Fix bad generate-at-use-site.

tests/language/pure_function2_test.dart

+// Copyright (c) 2014, 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.
+
+import "package:expect/expect.dart";
+
+// Regression test for issue 17483.
+
+confuse(x) {
+  if (new DateTime.now().millisecondsSinceEpoch == 42) return confuse(x);
+  return x;
+}
+
+foo(trace) {
+  trace.add("foo");
+  return "foo";
+}
+bar(trace) {
+  trace.add("bar");
+  return "bar";
+}
+
+main() {
+  var f = confuse(foo);
+  var b = confuse(bar);
+
+  var trace = [];
+  // Dart2js must keep the order of t1 and t2.
+  var t1 = f(trace);
+  var t2 = b(trace);
+  var t3 = identical(t2, "foo");
+  var t4 = trace.add(t1);
+  trace.add(t3);
+  trace.add(t3);
+  Expect.listEquals(["foo", "bar", "foo", false, false], trace);
+}