frank-king · frank-king · May 3, 2026 · May 3, 2026
diff --git a/compiler/rustc_mir_build/src/builder/matches/mod.rs b/compiler/rustc_mir_build/src/builder/matches/mod.rs
@@ -2694,8 +2694,11 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         ScheduleDrops::Yes,
                     );
 
-                    let rvalue =
-                        Rvalue::Ref(re_erased, util::ref_pat_borrow_kind(mutbl), binding.source);
+                    let rvalue = Rvalue::Ref(
+                        re_erased,
+                        util::ref_pat_borrow_kind(pinnedness, mutbl),
+                        binding.source,
+                    );
                     let rvalue = match pinnedness {
                         ty::Pinnedness::Not => rvalue,
                         ty::Pinnedness::Pinned => {
@@ -2739,8 +2742,11 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             let rvalue = match binding.binding_mode.0 {
                 ByRef::No => Rvalue::Use(self.consume_by_copy_or_move(binding.source)),
                 ByRef::Yes(pinnedness, mutbl) => {
-                    let rvalue =
-                        Rvalue::Ref(re_erased, util::ref_pat_borrow_kind(mutbl), binding.source);
+                    let rvalue = Rvalue::Ref(
+                        re_erased,
+                        util::ref_pat_borrow_kind(pinnedness, mutbl),
+                        binding.source,
+                    );
                     match pinnedness {
                         ty::Pinnedness::Not => rvalue,
                         ty::Pinnedness::Pinned => {

diff --git a/compiler/rustc_mir_build/src/builder/matches/test.rs b/compiler/rustc_mir_build/src/builder/matches/test.rs
@@ -339,7 +339,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             Mutability::Not => (LangItem::Deref, sym::deref),
             Mutability::Mut => (LangItem::DerefMut, sym::deref_mut),
         };
-        let borrow_kind = super::util::ref_pat_borrow_kind(mutability);
+        let borrow_kind = super::util::ref_pat_borrow_kind(ty::Pinnedness::Not, mutability);
         let source_info = self.source_info(span);
         let re_erased = self.tcx.lifetimes.re_erased;
         let trait_item = self.tcx.require_lang_item(trait_item, span);

diff --git a/compiler/rustc_mir_build/src/builder/matches/util.rs b/compiler/rustc_mir_build/src/builder/matches/util.rs
@@ -1,6 +1,6 @@
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_middle::mir::*;
-use rustc_middle::ty::Ty;
+use rustc_middle::ty::{self, Ty};
 use rustc_span::Span;
 use tracing::debug;
 
@@ -228,9 +228,15 @@ impl<'a, 'b, 'tcx> FakeBorrowCollector<'a, 'b, 'tcx> {
 }
 
 #[must_use]
-pub(crate) fn ref_pat_borrow_kind(ref_mutability: Mutability) -> BorrowKind {
-    match ref_mutability {
-        Mutability::Mut => BorrowKind::Mut { kind: MutBorrowKind::Default },
-        Mutability::Not => BorrowKind::Shared,
+pub(crate) fn ref_pat_borrow_kind(
+    pinnedness: ty::Pinnedness,
+    ref_mutability: Mutability,
+) -> BorrowKind {
+    match pinnedness {
+        ty::Pinnedness::Pinned => BorrowKind::Pinned(ref_mutability, PinBorrowKind::Persistent),
+        ty::Pinnedness::Not => match ref_mutability {
+            Mutability::Mut => BorrowKind::Mut { kind: MutBorrowKind::Default },
+            Mutability::Not => BorrowKind::Shared,
+        },
     }
 }
diff --git a/tests/ui/pin-ergonomics/borrow-pinned-projection.rs b/tests/ui/pin-ergonomics/borrow-pinned-projection.rs
@@ -21,6 +21,18 @@ fn mutable_borrow_of_pinned_projection() {
     //~^ ERROR cannot borrow `pair.0` as mutable because it is pinned
 }
 
+fn ref_pin_pattern_mutable_borrow_of_pinned_projection() {
+    let mut pair = (Foo::default(), Foo::default());
+
+    {
+        let ref pin mut _pin = pair.0;
+    }
+
+    let _other = &mut pair.1;
+    let _borrow = &mut pair.0;
+    //~^ ERROR cannot borrow `pair.0` as mutable because it is pinned
+}
+
 fn move_of_pinned_projection() {
     let mut pair = (Foo::default(), Foo::default());
 
@@ -33,6 +45,18 @@ fn move_of_pinned_projection() {
     //~^ ERROR cannot move out of `pair.0` because it is pinned
 }
 
+fn ref_pin_pattern_move_of_pinned_projection() {
+    let mut pair = (Foo::default(), Foo::default());
+
+    {
+        let ref pin mut _pin = pair.0;
+    }
+
+    let _other = &mut pair.1;
+    let _moved = pair.0;
+    //~^ ERROR cannot move out of `pair.0` because it is pinned
+}
+
 #[pin_v2]
 struct ContainsUnpinField {
     field: String,
@@ -48,6 +72,15 @@ fn pinned_parent_still_blocks_unpin_field_move(mut value: ContainsUnpinField) {
     //~^ ERROR cannot move out of `value.field` because it is pinned
 }
 
+fn ref_pin_pattern_parent_still_blocks_unpin_field_move(mut value: ContainsUnpinField) {
+    {
+        let ref pin mut _pin = value;
+    }
+
+    let _moved = value.field;
+    //~^ ERROR cannot move out of `value.field` because it is pinned
+}
+
 fn pinned_parent_still_blocks_unpin_field_mut_borrow(mut value: ContainsUnpinField) {
     {
         let _ = &pin mut value;
@@ -57,4 +90,13 @@ fn pinned_parent_still_blocks_unpin_field_mut_borrow(mut value: ContainsUnpinFie
     //~^ ERROR cannot borrow `value.field` as mutable because it is pinned
 }
 
+fn ref_pin_pattern_parent_still_blocks_unpin_field_mut_borrow(mut value: ContainsUnpinField) {
+    {
+        let ref pin mut _pin = value;
+    }
+
+    let _ = &mut value.field;
+    //~^ ERROR cannot borrow `value.field` as mutable because it is pinned
+}
+
 fn main() {}
diff --git a/tests/ui/pin-ergonomics/borrow-pinned-projection.stderr b/tests/ui/pin-ergonomics/borrow-pinned-projection.stderr
@@ -7,32 +7,68 @@ LL |         let _pin = &pin mut pair.0;
 LL |     let _borrow = &mut pair.0;
    |                   ^^^^^^^^^^^ borrow of `pair.0` as mutable occurs here
 
+error: cannot borrow `pair.0` as mutable because it is pinned
+  --> $DIR/borrow-pinned-projection.rs:32:19
+   |
+LL |         let ref pin mut _pin = pair.0;
+   |             ---------------- pin of `pair.0` occurs here
+...
+LL |     let _borrow = &mut pair.0;
+   |                   ^^^^^^^^^^^ borrow of `pair.0` as mutable occurs here
+
 error: cannot move out of `pair.0` because it is pinned
-  --> $DIR/borrow-pinned-projection.rs:32:18
+  --> $DIR/borrow-pinned-projection.rs:44:18
    |
 LL |         let _pin = &pin mut pair.0;
    |                    --------------- pin of `pair.0` occurs here
 ...
 LL |     let _moved = pair.0;
    |                  ^^^^^^ move out of `pair.0` occurs here
 
+error: cannot move out of `pair.0` because it is pinned
+  --> $DIR/borrow-pinned-projection.rs:56:18
+   |
+LL |         let ref pin mut _pin = pair.0;
+   |             ---------------- pin of `pair.0` occurs here
+...
+LL |     let _moved = pair.0;
+   |                  ^^^^^^ move out of `pair.0` occurs here
+
 error: cannot move out of `value.field` because it is pinned
-  --> $DIR/borrow-pinned-projection.rs:47:18
+  --> $DIR/borrow-pinned-projection.rs:71:18
    |
 LL |         let _ = &pin mut value;
    |                 -------------- pin of `value` occurs here
 ...
 LL |     let _moved = value.field;
    |                  ^^^^^^^^^^^ move out of `value.field` occurs here
 
+error: cannot move out of `value.field` because it is pinned
+  --> $DIR/borrow-pinned-projection.rs:80:18
+   |
+LL |         let ref pin mut _pin = value;
+   |             ---------------- pin of `value` occurs here
+...
+LL |     let _moved = value.field;
+   |                  ^^^^^^^^^^^ move out of `value.field` occurs here
+
 error: cannot borrow `value.field` as mutable because it is pinned
-  --> $DIR/borrow-pinned-projection.rs:56:13
+  --> $DIR/borrow-pinned-projection.rs:89:13
    |
 LL |         let _ = &pin mut value;
    |                 -------------- pin of `value` occurs here
 ...
 LL |     let _ = &mut value.field;
    |             ^^^^^^^^^^^^^^^^ borrow of `value.field` as mutable occurs here
 
-error: aborting due to 4 previous errors
+error: cannot borrow `value.field` as mutable because it is pinned
+  --> $DIR/borrow-pinned-projection.rs:98:13
+   |
+LL |         let ref pin mut _pin = value;
+   |             ---------------- pin of `value` occurs here
+...
+LL |     let _ = &mut value.field;
+   |             ^^^^^^^^^^^^^^^^ borrow of `value.field` as mutable occurs here
+
+error: aborting due to 8 previous errors
 
diff --git a/tests/ui/pin-ergonomics/borrow-unpin.pinned.stderr b/tests/ui/pin-ergonomics/borrow-unpin.pinned.stderr
@@ -85,8 +85,26 @@ LL | struct Foo(PhantomPinned);
 LL |     let x = &pin const foo; // ok
    |                        --- you could clone this value
 
+error: cannot move out of `foo` because it is pinned
+  --> $DIR/borrow-unpin.rs:65:14
+   |
+LL |         let ref pin mut _x = foo;
+   |             -------------- pin of `foo` occurs here
+LL |     }
+LL |     foo_move(foo);
+   |              ^^^ move out of `foo` occurs here
+
+error: cannot borrow `foo` as mutable because it is pinned
+  --> $DIR/borrow-unpin.rs:73:13
+   |
+LL |         let ref pin mut _x = foo;
+   |             -------------- pin of `foo` occurs here
+LL |     }
+LL |     foo_mut(&mut foo);
+   |             ^^^^^^^^ borrow of `foo` as mutable occurs here
+
 error[E0502]: cannot borrow `foo` as immutable because it is also borrowed as mutable
-  --> $DIR/borrow-unpin.rs:67:13
+  --> $DIR/borrow-unpin.rs:83:13
    |
 LL |     let x = &pin mut foo; // ok
    |             ------------ mutable borrow occurs here
@@ -96,7 +114,7 @@ LL |     foo_pin_mut(x);
    |                 - mutable borrow later used here
 
 error[E0499]: cannot borrow `foo` as mutable more than once at a time
-  --> $DIR/borrow-unpin.rs:89:17
+  --> $DIR/borrow-unpin.rs:105:17
    |
 LL |     let x = &pin mut foo; // ok
    |             ------------ first mutable borrow occurs here
@@ -106,7 +124,7 @@ LL |     foo_pin_mut(x);
    |                 - first borrow later used here
 
 error[E0502]: cannot borrow `foo` as mutable because it is also borrowed as immutable
-  --> $DIR/borrow-unpin.rs:100:17
+  --> $DIR/borrow-unpin.rs:116:17
    |
 LL |     let x = &pin const foo; // ok
    |             -------------- immutable borrow occurs here
@@ -116,7 +134,7 @@ LL |     foo_pin_ref(x);
    |                 - immutable borrow later used here
 
 error[E0502]: cannot borrow `foo` as immutable because it is also borrowed as mutable
-  --> $DIR/borrow-unpin.rs:111:17
+  --> $DIR/borrow-unpin.rs:127:17
    |
 LL |     let x = &pin mut foo; // ok
    |             ------------ mutable borrow occurs here
@@ -125,7 +143,7 @@ LL |     foo_pin_ref(&pin const foo);
 LL |     foo_pin_mut(x);
    |                 - mutable borrow later used here
 
-error: aborting due to 10 previous errors
+error: aborting due to 12 previous errors
 
 Some errors have detailed explanations: E0499, E0502, E0505.
 For more information about an error, try `rustc --explain E0499`.
diff --git a/tests/ui/pin-ergonomics/borrow-unpin.rs b/tests/ui/pin-ergonomics/borrow-unpin.rs
@@ -57,6 +57,22 @@ fn pin_ref_then_move() {
     foo_pin_ref(x);
 }
 
+fn ref_pin_mut_then_move() {
+    let mut foo = Foo::default();
+    {
+        let ref pin mut _x = foo;
+    }
+    foo_move(foo); //[pinned]~ ERROR cannot move out of `foo` because it is pinned
+}
+
+fn ref_pin_mut_then_mut_borrow() {
+    let mut foo = Foo::default();
+    {
+        let ref pin mut _x = foo;
+    }
+    foo_mut(&mut foo); //[pinned]~ ERROR cannot borrow `foo` as mutable because it is pinned
+}
+
 fn pin_mut_then_ref() {
     let mut foo = Foo::default();
     foo_pin_mut(&pin mut foo); // ok

diff --git a/tests/ui/pin-ergonomics/borrow-unpin.unpin.stderr b/tests/ui/pin-ergonomics/borrow-unpin.unpin.stderr
@@ -62,7 +62,7 @@ LL |     let x = &pin const foo; // ok
    |                        --- you could clone this value
 
 error[E0502]: cannot borrow `foo` as immutable because it is also borrowed as mutable
-  --> $DIR/borrow-unpin.rs:67:13
+  --> $DIR/borrow-unpin.rs:83:13
    |
 LL |     let x = &pin mut foo; // ok
    |             ------------ mutable borrow occurs here
@@ -72,7 +72,7 @@ LL |     foo_pin_mut(x);
    |                 - mutable borrow later used here
 
 error[E0499]: cannot borrow `foo` as mutable more than once at a time
-  --> $DIR/borrow-unpin.rs:89:17
+  --> $DIR/borrow-unpin.rs:105:17
    |
 LL |     let x = &pin mut foo; // ok
    |             ------------ first mutable borrow occurs here
@@ -82,7 +82,7 @@ LL |     foo_pin_mut(x);
    |                 - first borrow later used here
 
 error[E0502]: cannot borrow `foo` as mutable because it is also borrowed as immutable
-  --> $DIR/borrow-unpin.rs:100:17
+  --> $DIR/borrow-unpin.rs:116:17
    |
 LL |     let x = &pin const foo; // ok
    |             -------------- immutable borrow occurs here
@@ -92,7 +92,7 @@ LL |     foo_pin_ref(x);
    |                 - immutable borrow later used here
 
 error[E0502]: cannot borrow `foo` as immutable because it is also borrowed as mutable
-  --> $DIR/borrow-unpin.rs:111:17
+  --> $DIR/borrow-unpin.rs:127:17
    |
 LL |     let x = &pin mut foo; // ok
    |             ------------ mutable borrow occurs here

diff --git a/tests/ui/pin-ergonomics/borrow.rs b/tests/ui/pin-ergonomics/borrow.rs
@@ -44,4 +44,20 @@ fn baz(mut x: Foo, mut y: Foo) {
     let _y = y; //~ ERROR cannot move out of `y` because it is pinned
 }
 
+fn ref_pin_mut_then_mut_borrow_and_move(mut x: Foo) {
+    {
+        let ref pin mut _x = x;
+    }
+    let _x = &mut x; //~ ERROR cannot borrow `x` as mutable because it is pinned
+    let _x = x; //~ ERROR cannot move out of `x` because it is pinned
+}
+
+fn ref_pin_const_then_mut_borrow_and_move(mut y: Foo) {
+    {
+        let ref pin const _y = y;
+    }
+    let _y = &mut y; //~ ERROR cannot borrow `y` as mutable because it is pinned
+    let _y = y; //~ ERROR cannot move out of `y` because it is pinned
+}
+
 fn main() {}
diff --git a/tests/ui/pin-ergonomics/borrow.stderr b/tests/ui/pin-ergonomics/borrow.stderr
@@ -34,5 +34,41 @@ LL |         let _y = &pin const y;
 LL |     let _y = y;
    |              ^ move out of `y` occurs here
 
-error: aborting due to 4 previous errors
+error: cannot borrow `x` as mutable because it is pinned
+  --> $DIR/borrow.rs:51:14
+   |
+LL |         let ref pin mut _x = x;
+   |             -------------- pin of `x` occurs here
+LL |     }
+LL |     let _x = &mut x;
+   |              ^^^^^^ borrow of `x` as mutable occurs here
+
+error: cannot move out of `x` because it is pinned
+  --> $DIR/borrow.rs:52:14
+   |
+LL |         let ref pin mut _x = x;
+   |             -------------- pin of `x` occurs here
+...
+LL |     let _x = x;
+   |              ^ move out of `x` occurs here
+
+error: cannot borrow `y` as mutable because it is pinned
+  --> $DIR/borrow.rs:59:14
+   |
+LL |         let ref pin const _y = y;
+   |             ---------------- pin of `y` occurs here
+LL |     }
+LL |     let _y = &mut y;
+   |              ^^^^^^ borrow of `y` as mutable occurs here
+
+error: cannot move out of `y` because it is pinned
+  --> $DIR/borrow.rs:60:14
+   |
+LL |         let ref pin const _y = y;
+   |             ---------------- pin of `y` occurs here
+...
+LL |     let _y = y;
+   |              ^ move out of `y` occurs here
+
+error: aborting due to 8 previous errors