From 20e361dd761ec08405595f0cf37a4513c98410bf Mon Sep 17 00:00:00 2001
From: csmoe <csmoe@msn.com>
Date: Mon, 29 May 2023 23:45:14 +0800
Subject: [PATCH] use invariant for unique borrow in projection

---
 compiler/rustc_borrowck/src/type_check/mod.rs |  5 ++--
 tests/ui/mir/issue-112056.rs                  | 24 +++++++++++++++++++
 2 files changed, 27 insertions(+), 2 deletions(-)
 create mode 100644 tests/ui/mir/issue-112056.rs

diff --git a/compiler/rustc_borrowck/src/type_check/mod.rs b/compiler/rustc_borrowck/src/type_check/mod.rs
index 51a84ce6cadea..e20917abc2b2a 100644
--- a/compiler/rustc_borrowck/src/type_check/mod.rs
+++ b/compiler/rustc_borrowck/src/type_check/mod.rs
@@ -765,9 +765,10 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
         match context {
             PlaceContext::MutatingUse(_) => ty::Invariant,
             PlaceContext::NonUse(StorageDead | StorageLive | VarDebugInfo) => ty::Invariant,
+            PlaceContext::NonMutatingUse(UniqueBorrow) => ty::Invariant,
             PlaceContext::NonMutatingUse(
-                Inspect | Copy | Move | PlaceMention | SharedBorrow | ShallowBorrow | UniqueBorrow
-                | AddressOf | Projection,
+                Inspect | Copy | Move | PlaceMention | SharedBorrow | ShallowBorrow | AddressOf
+                | Projection,
             ) => ty::Covariant,
             PlaceContext::NonUse(AscribeUserTy(variance)) => variance,
         }
diff --git a/tests/ui/mir/issue-112056.rs b/tests/ui/mir/issue-112056.rs
new file mode 100644
index 0000000000000..6762b7363c254
--- /dev/null
+++ b/tests/ui/mir/issue-112056.rs
@@ -0,0 +1,24 @@
+struct Spooky<'b> {
+    owned: Option<&'static u32>,
+    borrowed: &'b &'static u32,
+}
+
+impl<'b> Spooky<'b> {
+    fn create_self_reference<'a>(&'a mut self) {
+        let mut closure = || {
+            if let Some(owned) = &self.owned {
+                let borrow: &'a &'static u32 = owned;
+                self.borrowed = borrow;
+                //~^ ERROR lifetime may not live long
+            }
+        };
+        closure();
+    }
+}
+
+fn main() {
+    let mut spooky: Spooky<'static> = Spooky { owned: Some(&1), borrowed: &&1 };
+    spooky.create_self_reference();
+    spooky.owned = None;
+    println!("{}", **spooky.borrowed);
+}