Map malformed function result type and malformed function parameter type to

tests/language/src/Prefix16Test.dart

Index: tests/language/src/Prefix16Test.dart
===================================================================
--- tests/language/src/Prefix16Test.dart	(revision 6753)
+++ tests/language/src/Prefix16Test.dart	(working copy)
@@ -2,13 +2,47 @@
 // 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.
 //
-// Unresolved symbols should be reported as an error.
+// Unresolved imported symbols are handled differently in production mode and
+// check modes. In this test, the function myFunc is malformed, because
+// lib12.Library13 is not resolved.
+// In checked mode, the assignment type check throws a run time type error.
+// In production, no assignment type checks are performed.
 
 #library("Prefix16NegativeTest.dart");
 #import("library12.dart", prefix:"lib12");
 
 typedef lib12.Library13 myFunc(lib12.Library13 param);
 
+isCheckedMode() {
+  try {
+    var i = 1;
+    String s = i;
+    return false;
+  } catch(var e) {
+    return true;
+  }
+}
+
 main() {
-  myFunc i = 0;
+  {
+    bool got_type_error = false;
+    try {
+      myFunc i = 0;
+    } catch (TypeError error) {
+      got_type_error = true;
+    }
+    // Type error in checked mode only.
+    Expect.isTrue(got_type_error == isCheckedMode());
+  }
+  {
+    bool got_type_error = false;
+    try {
+      // In production mode, malformed myFunc is mapped to (Dynamic) => Dynamic.
+      Expect.isTrue(((int x) => x) is myFunc);
+    } catch (TypeError error) {
+      got_type_error = true;
+    }
+    // Type error in checked mode only.
+    Expect.isTrue(got_type_error == isCheckedMode());
+  }
 }