fix #29530, field metadata generation

pkg/dev_compiler/lib/src/compiler/code_generator.dart

 // Copyright (c) 2015, 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 'dart:collection' show HashMap, HashSet;
 import 'dart:math' show min, max;
 
 import 'package:analyzer/analyzer.dart' hide ConstantEvaluator;
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 2940 matching lines @@
     return _emitAnnotatedResult(typeName, metadata);
   }
 
   JS.Expression _emitFieldSignature(DartType type,
       {List<Annotation> metadata, bool isFinal: true}) {
     var args = [_emitType(type)];
     if (options.emitMetadata && metadata != null && metadata.isNotEmpty) {
       args.add(new JS.ArrayInitializer(
           metadata.map(_instantiateAnnotation).toList()));
     }
-    return _callHelper(isFinal ? 'finalFieldType(#)' : 'fieldType(#)', args);
+    return _callHelper(isFinal ? 'finalFieldType(#)' : 'fieldType(#)', [args]);
   }
 
   JS.ArrayInitializer _emitTypeNames(
       List<DartType> types, List<FormalParameter> parameters,
       {bool nameType: true, bool hoistType: true}) {
     var result = <JS.Expression>[];
     for (int i = 0; i < types.length; ++i) {
       var metadata = parameters != null
           ? _parameterMetadata(parameters[i])
           : <Annotation>[];
@@ skipping 3165 matching lines @@
   if (targetIdentifier.staticElement is! PrefixElement) return false;
   var prefix = targetIdentifier.staticElement as PrefixElement;
 
   // The library the prefix is referring to must come from a deferred import.
   var containingLibrary = resolutionMap
       .elementDeclaredByCompilationUnit(target.root as CompilationUnit)
       .library;
   var imports = containingLibrary.getImportsWithPrefix(prefix);
   return imports.length == 1 && imports[0].isDeferred;
 }