1 files changed, 110 insertions, 0 deletions
diff --git a/src/test/ui/borrowck/borrowck-issue-14498.rs b/src/test/ui/borrowck/borrowck-issue-14498.rs
new file mode 100644
index 000000000..003533a51
--- /dev/null
+++ b/src/test/ui/borrowck/borrowck-issue-14498.rs
@@ -0,0 +1,110 @@
+// This tests that we can't modify Box<&mut T> contents while they
+// are borrowed (#14498).
+//
+// Also includes tests of the errors reported when the Box in question
+// is immutable (#14270).
+
+
+
+struct A { a: isize }
+struct B<'a> { a: Box<&'a mut isize> }
+
+fn indirect_write_to_imm_box() {
+    let mut x: isize = 1;
+    let y: Box<_> = Box::new(&mut x);
+    let p = &y;
+    ***p = 2; //~ ERROR cannot assign to `***p`
+    drop(p);
+}
+
+fn borrow_in_var_from_var() {
+    let mut x: isize = 1;
+    let mut y: Box<_> = Box::new(&mut x);
+    let p = &y;
+    let q = &***p;
+    **y = 2; //~ ERROR cannot assign to `**y` because it is borrowed
+    drop(p);
+    drop(q);
+}
+
+fn borrow_in_var_from_var_via_imm_box() {
+    let mut x: isize = 1;
+    let y: Box<_> = Box::new(&mut x);
+    let p = &y;
+    let q = &***p;
+    **y = 2; //~ ERROR cannot assign to `**y` because it is borrowed
+    drop(p);
+    drop(q);
+}
+
+fn borrow_in_var_from_field() {
+    let mut x = A { a: 1 };
+    let mut y: Box<_> = Box::new(&mut x.a);
+    let p = &y;
+    let q = &***p;
+    **y = 2; //~ ERROR cannot assign to `**y` because it is borrowed
+    drop(p);
+    drop(q);
+}
+
+fn borrow_in_var_from_field_via_imm_box() {
+    let mut x = A { a: 1 };
+    let y: Box<_> = Box::new(&mut x.a);
+    let p = &y;
+    let q = &***p;
+    **y = 2; //~ ERROR cannot assign to `**y` because it is borrowed
+    drop(p);
+    drop(q);
+}
+
+fn borrow_in_field_from_var() {
+    let mut x: isize = 1;
+    let mut y = B { a: Box::new(&mut x) };
+    let p = &y.a;
+    let q = &***p;
+    **y.a = 2; //~ ERROR cannot assign to `**y.a` because it is borrowed
+    drop(p);
+    drop(q);
+}
+
+fn borrow_in_field_from_var_via_imm_box() {
+    let mut x: isize = 1;
+    let y = B { a: Box::new(&mut x) };
+    let p = &y.a;
+    let q = &***p;
+    **y.a = 2; //~ ERROR cannot assign to `**y.a` because it is borrowed
+    drop(p);
+    drop(q);
+}
+
+fn borrow_in_field_from_field() {
+    let mut x = A { a: 1 };
+    let mut y = B { a: Box::new(&mut x.a) };
+    let p = &y.a;
+    let q = &***p;
+    **y.a = 2; //~ ERROR cannot assign to `**y.a` because it is borrowed
+    drop(p);
+    drop(q);
+}
+
+fn borrow_in_field_from_field_via_imm_box() {
+    let mut x = A { a: 1 };
+    let y = B { a: Box::new(&mut x.a) };
+    let p = &y.a;
+    let q = &***p;
+    **y.a = 2; //~ ERROR cannot assign to `**y.a` because it is borrowed
+    drop(p);
+    drop(q);
+}
+
+fn main() {
+    indirect_write_to_imm_box();
+    borrow_in_var_from_var();
+    borrow_in_var_from_var_via_imm_box();
+    borrow_in_var_from_field();
+    borrow_in_var_from_field_via_imm_box();
+    borrow_in_field_from_var();
+    borrow_in_field_from_var_via_imm_box();
+    borrow_in_field_from_field();
+    borrow_in_field_from_field_via_imm_box();
+}