Remove extern crate rustc_macros from numerous crates.

compiler/rustc_session/src/config.rs

@@ -15,6 +15,7 @@ use rustc_data_structures::stable_hasher::{StableOrd, ToStableHashKey};
 use rustc_errors::emitter::HumanReadableErrorType;
 use rustc_errors::{ColorConfig, DiagArgValue, DiagCtxtFlags, IntoDiagArg};
 use rustc_feature::UnstableFeatures;
+use rustc_macros::{Decodable, Encodable, HashStable_Generic};
 use rustc_span::edition::{Edition, DEFAULT_EDITION, EDITION_NAME_LIST, LATEST_STABLE_EDITION};
 use rustc_span::source_map::FilePathMapping;
 use rustc_span::{FileName, FileNameDisplayPreference, RealFileName, SourceFileHashAlgorithm};

compiler/rustc_session/src/cstore.rs

@@ -10,6 +10,7 @@ use rustc_hir::def_id::{
     CrateNum, DefId, LocalDefId, StableCrateId, StableCrateIdMap, LOCAL_CRATE,
 };
 use rustc_hir::definitions::{DefKey, DefPath, DefPathHash, Definitions};
+use rustc_macros::{Decodable, Encodable, HashStable_Generic};
 use rustc_span::symbol::Symbol;
 use rustc_span::Span;
 use rustc_target::spec::abi::Abi;

compiler/rustc_session/src/errors.rs

@@ -6,7 +6,7 @@ use rustc_errors::{
     codes::*, Diag, DiagCtxt, DiagMessage, Diagnostic, EmissionGuarantee, ErrorGuaranteed, Level,
     MultiSpan,
 };
-use rustc_macros::Diagnostic;
+use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_span::{Span, Symbol};
 use rustc_target::spec::{SplitDebuginfo, StackProtector, TargetTriple};
 

compiler/rustc_session/src/lib.rs

@@ -6,8 +6,6 @@
 #![feature(iter_intersperse)]
 #![allow(internal_features)]
 
-#[macro_use]
-extern crate rustc_macros;
 pub mod errors;
 
 #[macro_use]

compiler/rustc_session/src/search_paths.rs

@@ -1,5 +1,6 @@
 use crate::filesearch::make_target_lib_path;
 use crate::EarlyDiagCtxt;
+use rustc_macros::{Decodable, Encodable, HashStable_Generic};
 use rustc_target::spec::TargetTriple;
 use std::path::{Path, PathBuf};
 

compiler/rustc_session/src/utils.rs

@@ -1,6 +1,7 @@
 use crate::session::Session;
 use rustc_data_structures::profiling::VerboseTimingGuard;
 use rustc_fs_util::try_canonicalize;
+use rustc_macros::{Decodable, Encodable, HashStable_Generic};
 use std::{
     path::{Path, PathBuf},
     sync::OnceLock,

compiler/rustc_session/src/version.rs

@@ -1,3 +1,4 @@
+use rustc_macros::{current_rustc_version, Decodable, Encodable, HashStable_Generic};
 use std::fmt::{self, Display};
 
 #[derive(Encodable, Decodable, Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]