From bb3e60c94c682f1778b546d3682b738545f950da Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lena=20Hellstr=C3=B6m?= <lena@stygian.nexus>
Date: Mon, 10 Mar 2025 18:48:46 +0100
Subject: [PATCH] Fix issue when a foreign `Err` pollutes scope (#758)

---
 derive/src/derive_enum.rs | 2 +-
 tests/derive.rs           | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/derive/src/derive_enum.rs b/derive/src/derive_enum.rs
index c93ac8e..2ba17c5 100644
--- a/derive/src/derive_enum.rs
+++ b/derive/src/derive_enum.rs
@@ -162,7 +162,7 @@ impl DeriveEnum {
         //   if we have fixed value variants
         result.ident_str("variant");
         result.puncts("=>");
-        result.ident_str("Err");
+        result.push_parsed("core::result::Result::Err")?;
         result.group(Delimiter::Parenthesis, |err_inner| {
             err_inner.push_parsed(format!(
                 "{}::error::DecodeError::UnexpectedVariant",
diff --git a/tests/derive.rs b/tests/derive.rs
index 693aec5..c059c96 100644
--- a/tests/derive.rs
+++ b/tests/derive.rs
@@ -408,6 +408,10 @@ mod derive_with_polluted_scope {
     #[allow(non_snake_case)]
     fn Ok() {}
 
+    #[allow(dead_code)]
+    #[allow(non_snake_case)]
+    fn Err() {}
+
     #[derive(bincode::Encode, bincode::Decode)]
     struct A {
         a: u32,