,
                     span,
                     |lint| lint.build("floating-point types cannot be used in patterns").emit(),
diff --git a/src/librustc_mir_build/lints.rs b/src/librustc_mir_build/lints.rs
index 0017f800de7..8b1ddf7461a 100644
--- a/src/librustc_mir_build/lints.rs
+++ b/src/librustc_mir_build/lints.rs
@@ -1,11 +1,11 @@
 use rustc::hir::map::blocks::FnLikeNode;
-use rustc::lint::builtin::UNCONDITIONAL_RECURSION;
 use rustc::mir::{self, Body, TerminatorKind};
 use rustc::ty::subst::InternalSubsts;
 use rustc::ty::{self, AssocItem, AssocItemContainer, Instance, TyCtxt};
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::FnKind;
 use rustc_index::bit_set::BitSet;
+use rustc_session::lint::builtin::UNCONDITIONAL_RECURSION;
 
 crate fn check<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>, def_id: DefId) {
     let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
diff --git a/src/librustc_passes/check_const.rs b/src/librustc_passes/check_const.rs
index af06fc0c002..30737360b9c 100644
--- a/src/librustc_passes/check_const.rs
+++ b/src/librustc_passes/check_const.rs
@@ -8,8 +8,6 @@
 //! through, but errors for structured control flow in a `const` should be emitted here.
 
 use rustc::hir::map::Map;
-use rustc::session::config::nightly_options;
-use rustc::session::parse::feature_err;
 use rustc::ty::query::Providers;
 use rustc::ty::TyCtxt;
 use rustc_ast::ast::Mutability;
@@ -17,6 +15,8 @@ use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
+use rustc_session::config::nightly_options;
+use rustc_session::parse::feature_err;
 use rustc_span::{sym, Span, Symbol};
 
 use std::fmt;
diff --git a/src/librustc_passes/dead.rs b/src/librustc_passes/dead.rs
index 587b57eb322..4466dea89b0 100644
--- a/src/librustc_passes/dead.rs
+++ b/src/librustc_passes/dead.rs
@@ -210,7 +210,7 @@ impl<'a, 'tcx> MarkSymbolVisitor<'a, 'tcx> {
 }
 
 impl<'a, 'tcx> Visitor<'tcx> for MarkSymbolVisitor<'a, 'tcx> {
-    type Map = Map<'tcx>;
+    type Map = intravisit::ErasedMap<'tcx>;
 
     fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> {
         NestedVisitorMap::None
diff --git a/src/librustc_passes/entry.rs b/src/librustc_passes/entry.rs
index 2cabe786d0c..598d6bb3c48 100644
--- a/src/librustc_passes/entry.rs
+++ b/src/librustc_passes/entry.rs
@@ -1,6 +1,4 @@
 use rustc::hir::map::Map;
-use rustc::session::config::EntryFnType;
-use rustc::session::{config, Session};
 use rustc::ty::query::Providers;
 use rustc::ty::TyCtxt;
 use rustc_ast::attr;
@@ -9,6 +7,8 @@ use rustc_errors::struct_span_err;
 use rustc_hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
 use rustc_hir::{HirId, ImplItem, Item, ItemKind, TraitItem};
+use rustc_session::config::EntryFnType;
+use rustc_session::{config, Session};
 use rustc_span::symbol::sym;
 use rustc_span::{Span, DUMMY_SP};
 
diff --git a/src/librustc_passes/intrinsicck.rs b/src/librustc_passes/intrinsicck.rs
index 5cf9666797e..1b46aaeefcb 100644
--- a/src/librustc_passes/intrinsicck.rs
+++ b/src/librustc_passes/intrinsicck.rs
@@ -1,4 +1,3 @@
-use rustc::hir::map::Map;
 use rustc::ty::layout::{LayoutError, Pointer, SizeSkeleton, VariantIdx};
 use rustc::ty::query::Providers;
 use rustc::ty::{self, Ty, TyCtxt};
@@ -122,7 +121,7 @@ impl ExprVisitor<'tcx> {
 }
 
 impl Visitor<'tcx> for ItemVisitor<'tcx> {
-    type Map = Map<'tcx>;
+    type Map = intravisit::ErasedMap<'tcx>;
 
     fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
         NestedVisitorMap::None
@@ -139,7 +138,7 @@ impl Visitor<'tcx> for ItemVisitor<'tcx> {
 }
 
 impl Visitor<'tcx> for ExprVisitor<'tcx> {
-    type Map = Map<'tcx>;
+    type Map = intravisit::ErasedMap<'tcx>;
 
     fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
         NestedVisitorMap::None
diff --git a/src/librustc_passes/liveness.rs b/src/librustc_passes/liveness.rs
index d7208a00e09..556d6b40db4 100644
--- a/src/librustc_passes/liveness.rs
+++ b/src/librustc_passes/liveness.rs
@@ -97,7 +97,6 @@ use self::LiveNodeKind::*;
 use self::VarKind::*;
 
 use rustc::hir::map::Map;
-use rustc::lint;
 use rustc::ty::query::Providers;
 use rustc::ty::{self, TyCtxt};
 use rustc_ast::ast;
@@ -108,6 +107,7 @@ use rustc_hir::def::*;
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::{self, FnKind, NestedVisitorMap, Visitor};
 use rustc_hir::{Expr, HirId, HirIdMap, HirIdSet, Node};
+use rustc_session::lint;
 use rustc_span::symbol::sym;
 use rustc_span::Span;
 
@@ -1370,7 +1370,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
 // Checking for error conditions
 
 impl<'a, 'tcx> Visitor<'tcx> for Liveness<'a, 'tcx> {
-    type Map = Map<'tcx>;
+    type Map = intravisit::ErasedMap<'tcx>;
 
     fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
         NestedVisitorMap::None
diff --git a/src/librustc_passes/reachable.rs b/src/librustc_passes/reachable.rs
index 4643add5ac3..121e0368039 100644
--- a/src/librustc_passes/reachable.rs
+++ b/src/librustc_passes/reachable.rs
@@ -5,10 +5,8 @@
 // makes all other generics or inline functions that it references
 // reachable as well.
 
-use rustc::hir::map::Map;
 use rustc::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
 use rustc::middle::privacy;
-use rustc::session::config;
 use rustc::ty::query::Providers;
 use rustc::ty::{self, TyCtxt};
 use rustc_data_structures::fx::FxHashSet;
@@ -17,10 +15,10 @@ use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::LOCAL_CRATE;
 use rustc_hir::def_id::{CrateNum, DefId};
-use rustc_hir::intravisit;
-use rustc_hir::intravisit::{NestedVisitorMap, Visitor};
+use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
 use rustc_hir::{HirIdSet, Node};
+use rustc_session::config;
 use rustc_target::spec::abi::Abi;
 
 // Returns true if the given item must be inlined because it may be
@@ -83,7 +81,7 @@ struct ReachableContext<'a, 'tcx> {
 }
 
 impl<'a, 'tcx> Visitor<'tcx> for ReachableContext<'a, 'tcx> {
-    type Map = Map<'tcx>;
+    type Map = intravisit::ErasedMap<'tcx>;
 
     fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
         NestedVisitorMap::None
diff --git a/src/librustc_passes/region.rs b/src/librustc_passes/region.rs
index 640a3a35aa0..e771696a5b6 100644
--- a/src/librustc_passes/region.rs
+++ b/src/librustc_passes/region.rs
@@ -6,7 +6,6 @@
 //!
 //! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/borrow_check.html
 
-use rustc::hir::map::Map;
 use rustc::middle::region::*;
 use rustc::ty::query::Providers;
 use rustc::ty::TyCtxt;
@@ -696,7 +695,7 @@ impl<'tcx> RegionResolutionVisitor<'tcx> {
 }
 
 impl<'tcx> Visitor<'tcx> for RegionResolutionVisitor<'tcx> {
-    type Map = Map<'tcx>;
+    type Map = intravisit::ErasedMap<'tcx>;
 
     fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
         NestedVisitorMap::None
diff --git a/src/librustc_passes/stability.rs b/src/librustc_passes/stability.rs
index 6cf4132141b..11311a3e8aa 100644
--- a/src/librustc_passes/stability.rs
+++ b/src/librustc_passes/stability.rs
@@ -2,11 +2,8 @@
 //! propagating default levels lexically from parent to children ast nodes.
 
 use rustc::hir::map::Map;
-use rustc::lint;
 use rustc::middle::privacy::AccessLevels;
 use rustc::middle::stability::{DeprecationEntry, Index};
-use rustc::session::parse::feature_err;
-use rustc::session::Session;
 use rustc::ty::query::Providers;
 use rustc::ty::TyCtxt;
 use rustc_ast::ast::Attribute;
@@ -18,6 +15,9 @@ use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
 use rustc_hir::{Generics, HirId, Item, StructField, Variant};
+use rustc_session::lint;
+use rustc_session::parse::feature_err;
+use rustc_session::Session;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::Span;
 use rustc_trait_selection::traits::misc::can_type_implement_copy;
diff --git a/src/librustc_passes/upvars.rs b/src/librustc_passes/upvars.rs
index d20237a22d9..43f39e6c610 100644
--- a/src/librustc_passes/upvars.rs
+++ b/src/librustc_passes/upvars.rs
@@ -1,6 +1,5 @@
 //! Upvar (closure capture) collection from cross-body HIR uses of `Res::Local`s.
 
-use rustc::hir::map::Map;
 use rustc::ty::query::Providers;
 use rustc::ty::TyCtxt;
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
@@ -44,7 +43,7 @@ struct LocalCollector {
 }
 
 impl Visitor<'tcx> for LocalCollector {
-    type Map = Map<'tcx>;
+    type Map = intravisit::ErasedMap<'tcx>;
 
     fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
         NestedVisitorMap::None
@@ -73,7 +72,7 @@ impl CaptureCollector<'_, '_> {
 }
 
 impl Visitor<'tcx> for CaptureCollector<'a, 'tcx> {
-    type Map = Map<'tcx>;
+    type Map = intravisit::ErasedMap<'tcx>;
 
     fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
         NestedVisitorMap::None
diff --git a/src/librustc_passes/weak_lang_items.rs b/src/librustc_passes/weak_lang_items.rs
index d85c7d8c6de..cde489e8d2c 100644
--- a/src/librustc_passes/weak_lang_items.rs
+++ b/src/librustc_passes/weak_lang_items.rs
@@ -2,15 +2,13 @@
 
 use rustc::middle::lang_items;
 use rustc::middle::lang_items::whitelisted;
-use rustc::session::config;
-
-use rustc::hir::map::Map;
 use rustc::ty::TyCtxt;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
 use rustc_hir::weak_lang_items::WEAK_ITEMS_REFS;
+use rustc_session::config;
 use rustc_span::symbol::Symbol;
 use rustc_span::Span;
 
@@ -85,9 +83,9 @@ impl<'a, 'tcx> Context<'a, 'tcx> {
 }
 
 impl<'a, 'tcx, 'v> Visitor<'v> for Context<'a, 'tcx> {
-    type Map = Map<'v>;
+    type Map = intravisit::ErasedMap<'v>;
 
-    fn nested_visit_map(&mut self) -> NestedVisitorMap<Map<'v>> {
+    fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
         NestedVisitorMap::None
     }
 
diff --git a/src/librustc_plugin_impl/Cargo.toml b/src/librustc_plugin_impl/Cargo.toml
index 89313072590..372d6a534c8 100644
--- a/src/librustc_plugin_impl/Cargo.toml
+++ b/src/librustc_plugin_impl/Cargo.toml
@@ -17,4 +17,5 @@ rustc_hir = { path = "../librustc_hir" }
 rustc_lint = { path = "../librustc_lint" }
 rustc_metadata = { path = "../librustc_metadata" }
 rustc_ast = { path = "../librustc_ast" }
+rustc_session = { path = "../librustc_session" }
 rustc_span = { path = "../librustc_span" }
diff --git a/src/librustc_plugin_impl/load.rs b/src/librustc_plugin_impl/load.rs
index 9bd9bcb25ba..0810cf56d17 100644
--- a/src/librustc_plugin_impl/load.rs
+++ b/src/librustc_plugin_impl/load.rs
@@ -2,10 +2,10 @@
 
 use crate::Registry;
 use rustc::middle::cstore::MetadataLoader;
-use rustc::session::Session;
 use rustc_ast::ast::{Crate, Ident};
 use rustc_errors::struct_span_err;
 use rustc_metadata::locator;
+use rustc_session::Session;
 use rustc_span::symbol::sym;
 use rustc_span::Span;
 
diff --git a/src/librustc_privacy/Cargo.toml b/src/librustc_privacy/Cargo.toml
index 6d1272c117b..9854e0f6c53 100644
--- a/src/librustc_privacy/Cargo.toml
+++ b/src/librustc_privacy/Cargo.toml
@@ -14,6 +14,7 @@ rustc_attr = { path = "../librustc_attr" }
 rustc_errors = { path = "../librustc_errors" }
 rustc_hir = { path = "../librustc_hir" }
 rustc_typeck = { path = "../librustc_typeck" }
+rustc_session = { path = "../librustc_session" }
 rustc_ast = { path = "../librustc_ast" }
 rustc_span = { path = "../librustc_span" }
 rustc_data_structures = { path = "../librustc_data_structures" }
diff --git a/src/librustc_privacy/lib.rs b/src/librustc_privacy/lib.rs
index 108a8006409..f5b3de25125 100644
--- a/src/librustc_privacy/lib.rs
+++ b/src/librustc_privacy/lib.rs
@@ -5,7 +5,6 @@
 
 use rustc::bug;
 use rustc::hir::map::Map;
-use rustc::lint;
 use rustc::middle::privacy::{AccessLevel, AccessLevels};
 use rustc::ty::fold::TypeVisitor;
 use rustc::ty::query::Providers;
@@ -20,6 +19,7 @@ use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
 use rustc_hir::intravisit::{self, DeepVisitor, NestedVisitorMap, Visitor};
 use rustc_hir::{AssocItemKind, HirIdSet, Node, PatKind};
+use rustc_session::lint;
 use rustc_span::hygiene::Transparency;
 use rustc_span::symbol::{kw, sym};
 use rustc_span::Span;
@@ -1447,7 +1447,7 @@ impl<'a, 'tcx> ObsoleteVisiblePrivateTypesVisitor<'a, 'tcx> {
 }
 
 impl<'a, 'b, 'tcx, 'v> Visitor<'v> for ObsoleteCheckTypeForPrivatenessVisitor<'a, 'b, 'tcx> {
-    type Map = Map<'v>;
+    type Map = intravisit::ErasedMap<'v>;
 
     fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
         NestedVisitorMap::None
diff --git a/src/librustc_resolve/check_unused.rs b/src/librustc_resolve/check_unused.rs
index 722f843ab6e..35876176e3e 100644
--- a/src/librustc_resolve/check_unused.rs
+++ b/src/librustc_resolve/check_unused.rs
@@ -26,12 +26,13 @@
 use crate::imports::ImportKind;
 use crate::Resolver;
 
-use rustc::{lint, ty};
+use rustc::ty;
 use rustc_ast::ast;
 use rustc_ast::node_id::NodeMap;
 use rustc_ast::visit::{self, Visitor};
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::pluralize;
+use rustc_session::lint::builtin::{MACRO_USE_EXTERN_CRATE, UNUSED_IMPORTS};
 use rustc_session::lint::BuiltinLintDiagnostics;
 use rustc_span::{MultiSpan, Span, DUMMY_SP};
 
@@ -232,7 +233,7 @@ impl Resolver<'_> {
                     if let ImportKind::MacroUse = import.kind {
                         if !import.span.is_dummy() {
                             self.lint_buffer.buffer_lint(
-                                lint::builtin::MACRO_USE_EXTERN_CRATE,
+                                MACRO_USE_EXTERN_CRATE,
                                 import.id,
                                 import.span,
                                 "deprecated `#[macro_use]` attribute used to \
@@ -247,9 +248,8 @@ impl Resolver<'_> {
                     self.maybe_unused_extern_crates.push((import.id, import.span));
                 }
                 ImportKind::MacroUse => {
-                    let lint = lint::builtin::UNUSED_IMPORTS;
                     let msg = "unused `#[macro_use]` import";
-                    self.lint_buffer.buffer_lint(lint, import.id, import.span, msg);
+                    self.lint_buffer.buffer_lint(UNUSED_IMPORTS, import.id, import.span, msg);
                 }
                 _ => {}
             }
@@ -314,7 +314,7 @@ impl Resolver<'_> {
             };
 
             visitor.r.lint_buffer.buffer_lint_with_diagnostic(
-                lint::builtin::UNUSED_IMPORTS,
+                UNUSED_IMPORTS,
                 unused.use_tree_id,
                 ms,
                 &msg,
diff --git a/src/librustc_resolve/diagnostics.rs b/src/librustc_resolve/diagnostics.rs
index 7571dabcf7e..6f567ab65a7 100644
--- a/src/librustc_resolve/diagnostics.rs
+++ b/src/librustc_resolve/diagnostics.rs
@@ -3,7 +3,6 @@ use std::ptr;
 
 use log::debug;
 use rustc::bug;
-use rustc::session::Session;
 use rustc::ty::{self, DefIdTree};
 use rustc_ast::ast::{self, Ident, Path};
 use rustc_ast::util::lev_distance::find_best_match_for_name;
@@ -14,6 +13,7 @@ use rustc_feature::BUILTIN_ATTRIBUTES;
 use rustc_hir::def::Namespace::{self, *};
 use rustc_hir::def::{self, CtorKind, CtorOf, DefKind, NonMacroAttrKind};
 use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
+use rustc_session::Session;
 use rustc_span::hygiene::MacroKind;
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::{kw, Symbol};
diff --git a/src/librustc_resolve/imports.rs b/src/librustc_resolve/imports.rs
index 681c0392118..663e61ad2ad 100644
--- a/src/librustc_resolve/imports.rs
+++ b/src/librustc_resolve/imports.rs
@@ -10,7 +10,6 @@ use crate::{CrateLint, Module, ModuleOrUniformRoot, ParentScope, PerNS, ScopeSet
 use crate::{NameBinding, NameBindingKind, PathResult, PrivacyError, ToNameBinding};
 
 use rustc::hir::exports::Export;
-use rustc::lint::builtin::{PUB_USE_OF_PRIVATE_EXTERN_CRATE, UNUSED_IMPORTS};
 use rustc::ty;
 use rustc::{bug, span_bug};
 use rustc_ast::ast::{Ident, Name, NodeId};
@@ -21,6 +20,7 @@ use rustc_data_structures::ptr_key::PtrKey;
 use rustc_errors::{pluralize, struct_span_err, Applicability};
 use rustc_hir::def::{self, PartialRes};
 use rustc_hir::def_id::DefId;
+use rustc_session::lint::builtin::{PUB_USE_OF_PRIVATE_EXTERN_CRATE, UNUSED_IMPORTS};
 use rustc_session::lint::BuiltinLintDiagnostics;
 use rustc_session::DiagnosticMessageId;
 use rustc_span::hygiene::ExpnId;
diff --git a/src/librustc_resolve/late.rs b/src/librustc_resolve/late.rs
index 867aa8c6321..4a3c9f338d9 100644
--- a/src/librustc_resolve/late.rs
+++ b/src/librustc_resolve/late.rs
@@ -11,7 +11,7 @@ use crate::{path_names_to_string, BindingError, CrateLint, LexicalScopeBinding};
 use crate::{Module, ModuleOrUniformRoot, NameBindingKind, ParentScope, PathResult};
 use crate::{ResolutionError, Resolver, Segment, UseError};
 
-use rustc::{bug, lint, span_bug};
+use rustc::{bug, span_bug};
 use rustc_ast::ast::*;
 use rustc_ast::ptr::P;
 use rustc_ast::util::lev_distance::find_best_match_for_name;
@@ -23,6 +23,7 @@ use rustc_hir::def::Namespace::{self, *};
 use rustc_hir::def::{self, CtorKind, DefKind, PartialRes, PerNS};
 use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX};
 use rustc_hir::TraitCandidate;
+use rustc_session::lint;
 use rustc_span::symbol::{kw, sym};
 use rustc_span::Span;
 use smallvec::{smallvec, SmallVec};
diff --git a/src/librustc_resolve/late/diagnostics.rs b/src/librustc_resolve/late/diagnostics.rs
index 13d43305280..41380b2a4b7 100644
--- a/src/librustc_resolve/late/diagnostics.rs
+++ b/src/librustc_resolve/late/diagnostics.rs
@@ -5,7 +5,6 @@ use crate::path_names_to_string;
 use crate::{CrateLint, Module, ModuleKind, ModuleOrUniformRoot};
 use crate::{PathResult, PathSource, Segment};
 
-use rustc::session::config::nightly_options;
 use rustc_ast::ast::{self, Expr, ExprKind, Ident, Item, ItemKind, NodeId, Path, Ty, TyKind};
 use rustc_ast::util::lev_distance::find_best_match_for_name;
 use rustc_data_structures::fx::FxHashSet;
@@ -15,6 +14,7 @@ use rustc_hir::def::Namespace::{self, *};
 use rustc_hir::def::{self, CtorKind, DefKind};
 use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX};
 use rustc_hir::PrimTy;
+use rustc_session::config::nightly_options;
 use rustc_span::hygiene::MacroKind;
 use rustc_span::symbol::{kw, sym};
 use rustc_span::Span;
diff --git a/src/librustc_resolve/late/lifetimes.rs b/src/librustc_resolve/late/lifetimes.rs
index c015841cdc5..47d04964842 100644
--- a/src/librustc_resolve/late/lifetimes.rs
+++ b/src/librustc_resolve/late/lifetimes.rs
@@ -7,7 +7,6 @@
 
 use crate::late::diagnostics::{ForLifetimeSpanType, MissingLifetimeSpot};
 use rustc::hir::map::Map;
-use rustc::lint;
 use rustc::middle::resolve_lifetime::*;
 use rustc::ty::{self, DefIdTree, GenericParamDefKind, TyCtxt};
 use rustc::{bug, span_bug};
@@ -22,6 +21,7 @@ use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, LOCAL_CRATE};
 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
 use rustc_hir::{GenericArg, GenericParam, LifetimeName, Node, ParamName, QPath};
 use rustc_hir::{GenericParamKind, HirIdMap, HirIdSet, LifetimeParamKind};
+use rustc_session::lint;
 use rustc_span::symbol::{kw, sym};
 use rustc_span::Span;
 use std::borrow::Cow;
@@ -1123,7 +1123,7 @@ fn extract_labels(ctxt: &mut LifetimeContext<'_, '_>, body: &hir::Body<'_>) {
     gather.visit_body(body);
 
     impl<'v, 'a, 'tcx> Visitor<'v> for GatherLabels<'a, 'tcx> {
-        type Map = Map<'v>;
+        type Map = intravisit::ErasedMap<'v>;
 
         fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
             NestedVisitorMap::None
@@ -2173,7 +2173,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
             }
 
             impl<'a> Visitor<'a> for SelfVisitor<'a> {
-                type Map = Map<'a>;
+                type Map = intravisit::ErasedMap<'a>;
 
                 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
                     NestedVisitorMap::None
@@ -2264,7 +2264,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
         }
 
         impl<'v, 'a> Visitor<'v> for GatherLifetimes<'a> {
-            type Map = Map<'v>;
+            type Map = intravisit::ErasedMap<'v>;
 
             fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
                 NestedVisitorMap::None
@@ -2855,7 +2855,7 @@ fn insert_late_bound_lifetimes(
     }
 
     impl<'v> Visitor<'v> for ConstrainedCollector {
-        type Map = Map<'v>;
+        type Map = intravisit::ErasedMap<'v>;
 
         fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
             NestedVisitorMap::None
@@ -2898,7 +2898,7 @@ fn insert_late_bound_lifetimes(
     }
 
     impl<'v> Visitor<'v> for AllCollector {
-        type Map = Map<'v>;
+        type Map = intravisit::ErasedMap<'v>;
 
         fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
             NestedVisitorMap::None
diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index 1ad4fb78e08..8164998d55f 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -18,7 +18,6 @@ use Determinacy::*;
 
 use rustc::hir::exports::ExportMap;
 use rustc::hir::map::{DefKey, Definitions};
-use rustc::lint;
 use rustc::middle::cstore::{CrateStore, MetadataLoaderDyn};
 use rustc::span_bug;
 use rustc::ty::query::Providers;
@@ -42,6 +41,7 @@ use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, CRATE_DEF_INDEX, LOCAL_CRATE}
 use rustc_hir::PrimTy::{self, Bool, Char, Float, Int, Str, Uint};
 use rustc_hir::{GlobMap, TraitMap};
 use rustc_metadata::creader::{CStore, CrateLoader};
+use rustc_session::lint;
 use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
 use rustc_session::Session;
 use rustc_span::hygiene::{ExpnId, ExpnKind, MacroKind, SyntaxContext, Transparency};
diff --git a/src/librustc_resolve/macros.rs b/src/librustc_resolve/macros.rs
index 6c2a9cd8b10..6f2e0bce3ac 100644
--- a/src/librustc_resolve/macros.rs
+++ b/src/librustc_resolve/macros.rs
@@ -7,9 +7,7 @@ use crate::{AmbiguityError, AmbiguityErrorMisc, AmbiguityKind, Determinacy};
 use crate::{CrateLint, ParentScope, ResolutionError, Resolver, Scope, ScopeSet, Weak};
 use crate::{ModuleKind, ModuleOrUniformRoot, NameBinding, PathResult, Segment, ToNameBinding};
 use rustc::middle::stability;
-use rustc::session::parse::feature_err;
-use rustc::session::Session;
-use rustc::{lint, span_bug, ty};
+use rustc::{span_bug, ty};
 use rustc_ast::ast::{self, Ident, NodeId};
 use rustc_ast_pretty::pprust;
 use rustc_attr::{self as attr, StabilityLevel};
@@ -21,6 +19,9 @@ use rustc_expand::expand::{AstFragment, AstFragmentKind, Invocation, InvocationK
 use rustc_feature::is_builtin_attr_name;
 use rustc_hir::def::{self, DefKind, NonMacroAttrKind};
 use rustc_hir::def_id;
+use rustc_session::lint::builtin::UNUSED_MACROS;
+use rustc_session::parse::feature_err;
+use rustc_session::Session;
 use rustc_span::edition::Edition;
 use rustc_span::hygiene::{self, ExpnData, ExpnId, ExpnKind};
 use rustc_span::symbol::{kw, sym, Symbol};
@@ -329,12 +330,7 @@ impl<'a> base::Resolver for Resolver<'a> {
 
     fn check_unused_macros(&mut self) {
         for (&node_id, &span) in self.unused_macros.iter() {
-            self.lint_buffer.buffer_lint(
-                lint::builtin::UNUSED_MACROS,
-                node_id,
-                span,
-                "unused macro definition",
-            );
+            self.lint_buffer.buffer_lint(UNUSED_MACROS, node_id, span, "unused macro definition");
         }
     }
 
diff --git a/src/librustc_save_analysis/Cargo.toml b/src/librustc_save_analysis/Cargo.toml
index 0f4cc4192b6..4717664b6ba 100644
--- a/src/librustc_save_analysis/Cargo.toml
+++ b/src/librustc_save_analysis/Cargo.toml
@@ -18,6 +18,7 @@ rustc_hir = { path = "../librustc_hir" }
 rustc_parse = { path = "../librustc_parse" }
 serde_json = "1"
 rustc_ast = { path = "../librustc_ast" }
+rustc_session = { path = "../librustc_session" }
 rustc_span = { path = "../librustc_span" }
 rls-data = "0.19"
 rls-span = "0.5"
diff --git a/src/librustc_save_analysis/dump_visitor.rs b/src/librustc_save_analysis/dump_visitor.rs
index cf4a9e947be..8d1a39eab89 100644
--- a/src/librustc_save_analysis/dump_visitor.rs
+++ b/src/librustc_save_analysis/dump_visitor.rs
@@ -13,7 +13,6 @@
 //! DumpVisitor walks the AST and processes it, and Dumper is used for
 //! recording the output.
 
-use rustc::session::config::Input;
 use rustc::span_bug;
 use rustc::ty::{self, DefIdTree, TyCtxt};
 use rustc_ast::ast::{self, Attribute, NodeId, PatKind};
@@ -25,6 +24,7 @@ use rustc_ast_pretty::pprust::{bounds_to_string, generic_params_to_string, ty_to
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::def::{DefKind as HirDefKind, Res};
 use rustc_hir::def_id::DefId;
+use rustc_session::config::Input;
 use rustc_span::source_map::{respan, DUMMY_SP};
 use rustc_span::*;
 
diff --git a/src/librustc_save_analysis/lib.rs b/src/librustc_save_analysis/lib.rs
index 8b0120c34e0..98d81c62522 100644
--- a/src/librustc_save_analysis/lib.rs
+++ b/src/librustc_save_analysis/lib.rs
@@ -10,7 +10,6 @@ mod sig;
 
 use rustc::middle::cstore::ExternCrate;
 use rustc::middle::privacy::AccessLevels;
-use rustc::session::config::{CrateType, Input, OutputType};
 use rustc::ty::{self, DefIdTree, TyCtxt};
 use rustc::{bug, span_bug};
 use rustc_ast::ast::{self, Attribute, NodeId, PatKind, DUMMY_NODE_ID};
@@ -22,6 +21,7 @@ use rustc_hir as hir;
 use rustc_hir::def::{CtorOf, DefKind as HirDefKind, Res};
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_hir::Node;
+use rustc_session::config::{CrateType, Input, OutputType};
 use rustc_span::source_map::Spanned;
 use rustc_span::*;
 
diff --git a/src/librustc_save_analysis/span_utils.rs b/src/librustc_save_analysis/span_utils.rs
index 152435206fe..6620941c440 100644
--- a/src/librustc_save_analysis/span_utils.rs
+++ b/src/librustc_save_analysis/span_utils.rs
@@ -1,7 +1,7 @@
 use crate::generated_code;
-use rustc::session::Session;
 use rustc_ast::token::{self, TokenKind};
 use rustc_parse::lexer::{self, StringReader};
+use rustc_session::Session;
 use rustc_span::*;
 
 #[derive(Clone)]
diff --git a/src/librustc_trait_selection/opaque_types.rs b/src/librustc_trait_selection/opaque_types.rs
index 6cf1302783c..785d8b892be 100644
--- a/src/librustc_trait_selection/opaque_types.rs
+++ b/src/librustc_trait_selection/opaque_types.rs
@@ -1,6 +1,5 @@
 use crate::infer::InferCtxtExt as _;
 use crate::traits::{self, PredicateObligation};
-use rustc::session::config::nightly_options;
 use rustc::ty::fold::{BottomUpFolder, TypeFoldable, TypeFolder, TypeVisitor};
 use rustc::ty::free_region_map::FreeRegionRelations;
 use rustc::ty::subst::{GenericArg, GenericArgKind, InternalSubsts, SubstsRef};
@@ -13,6 +12,7 @@ use rustc_hir::Node;
 use rustc_infer::infer::error_reporting::unexpected_hidden_region_diagnostic;
 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use rustc_infer::infer::{self, InferCtxt, InferOk};
+use rustc_session::config::nightly_options;
 use rustc_span::Span;
 
 pub type OpaqueTypeMap<'tcx> = DefIdMap<OpaqueTypeDecl<'tcx>>;
diff --git a/src/librustc_trait_selection/traits/error_reporting/mod.rs b/src/librustc_trait_selection/traits/error_reporting/mod.rs
index 46654a4e8b4..ef62958a3f7 100644
--- a/src/librustc_trait_selection/traits/error_reporting/mod.rs
+++ b/src/librustc_trait_selection/traits/error_reporting/mod.rs
@@ -12,7 +12,6 @@ use crate::infer::error_reporting::{TyCategory, TypeAnnotationNeeded as ErrorCod
 use crate::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use crate::infer::{self, InferCtxt, TyCtxtInferExt};
 use rustc::mir::interpret::ErrorHandled;
-use rustc::session::DiagnosticMessageId;
 use rustc::ty::error::ExpectedFound;
 use rustc::ty::fast_reject;
 use rustc::ty::fold::TypeFolder;
@@ -25,6 +24,7 @@ use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticBuilder}
 use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_hir::{Node, QPath, TyKind, WhereBoundPredicate, WherePredicate};
+use rustc_session::DiagnosticMessageId;
 use rustc_span::source_map::SourceMap;
 use rustc_span::{ExpnKind, Span, DUMMY_SP};
 use std::fmt;
diff --git a/src/librustc_trait_selection/traits/error_reporting/suggestions.rs b/src/librustc_trait_selection/traits/error_reporting/suggestions.rs
index 6fe6d7aab28..dd03f9358c8 100644
--- a/src/librustc_trait_selection/traits/error_reporting/suggestions.rs
+++ b/src/librustc_trait_selection/traits/error_reporting/suggestions.rs
@@ -1567,7 +1567,7 @@ struct ReturnsVisitor<'v> {
 }
 
 impl<'v> Visitor<'v> for ReturnsVisitor<'v> {
-    type Map = rustc::hir::map::Map<'v>;
+    type Map = hir::intravisit::ErasedMap<'v>;
 
     fn nested_visit_map(&mut self) -> hir::intravisit::NestedVisitorMap<Self::Map> {
         hir::intravisit::NestedVisitorMap::None
diff --git a/src/librustc_ty/Cargo.toml b/src/librustc_ty/Cargo.toml
index 3c790bc4cb1..cf0b4b82eea 100644
--- a/src/librustc_ty/Cargo.toml
+++ b/src/librustc_ty/Cargo.toml
@@ -15,5 +15,6 @@ rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_hir = { path = "../librustc_hir" }
 rustc_infer = { path = "../librustc_infer" }
 rustc_span = { path = "../librustc_span" }
+rustc_session = { path = "../librustc_session" }
 rustc_target = { path = "../librustc_target" }
 rustc_trait_selection = { path = "../librustc_trait_selection" }
diff --git a/src/librustc_ty/ty.rs b/src/librustc_ty/ty.rs
index 387d1d9923d..4b522997537 100644
--- a/src/librustc_ty/ty.rs
+++ b/src/librustc_ty/ty.rs
@@ -1,10 +1,10 @@
 use rustc::hir::map as hir_map;
-use rustc::session::CrateDisambiguator;
 use rustc::ty::subst::Subst;
 use rustc::ty::{self, ToPredicate, Ty, TyCtxt, WithConstness};
 use rustc_data_structures::svh::Svh;
 use rustc_hir as hir;
 use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
+use rustc_session::CrateDisambiguator;
 use rustc_span::symbol::Symbol;
 use rustc_span::Span;
 use rustc_trait_selection::traits;
diff --git a/src/librustc_typeck/Cargo.toml b/src/librustc_typeck/Cargo.toml
index 83a48ee3995..e61a36f844f 100644
--- a/src/librustc_typeck/Cargo.toml
+++ b/src/librustc_typeck/Cargo.toml
@@ -19,6 +19,7 @@ rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_errors = { path = "../librustc_errors" }
 rustc_hir = { path = "../librustc_hir" }
 rustc_target = { path = "../librustc_target" }
+rustc_session = { path = "../librustc_session" }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
 rustc_ast = { path = "../librustc_ast" }
 rustc_span = { path = "../librustc_span" }
diff --git a/src/librustc_typeck/astconv.rs b/src/librustc_typeck/astconv.rs
index b273efa7827..9a8d161572b 100644
--- a/src/librustc_typeck/astconv.rs
+++ b/src/librustc_typeck/astconv.rs
@@ -6,13 +6,10 @@
 // ignore-tidy-filelength
 
 use crate::collect::PlaceholderHirTyCollector;
-use crate::lint;
 use crate::middle::lang_items::SizedTraitLangItem;
 use crate::middle::resolve_lifetime as rl;
 use crate::require_c_abi_if_c_variadic;
 use crate::util::common::ErrorReported;
-use rustc::lint::builtin::AMBIGUOUS_ASSOCIATED_ITEMS;
-use rustc::session::{parse::feature_err, Session};
 use rustc::ty::subst::{self, InternalSubsts, Subst, SubstsRef};
 use rustc::ty::{self, Const, DefIdTree, ToPredicate, Ty, TyCtxt, TypeFoldable, WithConstness};
 use rustc::ty::{GenericParamDef, GenericParamDefKind};
@@ -26,6 +23,9 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::Visitor;
 use rustc_hir::print;
 use rustc_hir::{Constness, ExprKind, GenericArg, GenericArgs};
+use rustc_session::lint::builtin::{AMBIGUOUS_ASSOCIATED_ITEMS, LATE_BOUND_LIFETIME_ARGUMENTS};
+use rustc_session::parse::feature_err;
+use rustc_session::Session;
 use rustc_span::symbol::sym;
 use rustc_span::{MultiSpan, Span, DUMMY_SP};
 use rustc_target::spec::abi;
@@ -33,8 +33,8 @@ use rustc_trait_selection::traits;
 use rustc_trait_selection::traits::astconv_object_safety_violations;
 use rustc_trait_selection::traits::error_reporting::report_object_safety_error;
 use rustc_trait_selection::traits::wf::object_region_bounds;
-use smallvec::SmallVec;
 
+use smallvec::SmallVec;
 use std::collections::BTreeSet;
 use std::iter;
 use std::slice;
@@ -340,7 +340,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     let mut multispan = MultiSpan::from_span(span);
                     multispan.push_span_label(span_late, note.to_string());
                     tcx.struct_span_lint_hir(
-                        lint::builtin::LATE_BOUND_LIFETIME_ARGUMENTS,
+                        LATE_BOUND_LIFETIME_ARGUMENTS,
                         args.args[0].id(),
                         multispan,
                         |lint| lint.build(msg).emit(),
diff --git a/src/librustc_typeck/check/autoderef.rs b/src/librustc_typeck/check/autoderef.rs
index 991347714e8..2315b42aec5 100644
--- a/src/librustc_typeck/check/autoderef.rs
+++ b/src/librustc_typeck/check/autoderef.rs
@@ -1,19 +1,18 @@
 use super::method::MethodCallee;
 use super::{FnCtxt, Needs, PlaceOp};
 
-use rustc::session::DiagnosticMessageId;
 use rustc::ty::adjustment::{Adjust, Adjustment, OverloadedDeref};
 use rustc::ty::{self, TraitRef, Ty, TyCtxt, WithConstness};
 use rustc::ty::{ToPredicate, TypeFoldable};
+use rustc_ast::ast::Ident;
 use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_infer::infer::{InferCtxt, InferOk};
+use rustc_session::DiagnosticMessageId;
+use rustc_span::Span;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt;
 use rustc_trait_selection::traits::{self, TraitEngine};
 
-use rustc_ast::ast::Ident;
-use rustc_span::Span;
-
 use std::iter;
 
 #[derive(Copy, Clone, Debug)]
diff --git a/src/librustc_typeck/check/cast.rs b/src/librustc_typeck/check/cast.rs
index d52b6c39ab5..2875d38a996 100644
--- a/src/librustc_typeck/check/cast.rs
+++ b/src/librustc_typeck/check/cast.rs
@@ -31,11 +31,9 @@
 use super::FnCtxt;
 
 use crate::hir::def_id::DefId;
-use crate::lint;
 use crate::type_error_struct;
 use crate::util::common::ErrorReported;
 use rustc::middle::lang_items;
-use rustc::session::Session;
 use rustc::ty::adjustment::AllowTwoPhase;
 use rustc::ty::cast::{CastKind, CastTy};
 use rustc::ty::error::TypeError;
@@ -44,6 +42,8 @@ use rustc::ty::{self, Ty, TypeAndMut, TypeFoldable};
 use rustc_ast::ast;
 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
 use rustc_hir as hir;
+use rustc_session::lint;
+use rustc_session::Session;
 use rustc_span::Span;
 use rustc_trait_selection::traits;
 use rustc_trait_selection::traits::error_reporting::report_object_safety_error;
diff --git a/src/librustc_typeck/check/coercion.rs b/src/librustc_typeck/check/coercion.rs
index d74623a063f..b0d74651847 100644
--- a/src/librustc_typeck/check/coercion.rs
+++ b/src/librustc_typeck/check/coercion.rs
@@ -52,7 +52,6 @@
 
 use crate::astconv::AstConv;
 use crate::check::{FnCtxt, Needs};
-use rustc::session::parse::feature_err;
 use rustc::ty::adjustment::{
     Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability, PointerCast,
 };
@@ -66,11 +65,13 @@ use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use rustc_infer::infer::{Coercion, InferOk, InferResult};
+use rustc_session::parse::feature_err;
 use rustc_span::symbol::sym;
 use rustc_span::{self, Span};
 use rustc_target::spec::abi::Abi;
 use rustc_trait_selection::traits::error_reporting::InferCtxtExt;
 use rustc_trait_selection::traits::{self, ObligationCause, ObligationCauseCode};
+
 use smallvec::{smallvec, SmallVec};
 use std::ops::Deref;
 
diff --git a/src/librustc_typeck/check/compare_method.rs b/src/librustc_typeck/check/compare_method.rs
index 779b87f6623..a2832d92d4a 100644
--- a/src/librustc_typeck/check/compare_method.rs
+++ b/src/librustc_typeck/check/compare_method.rs
@@ -1,4 +1,3 @@
-use rustc::hir::map::Map;
 use rustc::ty::error::{ExpectedFound, TypeError};
 use rustc::ty::subst::{InternalSubsts, Subst};
 use rustc::ty::util::ExplicitSelf;
@@ -890,7 +889,7 @@ fn compare_synthetic_generics<'tcx>(
                                     }
                                 }
                             }
-                            type Map = Map<'v>;
+                            type Map = intravisit::ErasedMap<'v>;
                             fn nested_visit_map(
                                 &mut self,
                             ) -> intravisit::NestedVisitorMap<Self::Map>
diff --git a/src/librustc_typeck/check/generator_interior.rs b/src/librustc_typeck/check/generator_interior.rs
index 5208e2f56a5..cdf68256a7a 100644
--- a/src/librustc_typeck/check/generator_interior.rs
+++ b/src/librustc_typeck/check/generator_interior.rs
@@ -4,7 +4,6 @@
 //! types computed here.
 
 use super::FnCtxt;
-use rustc::hir::map::Map;
 use rustc::middle::region::{self, YieldData};
 use rustc::ty::{self, Ty};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
@@ -209,7 +208,7 @@ pub fn resolve_interior<'a, 'tcx>(
 // librustc/middle/region.rs since `expr_count` is compared against the results
 // there.
 impl<'a, 'tcx> Visitor<'tcx> for InteriorVisitor<'a, 'tcx> {
-    type Map = Map<'tcx>;
+    type Map = intravisit::ErasedMap<'tcx>;
 
     fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
         NestedVisitorMap::None
diff --git a/src/librustc_typeck/check/method/probe.rs b/src/librustc_typeck/check/method/probe.rs
index 16bab09feee..45b1c7d6ea7 100644
--- a/src/librustc_typeck/check/method/probe.rs
+++ b/src/librustc_typeck/check/method/probe.rs
@@ -8,9 +8,7 @@ use crate::check::FnCtxt;
 use crate::hir::def::DefKind;
 use crate::hir::def_id::DefId;
 
-use rustc::lint;
 use rustc::middle::stability;
-use rustc::session::config::nightly_options;
 use rustc::ty::subst::{InternalSubsts, Subst, SubstsRef};
 use rustc::ty::GenericParamDefKind;
 use rustc::ty::{
@@ -28,6 +26,8 @@ use rustc_infer::infer::canonical::{Canonical, QueryResponse};
 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use rustc_infer::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind};
 use rustc_infer::infer::{self, InferOk, TyCtxtInferExt};
+use rustc_session::config::nightly_options;
+use rustc_session::lint;
 use rustc_span::{symbol::Symbol, Span, DUMMY_SP};
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt;
 use rustc_trait_selection::traits::query::method_autoderef::MethodAutoderefBadTy;
diff --git a/src/librustc_typeck/check/method/suggest.rs b/src/librustc_typeck/check/method/suggest.rs
index 3eb3624a296..94a582dfcfe 100644
--- a/src/librustc_typeck/check/method/suggest.rs
+++ b/src/librustc_typeck/check/method/suggest.rs
@@ -4,7 +4,6 @@
 use crate::check::FnCtxt;
 use crate::middle::lang_items::FnOnceTraitLangItem;
 use rustc::hir::map as hir_map;
-use rustc::hir::map::Map;
 use rustc::ty::print::with_crate_prefix;
 use rustc::ty::{self, ToPolyTraitRef, ToPredicate, Ty, TyCtxt, TypeFoldable, WithConstness};
 use rustc_ast::ast;
@@ -1347,7 +1346,7 @@ impl intravisit::Visitor<'tcx> for UsePlacementFinder<'tcx> {
         }
     }
 
-    type Map = Map<'tcx>;
+    type Map = intravisit::ErasedMap<'tcx>;
 
     fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> {
         intravisit::NestedVisitorMap::None
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 1766b688468..bfb0d25dea2 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -90,10 +90,8 @@ pub mod writeback;
 use crate::astconv::{AstConv, GenericArgCountMismatch, PathSeg};
 use crate::middle::lang_items;
 use rustc::hir::map::blocks::FnLikeNode;
-use rustc::hir::map::Map;
 use rustc::middle::region;
 use rustc::mir::interpret::ConstValue;
-use rustc::session::parse::feature_err;
 use rustc::ty::adjustment::{
     Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability, PointerCast,
 };
@@ -124,6 +122,10 @@ use rustc_infer::infer::error_reporting::TypeAnnotationNeeded::E0282;
 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use rustc_infer::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind};
 use rustc_infer::infer::{self, InferCtxt, InferOk, InferResult, TyCtxtInferExt};
+use rustc_session::config::{self, EntryFnType};
+use rustc_session::lint;
+use rustc_session::parse::feature_err;
+use rustc_session::Session;
 use rustc_span::hygiene::DesugaringKind;
 use rustc_span::source_map::{original_sp, DUMMY_SP};
 use rustc_span::symbol::{kw, sym, Ident};
@@ -146,10 +148,7 @@ use std::mem::replace;
 use std::ops::{self, Deref};
 use std::slice;
 
-use crate::lint;
 use crate::require_c_abi_if_c_variadic;
-use crate::session::config::EntryFnType;
-use crate::session::Session;
 use crate::util::common::{indenter, ErrorReported};
 use crate::TypeAndSubsts;
 
@@ -1177,7 +1176,7 @@ impl<'a, 'tcx> GatherLocalsVisitor<'a, 'tcx> {
 }
 
 impl<'a, 'tcx> Visitor<'tcx> for GatherLocalsVisitor<'a, 'tcx> {
-    type Map = Map<'tcx>;
+    type Map = intravisit::ErasedMap<'tcx>;
 
     fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
         NestedVisitorMap::None
@@ -5790,7 +5789,7 @@ fn fatally_break_rust(sess: &Session) {
     handler.note_without_error(&format!(
         "rustc {} running on {}",
         option_env!("CFG_VERSION").unwrap_or("unknown_version"),
-        crate::session::config::host_triple(),
+        config::host_triple(),
     ));
 }
 
diff --git a/src/librustc_typeck/check/regionck.rs b/src/librustc_typeck/check/regionck.rs
index b6d6d3a7a87..57a89614eb1 100644
--- a/src/librustc_typeck/check/regionck.rs
+++ b/src/librustc_typeck/check/regionck.rs
@@ -76,7 +76,6 @@ use crate::check::dropck;
 use crate::check::FnCtxt;
 use crate::mem_categorization as mc;
 use crate::middle::region;
-use rustc::hir::map::Map;
 use rustc::ty::adjustment;
 use rustc::ty::subst::{GenericArgKind, SubstsRef};
 use rustc::ty::{self, Ty};
@@ -408,7 +407,7 @@ impl<'a, 'tcx> Visitor<'tcx> for RegionCtxt<'a, 'tcx> {
     // hierarchy, and in particular the relationships between free
     // regions, until regionck, as described in #3238.
 
-    type Map = Map<'tcx>;
+    type Map = intravisit::ErasedMap<'tcx>;
 
     fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
         NestedVisitorMap::None
diff --git a/src/librustc_typeck/check/upvar.rs b/src/librustc_typeck/check/upvar.rs
index 7bc121733a4..44b960ad22b 100644
--- a/src/librustc_typeck/check/upvar.rs
+++ b/src/librustc_typeck/check/upvar.rs
@@ -35,7 +35,6 @@ use super::FnCtxt;
 use crate::expr_use_visitor as euv;
 use crate::mem_categorization as mc;
 use crate::mem_categorization::PlaceBase;
-use rustc::hir::map::Map;
 use rustc::ty::{self, Ty, TyCtxt, UpvarSubsts};
 use rustc_ast::ast;
 use rustc_data_structures::fx::FxIndexMap;
@@ -60,7 +59,7 @@ struct InferBorrowKindVisitor<'a, 'tcx> {
 }
 
 impl<'a, 'tcx> Visitor<'tcx> for InferBorrowKindVisitor<'a, 'tcx> {
-    type Map = Map<'tcx>;
+    type Map = intravisit::ErasedMap<'tcx>;
 
     fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
         NestedVisitorMap::None
diff --git a/src/librustc_typeck/check/wfcheck.rs b/src/librustc_typeck/check/wfcheck.rs
index e4a57f66196..3255d7b435c 100644
--- a/src/librustc_typeck/check/wfcheck.rs
+++ b/src/librustc_typeck/check/wfcheck.rs
@@ -2,7 +2,6 @@ use crate::check::{FnCtxt, Inherited};
 use crate::constrained_generic_params::{identify_constrained_generic_params, Parameter};
 
 use rustc::middle::lang_items;
-use rustc::session::parse::feature_err;
 use rustc::ty::subst::{InternalSubsts, Subst};
 use rustc::ty::trait_def::TraitSpecializationKind;
 use rustc::ty::{
@@ -11,17 +10,17 @@ use rustc::ty::{
 use rustc_ast::ast;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
+use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
+use rustc_hir::itemlikevisit::ParItemLikeVisitor;
 use rustc_hir::ItemKind;
+use rustc_session::parse::feature_err;
 use rustc_span::symbol::sym;
 use rustc_span::Span;
 use rustc_trait_selection::opaque_types::may_define_opaque_type;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt;
 use rustc_trait_selection::traits::{self, ObligationCause, ObligationCauseCode};
 
-use rustc_hir as hir;
-use rustc_hir::itemlikevisit::ParItemLikeVisitor;
-
 /// Helper type of a temporary returned by `.for_item(...)`.
 /// This is necessary because we can't write the following bound:
 ///
diff --git a/src/librustc_typeck/check/writeback.rs b/src/librustc_typeck/check/writeback.rs
index 8ed6cc3a943..9d574ee50a4 100644
--- a/src/librustc_typeck/check/writeback.rs
+++ b/src/librustc_typeck/check/writeback.rs
@@ -4,7 +4,6 @@
 
 use crate::check::FnCtxt;
 
-use rustc::hir::map::Map;
 use rustc::ty::adjustment::{Adjust, Adjustment, PointerCast};
 use rustc::ty::fold::{TypeFoldable, TypeFolder};
 use rustc::ty::{self, Ty, TyCtxt};
@@ -243,7 +242,7 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
 // traffic in node-ids or update tables in the type context etc.
 
 impl<'cx, 'tcx> Visitor<'tcx> for WritebackCx<'cx, 'tcx> {
-    type Map = Map<'tcx>;
+    type Map = intravisit::ErasedMap<'tcx>;
 
     fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
         NestedVisitorMap::None
diff --git a/src/librustc_typeck/check_unused.rs b/src/librustc_typeck/check_unused.rs
index 3517e09133c..d0414af5b21 100644
--- a/src/librustc_typeck/check_unused.rs
+++ b/src/librustc_typeck/check_unused.rs
@@ -1,4 +1,3 @@
-use crate::lint;
 use rustc::ty::TyCtxt;
 use rustc_ast::ast;
 use rustc_data_structures::fx::FxHashMap;
@@ -7,6 +6,7 @@ use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, DefIdSet, LOCAL_CRATE};
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
 use rustc_hir::print::visibility_qualified;
+use rustc_session::lint;
 use rustc_span::Span;
 
 pub fn check_crate(tcx: TyCtxt<'_>) {
diff --git a/src/librustc_typeck/collect.rs b/src/librustc_typeck/collect.rs
index 8e60bd2a4b3..7145b948f2f 100644
--- a/src/librustc_typeck/collect.rs
+++ b/src/librustc_typeck/collect.rs
@@ -17,14 +17,12 @@
 use crate::astconv::{AstConv, Bounds, SizedByDefault};
 use crate::check::intrinsic::intrinsic_operation_unsafety;
 use crate::constrained_generic_params as cgp;
-use crate::lint;
 use crate::middle::lang_items;
 use crate::middle::resolve_lifetime as rl;
 use rustc::hir::map::blocks::FnLikeNode;
 use rustc::hir::map::Map;
 use rustc::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
 use rustc::mir::mono::Linkage;
-use rustc::session::parse::feature_err;
 use rustc::ty::query::Providers;
 use rustc::ty::subst::{InternalSubsts, Subst};
 use rustc::ty::util::Discr;
@@ -42,6 +40,8 @@ use rustc_hir::def::{CtorKind, DefKind, Res};
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
 use rustc_hir::{GenericParamKind, Node, Unsafety};
+use rustc_session::lint;
+use rustc_session::parse::feature_err;
 use rustc_span::symbol::{kw, sym, Symbol};
 use rustc_span::{Span, DUMMY_SP};
 use rustc_target::spec::abi;
@@ -105,7 +105,7 @@ pub struct ItemCtxt<'tcx> {
 crate struct PlaceholderHirTyCollector(crate Vec<Span>);
 
 impl<'v> Visitor<'v> for PlaceholderHirTyCollector {
-    type Map = Map<'v>;
+    type Map = intravisit::ErasedMap<'v>;
 
     fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
         NestedVisitorMap::None
@@ -1060,7 +1060,7 @@ fn has_late_bound_regions<'tcx>(tcx: TyCtxt<'tcx>, node: Node<'tcx>) -> Option<S
     }
 
     impl Visitor<'tcx> for LateBoundRegionsDetector<'tcx> {
-        type Map = Map<'tcx>;
+        type Map = intravisit::ErasedMap<'tcx>;
 
         fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
             NestedVisitorMap::None
diff --git a/src/librustc_typeck/collect/type_of.rs b/src/librustc_typeck/collect/type_of.rs
index c5d3d276721..41c205bc11b 100644
--- a/src/librustc_typeck/collect/type_of.rs
+++ b/src/librustc_typeck/collect/type_of.rs
@@ -1,5 +1,4 @@
 use rustc::hir::map::Map;
-use rustc::session::parse::feature_err;
 use rustc::ty::subst::{GenericArgKind, InternalSubsts, Subst};
 use rustc::ty::util::IntTypeExt;
 use rustc::ty::{self, DefIdTree, Ty, TyCtxt, TypeFoldable};
@@ -11,6 +10,7 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit;
 use rustc_hir::intravisit::Visitor;
 use rustc_hir::Node;
+use rustc_session::parse::feature_err;
 use rustc_span::symbol::{sym, Ident};
 use rustc_span::{Span, DUMMY_SP};
 use rustc_trait_selection::traits;
diff --git a/src/librustc_typeck/lib.rs b/src/librustc_typeck/lib.rs
index bab354cff7c..e487e0d265c 100644
--- a/src/librustc_typeck/lib.rs
+++ b/src/librustc_typeck/lib.rs
@@ -88,10 +88,7 @@ mod outlives;
 mod structured_errors;
 mod variance;
 
-use rustc::lint;
 use rustc::middle;
-use rustc::session;
-use rustc::session::config::EntryFnType;
 use rustc::ty::query::Providers;
 use rustc::ty::subst::SubstsRef;
 use rustc::ty::{self, Ty, TyCtxt};
@@ -103,6 +100,7 @@ use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_hir::Node;
 use rustc_infer::infer::{InferOk, TyCtxtInferExt};
 use rustc_infer::traits::TraitEngineExt as _;
+use rustc_session::config::EntryFnType;
 use rustc_span::{Span, DUMMY_SP};
 use rustc_target::spec::abi::Abi;
 use rustc_trait_selection::traits::error_reporting::InferCtxtExt as _;
diff --git a/src/librustc_typeck/structured_errors.rs b/src/librustc_typeck/structured_errors.rs
index 99b7b2001a9..a4f8472ae28 100644
--- a/src/librustc_typeck/structured_errors.rs
+++ b/src/librustc_typeck/structured_errors.rs
@@ -1,6 +1,6 @@
-use rustc::session::Session;
 use rustc::ty::{Ty, TypeFoldable};
 use rustc_errors::{Applicability, DiagnosticBuilder, DiagnosticId};
+use rustc_session::Session;
 use rustc_span::Span;
 
 pub trait StructuredDiagnostic<'tcx> {
diff --git a/src/librustdoc/config.rs b/src/librustdoc/config.rs
index 58c8a7d82bf..179c5bfacf3 100644
--- a/src/librustdoc/config.rs
+++ b/src/librustdoc/config.rs
@@ -4,15 +4,14 @@ use std::ffi::OsStr;
 use std::fmt;
 use std::path::PathBuf;
 
-use rustc::lint::Level;
-use rustc::session;
-use rustc::session::config::{
+use rustc_session::config::{self, parse_crate_types_from_list, parse_externs, CrateType};
+use rustc_session::config::{
     build_codegen_options, build_debugging_options, get_cmd_lint_options, host_triple,
     nightly_options,
 };
-use rustc::session::config::{parse_crate_types_from_list, parse_externs, CrateType};
-use rustc::session::config::{CodegenOptions, DebuggingOptions, ErrorOutputType, Externs};
-use rustc::session::search_paths::SearchPath;
+use rustc_session::config::{CodegenOptions, DebuggingOptions, ErrorOutputType, Externs};
+use rustc_session::lint::Level;
+use rustc_session::search_paths::SearchPath;
 use rustc_span::edition::{Edition, DEFAULT_EDITION};
 use rustc_target::spec::TargetTriple;
 
@@ -299,9 +298,9 @@ impl Options {
             return Err(0);
         }
 
-        let color = session::config::parse_color(&matches);
-        let (json_rendered, _artifacts) = session::config::parse_json(&matches);
-        let error_format = session::config::parse_error_format(&matches, color, json_rendered);
+        let color = config::parse_color(&matches);
+        let (json_rendered, _artifacts) = config::parse_json(&matches);
+        let error_format = config::parse_error_format(&matches, color, json_rendered);
 
         let codegen_options = build_codegen_options(matches, error_format);
         let debugging_options = build_debugging_options(matches, error_format);
diff --git a/src/librustdoc/core.rs b/src/librustdoc/core.rs
index b9ae3d53afc..f0b9ad2852f 100644
--- a/src/librustdoc/core.rs
+++ b/src/librustdoc/core.rs
@@ -1,23 +1,22 @@
 use rustc::middle::cstore::CrateStore;
 use rustc::middle::privacy::AccessLevels;
-use rustc::session::config::ErrorOutputType;
-use rustc::session::DiagnosticOutput;
-use rustc::session::{self, config};
 use rustc::ty::{Ty, TyCtxt};
+use rustc_ast::ast::CRATE_NODE_ID;
+use rustc_attr as attr;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_driver::abort_on_err;
+use rustc_errors::emitter::{Emitter, EmitterWriter};
+use rustc_errors::json::JsonEmitter;
 use rustc_feature::UnstableFeatures;
 use rustc_hir::def::Namespace::TypeNS;
 use rustc_hir::def_id::{CrateNum, DefId, DefIndex, LOCAL_CRATE};
 use rustc_hir::HirId;
 use rustc_interface::interface;
 use rustc_resolve as resolve;
+use rustc_session::config::ErrorOutputType;
 use rustc_session::lint;
-
-use rustc_ast::ast::CRATE_NODE_ID;
-use rustc_attr as attr;
-use rustc_errors::emitter::{Emitter, EmitterWriter};
-use rustc_errors::json::JsonEmitter;
+use rustc_session::DiagnosticOutput;
+use rustc_session::{config, Session};
 use rustc_span::source_map;
 use rustc_span::symbol::sym;
 use rustc_span::DUMMY_SP;
@@ -34,8 +33,8 @@ use crate::html::render::RenderInfo;
 
 use crate::passes::{self, Condition::*, ConditionalPass};
 
-pub use rustc::session::config::{CodegenOptions, DebuggingOptions, Input, Options};
-pub use rustc::session::search_paths::SearchPath;
+pub use rustc_session::config::{CodegenOptions, DebuggingOptions, Input, Options};
+pub use rustc_session::search_paths::SearchPath;
 
 pub type ExternalPaths = FxHashMap<DefId, (Vec<String>, clean::TypeKind)>;
 
@@ -68,7 +67,7 @@ pub struct DocContext<'tcx> {
 }
 
 impl<'tcx> DocContext<'tcx> {
-    pub fn sess(&self) -> &session::Session {
+    pub fn sess(&self) -> &Session {
         &self.tcx.sess
     }
 
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 2e90d6082ba..3c1f0509bba 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -49,8 +49,8 @@ use std::env;
 use std::panic;
 use std::process;
 
-use rustc::session::config::{make_crate_type_option, ErrorOutputType, RustcOptGroup};
-use rustc::session::{early_error, early_warn};
+use rustc_session::config::{make_crate_type_option, ErrorOutputType, RustcOptGroup};
+use rustc_session::{early_error, early_warn};
 
 #[macro_use]
 mod externalfiles;
diff --git a/src/librustdoc/passes/collect_intra_doc_links.rs b/src/librustdoc/passes/collect_intra_doc_links.rs
index 75355b84fee..72106afbe0e 100644
--- a/src/librustdoc/passes/collect_intra_doc_links.rs
+++ b/src/librustdoc/passes/collect_intra_doc_links.rs
@@ -1,4 +1,3 @@
-use rustc::lint;
 use rustc::ty;
 use rustc_ast::ast::{self, Ident};
 use rustc_errors::Applicability;
@@ -12,6 +11,7 @@ use rustc_hir::def::{
 };
 use rustc_hir::def_id::DefId;
 use rustc_resolve::ParentScope;
+use rustc_session::lint;
 use rustc_span::symbol::Symbol;
 use rustc_span::DUMMY_SP;
 
diff --git a/src/librustdoc/passes/mod.rs b/src/librustdoc/passes/mod.rs
index 71cff637c12..38f371783e9 100644
--- a/src/librustdoc/passes/mod.rs
+++ b/src/librustdoc/passes/mod.rs
@@ -1,9 +1,9 @@
 //! Contains information about "passes", used to modify crate information during the documentation
 //! process.
 
-use rustc::lint;
 use rustc::middle::privacy::AccessLevels;
 use rustc_hir::def_id::{DefId, DefIdSet};
+use rustc_session::lint;
 use rustc_span::{InnerSpan, Span, DUMMY_SP};
 use std::mem;
 use std::ops::Range;
diff --git a/src/librustdoc/test.rs b/src/librustdoc/test.rs
index b1a60e2746f..c5aa4677d56 100644
--- a/src/librustdoc/test.rs
+++ b/src/librustdoc/test.rs
@@ -1,5 +1,4 @@
 use rustc::hir::map::Map;
-use rustc::session::{self, config, DiagnosticOutput};
 use rustc::util::common::ErrorReported;
 use rustc_ast::ast;
 use rustc_ast::with_globals;
@@ -8,6 +7,7 @@ use rustc_feature::UnstableFeatures;
 use rustc_hir as hir;
 use rustc_hir::intravisit;
 use rustc_interface::interface;
+use rustc_session::{self, config, DiagnosticOutput, Session};
 use rustc_span::edition::Edition;
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::sym;
@@ -52,7 +52,7 @@ pub fn run(options: Options) -> i32 {
         cg: options.codegen_options.clone(),
         externs: options.externs.clone(),
         unstable_features: UnstableFeatures::from_environment(),
-        lint_cap: Some(::rustc::lint::Level::Allow),
+        lint_cap: Some(rustc_session::lint::Level::Allow),
         actually_rustdoc: true,
         debugging_opts: config::DebuggingOptions { ..config::basic_debugging_options() },
         edition: options.edition,
@@ -854,7 +854,7 @@ impl Tester for Collector {
 }
 
 struct HirCollector<'a, 'hir> {
-    sess: &'a session::Session,
+    sess: &'a Session,
     collector: &'a mut Collector,
     map: Map<'hir>,
     codes: ErrorCodes,
diff --git a/src/test/run-make-fulldeps/hotplug_codegen_backend/the_backend.rs b/src/test/run-make-fulldeps/hotplug_codegen_backend/the_backend.rs
index 07ef2424cc8..d975af52f5b 100644
--- a/src/test/run-make-fulldeps/hotplug_codegen_backend/the_backend.rs
+++ b/src/test/run-make-fulldeps/hotplug_codegen_backend/the_backend.rs
@@ -7,14 +7,12 @@ extern crate rustc_data_structures;
 extern crate rustc_hir;
 extern crate rustc_target;
 extern crate rustc_driver;
+extern crate rustc_session;
 extern crate rustc_span;
 
 use std::any::Any;
 use std::sync::Arc;
 use std::path::Path;
-use rustc_span::symbol::Symbol;
-use rustc::session::Session;
-use rustc::session::config::OutputFilenames;
 use rustc::ty::TyCtxt;
 use rustc::ty::query::Providers;
 use rustc::middle::cstore::{EncodedMetadata, MetadataLoader, MetadataLoaderDyn};
@@ -23,6 +21,9 @@ use rustc::util::common::ErrorReported;
 use rustc_codegen_utils::codegen_backend::CodegenBackend;
 use rustc_data_structures::sync::MetadataRef;
 use rustc_data_structures::owning_ref::OwningRef;
+use rustc_session::Session;
+use rustc_session::config::OutputFilenames;
+use rustc_span::symbol::Symbol;
 use rustc_target::spec::Target;
 
 pub struct NoLlvmMetadataLoader;
@@ -89,7 +90,7 @@ impl CodegenBackend for TheBackend {
         outputs: &OutputFilenames,
     ) -> Result<(), ErrorReported> {
         use std::io::Write;
-        use rustc::session::config::CrateType;
+        use rustc_session::config::CrateType;
         use rustc_codegen_utils::link::out_filename;
         let crate_name = codegen_results.downcast::<Symbol>()
             .expect("in link: codegen_results is not a Symbol");
diff --git a/src/test/run-make-fulldeps/issue-19371/foo.rs b/src/test/run-make-fulldeps/issue-19371/foo.rs
index 12da64fc88f..af84faa7511 100644
--- a/src/test/run-make-fulldeps/issue-19371/foo.rs
+++ b/src/test/run-make-fulldeps/issue-19371/foo.rs
@@ -1,13 +1,12 @@
 #![feature(rustc_private)]
 
-extern crate rustc;
 extern crate rustc_interface;
 extern crate rustc_driver;
+extern crate rustc_session;
 extern crate rustc_span;
 
-use rustc::session::DiagnosticOutput;
-use rustc::session::config::{Input, Options,
-                             OutputType, OutputTypes};
+use rustc_session::DiagnosticOutput;
+use rustc_session::config::{Input, Options, OutputType, OutputTypes};
 use rustc_interface::interface;
 use rustc_span::source_map::FileName;