fixes #219, able to compile multiple entry points

test/codegen/expect/expect.js

 dart_library.library('expect', null, /* Imports */[
   "dart_runtime/dart",
   'dart/core'
 ], /* Lazy imports */[
 ], function(exports, dart, core) {
   'use strict';
   let dartx = dart.dartx;
   class Expect extends core.Object {
     static _truncateString(string, start, end, length) {
       if (dart.notNull(end) - dart.notNull(start) > dart.notNull(length)) {
@@ skipping 48 matching lines @@
       }
       return null;
     }
     static equals(expected, actual, reason) {
       if (reason === void 0)
         reason = null;
       if (dart.equals(expected, actual))
         return;
       let msg = Expect._getMessage(reason);
       if (typeof expected == 'string' && typeof actual == 'string') {
-        let stringDifference = Expect._stringDifference(dart.as(expected, core.String), dart.as(actual, core.String));
+        let stringDifference = Expect._stringDifference(dart.as(dart.as(dart.as(expected, core.String), core.String), core.String), dart.as(dart.as(dart.as(actual, core.String), core.String), core.String));

[Jennifer Messerly, 2015/07/15 21:45:15]

Eeeeep. We appear to be mutating the AST. Investigating...

[Jennifer Messerly, 2015/07/15 22:31:35]

aha, so this is the problem we knew we were going to hit if we reuse the same
analysis context, CoercionReifier mutates the AST. We're generating expect.dart
twice because codegen_test fires up two BatchCompilers on the same analysis
context.

this is super tricky to actually fix =| ... AstCloner doesn't work because we
lose attachment to the element model. I'm probably going to put in a hack for
the short term, since the bug already existed.

         if (stringDifference != null) {
           Expect._fail(`Expect.equals(${stringDifference}${msg}) fails.`);
         }
       }
       Expect._fail(`Expect.equals(expected: <${expected}>, actual: <${actual}>${msg}) fails.`);
     }
     static isTrue(actual, reason) {
       if (reason === void 0)
         reason = null;
       if (dart.notNull(_identical(actual, true)))
@@ skipping 252 matching lines @@
   dart.setSignature(AssumeDynamic, {
     constructors: () => ({AssumeDynamic: [AssumeDynamic, []]})
   });
   // Exports:
   exports.Expect = Expect;
   exports.ExpectException = ExpectException;
   exports.NoInline = NoInline;
   exports.TrustTypeAnnotations = TrustTypeAnnotations;
   exports.AssumeDynamic = AssumeDynamic;
 });