1 files changed, 142 insertions, 0 deletions
diff --git a/src/test/ui/span/borrowck-borrow-overloaded-auto-deref-mut.rs b/src/test/ui/span/borrowck-borrow-overloaded-auto-deref-mut.rs
new file mode 100644
index 000000000..76a1d12ea
--- /dev/null
+++ b/src/test/ui/span/borrowck-borrow-overloaded-auto-deref-mut.rs
@@ -0,0 +1,142 @@
+// Test how overloaded deref interacts with borrows when DerefMut
+// is implemented.
+
+use std::ops::{Deref, DerefMut};
+
+struct Own<T> {
+    value: *mut T
+}
+
+impl<T> Deref for Own<T> {
+    type Target = T;
+
+    fn deref(&self) -> &T {
+        unsafe { &*self.value }
+    }
+}
+
+impl<T> DerefMut for Own<T> {
+    fn deref_mut(&mut self) -> &mut T {
+        unsafe { &mut *self.value }
+    }
+}
+
+struct Point {
+    x: isize,
+    y: isize
+}
+
+impl Point {
+    fn get(&self) -> (isize, isize) {
+        (self.x, self.y)
+    }
+
+    fn set(&mut self, x: isize, y: isize) {
+        self.x = x;
+        self.y = y;
+    }
+
+    fn x_ref(&self) -> &isize {
+        &self.x
+    }
+
+    fn y_mut(&mut self) -> &mut isize {
+        &mut self.y
+    }
+}
+
+fn deref_imm_field(x: Own<Point>) {
+    let __isize = &x.y;
+}
+
+fn deref_mut_field1(x: Own<Point>) {
+    let __isize = &mut x.y; //~ ERROR cannot borrow
+}
+
+fn deref_mut_field2(mut x: Own<Point>) {
+    let __isize = &mut x.y;
+}
+
+fn deref_extend_field(x: &Own<Point>) -> &isize {
+    &x.y
+}
+
+fn deref_extend_mut_field1(x: &Own<Point>) -> &mut isize {
+    &mut x.y //~ ERROR cannot borrow
+}
+
+fn deref_extend_mut_field2(x: &mut Own<Point>) -> &mut isize {
+    &mut x.y
+}
+
+fn deref_extend_mut_field3(x: &mut Own<Point>) {
+    // Hmm, this is unfortunate, because with box it would work,
+    // but it's presently the expected outcome. See `deref_extend_mut_field4`
+    // for the workaround.
+
+    let _x = &mut x.x;
+    let _y = &mut x.y; //~ ERROR cannot borrow
+    use_mut(_x);
+}
+fn deref_extend_mut_field4<'a>(x: &'a mut Own<Point>) {
+    let p = &mut **x;
+    let _x = &mut p.x;
+    let _y = &mut p.y;
+}
+
+fn assign_field1<'a>(x: Own<Point>) {
+    x.y = 3; //~ ERROR cannot borrow
+}
+
+fn assign_field2<'a>(x: &'a Own<Point>) {
+    x.y = 3; //~ ERROR cannot borrow
+}
+
+fn assign_field3<'a>(x: &'a mut Own<Point>) {
+    x.y = 3;
+}
+
+fn assign_field4<'a>(x: &'a mut Own<Point>) {
+    let _p: &mut Point = &mut **x;
+    x.y = 3; //~ ERROR cannot borrow
+    use_mut(_p);
+}
+fn deref_imm_method(x: Own<Point>) {
+    let __isize = x.get();
+}
+
+fn deref_mut_method1(x: Own<Point>) {
+    x.set(0, 0); //~ ERROR cannot borrow
+}
+
+fn deref_mut_method2(mut x: Own<Point>) {
+    x.set(0, 0);
+}
+
+fn deref_extend_method(x: &Own<Point>) -> &isize {
+    x.x_ref()
+}
+
+fn deref_extend_mut_method1(x: &Own<Point>) -> &mut isize {
+    x.y_mut() //~ ERROR cannot borrow
+}
+
+fn deref_extend_mut_method2(x: &mut Own<Point>) -> &mut isize {
+    x.y_mut()
+}
+
+fn assign_method1<'a>(x: Own<Point>) {
+    *x.y_mut() = 3; //~ ERROR cannot borrow
+}
+
+fn assign_method2<'a>(x: &'a Own<Point>) {
+    *x.y_mut() = 3; //~ ERROR cannot borrow
+}
+
+fn assign_method3<'a>(x: &'a mut Own<Point>) {
+    *x.y_mut() = 3;
+}
+
+pub fn main() {}
+
+fn use_mut<T>(_: &mut T) {}