Remove #[macro_use] extern crate tracing from rustc_metadata.

Author: nnethercote

compiler/rustc_metadata/src/creader.rs

@@ -27,6 +27,7 @@ use rustc_span::edition::Edition;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::{Span, DUMMY_SP};
 use rustc_target::spec::{PanicStrategy, Target, TargetTriple};
+use tracing::{debug, info, trace};
 
 use proc_macro::bridge::client::ProcMacro;
 use std::error::Error;

compiler/rustc_metadata/src/dependency_format.rs

@@ -65,6 +65,7 @@ use rustc_middle::ty::TyCtxt;
 use rustc_session::config::CrateType;
 use rustc_session::cstore::CrateDepKind;
 use rustc_session::cstore::LinkagePreference::{self, RequireDynamic, RequireStatic};
+use tracing::info;
 
 pub(crate) fn calculate(tcx: TyCtxt<'_>) -> Dependencies {
     tcx.crate_types()

compiler/rustc_metadata/src/lib.rs

@@ -20,9 +20,6 @@
 
 extern crate proc_macro;
 
-#[macro_use]
-extern crate tracing;
-
 pub use rmeta::provide;
 
 mod dependency_format;

compiler/rustc_metadata/src/locator.rs

@@ -231,6 +231,7 @@ use rustc_session::Session;
 use rustc_span::symbol::Symbol;
 use rustc_span::Span;
 use rustc_target::spec::{Target, TargetTriple};
+use tracing::{debug, info};
 
 use snap::read::FrameDecoder;
 use std::borrow::Cow;

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -28,6 +28,7 @@ use rustc_session::cstore::{CrateSource, ExternCrate};
 use rustc_session::Session;
 use rustc_span::symbol::kw;
 use rustc_span::{BytePos, Pos, SpanData, SpanDecoder, SyntaxContext, DUMMY_SP};
+use tracing::debug;
 
 use proc_macro::bridge::client::ProcMacro;
 use std::iter::TrustedLen;

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -33,6 +33,7 @@ use std::collections::hash_map::Entry;
 use std::fs::File;
 use std::io::{Read, Seek, Write};
 use std::path::{Path, PathBuf};
+use tracing::{debug, instrument, trace};
 
 pub(super) struct EncodeContext<'a, 'tcx> {
     opaque: opaque::FileEncoder,

compiler/rustc_metadata/src/rmeta/table.rs

@@ -2,6 +2,7 @@ use crate::rmeta::*;
 
 use rustc_hir::def::CtorOf;
 use rustc_index::Idx;
+use tracing::trace;
 
 pub(super) trait IsDefault: Default {
     fn is_default(&self) -> bool;