1 files changed, 47 insertions, 0 deletions
diff --git a/tests/ui/traits/assignability-trait.rs b/tests/ui/traits/assignability-trait.rs
new file mode 100644
index 000000000..a8547c1d2
--- /dev/null
+++ b/tests/ui/traits/assignability-trait.rs
@@ -0,0 +1,47 @@
+// run-pass
+#![allow(non_camel_case_types)]
+
+// Tests that type assignability is used to search for instances when
+// making method calls, but only if there aren't any matches without
+// it.
+
+trait iterable<A> {
+    fn iterate<F>(&self, blk: F) -> bool where F: FnMut(&A) -> bool;
+}
+
+impl<'a,A> iterable<A> for &'a [A] {
+    fn iterate<F>(&self, f: F) -> bool where F: FnMut(&A) -> bool {
+        self.iter().all(f)
+    }
+}
+
+impl<A> iterable<A> for Vec<A> {
+    fn iterate<F>(&self, f: F) -> bool where F: FnMut(&A) -> bool {
+        self.iter().all(f)
+    }
+}
+
+fn length<A, T: iterable<A>>(x: T) -> usize {
+    let mut len = 0;
+    x.iterate(|_y| {
+        len += 1;
+        true
+    });
+    return len;
+}
+
+pub fn main() {
+    let x: Vec<isize> = vec![0,1,2,3];
+    // Call a method
+    x.iterate(|y| { assert_eq!(x[*y as usize], *y); true });
+    // Call a parameterized function
+    assert_eq!(length(x.clone()), x.len());
+    // Call a parameterized function, with type arguments that require
+    // a borrow
+    assert_eq!(length::<isize, &[isize]>(&*x), x.len());
+
+    // Now try it with a type that *needs* to be borrowed
+    let z = [0,1,2,3];
+    // Call a parameterized function
+    assert_eq!(length::<isize, &[isize]>(&z), z.len());
+}