From 4930c02c008211f06482fef848dbf5d459475efb Mon Sep 17 00:00:00 2001
From: lcnr <rust@lcnr.de>
Date: Mon, 29 May 2023 17:49:19 +0200
Subject: [PATCH] add FIXME

---
 compiler/rustc_middle/src/mir/syntax.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/compiler/rustc_middle/src/mir/syntax.rs b/compiler/rustc_middle/src/mir/syntax.rs
index 135889d0da810..93800d484072d 100644
--- a/compiler/rustc_middle/src/mir/syntax.rs
+++ b/compiler/rustc_middle/src/mir/syntax.rs
@@ -220,6 +220,11 @@ pub enum BorrowKind {
     /// immutable, but not aliasable. This solves the problem. For
     /// simplicity, we don't give users the way to express this
     /// borrow, it's just used when translating closures.
+    ///
+    // FIXME(#112072): This is wrong. Unique borrows are mutable borrows except
+    // that they do not require their pointee to be marked as a mutable.
+    // They should still be treated as mutable borrows in every other way,
+    // e.g. for variance or overlap checking.
     Unique,
 
     /// Data is mutable and not aliasable.