Fix issue #364 - Broken # operator in macros

Caused by inability to access private field,
so was not caught by unit tests as those are in the same crate.

Author: Techcable

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ## [Unreleased]
 
 ### Fixes
+* Fix use of `#` operator in macros due to private field (issue #364)
+  * Thanks to @Manishearth for identifying this.
 * ci: Check the tests pass with `-Zminimal-versions`
 
 ## 2.8.1 - 2025-10-05

src/lib.rs

@@ -3541,7 +3541,7 @@ where
 /// be used directly.
 #[cfg(has_std_error)]
 #[doc(hidden)]
-pub struct ErrorTagWrapper<E>(E);
+pub struct ErrorTagWrapper<E>(pub E);
 
 #[cfg(has_std_error)]
 #[test]

tests/issue364.rs

@@ -0,0 +1,13 @@
+#![cfg(feature = "std")]
+use slog::Logger;
+use std::io::{Error, ErrorKind};
+
+#[test]
+fn ok() {
+    repro(slog::Logger::root(slog::Discard, slog::o!()))
+}
+
+fn repro(log: Logger) {
+    let err = Error::new(ErrorKind::Other, "some error");
+    slog::info!(log, "oops"; "err" => #err);
+}