Re-export more rustc_span::symbol things from rustc_span.

`rustc_span::symbol` defines some things that are re-exported from
`rustc_span`, such as `Symbol` and `sym`. But it doesn't re-export some
closely related things such as `Ident` and `kw`. So you can do `use
rustc_span::{Symbol, sym}` but you have to do `use
rustc_span::symbol::{Ident, kw}`, which is inconsistent for no good
reason.

This commit re-exports `Ident`, `kw`, and `MacroRulesNormalizedIdent`,
and changes many `rustc_span::symbol::` qualifiers in `compiler/` to
`rustc_span::`. This is a 200+ net line of code reduction, mostly
because many files with two `use rustc_span` items can be reduced to
one.

compiler/rustc_passes/src/abi_test.rs

@@ -5,7 +5,7 @@ use rustc_middle::span_bug;
 use rustc_middle::ty::layout::{FnAbiError, LayoutError};
 use rustc_middle::ty::{self, GenericArgs, Instance, Ty, TyCtxt};
 use rustc_span::source_map::Spanned;
-use rustc_span::symbol::sym;
+use rustc_span::sym;
 use rustc_target::abi::call::FnAbi;
 
 use super::layout_test::ensure_wf;

compiler/rustc_passes/src/check_attr.rs

@@ -30,8 +30,7 @@ use rustc_session::lint::builtin::{
     UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES, UNUSED_ATTRIBUTES,
 };
 use rustc_session::parse::feature_err;
-use rustc_span::symbol::{Symbol, kw, sym};
-use rustc_span::{BytePos, DUMMY_SP, Span};
+use rustc_span::{BytePos, DUMMY_SP, Span, Symbol, kw, sym};
 use rustc_target::abi::Size;
 use rustc_target::spec::abi::Abi;
 use rustc_trait_selection::error_reporting::InferCtxtErrorExt;

compiler/rustc_passes/src/dead.rs

@@ -22,7 +22,7 @@ use rustc_middle::ty::{self, TyCtxt};
 use rustc_middle::{bug, span_bug};
 use rustc_session::lint;
 use rustc_session::lint::builtin::DEAD_CODE;
-use rustc_span::symbol::{Symbol, sym};
+use rustc_span::{Symbol, sym};
 
 use crate::errors::{
     ChangeFields, IgnoredDerivedImpls, MultipleDeadCodes, ParentInfo, UselessAssignment,

compiler/rustc_passes/src/diagnostic_items.rs

@@ -14,7 +14,7 @@ use rustc_hir::{Attribute, OwnerId};
 use rustc_middle::query::{LocalCrate, Providers};
 use rustc_middle::ty::TyCtxt;
 use rustc_span::def_id::{DefId, LOCAL_CRATE};
-use rustc_span::symbol::{Symbol, sym};
+use rustc_span::{Symbol, sym};
 
 use crate::errors::DuplicateDiagnosticItemInCrate;
 

compiler/rustc_passes/src/entry.rs

@@ -8,8 +8,7 @@ use rustc_middle::query::Providers;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::RemapFileNameExt;
 use rustc_session::config::{CrateType, EntryFnType, RemapPathScopeComponents, sigpipe};
-use rustc_span::symbol::sym;
-use rustc_span::{Span, Symbol};
+use rustc_span::{Span, Symbol, sym};
 
 use crate::errors::{
     AttrOnlyInFunctions, ExternMain, MultipleRustcMain, MultipleStartFunctions, NoMainErr,

compiler/rustc_passes/src/lang_items.rs

@@ -16,8 +16,7 @@ use rustc_hir::{LangItem, LanguageItems, MethodKind, Target};
 use rustc_middle::query::Providers;
 use rustc_middle::ty::{ResolverAstLowering, TyCtxt};
 use rustc_session::cstore::ExternCrate;
-use rustc_span::Span;
-use rustc_span::symbol::kw::Empty;
+use rustc_span::{Span, kw};
 
 use crate::errors::{
     DuplicateLangItem, IncorrectTarget, LangItemOnIncorrectTarget, UnknownLangItem,
@@ -99,7 +98,7 @@ impl<'ast, 'tcx> LanguageItemCollector<'ast, 'tcx> {
         {
             let lang_item_name = lang_item.name();
             let crate_name = self.tcx.crate_name(item_def_id.krate);
-            let mut dependency_of = Empty;
+            let mut dependency_of = kw::Empty;
             let is_local = item_def_id.is_local();
             let path = if is_local {
                 String::new()
@@ -113,8 +112,8 @@ impl<'ast, 'tcx> LanguageItemCollector<'ast, 'tcx> {
             };
 
             let first_defined_span = self.item_spans.get(&original_def_id).copied();
-            let mut orig_crate_name = Empty;
-            let mut orig_dependency_of = Empty;
+            let mut orig_crate_name = kw::Empty;
+            let mut orig_dependency_of = kw::Empty;
             let orig_is_local = original_def_id.is_local();
             let orig_path = if orig_is_local {
                 String::new()

compiler/rustc_passes/src/layout_test.rs

@@ -5,9 +5,8 @@ use rustc_hir::def_id::LocalDefId;
 use rustc_middle::span_bug;
 use rustc_middle::ty::layout::{HasTyCtxt, HasTypingEnv, LayoutError, LayoutOfHelpers};
 use rustc_middle::ty::{self, Ty, TyCtxt};
-use rustc_span::Span;
 use rustc_span::source_map::Spanned;
-use rustc_span::symbol::sym;
+use rustc_span::{Span, sym};
 use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::infer::TyCtxtInferExt;
 use rustc_trait_selection::traits;

compiler/rustc_passes/src/lib_features.rs

@@ -11,8 +11,7 @@ use rustc_middle::hir::nested_filter;
 use rustc_middle::middle::lib_features::{FeatureStability, LibFeatures};
 use rustc_middle::query::{LocalCrate, Providers};
 use rustc_middle::ty::TyCtxt;
-use rustc_span::symbol::Symbol;
-use rustc_span::{Span, sym};
+use rustc_span::{Span, Symbol, sym};
 
 use crate::errors::{FeaturePreviouslyDeclared, FeatureStableTwice};
 

compiler/rustc_passes/src/liveness.rs

@@ -96,8 +96,7 @@ use rustc_middle::query::Providers;
 use rustc_middle::span_bug;
 use rustc_middle::ty::{self, RootVariableMinCaptureList, Ty, TyCtxt};
 use rustc_session::lint;
-use rustc_span::symbol::{Symbol, kw, sym};
-use rustc_span::{BytePos, Span};
+use rustc_span::{BytePos, Span, Symbol, kw, sym};
 use tracing::{debug, instrument};
 
 use self::LiveNodeKind::*;

compiler/rustc_passes/src/naked_functions.rs

@@ -10,8 +10,7 @@ use rustc_middle::query::Providers;
 use rustc_middle::span_bug;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::lint::builtin::UNDEFINED_NAKED_FUNCTION_ABI;
-use rustc_span::Span;
-use rustc_span::symbol::sym;
+use rustc_span::{Span, sym};
 use rustc_target::spec::abi::Abi;
 
 use crate::errors::{

compiler/rustc_passes/src/stability.rs

@@ -25,8 +25,7 @@ use rustc_middle::query::Providers;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::lint;
 use rustc_session::lint::builtin::{INEFFECTIVE_UNSTABLE_TRAIT_IMPL, USELESS_DEPRECATED};
-use rustc_span::Span;
-use rustc_span::symbol::{Symbol, sym};
+use rustc_span::{Span, Symbol, sym};
 use tracing::{debug, info};
 
 use crate::errors;