Move /src/test to /tests

tests/ui/array-slice-vec/variance-vec-covariant.rs

@@ -0,0 +1,20 @@
+// run-pass
+
+// Test that vec is now covariant in its argument type.
+
+#![allow(dead_code)]
+
+fn foo<'a,'b>(v1: Vec<&'a i32>, v2: Vec<&'b i32>) -> i32 {
+    bar(v1, v2).cloned().unwrap_or(0) // only type checks if we can intersect 'a and 'b
+}
+
+fn bar<'c>(v1: Vec<&'c i32>, v2: Vec<&'c i32>) -> Option<&'c i32> {
+    v1.get(0).cloned().or_else(|| v2.get(0).cloned())
+}
+
+fn main() {
+    let x = 22;
+    let y = 44;
+    assert_eq!(foo(vec![&x], vec![&y]), 22);
+    assert_eq!(foo(vec![&y], vec![&x]), 44);
+}