Support for a.b.c.d extract property sequence.

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

Index: pkg/analyzer/lib/src/summary/link.dart
diff --git a/pkg/analyzer/lib/src/summary/link.dart b/pkg/analyzer/lib/src/summary/link.dart
index a4b896dd97198bba49ec40695821f1fd7ed2a6e6..3d8068a5a14fdd32ffb94e19932065635ca01e13 100644
--- a/pkg/analyzer/lib/src/summary/link.dart
+++ b/pkg/analyzer/lib/src/summary/link.dart
@@ -3277,7 +3277,7 @@ class ParameterElementForLink implements ParameterElementImpl {
  * linking.
  */
 abstract class PropertyAccessorElementForLink
-    implements PropertyAccessorElementImpl {
+    implements PropertyAccessorElementImpl, ReferenceableElementForLink {
   void link(CompilationUnitElementInBuildUnit compilationUnit);
 }
 
@@ -3334,6 +3334,15 @@ class PropertyAccessorElementForLink_Variable
   PropertyAccessorElementForLink_Variable(this._variable, this.isSetter);
 
   @override
+  DartType get asStaticType => returnType;
+
+  @override
+  TypeInferenceNode get asTypeInferenceNode {
+    // TODO(scheglov) is this correct?

[Paul Berry, 2016/04/15 21:15:52]

Yes, I believe this is correct, but only because of a shortcut I took earlier in
the linker implementation.  We always call asTypeInferenceNode on the return
value of getContainedName(), and getContainedName() never returns accessors; it
returns top level variable elements or fields.

This is awkward and not really in line with Dart semantics; really
getContainedName() should return the accessor, and then
PropertyAccessorElementForLink_Variable should return
_variable._typeInferenceNode.

But I think we can wait until a future CL to clean this up :)

+    return null;
+  }
+
+  @override
   Element get enclosingElement => _variable.enclosingElement;
 
   @override
@@ -3381,6 +3390,19 @@ class PropertyAccessorElementForLink_Variable
     return const [];
   }
 
+  ReferenceableElementForLink getContainedName(String name) {
+    DartType type = returnType;
+    if (type is InterfaceType) {
+      PropertyAccessorElement getter =
+          type.lookUpGetter(name, _variable.compilationUnit.library);
+      print('getter: $getter');

[Paul Berry, 2016/04/15 21:15:52]

Looks like temporary debugging code; should be removed before committing.

+      if (getter is PropertyAccessorElementForLink) {
+        return getter;
+      }
+    }
+    return new NonstaticMemberElementForLink(null);
+  }
+
   @override
   bool isAccessibleIn(LibraryElement library) =>
       !Identifier.isPrivateName(name) || identical(this.library, library);
@@ -4077,6 +4099,14 @@ class VariableElementForLink
       DynamicTypeImpl.instance;
 
   ReferenceableElementForLink getContainedName(String name) {
+    DartType type = asStaticType;
+    if (type is InterfaceType) {
+      PropertyAccessorElement getter =
+          type.lookUpGetter(name, compilationUnit.library);
+      if (getter is PropertyAccessorElementForLink) {
+        return getter;
+      }
+    }
     return new NonstaticMemberElementForLink(_constNode);
   }