enable compatiblity with 1.18 SDKs

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';
 import 'package:analyzer/dart/ast/token.dart' show Token, TokenType;
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/ast/token.dart' show StringToken;
-//TODO(leafp): Remove deprecated dependency
-//ignore: DEPRECATED_MEMBER_USE
-import 'package:analyzer/src/generated/element.dart'
-    show DynamicTypeImpl, LocalVariableElementImpl;
+import 'package:analyzer/src/dart/element/element.dart'
+    show LocalVariableElementImpl;
+import 'package:analyzer/src/dart/element/type.dart' show DynamicTypeImpl;
 import 'package:analyzer/src/generated/engine.dart' show AnalysisContext;
 import 'package:analyzer/src/generated/resolver.dart'
     show TypeProvider, NamespaceBuilder;
 import 'package:analyzer/src/generated/type_system.dart'
     show StrongTypeSystemImpl;
 import 'package:analyzer/src/summary/summarize_elements.dart'
     show PackageBundleAssembler;
 import 'package:analyzer/src/task/strong/info.dart' show DynamicInvoke;
 import 'package:source_maps/source_maps.dart';
 import 'package:path/path.dart' show separator;
@@ skipping 256 matching lines @@
 
     // Optional: lower module format. Otherwise just return it.
     switch (options.moduleFormat) {
       case ModuleFormat.legacy:
         return new LegacyModuleBuilder().build(module);
       case ModuleFormat.node:
         return new NodeModuleBuilder().build(module);
       case ModuleFormat.es6:
         return module;
     }
+    return null; // unreachable. It is here to suppress a bogus Analyzer message
   }
 
   List<String> _getJSName(Element e) {
     if (findAnnotation(e.library, isPublicJSAnnotation) == null) {
       return null;
     }
 
     var libraryJSName = getAnnotationName(e.library, isPublicJSAnnotation);
     var libraryPrefix = <String>[];
     if (libraryJSName != null && libraryJSName.isNotEmpty) {
@@ skipping 1858 matching lines @@
 
   JS.Expression _emitFunctionTagged(JS.Expression fn, DartType type,
       {topLevel: false}) {
     var lazy = topLevel && !_typeIsLoaded(type);
     var typeRep = _emitFunctionType(type, definite: true);
     if (lazy) {
       return js.call('dart.lazyFn(#, () => #)', [fn, typeRep]);
     } else {
       return js.call('dart.fn(#, #)', [fn, typeRep]);
     }
-    throw 'Function has non function type: $type';
   }
 
   /// Emits an arrow FunctionExpression node.
   ///
   /// This should be used for all places in Dart's AST where FunctionExpression
   /// appears and the function is actually in an Expression context. These
   /// correspond to arrow functions in Dart.
   ///
   /// Contrast with [_emitFunction].
   @override
@@ skipping 2791 matching lines @@
 }
 
 bool isLibraryPrefix(Expression node) =>
     node is SimpleIdentifier && node.staticElement is PrefixElement;
 
 LibraryElement _getLibrary(AnalysisContext c, String uri) =>
     c.computeLibraryElement(c.sourceFactory.forUri(uri));
 
 bool _isDartRuntime(LibraryElement l) =>
     l.isInSdk && l.source.uri.toString() == 'dart:_runtime';