Abort tracing in type inference in the presence of await.

BUG= http://dartbug.com/22868 http://dartbug.com/22895
R=floitsch@google.com

Committed: https://code.google.com/p/dart/source/detail?r=44555

Reverted: https://code.google.com/p/dart/source/detail?r=44556

Review URL: https://codereview.chromium.org//1013803006

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@44573 260f80e4-7a28-3924-810f-c04153c831b5

pkg/compiler/lib/src/inferrer/concrete_types_inferrer.dart

@@ -2243,6 +2243,11 @@ class ConcreteTypesInferrer
     return result;
   }
 
+  ConcreteType registerAwait(Node node, ConcreteType argumentType) {
+    // TODO(polux): Properly handle await expressions.
+    return types.dynamicType;
+  }
+
   @override
   void setDefaultTypeOfParameter(ParameterElement parameter,
                                  ConcreteType type) {

pkg/compiler/lib/src/inferrer/node_tracer.dart

@@ -144,6 +144,10 @@ abstract class TracerVisitor<T extends TypeInformation>
     continueAnalyzing = false;
   }
 
+  void visitAwaitTypeInformation(AwaitTypeInformation info) {
+    bailout("Passed through await");
+  }
+
   void visitNarrowTypeInformation(NarrowTypeInformation info) {
     addNewEscapeInformation(info);
   }

pkg/compiler/lib/src/inferrer/simple_types_inferrer.dart

@@ -280,6 +280,12 @@ abstract class InferrerEngine<T, V extends TypeSystem>
                           SideEffects sideEffects,
                           bool inLoop);
 
+  /**
+   * Registers a call to await with an expression of type [argumentType] as
+   * argument.
+   */
+  T registerAwait(ast.Node node, T argumentType);
+
   /**
    * Notifies to the inferrer that [analyzedElement] can have return
    * type [newType]. [currentType] is the type the [InferrerVisitor]
@@ -1011,8 +1017,7 @@ class SimpleTypeInferrerVisitor<T>
 
   T visitAwait(ast.Await node) {
     T futureType = node.expression.accept(this);
-    // TODO(herhut): Return a better type here if possible.
-    return types.dynamicType;
+    return inferrer.registerAwait(node, futureType);
   }
 
   T visitStaticSend(ast.Send node) {

pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart

@@ -1128,6 +1128,14 @@ class TypeGraphInferrerEngine
     return info;
   }
 
+  TypeInformation registerAwait(ast.Node node, TypeInformation argument) {
+    AwaitTypeInformation info = new AwaitTypeInformation(types.currentMember,
+                                                         node);
+    info.addAssignment(argument);
+    types.allocatedTypes.add(info);
+    return info;
+  }
+
   TypeInformation registerCalledClosure(ast.Node node,
                                         Selector selector,
                                         TypeInformation closure,

pkg/compiler/lib/src/inferrer/type_graph_nodes.dart

@@ -1518,6 +1518,22 @@ abstract class TracedTypeInformation implements TypeInformation {
   }
 }
 
+class AwaitTypeInformation extends TypeInformation {
+  final ast.Node node;
+
+  AwaitTypeInformation(MemberTypeInformation context, this.node)
+      : super(context);
+
+  // TODO(22894): Compute a better type here.
+  TypeMask computeType(TypeGraphInferrerEngine inferrer) => safeType(inferrer);
+
+  String toString() => 'Await';
+
+  accept(TypeInformationVisitor visitor) {
+    return visitor.visitAwaitTypeInformation(this);
+  }
+}
+
 abstract class TypeInformationVisitor<T> {
   T visitNarrowTypeInformation(NarrowTypeInformation info);
   T visitPhiElementTypeInformation(PhiElementTypeInformation info);
@@ -1535,4 +1551,5 @@ abstract class TypeInformationVisitor<T> {
   T visitMemberTypeInformation(MemberTypeInformation info);
   T visitParameterTypeInformation(ParameterTypeInformation info);
   T visitClosureTypeInformation(ClosureTypeInformation info);
+  T visitAwaitTypeInformation(AwaitTypeInformation info);
 }

tests/compiler/dart2js_extra/22868_test.dart

@@ -0,0 +1,12 @@
+// 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.
+
+// Regression test for http://dartbug.com/22868/
+// Ensure that the closure tracer properly handles await.
+
+main() async {
+  var closures = [(x, y) => x + y];
+  print(((await closures)[0])(4, 2));
+}
+

tests/compiler/dart2js_extra/22895.dart

@@ -0,0 +1,11 @@
+// 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.
+
+// Regression test for http://dartbug.com/22895/
+// Ensure that the type graph is retained in presence of await.
+
+main() async {
+  var closures = [(x, y) => x + y];
+  print(((await closures)[0])(4, 2));
+}