implement user-defined nSM, Object members on functions

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;
@@ skipping 237 matching lines @@
     // any nodes.
     var nodes = new HashMap<Element, AstNode>.identity();
     var sdkBootstrappingFns = new List<FunctionElement>();
     for (var unit in compilationUnits) {
       if (_isDartRuntime(unit.element.library)) {
         sdkBootstrappingFns.addAll(unit.element.functions);
       }
       _collectElements(unit, nodes);
     }
     _loader = new ElementLoader(nodes);
+    if (compilationUnits.isNotEmpty) {
+      _constField = new ConstFieldVisitor(types,
+          dummySource: compilationUnits.first.element.source);
+    }
 
     // Add implicit dart:core dependency so it is first.
     emitLibraryName(dartCoreLibrary);
 
     // Emit SDK bootstrapping functions first, if any.
     sdkBootstrappingFns.forEach(_emitDeclaration);
 
     // Visit each compilation unit and emit its code.
     //
     // NOTE: declarations are not necessarily emitted in this order.
     // Order will be changed as needed so the resulting code can execute.
     // This is done by forward declaring items.
-    compilationUnits.forEach(visitCompilationUnit);
+    compilationUnits.forEach(_finishDeclarationsInUnit);
 
     // Declare imports
     _finishImports(items);
 
     // Discharge the type table cache variables and
     // hoisted definitions.
     items.addAll(_typeTable.discharge());
 
     // Add the module's code (produced by visiting compilation units, above)
     _copyAndFlattenBlocks(items, _moduleItems);
@@ skipping 151 matching lines @@
       return _visit(node);
     });
 
     if (item != null) _moduleItems.add(item);
   }
 
   void _declareBeforeUse(Element e) {
     _loader.declareBeforeUse(e, _emitDeclaration);
   }
 
-  @override
-  void visitCompilationUnit(CompilationUnit unit) {
-    _constField = new ConstFieldVisitor(types, unit.element.source);
-
+  void _finishDeclarationsInUnit(CompilationUnit unit) {
+    // NOTE: this method isn't the right place to initialize
+    // per-compilation-unit state. Declarations can be visited out of order,
+    // this is only to catch things that haven't been emitted yet.
+    //
+    // See _emitDeclaration.
     for (var declaration in unit.declarations) {
       var element = declaration.element;
       if (element != null) {
         _emitDeclaration(element);
       } else {
         declaration.accept(this);
       }
     }
     for (var directive in unit.directives) {
       directive.accept(this);
@@ skipping 3779 matching lines @@
   /// For example `null.toString()` is legal in Dart, so we need to generate
   /// that as `dart.toString(obj)`.
   bool _isObjectMemberCall(Expression target, String memberName) {
     if (!isObjectMember(memberName)) {
       return false;
     }
 
     // Check if the target could be `null`, is dynamic, or may be an extension
     // native type. In all of those cases we need defensive code generation.
     var type = getStaticType(target);
+
     return isNullable(target) ||
+        _targetIsFunction(target) ||
         type.isDynamic ||
         (_extensionTypes.hasNativeSubtype(type) && target is! SuperExpression);
   }
 
+  bool _targetIsFunction(Expression expr) {
+    Element element = null;
+    if (expr is PropertyAccess) {

[vsm, 2016/06/16 23:41:13]

Is this sufficient?  I.e., what about FunctionExpressions or other expressions
with a FunctionType?

[Jennifer Messerly, 2016/06/16 23:44:14]

I think those should be handled by isNullable (I started by taking this code
from isNullable)... mainly I wanted to break the "return true" branch. But
you're right, checking for function types would be *way* simpler. Thanks, I'll
fix that. :)

+      element = expr.propertyName.staticElement;
+    } else if (expr is Identifier) {
+      element = expr.staticElement;
+    }
+    return element is FunctionElement || element is MethodElement;
+  }
+
   /// Shared code for [PrefixedIdentifier] and [PropertyAccess].
   JS.Expression _emitAccess(
       Expression target, SimpleIdentifier memberId, DartType resultType) {
     Element member = memberId.staticElement;
     if (member is PropertyAccessorElement) {
       member = (member as PropertyAccessorElement).variable;
     }
     String memberName = memberId.name;
     var typeArgs = _getTypeArgs(member, resultType);
 
@@ skipping 873 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';