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_metadata/src/creader.rs

@@ -29,8 +29,7 @@ use rustc_session::lint::{self, BuiltinLintDiag};
 use rustc_session::output::validate_crate_name;
 use rustc_session::search_paths::PathKind;
 use rustc_span::edition::Edition;
-use rustc_span::symbol::{Ident, Symbol, sym};
-use rustc_span::{DUMMY_SP, Span};
+use rustc_span::{DUMMY_SP, Ident, Span, Symbol, sym};
 use rustc_target::spec::{PanicStrategy, Target, TargetTuple};
 use tracing::{debug, info, trace};
 

compiler/rustc_metadata/src/locator.rs

@@ -229,8 +229,7 @@ use rustc_session::cstore::CrateSource;
 use rustc_session::filesearch::FileSearch;
 use rustc_session::search_paths::PathKind;
 use rustc_session::utils::CanonicalizedPath;
-use rustc_span::Span;
-use rustc_span::symbol::Symbol;
+use rustc_span::{Span, Symbol};
 use rustc_target::spec::{Target, TargetTuple};
 use tracing::{debug, info};
 

compiler/rustc_metadata/src/native_libs.rs

@@ -16,7 +16,7 @@ use rustc_session::parse::feature_err;
 use rustc_session::search_paths::PathKind;
 use rustc_session::utils::NativeLibKind;
 use rustc_span::def_id::{DefId, LOCAL_CRATE};
-use rustc_span::symbol::{Symbol, sym};
+use rustc_span::{Symbol, sym};
 use rustc_target::spec::LinkSelfContainedComponents;
 
 use crate::{errors, fluent_generated};

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -31,8 +31,7 @@ use rustc_serialize::{Decodable, Decoder};
 use rustc_session::Session;
 use rustc_session::cstore::{CrateSource, ExternCrate};
 use rustc_span::hygiene::HygieneDecodeContext;
-use rustc_span::symbol::kw;
-use rustc_span::{BytePos, DUMMY_SP, Pos, SpanData, SpanDecoder, SyntaxContext};
+use rustc_span::{BytePos, DUMMY_SP, Pos, SpanData, SpanDecoder, SyntaxContext, kw};
 use tracing::debug;
 
 use crate::creader::CStore;
@@ -874,7 +873,7 @@ impl MetadataBlob {
                         let def_key = root.tables.def_keys.get(blob, item).unwrap().decode(blob);
                         #[cfg_attr(not(bootstrap), allow(rustc::symbol_intern_string_literal))]
                         let def_name = if item == CRATE_DEF_INDEX {
-                            rustc_span::symbol::kw::Crate
+                            kw::Crate
                         } else {
                             def_key
                                 .disambiguated_data

compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs

@@ -17,9 +17,8 @@ use rustc_middle::ty::{self, TyCtxt};
 use rustc_middle::util::Providers;
 use rustc_session::cstore::{CrateStore, ExternCrate};
 use rustc_session::{Session, StableCrateId};
-use rustc_span::Span;
 use rustc_span::hygiene::ExpnId;
-use rustc_span::symbol::{Symbol, kw};
+use rustc_span::{Span, Symbol, kw};
 
 use super::{Decodable, DecodeContext, DecodeIterator};
 use crate::creader::{CStore, LoadedMacro};

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -27,9 +27,9 @@ use rustc_middle::{bug, span_bug};
 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder, opaque};
 use rustc_session::config::{CrateType, OptLevel};
 use rustc_span::hygiene::HygieneEncodeContext;
-use rustc_span::symbol::sym;
 use rustc_span::{
     ExternalSource, FileName, SourceFile, SpanData, SpanEncoder, StableSourceFileId, SyntaxContext,
+    sym,
 };
 use tracing::{debug, instrument, trace};
 

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -36,8 +36,7 @@ use rustc_session::config::SymbolManglingVersion;
 use rustc_session::cstore::{CrateDepKind, ForeignModule, LinkagePreference, NativeLib};
 use rustc_span::edition::Edition;
 use rustc_span::hygiene::{ExpnIndex, MacroKind, SyntaxContextData};
-use rustc_span::symbol::{Ident, Symbol};
-use rustc_span::{self, ExpnData, ExpnHash, ExpnId, Span};
+use rustc_span::{self, ExpnData, ExpnHash, ExpnId, Ident, Span, Symbol};
 use rustc_target::spec::{PanicStrategy, TargetTuple};
 use table::TableBuilder;
 use {rustc_ast as ast, rustc_attr_parsing as attr, rustc_hir as hir};