Remove #[macro_use] extern crate tracing from rustc_incremental.

Author: nnethercote

compiler/rustc_incremental/src/assert_dep_graph.rs

@@ -49,10 +49,10 @@ use rustc_middle::ty::TyCtxt;
 use rustc_middle::{bug, span_bug};
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::Span;
-
 use std::env;
 use std::fs::{self, File};
 use std::io::{BufWriter, Write};
+use tracing::debug;
 
 #[allow(missing_docs)]
 pub fn assert_dep_graph(tcx: TyCtxt<'_>) {

compiler/rustc_incremental/src/lib.rs

@@ -6,9 +6,6 @@
 #![feature(rustdoc_internals)]
 #![allow(internal_features)]
 
-#[macro_use]
-extern crate tracing;
-
 mod assert_dep_graph;
 mod errors;
 mod persist;

compiler/rustc_incremental/src/persist/dirty_clean.rs

@@ -33,6 +33,7 @@ use rustc_middle::ty::TyCtxt;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::Span;
 use thin_vec::ThinVec;
+use tracing::debug;
 
 const LOADED_FROM_DISK: Symbol = sym::loaded_from_disk;
 const EXCEPT: Symbol = sym::except;

compiler/rustc_incremental/src/persist/file_format.rs

@@ -19,6 +19,7 @@ use std::env;
 use std::fs;
 use std::io::{self, Read};
 use std::path::{Path, PathBuf};
+use tracing::debug;
 
 /// The first few bytes of files generated by incremental compilation.
 const FILE_MAGIC: &[u8] = b"RSIC";

compiler/rustc_incremental/src/persist/fs.rs

@@ -125,6 +125,7 @@ use std::path::{Path, PathBuf};
 use std::time::{Duration, SystemTime, UNIX_EPOCH};
 
 use rand::{thread_rng, RngCore};
+use tracing::debug;
 
 #[cfg(test)]
 mod tests;

compiler/rustc_incremental/src/persist/load.rs

@@ -12,6 +12,7 @@ use rustc_session::Session;
 use rustc_span::ErrorGuaranteed;
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
+use tracing::{debug, warn};
 
 use super::data::*;
 use super::file_format;

compiler/rustc_incremental/src/persist/save.rs

@@ -11,6 +11,7 @@ use rustc_serialize::Encodable as RustcEncodable;
 use rustc_session::Session;
 use std::fs;
 use std::sync::Arc;
+use tracing::debug;
 
 use super::data::*;
 use super::dirty_clean;

compiler/rustc_incremental/src/persist/work_product.rs

@@ -10,6 +10,7 @@ use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
 use rustc_session::Session;
 use std::fs as std_fs;
 use std::path::Path;
+use tracing::debug;
 
 /// Copies a CGU work product to the incremental compilation directory, so next compilation can
 /// find and reuse it.