Support for AwaitExpression in unlinked expressions.

pkg/analyzer/lib/src/summary/link.dart

 // Copyright (c) 2016, 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.
 
 /**
  * This library is capable of producing linked summaries from unlinked
  * ones (or prelinked ones).  It functions by building a miniature
  * element model to represent the contents of the summaries, and then
  * scanning the element model to gather linked information and adding
  * it to the summary data structures.
@@ skipping 2210 matching lines @@
           break;
         case UnlinkedExprOperation.assignToRef:
           _doAssignToRef();
           break;
         case UnlinkedExprOperation.assignToProperty:
           _doAssignToProperty();
           break;
         case UnlinkedExprOperation.assignToIndex:
           _doAssignToIndex();
           break;
+        case UnlinkedExprOperation.await:
+          _doAwait();
+          break;
         case UnlinkedExprOperation.extractIndex:
           _doExtractIndex();
           break;
         case UnlinkedExprOperation.invokeMethodRef:
           _doInvokeMethodRef();
           break;
         case UnlinkedExprOperation.invokeMethod:
           _doInvokeMethod();
           break;
         case UnlinkedExprOperation.cascadeSectionBegin:
@@ skipping 115 matching lines @@
     } else if (isIncrementOrDecrement(operator)) {
       // TODO(scheglov) implement
       stack.add(DynamicTypeImpl.instance);
     } else {
       stack.removeLast();
       // TODO(scheglov) implement
       stack.add(DynamicTypeImpl.instance);
     }
   }
 
+  void _doAwait() {
+    DartType type = stack.removeLast();
+    DartType typeArgument = linker.typeSystem
+        .mostSpecificTypeArgument(type, linker.typeProvider.futureType);
+    typeArgument = _dynamicIfNull(typeArgument);
+    stack.add(typeArgument);

[Paul Berry, 2016/11/29 19:15:57]

Do we need to flatten futures here?  The spec says that the static type of an
await expression is flattened.

[scheglov, 2016/11/29 19:39:13]

Done.

+  }
+
   void _doConditional() {
     DartType elseType = stack.removeLast();
     DartType thenType = stack.removeLast();
     stack.removeLast();
     DartType type = _leastUpperBound(thenType, elseType);
     type = _dynamicIfNull(type);
     stack.add(type);
   }
 
   void _doExtractIndex() {
@@ skipping 1030 matching lines @@
       _linkedLibrary.exportDependencies.map(_getDependency).toList();
 
   @override
   String get identifier => _absoluteUri.toString();
 
   @override
   List<LibraryElementForLink> get importedLibraries => _importedLibraries ??=
       _linkedLibrary.importDependencies.map(_getDependency).toList();
 
   @override
-  bool get isDartAsync => _absoluteUri == 'dart:async';
+  bool get isDartAsync => _absoluteUri.toString() == 'dart:async';
 
   @override
-  bool get isDartCore => _absoluteUri == 'dart:core';
+  bool get isDartCore => _absoluteUri.toString() == 'dart:core';
 
   /**
    * If this library is part of the build unit being linked, return the library
    * cycle it is part of.  Otherwise return `null`.
    */
   LibraryCycleForLink get libraryCycleForLink;
 
   @override
   String get name {
     return _definingUnlinkedUnit.libraryName;
@@ skipping 1666 matching lines @@
    * there are no type parameters in scope.
    */
   TypeParameterizedElementMixin get _typeParameterContext;
 
   @override
   noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
 
   @override
   String toString() => '$enclosingElement.$name';
 }