1 files changed, 15 insertions, 0 deletions

diff --git a/tests/ui/issues/auxiliary/issue-3979-traits.rs b/tests/ui/issues/auxiliary/issue-3979-traits.rs
new file mode 100644
index 000000000..5d03a0e9e
--- /dev/null
+++ b/tests/ui/issues/auxiliary/issue-3979-traits.rs
@@ -0,0 +1,15 @@
+#![crate_name="issue_3979_traits"]
+
+#![crate_type = "lib"]
+
+pub trait Positioned {
+  fn SetX(&mut self, _: isize);
+  fn X(&self) -> isize;
+}
+
+pub trait Movable: Positioned {
+  fn translate(&mut self, dx: isize) {
+    let x = self.X() + dx;
+    self.SetX(x);
+  }
+}