Remove extern crate tracing from numerous crates.

compiler/rustc_query_system/src/dep_graph/graph.rs

@@ -15,6 +15,7 @@ use std::hash::Hash;
 use std::marker::PhantomData;
 use std::sync::atomic::Ordering;
 use std::sync::Arc;
+use tracing::{debug, instrument};
 
 use super::query::DepGraphQuery;
 use super::serialized::{GraphEncoder, SerializedDepGraph, SerializedDepNodeIndex};

compiler/rustc_query_system/src/dep_graph/mod.rs

@@ -11,13 +11,12 @@ pub use graph::{hash_result, DepGraph, DepNodeIndex, TaskDepsRef, WorkProduct, W
 pub use query::DepGraphQuery;
 pub use serialized::{SerializedDepGraph, SerializedDepNodeIndex};
 
+use self::graph::{print_markframe_trace, MarkFrame};
 use crate::ich::StableHashingContext;
 use rustc_data_structures::profiling::SelfProfilerRef;
 use rustc_session::Session;
-
 use std::panic;
-
-use self::graph::{print_markframe_trace, MarkFrame};
+use tracing::instrument;
 
 pub trait DepContext: Copy {
     type Deps: Deps;

compiler/rustc_query_system/src/dep_graph/serialized.rs

@@ -51,6 +51,7 @@ use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
 use std::iter;
 use std::marker::PhantomData;
 use std::sync::Arc;
+use tracing::{debug, instrument};
 
 // The maximum value of `SerializedDepNodeIndex` leaves the upper two bits
 // unused so that we can store multiple index types in `CompressedHybridIndex`,

compiler/rustc_query_system/src/lib.rs

@@ -5,9 +5,6 @@
 #![feature(let_chains)]
 #![allow(rustc::potential_query_instability, internal_features)]
 
-#[macro_use]
-extern crate tracing;
-
 pub mod cache;
 pub mod dep_graph;
 mod error;

compiler/rustc_query_system/src/query/plumbing.rs

@@ -27,6 +27,7 @@ use std::fmt::Debug;
 use std::hash::Hash;
 use std::mem;
 use thin_vec::ThinVec;
+use tracing::instrument;
 
 use super::QueryConfig;