Remove #[macro_use] extern crate tracing from rustc_resolve.

Explicit imports are more standard nowadays and easier to read.

compiler/rustc_resolve/src/lib.rs

@@ -23,12 +23,6 @@
 #![feature(rustdoc_internals)]
 // tidy-alphabetical-end
 
-#[macro_use]
-extern crate tracing;
-
-use errors::{
-    ParamKindInEnumDiscriminant, ParamKindInNonTrivialAnonConst, ParamKindInTyOfConstParam,
-};
 use rustc_arena::{DroplessArena, TypedArena};
 use rustc_ast::expand::StrippedCfgItem;
 use rustc_ast::node_id::NodeMap;
@@ -61,19 +55,21 @@ use rustc_session::lint::LintBuffer;
 use rustc_span::hygiene::{ExpnId, LocalExpnId, MacroKind, SyntaxContext, Transparency};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
-
 use smallvec::{smallvec, SmallVec};
 use std::cell::{Cell, RefCell};
 use std::collections::BTreeSet;
 use std::fmt;
+use tracing::debug;
 
 use diagnostics::{ImportSuggestion, LabelSuggestion, Suggestion};
+use effective_visibilities::EffectiveVisibilitiesVisitor;
+use errors::{
+    ParamKindInEnumDiscriminant, ParamKindInNonTrivialAnonConst, ParamKindInTyOfConstParam,
+};
 use imports::{Import, ImportData, ImportKind, NameResolution};
 use late::{HasGenericParams, PathSource, PatternSource, UnnecessaryQualification};
 use macros::{MacroRulesBinding, MacroRulesScope, MacroRulesScopeRef};
 
-use crate::effective_visibilities::EffectiveVisibilitiesVisitor;
-
 type Res = def::Res<NodeId>;
 
 mod build_reduced_graph;