Auto merge of #117507 - nnethercote:rustc_span, r=Nilstrieb

`rustc_span` cleanups

Just some things I found while looking over this crate.

r? `@oli-obk`

47 files changed, 103 insertions, 166 deletions

diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs
index 93805710cb5..0fff9a6be92 100644
--- a/compiler/rustc_ast_lowering/src/expr.rs
+++ b/compiler/rustc_ast_lowering/src/expr.rs
@@ -15,9 +15,10 @@ use rustc_hir as hir;
 use rustc_hir::def::Res;
 use rustc_hir::definitions::DefPathData;
 use rustc_session::errors::report_lit_error;
-use rustc_span::source_map::{respan, DesugaringKind, Span, Spanned};
+use rustc_span::source_map::{respan, Spanned};
 use rustc_span::symbol::{sym, Ident, Symbol};
 use rustc_span::DUMMY_SP;
+use rustc_span::{DesugaringKind, Span};
 use thin_vec::{thin_vec, ThinVec};
 
 impl<'hir> LoweringContext<'_, 'hir> {
diff --git a/compiler/rustc_ast_lowering/src/item.rs b/compiler/rustc_ast_lowering/src/item.rs
index 299ca91460d..c73d2382db8 100644
--- a/compiler/rustc_ast_lowering/src/item.rs
+++ b/compiler/rustc_ast_lowering/src/item.rs
@@ -16,9 +16,8 @@ use rustc_hir::PredicateOrigin;
 use rustc_index::{Idx, IndexSlice, IndexVec};
 use rustc_middle::ty::{ResolverAstLowering, TyCtxt};
 use rustc_span::edit_distance::find_best_match_for_name;
-use rustc_span::source_map::DesugaringKind;
 use rustc_span::symbol::{kw, sym, Ident};
-use rustc_span::{Span, Symbol};
+use rustc_span::{DesugaringKind, Span, Symbol};
 use rustc_target::spec::abi;
 use smallvec::{smallvec, SmallVec};
 use thin_vec::ThinVec;
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
index bc656585d47..a88493acf98 100644
--- a/compiler/rustc_ast_lowering/src/lib.rs
+++ b/compiler/rustc_ast_lowering/src/lib.rs
@@ -71,9 +71,8 @@ use rustc_middle::{
 };
 use rustc_session::parse::{add_feature_diagnostics, feature_err};
 use rustc_span::hygiene::MacroKind;
-use rustc_span::source_map::DesugaringKind;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
-use rustc_span::{Span, DUMMY_SP};
+use rustc_span::{DesugaringKind, Span, DUMMY_SP};
 use smallvec::SmallVec;
 use std::collections::hash_map::Entry;
 use thin_vec::ThinVec;
diff --git a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
index 003254b8da1..dde46eef6a0 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
@@ -9,9 +9,8 @@ use rustc_middle::{
     hir::place::PlaceBase,
     mir::{self, BindingForm, Local, LocalDecl, LocalInfo, LocalKind, Location},
 };
-use rustc_span::source_map::DesugaringKind;
 use rustc_span::symbol::{kw, Symbol};
-use rustc_span::{sym, BytePos, Span};
+use rustc_span::{sym, BytePos, DesugaringKind, Span};
 use rustc_target::abi::FieldIdx;
 
 use crate::diagnostics::BorrowedContentSource;
diff --git a/compiler/rustc_borrowck/src/diagnostics/var_name.rs b/compiler/rustc_borrowck/src/diagnostics/var_name.rs
index 8832d345df2..3a104c52431 100644
--- a/compiler/rustc_borrowck/src/diagnostics/var_name.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/var_name.rs
@@ -6,8 +6,8 @@ use crate::Upvar;
 use rustc_index::IndexSlice;
 use rustc_middle::mir::{Body, Local};
 use rustc_middle::ty::{RegionVid, TyCtxt};
-use rustc_span::source_map::Span;
 use rustc_span::symbol::Symbol;
+use rustc_span::Span;
 
 impl<'tcx> RegionInferenceContext<'tcx> {
     pub(crate) fn get_var_name_and_span_for_region(
diff --git a/compiler/rustc_builtin_macros/src/deriving/generic/ty.rs b/compiler/rustc_builtin_macros/src/deriving/generic/ty.rs
index 26f91b714b4..2d5043112b6 100644
--- a/compiler/rustc_builtin_macros/src/deriving/generic/ty.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/generic/ty.rs
@@ -6,9 +6,10 @@ pub use Ty::*;
 use rustc_ast::ptr::P;
 use rustc_ast::{self as ast, Expr, GenericArg, GenericParamKind, Generics, SelfKind};
 use rustc_expand::base::ExtCtxt;
-use rustc_span::source_map::{respan, DUMMY_SP};
+use rustc_span::source_map::respan;
 use rustc_span::symbol::{kw, Ident, Symbol};
 use rustc_span::Span;
+use rustc_span::DUMMY_SP;
 use thin_vec::ThinVec;
 
 /// A path, e.g., `::std::option::Option::<i32>` (global). Has support
diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
index b4b2ab1e1f8..4dd6372b5e0 100644
--- a/compiler/rustc_codegen_llvm/src/context.rs
+++ b/compiler/rustc_codegen_llvm/src/context.rs
@@ -26,8 +26,8 @@ use rustc_middle::{bug, span_bug};
 use rustc_session::config::{BranchProtection, CFGuard, CFProtection};
 use rustc_session::config::{CrateType, DebugInfo, PAuthKey, PacRet};
 use rustc_session::Session;
-use rustc_span::source_map::Span;
 use rustc_span::source_map::Spanned;
+use rustc_span::Span;
 use rustc_target::abi::{
     call::FnAbi, HasDataLayout, PointeeInfo, Size, TargetDataLayout, VariantIdx,
 };
diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index 22afb406326..3d2d8f8b509 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -17,8 +17,7 @@ use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf, ValidityRequirement};
 use rustc_middle::ty::print::{with_no_trimmed_paths, with_no_visible_paths};
 use rustc_middle::ty::{self, Instance, Ty};
 use rustc_session::config::OptLevel;
-use rustc_span::source_map::Span;
-use rustc_span::{sym, Symbol};
+use rustc_span::{sym, Span, Symbol};
 use rustc_target::abi::call::{ArgAbi, FnAbi, PassMode, Reg};
 use rustc_target::abi::{self, HasDataLayout, WrappingRange};
 use rustc_target::spec::abi::Abi;
diff --git a/compiler/rustc_codegen_ssa/src/mir/rvalue.rs b/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
index b0f757898e3..8e5019967a4 100644
--- a/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
@@ -13,7 +13,7 @@ use rustc_middle::ty::cast::{CastTy, IntTy};
 use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf, TyAndLayout};
 use rustc_middle::ty::{self, adjustment::PointerCoercion, Instance, Ty, TyCtxt};
 use rustc_session::config::OptLevel;
-use rustc_span::source_map::{Span, DUMMY_SP};
+use rustc_span::{Span, DUMMY_SP};
 use rustc_target::abi::{self, FIRST_VARIANT};
 
 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
diff --git a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
index 7782cb8fd38..13937a94198 100644
--- a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
+++ b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
@@ -10,7 +10,7 @@ use rustc_middle::traits::Reveal;
 use rustc_middle::ty::layout::LayoutOf;
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::{self, TyCtxt};
-use rustc_span::source_map::Span;
+use rustc_span::Span;
 use rustc_target::abi::{self, Abi};
 
 use super::{CanAccessStatics, CompileTimeEvalContext, CompileTimeInterpreter};
diff --git a/compiler/rustc_const_eval/src/const_eval/mod.rs b/compiler/rustc_const_eval/src/const_eval/mod.rs
index e53282ffaeb..f6942366cbd 100644
--- a/compiler/rustc_const_eval/src/const_eval/mod.rs
+++ b/compiler/rustc_const_eval/src/const_eval/mod.rs
@@ -6,7 +6,7 @@ use rustc_middle::mir;
 use rustc_middle::mir::interpret::{EvalToValTreeResult, GlobalId};
 use rustc_middle::query::TyCtxtAt;
 use rustc_middle::ty::{self, Ty, TyCtxt};
-use rustc_span::source_map::DUMMY_SP;
+use rustc_span::DUMMY_SP;
 
 mod error;
 mod eval_queries;
diff --git a/compiler/rustc_const_eval/src/const_eval/valtrees.rs b/compiler/rustc_const_eval/src/const_eval/valtrees.rs
index 3aaaf08c856..bda6a905503 100644
--- a/compiler/rustc_const_eval/src/const_eval/valtrees.rs
+++ b/compiler/rustc_const_eval/src/const_eval/valtrees.rs
@@ -10,7 +10,7 @@ use crate::interpret::{
 use rustc_middle::mir;
 use rustc_middle::ty::layout::{LayoutCx, LayoutOf, TyAndLayout};
 use rustc_middle::ty::{self, ScalarInt, Ty, TyCtxt};
-use rustc_span::source_map::DUMMY_SP;
+use rustc_span::DUMMY_SP;
 use rustc_target::abi::VariantIdx;
 
 #[instrument(skip(ecx), level = "debug")]
diff --git a/compiler/rustc_driver_impl/src/lib.rs b/compiler/rustc_driver_impl/src/lib.rs
index e4cb3fd25cd..2c7cc707e29 100644
--- a/compiler/rustc_driver_impl/src/lib.rs
+++ b/compiler/rustc_driver_impl/src/lib.rs
@@ -43,8 +43,9 @@ use rustc_session::cstore::MetadataLoader;
 use rustc_session::getopts::{self, Matches};
 use rustc_session::lint::{Lint, LintId};
 use rustc_session::{config, EarlyErrorHandler, Session};
-use rustc_span::source_map::{FileLoader, FileName};
+use rustc_span::source_map::FileLoader;
 use rustc_span::symbol::sym;
+use rustc_span::FileName;
 use rustc_target::json::ToJson;
 use rustc_target::spec::{Target, TargetTriple};
 
diff --git a/compiler/rustc_expand/src/placeholders.rs b/compiler/rustc_expand/src/placeholders.rs
index 82cac229284..1292a855230 100644
--- a/compiler/rustc_expand/src/placeholders.rs
+++ b/compiler/rustc_expand/src/placeholders.rs
@@ -4,8 +4,8 @@ use rustc_ast::mut_visit::*;
 use rustc_ast::ptr::P;
 use rustc_ast::token::Delimiter;
 use rustc_data_structures::fx::FxHashMap;
-use rustc_span::source_map::DUMMY_SP;
 use rustc_span::symbol::Ident;
+use rustc_span::DUMMY_SP;
 use smallvec::{smallvec, SmallVec};
 use thin_vec::ThinVec;
 
diff --git a/compiler/rustc_expand/src/tests.rs b/compiler/rustc_expand/src/tests.rs
index 8e3219c138c..9f52669e188 100644
--- a/compiler/rustc_expand/src/tests.rs
+++ b/compiler/rustc_expand/src/tests.rs
@@ -2,7 +2,7 @@ use rustc_ast as ast;
 use rustc_ast::tokenstream::TokenStream;
 use rustc_parse::{new_parser_from_source_str, parser::Parser, source_file_to_stream};
 use rustc_session::parse::ParseSess;
-use rustc_span::create_default_session_if_not_set_then;
+use rustc_span::create_default_session_globals_then;
 use rustc_span::source_map::{FilePathMapping, SourceMap};
 use rustc_span::{BytePos, Span};
 
@@ -181,7 +181,7 @@ impl<T: Write> Write for Shared<T> {
 }
 
 fn test_harness(file_text: &str, span_labels: Vec<SpanLabel>, expected_output: &str) {
-    create_default_session_if_not_set_then(|_| {
+    create_default_session_globals_then(|| {
         let (handler, source_map, output) = create_test_handler();
         source_map.new_source_file(Path::new("test.rs").to_owned().into(), file_text.to_owned());
 
diff --git a/compiler/rustc_hir/src/tests.rs b/compiler/rustc_hir/src/tests.rs
index a40a0178710..74b8e88a977 100644
--- a/compiler/rustc_hir/src/tests.rs
+++ b/compiler/rustc_hir/src/tests.rs
@@ -2,7 +2,7 @@ use crate::definitions::{DefKey, DefPathData, DisambiguatedDefPathData};
 use rustc_data_structures::stable_hasher::Hash64;
 use rustc_span::def_id::{DefPathHash, StableCrateId};
 use rustc_span::edition::Edition;
-use rustc_span::{create_session_if_not_set_then, Symbol};
+use rustc_span::{create_session_globals_then, Symbol};
 
 #[test]
 fn def_path_hash_depends_on_crate_id() {
@@ -14,7 +14,7 @@ fn def_path_hash_depends_on_crate_id() {
     // the crate by changing the crate disambiguator (e.g. via bumping the
     // crate's version number).
 
-    create_session_if_not_set_then(Edition::Edition2024, |_| {
+    create_session_globals_then(Edition::Edition2024, || {
         let id0 = StableCrateId::new(Symbol::intern("foo"), false, vec!["1".to_string()], "");
         let id1 = StableCrateId::new(Symbol::intern("foo"), false, vec!["2".to_string()], "");
 
diff --git a/compiler/rustc_hir_analysis/src/check/mod.rs b/compiler/rustc_hir_analysis/src/check/mod.rs
index 8da953e6e2e..15c5558fc0b 100644
--- a/compiler/rustc_hir_analysis/src/check/mod.rs
+++ b/compiler/rustc_hir_analysis/src/check/mod.rs
@@ -90,9 +90,8 @@ use rustc_middle::ty::error::{ExpectedFound, TypeError};
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_middle::ty::{GenericArgs, GenericArgsRef};
 use rustc_session::parse::feature_err;
-use rustc_span::source_map::DUMMY_SP;
 use rustc_span::symbol::{kw, Ident};
-use rustc_span::{self, def_id::CRATE_DEF_ID, BytePos, Span, Symbol};
+use rustc_span::{self, def_id::CRATE_DEF_ID, BytePos, Span, Symbol, DUMMY_SP};
 use rustc_target::abi::VariantIdx;
 use rustc_target::spec::abi::Abi;
 use rustc_trait_selection::traits::error_reporting::suggestions::ReturnsVisitor;
diff --git a/compiler/rustc_hir_analysis/src/constrained_generic_params.rs b/compiler/rustc_hir_analysis/src/constrained_generic_params.rs
index 5591fa6f2a5..ed5e9dd2b5a 100644
--- a/compiler/rustc_hir_analysis/src/constrained_generic_params.rs
+++ b/compiler/rustc_hir_analysis/src/constrained_generic_params.rs
@@ -1,7 +1,7 @@
 use rustc_data_structures::fx::FxHashSet;
 use rustc_middle::ty::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitor};
 use rustc_middle::ty::{self, Ty, TyCtxt};
-use rustc_span::source_map::Span;
+use rustc_span::Span;
 use std::ops::ControlFlow;
 
 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
diff --git a/compiler/rustc_hir_typeck/src/closure.rs b/compiler/rustc_hir_typeck/src/closure.rs
index d6073dbc128..a70ead8e57d 100644
--- a/compiler/rustc_hir_typeck/src/closure.rs
+++ b/compiler/rustc_hir_typeck/src/closure.rs
@@ -14,8 +14,7 @@ use rustc_middle::ty::visit::{TypeVisitable, TypeVisitableExt};
 use rustc_middle::ty::GenericArgs;
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeSuperVisitable, TypeVisitor};
 use rustc_span::def_id::LocalDefId;
-use rustc_span::source_map::Span;
-use rustc_span::sym;
+use rustc_span::{sym, Span};
 use rustc_target::spec::abi::Abi;
 use rustc_trait_selection::traits;
 use rustc_trait_selection::traits::error_reporting::ArgKind;
diff --git a/compiler/rustc_hir_typeck/src/diverges.rs b/compiler/rustc_hir_typeck/src/diverges.rs
index 963a93a95c2..29fcc61cbb5 100644
--- a/compiler/rustc_hir_typeck/src/diverges.rs
+++ b/compiler/rustc_hir_typeck/src/diverges.rs
@@ -1,5 +1,4 @@
-use rustc_span::source_map::DUMMY_SP;
-use rustc_span::{self, Span};
+use rustc_span::{self, Span, DUMMY_SP};
 use std::{cmp, ops};
 
 /// Tracks whether executing a node may exit normally (versus
diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs
index bdac886bf9e..a11fe10c01c 100644
--- a/compiler/rustc_hir_typeck/src/expr.rs
+++ b/compiler/rustc_hir_typeck/src/expr.rs
@@ -52,8 +52,9 @@ use rustc_session::errors::ExprParenthesesNeeded;
 use rustc_session::parse::feature_err;
 use rustc_span::edit_distance::find_best_match_for_name;
 use rustc_span::hygiene::DesugaringKind;
-use rustc_span::source_map::{Span, Spanned};
+use rustc_span::source_map::Spanned;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
+use rustc_span::Span;
 use rustc_target::abi::{FieldIdx, FIRST_VARIANT};
 use rustc_target::spec::abi::Abi::RustIntrinsic;
 use rustc_trait_selection::infer::InferCtxtExt;
diff --git a/compiler/rustc_hir_typeck/src/pat.rs b/compiler/rustc_hir_typeck/src/pat.rs
index e0ccf04ab63..50684482c0d 100644
--- a/compiler/rustc_hir_typeck/src/pat.rs
+++ b/compiler/rustc_hir_typeck/src/pat.rs
@@ -17,8 +17,9 @@ use rustc_middle::ty::{self, Adt, BindingMode, Ty, TypeVisitableExt};
 use rustc_session::lint::builtin::NON_EXHAUSTIVE_OMITTED_PATTERNS;
 use rustc_span::edit_distance::find_best_match_for_name;
 use rustc_span::hygiene::DesugaringKind;
-use rustc_span::source_map::{Span, Spanned};
+use rustc_span::source_map::Spanned;
 use rustc_span::symbol::{kw, sym, Ident};
+use rustc_span::Span;
 use rustc_span::{BytePos, DUMMY_SP};
 use rustc_target::abi::FieldIdx;
 use rustc_trait_selection::traits::{ObligationCause, Pattern};
diff --git a/compiler/rustc_infer/src/infer/canonical/mod.rs b/compiler/rustc_infer/src/infer/canonical/mod.rs
index 280dcae3451..3c4c4644fe6 100644
--- a/compiler/rustc_infer/src/infer/canonical/mod.rs
+++ b/compiler/rustc_infer/src/infer/canonical/mod.rs
@@ -27,7 +27,7 @@ use rustc_index::IndexVec;
 use rustc_middle::ty::fold::TypeFoldable;
 use rustc_middle::ty::GenericArg;
 use rustc_middle::ty::{self, List, Ty, TyCtxt};
-use rustc_span::source_map::Span;
+use rustc_span::Span;
 
 pub use rustc_middle::infer::canonical::*;
 pub use substitute::CanonicalExt;
diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mod.rs
index 59fb74eb543..2a70c4673b0 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mod.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mod.rs
@@ -3,7 +3,7 @@ use crate::infer::lexical_region_resolve::RegionResolutionError;
 use crate::infer::lexical_region_resolve::RegionResolutionError::*;
 use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed};
 use rustc_middle::ty::{self, TyCtxt};
-use rustc_span::source_map::Span;
+use rustc_span::Span;
 
 mod different_lifetimes;
 pub mod find_anon_type;
diff --git a/compiler/rustc_interface/src/interface.rs b/compiler/rustc_interface/src/interface.rs
index ffdc05526f2..8fb6216f381 100644
--- a/compiler/rustc_interface/src/interface.rs
+++ b/compiler/rustc_interface/src/interface.rs
@@ -21,8 +21,9 @@ use rustc_session::config::{
 use rustc_session::filesearch::sysroot_candidates;
 use rustc_session::parse::ParseSess;
 use rustc_session::{lint, CompilerIO, EarlyErrorHandler, Session};
-use rustc_span::source_map::{FileLoader, FileName};
+use rustc_span::source_map::FileLoader;
 use rustc_span::symbol::sym;
+use rustc_span::FileName;
 use std::path::PathBuf;
 use std::result;
 use std::sync::Arc;
diff --git a/compiler/rustc_middle/src/lint.rs b/compiler/rustc_middle/src/lint.rs
index 59849e8eb40..07142293f38 100644
--- a/compiler/rustc_middle/src/lint.rs
+++ b/compiler/rustc_middle/src/lint.rs
@@ -9,9 +9,8 @@ use rustc_session::lint::{
     FutureIncompatibilityReason, Level, Lint, LintId,
 };
 use rustc_session::Session;
-use rustc_span::hygiene::MacroKind;
-use rustc_span::source_map::{DesugaringKind, ExpnKind};
-use rustc_span::{symbol, Span, Symbol, DUMMY_SP};
+use rustc_span::hygiene::{ExpnKind, MacroKind};
+use rustc_span::{symbol, DesugaringKind, Span, Symbol, DUMMY_SP};
 
 use crate::ty::TyCtxt;
 
diff --git a/compiler/rustc_middle/src/mir/mono.rs b/compiler/rustc_middle/src/mir/mono.rs
index 403e80bd34c..91fdf0b3129 100644
--- a/compiler/rustc_middle/src/mir/mono.rs
+++ b/compiler/rustc_middle/src/mir/mono.rs
@@ -10,8 +10,8 @@ use rustc_hir::ItemId;
 use rustc_index::Idx;
 use rustc_query_system::ich::StableHashingContext;
 use rustc_session::config::OptLevel;
-use rustc_span::source_map::Span;
 use rustc_span::symbol::Symbol;
+use rustc_span::Span;
 use std::fmt;
 use std::hash::Hash;
 
diff --git a/compiler/rustc_middle/src/traits/query.rs b/compiler/rustc_middle/src/traits/query.rs
index 975e3e3ac62..3cceb8b2c59 100644
--- a/compiler/rustc_middle/src/traits/query.rs
+++ b/compiler/rustc_middle/src/traits/query.rs
@@ -10,7 +10,7 @@ use crate::infer::canonical::{Canonical, QueryResponse};
 use crate::ty::error::TypeError;
 use crate::ty::GenericArg;
 use crate::ty::{self, Ty, TyCtxt};
-use rustc_span::source_map::Span;
+use rustc_span::Span;
 
 pub mod type_op {
     use crate::ty::fold::TypeFoldable;
diff --git a/compiler/rustc_monomorphize/src/collector.rs b/compiler/rustc_monomorphize/src/collector.rs
index 82fee7c8dfe..65bdcf10762 100644
--- a/compiler/rustc_monomorphize/src/collector.rs
+++ b/compiler/rustc_monomorphize/src/collector.rs
@@ -186,8 +186,9 @@ use rustc_middle::{middle::codegen_fn_attrs::CodegenFnAttrFlags, mir::visit::TyC
 use rustc_session::config::EntryFnType;
 use rustc_session::lint::builtin::LARGE_ASSIGNMENTS;
 use rustc_session::Limit;
-use rustc_span::source_map::{dummy_spanned, respan, Span, Spanned, DUMMY_SP};
+use rustc_span::source_map::{dummy_spanned, respan, Spanned};
 use rustc_span::symbol::{sym, Ident};
+use rustc_span::{Span, DUMMY_SP};
 use rustc_target::abi::Size;
 use std::path::PathBuf;
 
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 0b5ec9b59ea..36125e138b2 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -32,10 +32,10 @@ use rustc_macros::Subdiagnostic;
 use rustc_session::errors::{report_lit_error, ExprParenthesesNeeded};
 use rustc_session::lint::builtin::BREAK_WITH_LABEL_AND_LOOP;
 use rustc_session::lint::BuiltinLintDiagnostics;
-use rustc_span::source_map::{self, Span, Spanned};
+use rustc_span::source_map::{self, Spanned};
 use rustc_span::symbol::kw::PathRoot;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
-use rustc_span::{BytePos, Pos};
+use rustc_span::{BytePos, Pos, Span};
 use thin_vec::{thin_vec, ThinVec};
 
 /// Possibly accepts an `token::Interpolated` expression (a pre-parsed expression
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index f0cf6bb58ca..253dd2a3b34 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -22,9 +22,9 @@ use rustc_errors::{
 };
 use rustc_span::edit_distance::edit_distance;
 use rustc_span::edition::Edition;
-use rustc_span::source_map::{self, Span};
+use rustc_span::source_map;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
-use rustc_span::DUMMY_SP;
+use rustc_span::{Span, DUMMY_SP};
 use std::fmt::Write;
 use std::mem;
 use thin_vec::{thin_vec, ThinVec};
diff --git a/compiler/rustc_parse/src/parser/mod.rs b/compiler/rustc_parse/src/parser/mod.rs
index 59b51954542..1a7ae406911 100644
--- a/compiler/rustc_parse/src/parser/mod.rs
+++ b/compiler/rustc_parse/src/parser/mod.rs
@@ -36,8 +36,8 @@ use rustc_errors::{
     Applicability, DiagnosticBuilder, ErrorGuaranteed, FatalError, IntoDiagnostic, MultiSpan,
 };
 use rustc_session::parse::ParseSess;
-use rustc_span::source_map::{Span, DUMMY_SP};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
+use rustc_span::{Span, DUMMY_SP};
 use std::ops::Range;
 use std::{mem, slice};
 use thin_vec::ThinVec;
diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs
index 3378e4d46b7..0a4c7c17d06 100644
--- a/compiler/rustc_parse/src/parser/pat.rs
+++ b/compiler/rustc_parse/src/parser/pat.rs
@@ -20,8 +20,9 @@ use rustc_ast::{
 use rustc_ast_pretty::pprust;
 use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed, IntoDiagnostic, PResult};
 use rustc_session::errors::ExprParenthesesNeeded;
-use rustc_span::source_map::{respan, Span, Spanned};
+use rustc_span::source_map::{respan, Spanned};
 use rustc_span::symbol::{kw, sym, Ident};
+use rustc_span::Span;
 use thin_vec::{thin_vec, ThinVec};
 
 #[derive(PartialEq, Copy, Clone)]
diff --git a/compiler/rustc_parse/src/parser/path.rs b/compiler/rustc_parse/src/parser/path.rs
index 4969e672a72..8626dbe40af 100644
--- a/compiler/rustc_parse/src/parser/path.rs
+++ b/compiler/rustc_parse/src/parser/path.rs
@@ -10,8 +10,8 @@ use rustc_ast::{
     Path, PathSegment, QSelf,
 };
 use rustc_errors::{Applicability, IntoDiagnostic, PResult};
-use rustc_span::source_map::{BytePos, Span};
 use rustc_span::symbol::{kw, sym, Ident};
+use rustc_span::{BytePos, Span};
 use std::mem;
 use thin_vec::ThinVec;
 use tracing::debug;
diff --git a/compiler/rustc_parse/src/parser/stmt.rs b/compiler/rustc_parse/src/parser/stmt.rs
index 8e3c4568694..aa939a71d63 100644
--- a/compiler/rustc_parse/src/parser/stmt.rs
+++ b/compiler/rustc_parse/src/parser/stmt.rs
@@ -20,8 +20,8 @@ use rustc_ast::{AttrStyle, AttrVec, LocalKind, MacCall, MacCallStmt, MacStmtStyl
 use rustc_ast::{Block, BlockCheckMode, Expr, ExprKind, HasAttrs, Local, Stmt};
 use rustc_ast::{StmtKind, DUMMY_NODE_ID};
 use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed, PResult};
-use rustc_span::source_map::{BytePos, Span};
 use rustc_span::symbol::{kw, sym, Ident};
+use rustc_span::{BytePos, Span};
 
 use std::borrow::Cow;
 use std::mem;
diff --git a/compiler/rustc_parse/src/parser/ty.rs b/compiler/rustc_parse/src/parser/ty.rs
index badea5d6133..be2cbaf3020 100644
--- a/compiler/rustc_parse/src/parser/ty.rs
+++ b/compiler/rustc_parse/src/parser/ty.rs
@@ -18,9 +18,8 @@ use rustc_ast::{
     TraitObjectSyntax, Ty, TyKind,
 };
 use rustc_errors::{Applicability, PResult};
-use rustc_span::source_map::Span;
 use rustc_span::symbol::{kw, sym, Ident};
-use rustc_span::Symbol;
+use rustc_span::{Span, Symbol};
 use thin_vec::{thin_vec, ThinVec};
 
 /// Any `?`, `!`, or `~const` modifiers that appear at the start of a bound.
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index 715a7f9cb63..c94e0d0ed39 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -18,10 +18,9 @@ use rustc_target::spec::{Target, TargetTriple, TargetWarnings, TARGETS};
 
 use rustc_feature::UnstableFeatures;
 use rustc_span::edition::{Edition, DEFAULT_EDITION, EDITION_NAME_LIST, LATEST_STABLE_EDITION};
-use rustc_span::source_map::{FileName, FilePathMapping};
+use rustc_span::source_map::FilePathMapping;
 use rustc_span::symbol::{sym, Symbol};
-use rustc_span::SourceFileHashAlgorithm;
-use rustc_span::{FileNameDisplayPreference, RealFileName};
+use rustc_span::{FileName, FileNameDisplayPreference, RealFileName, SourceFileHashAlgorithm};
 
 use rustc_errors::emitter::HumanReadableErrorType;
 use rustc_errors::{ColorConfig, DiagnosticArgValue, HandlerFlags, IntoDiagnosticArg};
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index f823b556154..80a549b30f7 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -31,8 +31,8 @@ use rustc_errors::{
 use rustc_macros::HashStable_Generic;
 pub use rustc_span::def_id::StableCrateId;
 use rustc_span::edition::Edition;
-use rustc_span::source_map::{FileLoader, RealFileLoader, SourceMap, Span};
-use rustc_span::{SourceFileHashAlgorithm, Symbol};
+use rustc_span::source_map::{FileLoader, RealFileLoader, SourceMap};
+use rustc_span::{SourceFileHashAlgorithm, Span, Symbol};
 use rustc_target::asm::InlineAsmArch;
 use rustc_target::spec::{CodeModel, PanicStrategy, RelocModel, RelroLevel};
 use rustc_target::spec::{
diff --git a/compiler/rustc_span/src/fatal_error.rs b/compiler/rustc_span/src/fatal_error.rs
index fa84c486df5..8b4f77a0566 100644
--- a/compiler/rustc_span/src/fatal_error.rs
+++ b/compiler/rustc_span/src/fatal_error.rs
@@ -1,13 +1,11 @@
-/// Used as a return value to signify a fatal error occurred. (It is also
-/// used as the argument to panic at the moment, but that will eventually
-/// not be true.)
+/// Used as a return value to signify a fatal error occurred.
 #[derive(Copy, Clone, Debug)]
 #[must_use]
 pub struct FatalError;
 
 pub struct FatalErrorMarker;
 
-// Don't implement Send on FatalError. This makes it impossible to panic!(FatalError).
+// Don't implement Send on FatalError. This makes it impossible to `panic_any!(FatalError)`.
 // We don't want to invoke the panic handler and print a backtrace for fatal errors.
 impl !Send for FatalError {}
 
diff --git a/compiler/rustc_span/src/hygiene.rs b/compiler/rustc_span/src/hygiene.rs
index 88081700c3b..36731d0fe74 100644
--- a/compiler/rustc_span/src/hygiene.rs
+++ b/compiler/rustc_span/src/hygiene.rs
@@ -24,16 +24,13 @@
 // because getting it wrong can lead to nested `HygieneData::with` calls that
 // trigger runtime aborts. (Fortunately these are obvious and easy to fix.)
 
+use crate::def_id::{CrateNum, DefId, StableCrateId, CRATE_DEF_ID, LOCAL_CRATE};
 use crate::edition::Edition;
 use crate::symbol::{kw, sym, Symbol};
-use crate::with_session_globals;
-use crate::{HashStableContext, Span, DUMMY_SP};
-
-use crate::def_id::{CrateNum, DefId, StableCrateId, CRATE_DEF_ID, LOCAL_CRATE};
+use crate::{with_session_globals, HashStableContext, Span, DUMMY_SP};
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_data_structures::stable_hasher::HashingControls;
-use rustc_data_structures::stable_hasher::{Hash64, HashStable, StableHasher};
+use rustc_data_structures::stable_hasher::{Hash64, HashStable, HashingControls, StableHasher};
 use rustc_data_structures::sync::{Lock, Lrc, WorkerLocal};
 use rustc_data_structures::unhash::UnhashMap;
 use rustc_index::IndexVec;
@@ -130,7 +127,7 @@ impl ExpnHash {
 
     /// Returns the crate-local part of the [ExpnHash].
     ///
-    /// Used for tests.
+    /// Used for assertions.
     #[inline]
     pub fn local_hash(self) -> Hash64 {
         self.0.split().1
@@ -173,7 +170,7 @@ impl LocalExpnId {
     pub const ROOT: LocalExpnId = LocalExpnId::from_u32(0);
 
     #[inline]
-    pub fn from_raw(idx: ExpnIndex) -> LocalExpnId {
+    fn from_raw(idx: ExpnIndex) -> LocalExpnId {
         LocalExpnId::from_u32(idx.as_u32())
     }
 
@@ -205,11 +202,6 @@ impl LocalExpnId {
     }
 
     #[inline]
-    pub fn expn_hash(self) -> ExpnHash {
-        HygieneData::with(|data| data.local_expn_hash(self))
-    }
-
-    #[inline]
     pub fn expn_data(self) -> ExpnData {
         HygieneData::with(|data| data.local_expn_data(self).clone())
     }
@@ -239,13 +231,6 @@ impl LocalExpnId {
         self.to_expn_id().is_descendant_of(ancestor.to_expn_id())
     }
 
-    /// `expn_id.outer_expn_is_descendant_of(ctxt)` is equivalent to but faster than
-    /// `expn_id.is_descendant_of(ctxt.outer_expn())`.
-    #[inline]
-    pub fn outer_expn_is_descendant_of(self, ctxt: SyntaxContext) -> bool {
-        self.to_expn_id().outer_expn_is_descendant_of(ctxt)
-    }
-
     /// Returns span for the macro which originally caused this expansion to happen.
     ///
     /// Stops backtracing at include! boundary.
@@ -253,12 +238,6 @@ impl LocalExpnId {
     pub fn expansion_cause(self) -> Option<Span> {
         self.to_expn_id().expansion_cause()
     }
-
-    #[inline]
-    #[track_caller]
-    pub fn parent(self) -> LocalExpnId {
-        self.expn_data().parent.as_local().unwrap()
-    }
 }
 
 impl ExpnId {
@@ -333,7 +312,7 @@ impl ExpnId {
 }
 
 #[derive(Debug)]
-pub struct HygieneData {
+pub(crate) struct HygieneData {
     /// Each expansion should have an associated expansion data, but sometimes there's a delay
     /// between creation of an expansion ID and obtaining its data (e.g. macros are collected
     /// first and then resolved later), so we use an `Option` here.
@@ -384,16 +363,11 @@ impl HygieneData {
         }
     }
 
-    pub fn with<T, F: FnOnce(&mut HygieneData) -> T>(f: F) -> T {
+    fn with<T, F: FnOnce(&mut HygieneData) -> T>(f: F) -> T {
         with_session_globals(|session_globals| f(&mut session_globals.hygiene_data.borrow_mut()))
     }
 
     #[inline]
-    fn local_expn_hash(&self, expn_id: LocalExpnId) -> ExpnHash {
-        self.local_expn_hashes[expn_id]
-    }
-
-    #[inline]
     fn expn_hash(&self, expn_id: ExpnId) -> ExpnHash {
         match expn_id.as_local() {
             Some(expn_id) => self.local_expn_hashes[expn_id],
@@ -746,7 +720,7 @@ impl SyntaxContext {
     }
 
     /// Like `SyntaxContext::adjust`, but also normalizes `self` to macros 2.0.
-    pub fn normalize_to_macros_2_0_and_adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId> {
+    pub(crate) fn normalize_to_macros_2_0_and_adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId> {
         HygieneData::with(|data| {
             *self = data.normalize_to_macros_2_0(*self);
             data.adjust(self, expn_id)
@@ -779,7 +753,11 @@ impl SyntaxContext {
     /// ```
     /// This returns `None` if the context cannot be glob-adjusted.
     /// Otherwise, it returns the scope to use when privacy checking (see `adjust` for details).
-    pub fn glob_adjust(&mut self, expn_id: ExpnId, glob_span: Span) -> Option<Option<ExpnId>> {
+    pub(crate) fn glob_adjust(
+        &mut self,
+        expn_id: ExpnId,
+        glob_span: Span,
+    ) -> Option<Option<ExpnId>> {
         HygieneData::with(|data| {
             let mut scope = None;
             let mut glob_ctxt = data.normalize_to_macros_2_0(glob_span.ctxt());
@@ -803,7 +781,7 @@ impl SyntaxContext {
     ///     assert!(self.glob_adjust(expansion, glob_ctxt) == Some(privacy_checking_scope));
     /// }
     /// ```
-    pub fn reverse_glob_adjust(
+    pub(crate) fn reverse_glob_adjust(
         &mut self,
         expn_id: ExpnId,
         glob_span: Span,
@@ -858,11 +836,11 @@ impl SyntaxContext {
     }
 
     #[inline]
-    pub fn outer_mark(self) -> (ExpnId, Transparency) {
+    fn outer_mark(self) -> (ExpnId, Transparency) {
         HygieneData::with(|data| data.outer_mark(self))
     }
 
-    pub fn dollar_crate_name(self) -> Symbol {
+    pub(crate) fn dollar_crate_name(self) -> Symbol {
         HygieneData::with(|data| data.syntax_context_data[self.0 as usize].dollar_crate_name)
     }
 
@@ -961,12 +939,12 @@ pub struct ExpnData {
     /// The normal module (`mod`) in which the expanded macro was defined.
     pub parent_module: Option<DefId>,
     /// Suppresses the `unsafe_code` lint for code produced by this macro.
-    pub allow_internal_unsafe: bool,
+    pub(crate) allow_internal_unsafe: bool,
     /// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`) for this macro.
     pub local_inner_macros: bool,
     /// Should debuginfo for the macro be collapsed to the outermost expansion site (in other
     /// words, was the macro definition annotated with `#[collapse_debuginfo]`)?
-    pub collapse_debuginfo: bool,
+    pub(crate) collapse_debuginfo: bool,
 }
 
 impl !PartialEq for ExpnData {}
diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs
index 1a94b7e98fd..fc13bdff36f 100644
--- a/compiler/rustc_span/src/lib.rs
+++ b/compiler/rustc_span/src/lib.rs
@@ -4,10 +4,12 @@
 //!
 //! - the *span*, represented by [`SpanData`] and related types;
 //! - source code as represented by a [`SourceMap`]; and
-//! - interned strings, represented by [`Symbol`]s, with some common symbols available statically in the [`sym`] module.
+//! - interned strings, represented by [`Symbol`]s, with some common symbols available statically
+//!   in the [`sym`] module.
 //!
-//! Unlike most compilers, the span contains not only the position in the source code, but also various other metadata,
-//! such as the edition and macro hygiene. This metadata is stored in [`SyntaxContext`] and [`ExpnData`].
+//! Unlike most compilers, the span contains not only the position in the source code, but also
+//! various other metadata, such as the edition and macro hygiene. This metadata is stored in
+//! [`SyntaxContext`] and [`ExpnData`].
 //!
 //! ## Note
 //!
@@ -117,7 +119,6 @@ impl SessionGlobals {
     }
 }
 
-#[inline]
 pub fn create_session_globals_then<R>(edition: Edition, f: impl FnOnce() -> R) -> R {
     assert!(
         !SESSION_GLOBALS.is_set(),
@@ -128,7 +129,6 @@ pub fn create_session_globals_then<R>(edition: Edition, f: impl FnOnce() -> R) -
     SESSION_GLOBALS.set(&session_globals, f)
 }
 
-#[inline]
 pub fn set_session_globals_then<R>(session_globals: &SessionGlobals, f: impl FnOnce() -> R) -> R {
     assert!(
         !SESSION_GLOBALS.is_set(),
@@ -138,7 +138,6 @@ pub fn set_session_globals_then<R>(session_globals: &SessionGlobals, f: impl FnO
     SESSION_GLOBALS.set(session_globals, f)
 }
 
-#[inline]
 pub fn create_default_session_if_not_set_then<R, F>(f: F) -> R
 where
     F: FnOnce(&SessionGlobals) -> R,
@@ -146,7 +145,6 @@ where
     create_session_if_not_set_then(edition::DEFAULT_EDITION, f)
 }
 
-#[inline]
 pub fn create_session_if_not_set_then<R, F>(edition: Edition, f: F) -> R
 where
     F: FnOnce(&SessionGlobals) -> R,
@@ -159,7 +157,6 @@ where
     }
 }
 
-#[inline]
 pub fn with_session_globals<R, F>(f: F) -> R
 where
     F: FnOnce(&SessionGlobals) -> R,
@@ -167,7 +164,6 @@ where
     SESSION_GLOBALS.with(f)
 }
 
-#[inline]
 pub fn create_default_session_globals_then<R>(f: impl FnOnce() -> R) -> R {
     create_session_globals_then(edition::DEFAULT_EDITION, f)
 }
@@ -179,8 +175,7 @@ scoped_tls::scoped_thread_local!(static SESSION_GLOBALS: SessionGlobals);
 
 // FIXME: We should use this enum or something like it to get rid of the
 // use of magic `/rust/1.x/...` paths across the board.
-#[derive(Debug, Eq, PartialEq, Clone, Ord, PartialOrd)]
-#[derive(Decodable)]
+#[derive(Debug, Eq, PartialEq, Clone, Ord, PartialOrd, Decodable)]
 pub enum RealFileName {
     LocalPath(PathBuf),
     /// For remapped paths (namely paths into libstd that have been mapped
@@ -217,8 +212,8 @@ impl<S: Encoder> Encodable<S> for RealFileName {
 
             RealFileName::Remapped { ref local_path, ref virtual_name } => encoder
                 .emit_enum_variant(1, |encoder| {
-                    // For privacy and build reproducibility, we must not embed host-dependant path in artifacts
-                    // if they have been remapped by --remap-path-prefix
+                    // For privacy and build reproducibility, we must not embed host-dependant path
+                    // in artifacts if they have been remapped by --remap-path-prefix
                     assert!(local_path.is_none());
                     local_path.encode(encoder);
                     virtual_name.encode(encoder);
@@ -954,7 +949,7 @@ impl Span {
     /// Produces a span with the same location as `self` and context produced by a macro with the
     /// given ID and transparency, assuming that macro was defined directly and not produced by
     /// some other macro (which is the case for built-in and procedural macros).
-    pub fn with_ctxt_from_mark(self, expn_id: ExpnId, transparency: Transparency) -> Span {
+    fn with_ctxt_from_mark(self, expn_id: ExpnId, transparency: Transparency) -> Span {
         self.with_ctxt(SyntaxContext::root().apply_mark(expn_id, transparency))
     }
 
@@ -1529,7 +1524,8 @@ impl SourceFile {
         })
     }
 
-    /// This converts the `lines` field to contain `SourceFileLines::Lines` if needed and freezes it.
+    /// This converts the `lines` field to contain `SourceFileLines::Lines` if needed and freezes
+    /// it.
     fn convert_diffs_to_lines_frozen(&self) {
         let mut guard = if let Some(guard) = self.lines.try_write() { guard } else { return };
 
@@ -2247,6 +2243,9 @@ where
 
 /// Useful type to use with `Result<>` indicate that an error has already
 /// been reported to the user, so no need to continue checking.
+///
+/// The `()` field is necessary: it is non-`pub`, which means values of this
+/// type cannot be constructed outside of this crate.
 #[derive(Clone, Copy, Debug, Hash, PartialEq, Eq, PartialOrd, Ord)]
 #[derive(HashStable_Generic)]
 pub struct ErrorGuaranteed(());
@@ -2264,7 +2263,8 @@ impl<E: rustc_serialize::Encoder> Encodable<E> for ErrorGuaranteed {
     #[inline]
     fn encode(&self, _e: &mut E) {
         panic!(
-            "should never serialize an `ErrorGuaranteed`, as we do not write metadata or incremental caches in case errors occurred"
+            "should never serialize an `ErrorGuaranteed`, as we do not write metadata or \
+            incremental caches in case errors occurred"
         )
     }
 }
diff --git a/compiler/rustc_span/src/source_map.rs b/compiler/rustc_span/src/source_map.rs
index 612d396b099..dcf346acb33 100644
--- a/compiler/rustc_span/src/source_map.rs
+++ b/compiler/rustc_span/src/source_map.rs
@@ -9,21 +9,16 @@
 //! within the `SourceMap`, which upon request can be converted to line and column
 //! information, source code snippets, etc.
 
-pub use crate::hygiene::{ExpnData, ExpnKind};
-pub use crate::*;
-
+use crate::*;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::{Hash128, Hash64, StableHasher};
 use rustc_data_structures::sync::{IntoDynSyncSend, Lrc, MappedReadGuard, ReadGuard, RwLock};
 use std::cmp;
+use std::fs;
 use std::hash::Hash;
+use std::io::{self, BorrowedBuf, Read};
 use std::path::{self, Path, PathBuf};
 
-use std::fs;
-use std::io;
-use std::io::BorrowedBuf;
-use std::io::Read;
-
 #[cfg(test)]
 mod tests;
 
@@ -41,7 +36,7 @@ pub fn original_sp(sp: Span, enclosing_sp: Span) -> Span {
     }
 }
 
-pub mod monotonic {
+mod monotonic {
     use std::ops::{Deref, DerefMut};
 
     /// A `MonotonicVec` is a `Vec` which can only be grown.
@@ -51,18 +46,14 @@ pub mod monotonic {
     // field is inaccessible
     pub struct MonotonicVec<T>(Vec<T>);
     impl<T> MonotonicVec<T> {
-        pub fn new(val: Vec<T>) -> MonotonicVec<T> {
-            MonotonicVec(val)
-        }
-
-        pub fn push(&mut self, val: T) {
+        pub(super) fn push(&mut self, val: T) {
             self.0.push(val);
         }
     }
 
     impl<T> Default for MonotonicVec<T> {
         fn default() -> Self {
-            MonotonicVec::new(vec![])
+            MonotonicVec(vec![])
         }
     }
 
@@ -207,7 +198,7 @@ impl StableSourceFileId {
 //
 
 #[derive(Default)]
-pub(super) struct SourceMapFiles {
+struct SourceMapFiles {
     source_files: monotonic::MonotonicVec<Lrc<SourceFile>>,
     stable_id_to_source_file: FxHashMap<StableSourceFileId, Lrc<SourceFile>>,
 }
@@ -466,33 +457,6 @@ impl SourceMap {
         self.span_to_string(sp, FileNameDisplayPreference::Remapped)
     }
 
-    /// Format the span location suitable for pretty printing annotations with relative line numbers
-    pub fn span_to_relative_line_string(&self, sp: Span, relative_to: Span) -> String {
-        if self.files.borrow().source_files.is_empty() || sp.is_dummy() || relative_to.is_dummy() {
-            return "no-location".to_string();
-        }
-
-        let lo = self.lookup_char_pos(sp.lo());
-        let hi = self.lookup_char_pos(sp.hi());
-        let offset = self.lookup_char_pos(relative_to.lo());
-
-        if lo.file.name != offset.file.name || !relative_to.contains(sp) {
-            return self.span_to_embeddable_string(sp);
-        }
-
-        let lo_line = lo.line.saturating_sub(offset.line);
-        let hi_line = hi.line.saturating_sub(offset.line);
-
-        format!(
-            "{}:+{}:{}: +{}:{}",
-            lo.file.name.display(FileNameDisplayPreference::Remapped),
-            lo_line,
-            lo.col.to_usize() + 1,
-            hi_line,
-            hi.col.to_usize() + 1,
-        )
-    }
-
     /// Format the span location to be printed in diagnostics. Must not be emitted
     /// to build artifacts as this may leak local file paths. Use span_to_embeddable_string
     /// for string suitable for embedding.
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 6a131c0d78b..ff470ce1fa0 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -20,8 +20,8 @@ mod tests;
 
 // The proc macro code for this is in `compiler/rustc_macros/src/symbols.rs`.
 symbols! {
-    // After modifying this list adjust `is_special`, `is_used_keyword`/`is_unused_keyword`,
-    // this should be rarely necessary though if the keywords are kept in alphabetic order.
+    // If you modify this list, adjust `is_special` and `is_used_keyword`/`is_unused_keyword`.
+    // But this should rarely be necessary if the keywords are kept in alphabetic order.
     Keywords {
         // Special reserved identifiers used internally for elided lifetimes,
         // unnamed method parameters, crate root module, error recovery etc.
@@ -894,7 +894,7 @@ symbols! {
         inline_const_pat,
         inout,
         instruction_set,
-        integer_: "integer",
+        integer_: "integer", // underscore to avoid clashing with the function `sym::integer` below
         integral,
         into_future,
         into_iter,
diff --git a/compiler/rustc_trait_selection/src/traits/query/dropck_outlives.rs b/compiler/rustc_trait_selection/src/traits/query/dropck_outlives.rs
index c5fcedcac99..f8efa6a1f6c 100644
--- a/compiler/rustc_trait_selection/src/traits/query/dropck_outlives.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/dropck_outlives.rs
@@ -5,7 +5,7 @@ use crate::traits::{Normalized, ObligationCause, ObligationCtxt};
 use rustc_data_structures::fx::FxHashSet;
 use rustc_middle::traits::query::{DropckConstraint, DropckOutlivesResult};
 use rustc_middle::ty::{self, EarlyBinder, ParamEnvAnd, Ty, TyCtxt};
-use rustc_span::source_map::{Span, DUMMY_SP};
+use rustc_span::{Span, DUMMY_SP};
 
 /// This returns true if the type `ty` is "trivial" for
 /// dropck-outlives -- that is, if it doesn't require any types to
diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs
index c99e018e9ae..c81bc579003 100644
--- a/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs
@@ -6,8 +6,7 @@ use rustc_errors::ErrorGuaranteed;
 use rustc_infer::infer::region_constraints::RegionConstraintData;
 use rustc_middle::traits::query::NoSolution;
 use rustc_middle::ty::{TyCtxt, TypeFoldable};
-use rustc_span::source_map::DUMMY_SP;
-use rustc_span::Span;
+use rustc_span::{Span, DUMMY_SP};
 
 use std::fmt;
 
diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs
index e415d70479e..e345fc39ead 100644
--- a/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs
@@ -10,7 +10,7 @@ use rustc_middle::infer::canonical::CanonicalQueryResponse;
 use rustc_middle::traits::ObligationCause;
 use rustc_middle::ty::{self, ParamEnvAnd, Ty, TyCtxt, TypeVisitableExt};
 use rustc_span::def_id::CRATE_DEF_ID;
-use rustc_span::source_map::DUMMY_SP;
+use rustc_span::DUMMY_SP;
 use smallvec::{smallvec, SmallVec};
 
 #[derive(Copy, Clone, Debug, HashStable, TypeFoldable, TypeVisitable)]
diff --git a/compiler/rustc_traits/src/evaluate_obligation.rs b/compiler/rustc_traits/src/evaluate_obligation.rs
index e8917d72483..9fd550495aa 100644
--- a/compiler/rustc_traits/src/evaluate_obligation.rs
+++ b/compiler/rustc_traits/src/evaluate_obligation.rs
@@ -1,7 +1,7 @@
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::{ParamEnvAnd, TyCtxt};
-use rustc_span::source_map::DUMMY_SP;
+use rustc_span::DUMMY_SP;
 use rustc_trait_selection::traits::query::CanonicalPredicateGoal;
 use rustc_trait_selection::traits::{
     EvaluationResult, Obligation, ObligationCause, OverflowError, SelectionContext, TraitQueryMode,