1 files changed, 27 insertions, 0 deletions
diff --git a/src/test/ui/span/mut-arg-hint.stderr b/src/test/ui/span/mut-arg-hint.stderr
new file mode 100644
index 000000000..8a7c504f0
--- /dev/null
+++ b/src/test/ui/span/mut-arg-hint.stderr
@@ -0,0 +1,27 @@
+error[E0596]: cannot borrow `*a` as mutable, as it is behind a `&` reference
+  --> $DIR/mut-arg-hint.rs:3:9
+   |
+LL |     fn foo(mut a: &String) {
+   |                   ------- help: consider changing this to be a mutable reference: `&mut String`
+LL |         a.push_str("bar");
+   |         ^^^^^^^^^^^^^^^^^ `a` is a `&` reference, so the data it refers to cannot be borrowed as mutable
+
+error[E0596]: cannot borrow `*a` as mutable, as it is behind a `&` reference
+  --> $DIR/mut-arg-hint.rs:8:5
+   |
+LL | pub fn foo<'a>(mut a: &'a String) {
+   |                       ---------- help: consider changing this to be a mutable reference: `&'a mut String`
+LL |     a.push_str("foo");
+   |     ^^^^^^^^^^^^^^^^^ `a` is a `&` reference, so the data it refers to cannot be borrowed as mutable
+
+error[E0596]: cannot borrow `*a` as mutable, as it is behind a `&` reference
+  --> $DIR/mut-arg-hint.rs:15:9
+   |
+LL |     pub fn foo(mut a: &String) {
+   |                       ------- help: consider changing this to be a mutable reference: `&mut String`
+LL |         a.push_str("foo");
+   |         ^^^^^^^^^^^^^^^^^ `a` is a `&` reference, so the data it refers to cannot be borrowed as mutable
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0596`.