have LangItemError derive everything LangItem does

CleanCut · CleanCut · commit 82d609c8dfab · 2022-08-25T11:06:45.000-06:00
diff --git a/compiler/rustc_hir/src/errors.rs b/compiler/rustc_hir/src/errors.rs
@@ -1,5 +1,6 @@
 use crate::LangItem;
 
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable)]
 pub struct LangItemError(pub LangItem);
 
 impl ToString for LangItemError {
