Correctly compile unresolved for-in loops.

dart/tests/compiler/dart2js/bad_loop_test.dart

+// Copyright (c) 2013, 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';
+import 'memory_source_file_helper.dart';
+
+import '../../../sdk/lib/_internal/compiler/compiler.dart'
+       show Diagnostic;
+
+main() {
+  Uri cwd = getCurrentDirectory();
+  Uri script = cwd.resolve(nativeToUriPath(new Options().script));
+  Uri libraryRoot = script.resolve('../../../sdk/');
+  Uri packageRoot = script.resolve('./packages/');
+
+  MemorySourceFileProvider.MEMORY_SOURCE_FILES = MEMORY_SOURCE_FILES;
+  var provider = new MemorySourceFileProvider();
+  int warningCount = 0;
+  int errorCount = 0;
+  void diagnosticHandler(Uri uri, int begin, int end,
+                         String message, Diagnostic kind) {
+    if (kind == Diagnostic.VERBOSE_INFO) {
+      return;
+    }
+    if (kind == Diagnostic.ERROR) {
+      errorCount++;
+    } else if (kind == Diagnostic.WARNING) {
+      warningCount++;
+    } else {
+      throw 'unexpected diagnostic $kind: $message';
+    }
+  }
+
+  Compiler compiler = new Compiler(provider.readStringFromUri,
+                                   (name, extension) => null,
+                                   diagnosticHandler,
+                                   libraryRoot,
+                                   packageRoot,
+                                   ['--analyze-only']);
+  compiler.run(new Uri('memory:main.dart'));
+  Expect.isTrue(compiler.compilationFailed);
+  Expect.equals(5, errorCount);
+  Expect.equals(1, warningCount);
+}
+
+const Map MEMORY_SOURCE_FILES = const {
+  'main.dart': """
+main() {
+  for (var x, y in []) {
+  }
+
+  for (var x = 10 in []) {
+  }
+
+  for (x.y in []) { // Also causes a warning "x unresolved".
+  }
+
+  for ((){}() in []) {
+  }
+
+  for (1 in []) {
+  }
+}
+"""
+};