testsuite: Tweak tests for #3888

src/test/compile-fail/issue-3888.rs

@@ -8,14 +8,16 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// xfail-test
+// n.b. This should be a run-pass test, but for now I'm testing
-
+// that we don't see an "unknown scope" error.
 fn vec_peek<T>(v: &r/[T]) -> Option< (&r/T, &r/[T]) > {
     if v.len() == 0 {
         None
     } else {
+        let vec_len = v.len();
         let head = &v[0];
-        let tail = v.view(1, v.len());
+        // note: this *shouldn't* be an illegal borrow! See #3888
+        let tail = v.view(1, vec_len); //~ ERROR illegal borrow: borrowed value does not live long enough
         Some( (head, tail) )
     }
 }

src/test/run-pass/issue-3888-2.rs

@@ -0,0 +1,17 @@
+// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn vec_peek<T>(v: &r/[T]) -> &r/[T] {
+// This doesn't work, and should.
+//    v.view(1, 5)
+    vec::view(v, 1, 5)
+}
+
+fn main() {}