1 files changed, 36 insertions, 0 deletions
diff --git a/tests/ui/span/mut-arg-hint.stderr b/tests/ui/span/mut-arg-hint.stderr
new file mode 100644
index 000000000..96ce4d5bc
--- /dev/null
+++ b/tests/ui/span/mut-arg-hint.stderr
@@ -0,0 +1,36 @@
+error[E0596]: cannot borrow `*a` as mutable, as it is behind a `&` reference
+  --> $DIR/mut-arg-hint.rs:3:9
+   |
+LL |         a.push_str("bar");
+   |         ^^^^^^^^^^^^^^^^^ `a` is a `&` reference, so the data it refers to cannot be borrowed as mutable
+   |
+help: consider changing this to be a mutable reference
+   |
+LL |     fn foo(mut a: &mut String) {
+   |                   ~~~~~~~~~~~
+
+error[E0596]: cannot borrow `*a` as mutable, as it is behind a `&` reference
+  --> $DIR/mut-arg-hint.rs:8:5
+   |
+LL |     a.push_str("foo");
+   |     ^^^^^^^^^^^^^^^^^ `a` is a `&` reference, so the data it refers to cannot be borrowed as mutable
+   |
+help: consider changing this to be a mutable reference
+   |
+LL | pub fn foo<'a>(mut a: &'a mut String) {
+   |                       ~~~~~~~~~~~~~~
+
+error[E0596]: cannot borrow `*a` as mutable, as it is behind a `&` reference
+  --> $DIR/mut-arg-hint.rs:15:9
+   |
+LL |         a.push_str("foo");
+   |         ^^^^^^^^^^^^^^^^^ `a` is a `&` reference, so the data it refers to cannot be borrowed as mutable
+   |
+help: consider changing this to be a mutable reference
+   |
+LL |     pub fn foo(mut a: &mut String) {
+   |                       ~~~~~~~~~~~
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0596`.