Do not needlessly write-lock

Mark-Simulacrum · Mark-Simulacrum · commit 417c09ab2705 · 2019-11-03T16:52:27.000-05:00
diff --git a/src/librustc_lint/unused.rs b/src/librustc_lint/unused.rs
@@ -309,7 +309,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedAttributes {
             }
         }
 
-        let plugin_attributes = cx.sess().plugin_attributes.borrow_mut();
+        let plugin_attributes = cx.sess().plugin_attributes.borrow();
         for &(name, ty) in plugin_attributes.iter() {
             if ty == AttributeType::Whitelisted && attr.check_name(name) {
                 debug!("{:?} (plugin attr) is whitelisted with ty {:?}", name, ty);

Original file line number	Diff line number	Diff line change
`@@ -309,7 +309,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedAttributes {`
`309`	`309`	`}`
`310`	`310`	`}`
`311`	`311`
`312`		`- let plugin_attributes = cx.sess().plugin_attributes.borrow_mut();`
	`312`	`+ let plugin_attributes = cx.sess().plugin_attributes.borrow();`
`313`	`313`	`for &(name, ty) in plugin_attributes.iter() {`
`314`	`314`	`if ty == AttributeType::Whitelisted && attr.check_name(name) {`
`315`	`315`	`debug!("{:?} (plugin attr) is whitelisted with ty {:?}", name, ty);`