Always import all tracing macros for the entire crate instead of piecemeal by module

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -11,8 +11,6 @@ use rustc_span::source_map::Spanned;
 use rustc_span::symbol::sym;
 use rustc_span::Span;
 
-use tracing::debug;
-
 macro_rules! gate_feature_fn {
     ($visitor: expr, $has_feature: expr, $span: expr, $name: expr, $explain: expr, $help: expr) => {{
         let (visitor, has_feature, span, name, explain, help) =

compiler/rustc_ast_passes/src/lib.rs

@@ -12,6 +12,9 @@
 #![feature(let_else)]
 #![recursion_limit = "256"]
 
+#[macro_use]
+extern crate tracing;
+
 pub mod ast_validation;
 mod errors;
 pub mod feature_gate;