Capturing for loop variables correctly

tests/language/src/For2Test.dart

+// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+// Dart test program for testing for statement which captures loop variable.
+
+var f;
+
+main() {
+  // Capture the loop variable, ensure we capture the right value.
+  for (int i = 0; i < 10; i++) {
+    if (i == 7) {
+      f = () => "i = $i";
+    }
+  }
+  Expect.equals("i = 7", f());
+
+  // There is only one instance of k. The captured variable continues
+  // to change.
+  int k;
+  for (k = 0; k < 10; k++) {
+    if (k == 7) {
+      f = () => "k = $k";
+    }
+  }
+  Expect.equals("k = 10", f());
+
+  // l gets modified after it's captured. n++ is executed on the
+  // newly introduced instance of n (i.e. the instance of the loop
+  // iteration after the value is captured).
+  for (int n = 0; n < 10; n++) {
+    var l = n;
+    if (l == 7) {
+      f = () => "l = $l, n = 7";
+    }
+    l++;
+  }
+  Expect.equals("l = 8, n = 7", f());
+}