Remove #[macro_use] extern crate tracing from rustc_passes.

Author: nnethercote

compiler/rustc_passes/src/check_attr.rs

@@ -39,6 +39,7 @@ use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt;
 use rustc_trait_selection::traits::ObligationCtxt;
 use std::cell::Cell;
 use std::collections::hash_map::Entry;
+use tracing::debug;
 
 #[derive(LintDiagnostic)]
 #[diag(passes_diagnostic_diagnostic_on_unimplemented_only_for_traits)]

compiler/rustc_passes/src/lib.rs

@@ -12,9 +12,6 @@
 #![feature(map_try_insert)]
 #![feature(try_blocks)]
 
-#[macro_use]
-extern crate tracing;
-
 use rustc_middle::query::Providers;
 
 pub mod abi_test;

compiler/rustc_passes/src/liveness.rs

@@ -99,10 +99,10 @@ use rustc_middle::ty::{self, RootVariableMinCaptureList, Ty, TyCtxt};
 use rustc_session::lint;
 use rustc_span::symbol::{kw, sym, Symbol};
 use rustc_span::{BytePos, Span};
-
 use std::io;
 use std::io::prelude::*;
 use std::rc::Rc;
+use tracing::{debug, instrument};
 
 mod rwu_table;
 

compiler/rustc_passes/src/reachable.rs

@@ -37,6 +37,7 @@ use rustc_middle::query::Providers;
 use rustc_middle::ty::{self, ExistentialTraitRef, TyCtxt};
 use rustc_privacy::DefIdVisitor;
 use rustc_session::config::CrateType;
+use tracing::debug;
 
 /// Determines whether this item is recursive for reachability. See `is_recursively_reachable_local`
 /// below for details.

compiler/rustc_passes/src/stability.rs

@@ -25,9 +25,9 @@ use rustc_session::lint::builtin::{INEFFECTIVE_UNSTABLE_TRAIT_IMPL, USELESS_DEPR
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::Span;
 use rustc_target::spec::abi::Abi;
-
 use std::mem::replace;
 use std::num::NonZero;
+use tracing::{debug, info};
 
 #[derive(PartialEq)]
 enum AnnotationKind {