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-rw-r--r--tests/ui/higher-rank-trait-bounds/hrtb-fn-like-trait.rs27
1 files changed, 27 insertions, 0 deletions
diff --git a/tests/ui/higher-rank-trait-bounds/hrtb-fn-like-trait.rs b/tests/ui/higher-rank-trait-bounds/hrtb-fn-like-trait.rs
new file mode 100644
index 000000000..afab9986c
--- /dev/null
+++ b/tests/ui/higher-rank-trait-bounds/hrtb-fn-like-trait.rs
@@ -0,0 +1,27 @@
+// run-pass
+// A basic test of using a higher-ranked trait bound.
+
+
+trait FnLike<A,R> {
+ fn call(&self, arg: A) -> R;
+}
+
+struct Identity;
+
+impl<'a, T> FnLike<&'a T, &'a T> for Identity {
+ fn call(&self, arg: &'a T) -> &'a T {
+ arg
+ }
+}
+
+fn call_repeatedly<F>(f: F)
+ where F : for<'a> FnLike<&'a isize, &'a isize>
+{
+ let x = 3;
+ let y = f.call(&x);
+ assert_eq!(3, *y);
+}
+
+fn main() {
+ call_repeatedly(Identity);
+}