fix #30591, ensure all extension methods are generated

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 945 matching lines @@
 
     // Emit things that come after the ES6 `class ... { ... }`.
     var jsPeerNames = _getJSPeerNames(classElem);
     JS.Statement deferredBaseClass =
         _setBaseClass(classElem, className, jsPeerNames, body);
 
     var finishGenericTypeTest = _emitClassTypeTests(classElem, className, body);
 
     _emitVirtualFieldSymbols(classElem, body);
     _emitClassSignature(methods, allFields, classElem, ctors, className, body);
+    _initExtensionSymbols(classElem, methods, fields);
     _defineExtensionMembers(className, body);
     _emitClassMetadata(node.metadata, className, body);
 
     JS.Statement classDef = _statement(body);
 
     var typeFormals = classElem.typeParameters;
     if (typeFormals.isNotEmpty) {
       classDef = _defineClassTypeArguments(
           classElem, typeFormals, classDef, className, deferredBaseClass);
     }
@@ skipping 999 matching lines @@
     if (options.emitMetadata && metadata.isNotEmpty) {
       body.add(js.statement('#[#.metadata] = () => #;', [
         className,
         _runtimeModule,
         new JS.ArrayInitializer(
             new List<JS.Expression>.from(metadata.map(_instantiateAnnotation)))
       ]));
     }
   }
 
+  /// Ensure `dartx.` symbols we will use are present.
+  void _initExtensionSymbols(ClassElement classElem,
+      List<MethodDeclaration> methods, List<FieldDeclaration> fields) {
+    if (_extensionTypes.hasNativeSubtype(classElem.type)) {
+      for (var m in methods) {
+        if (!m.isAbstract &&
+            !m.isStatic &&
+            resolutionMap.elementDeclaredByMethodDeclaration(m).isPublic) {
+          _declareMemberName(m.element, useExtension: true);

[Jennifer Messerly, 2017/08/31 21:00:48]

FYI, this is mostly the original code, restored from prior to my extension
symbol CL.

The only change is the `_declareMemberName` lines, we used to gather up
non-symbolized names for the `dart.defineExtensionNames` runtime call, now we
just make sure the dartx.<name> is generated.

+        }
+      }
+      for (var fieldDecl in fields) {
+        if (!fieldDecl.isStatic) {
+          for (var field in fieldDecl.fields.variables) {
+            var e = field.element as FieldElement;
+            if (e.isPublic) {
+              _declareMemberName(e.getter, useExtension: true);
+            }
+          }
+        }
+      }
+    }
+  }
+
   /// If a concrete class implements one of our extensions, we might need to
   /// add forwarders.
   void _defineExtensionMembers(
       JS.Expression className, List<JS.Statement> body) {
     void emitExtensions(
         JS.Expression target, Iterable<ExecutableElement> extensions) {
       if (extensions.isEmpty) return;
 
       var names = extensions
           .map((e) => _declareMemberName(e, useExtension: false))
@@ skipping 4103 matching lines @@
   '~/': 'floorDivide',
   '*': 'times',
   '%': 'modulo',
   '|': 'bitOr',
   '^': 'bitXor',
   '&': 'bitAnd',
   '<<': 'leftShift',
   '>>': 'rightShift',
   '~': 'bitNot'
 };