Test illustrating issue #2263.

Author: lkuper

src/test/run-pass/regions-fn-subtyping.rs

@@ -0,0 +1,24 @@
+//xfail-test
+
+// Issue #2263.
+
+// Should pass region checking.
+fn ok(f: fn@(x: &uint)) {
+    // Here, g is a function that can accept a uint pointer with
+    // lifetime r, and f is a function that can accept a uint pointer
+    // with any lifetime.  The assignment g = f should be OK (i.e., f
+    // should be a subtype of g), because f can be used in any context
+    // that expects g's type.  But this currently fails.
+    let mut g: fn@(y: &r.uint) = fn@(x: &r.uint) { };
+    g = f;
+}
+
+// This version is the same as above, except that here, g's type is
+// inferred.
+fn ok_inferred(f: fn@(x: &uint)) {
+    let mut g = fn@(x: &r.uint) { };
+    g = f;
+}
+
+fn main() {
+}