Use property accessor elements for type inference rather than field elements.

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 301 matching lines @@
   ConstructorElementForLink get unnamedConstructor;
 
   @override
   ReferenceableElementForLink getContainedName(String name) {
     if (_containedNames == null) {
       _containedNames = <String, ReferenceableElementForLink>{};
       // TODO(paulberry): what's the correct way to handle name conflicts?
       for (ConstructorElementForLink constructor in constructors) {
         _containedNames[constructor.name] = constructor;
       }
-      for (FieldElementForLink field in fields) {
-        // TODO(paulberry): do we need to handle nonstatic fields for
-        // consistent behavior with erroneous code?
-        if (field.isStatic) {
-          _containedNames[field.name] = field;
-        }
-      }
       for (PropertyAccessorElementForLink accessor in accessors) {
-        if (accessor.isStatic && !accessor.isSynthetic) {
-          // TODO(paulberry): add synthetic elements too?
+        if (accessor.isStatic) {
           _containedNames[accessor.name] = accessor;
         }
       }
       // TODO(paulberry): add methods.
     }
     return _containedNames.putIfAbsent(
         name, () => UndefinedElementForLink.instance);
   }
 
   /**
@@ skipping 54 matching lines @@
                   this, unlinkedExecutable, syntheticVariable);
           _accessors.add(accessor);
           if (unlinkedExecutable.kind == UnlinkedExecutableKind.getter) {
             syntheticVariable._getter = accessor;
           } else {
             syntheticVariable._setter = accessor;
           }
         }
       }
       for (FieldElementForLink_ClassField field in fields) {
-        _accessors
-            .add(new PropertyAccessorElementForLink_Variable(field, false));
+        _accessors.add(field.getter);
         if (!field.isConst && !field.isFinal) {
-          _accessors
-              .add(new PropertyAccessorElementForLink_Variable(field, true));
+          _accessors.add(field.setter);
         }
       }
     }
     return _accessors;
   }
 
   @override
   List<ConstructorElementForLink> get constructors {
     if (_constructors == null) {
       _constructors = <ConstructorElementForLink>[];
@@ skipping 835 matching lines @@
         if (superClass != null && !superClass.isObject) {
           ConstructorElementForLink unnamedConstructor =
               superClass.unnamedConstructor;
           safeAddDependency(unnamedConstructor?._constNode);
         }
       }
       for (FieldElementForLink field in enclosingClass.fields) {
         // Note: non-static const isn't allowed but we handle it anyway so
         // that we won't be confused by incorrect code.
         if ((field.isFinal || field.isConst) && !field.isStatic) {
-          safeAddDependency(field.asConstVariable);
+          safeAddDependency(field.getter.asConstVariable);
         }
       }
       for (ParameterElementForLink parameterElement
           in constructorElement.parameters) {
         safeAddDependency(parameterElement._constNode);
       }
     }
     return dependencies;
   }
 
@@ skipping 1174 matching lines @@
       return DynamicTypeImpl.instance;
     }
     return type;
   }
 }
 
 /**
  * Element representing a field resynthesized from a summary during
  * linking.
  */
-abstract class FieldElementForLink
-    implements FieldElement, ReferenceableElementForLink {}
+abstract class FieldElementForLink implements FieldElement {
+  @override
+  PropertyAccessorElementForLink get getter;
+
+  @override
+  PropertyAccessorElementForLink get setter;
+}
 
 /**
  * Specialization of [FieldElementForLink] for class fields.
  */
 class FieldElementForLink_ClassField extends VariableElementForLink
     implements FieldElementForLink {
   @override
   final ClassElementForLink_Class enclosingElement;
 
+  PropertyAccessorElementForLink_Variable _getter;
+  PropertyAccessorElementForLink_Variable _setter;
+
   /**
    * If this is an instance field, the type that was computed by
    * [InstanceMemberInferrer] (if any).  Otherwise `null`.
    */
   DartType _inferredInstanceType;
 
   FieldElementForLink_ClassField(ClassElementForLink_Class enclosingElement,
       UnlinkedVariable unlinkedVariable)
       : enclosingElement = enclosingElement,
         super(unlinkedVariable, enclosingElement.enclosingElement);
 
   @override
+  PropertyAccessorElementForLink_Variable get getter =>
+      _getter ??= new PropertyAccessorElementForLink_Variable(this, false);
+
+  @override
   bool get isStatic => unlinkedVariable.isStatic;
 
   @override
+  PropertyAccessorElementForLink_Variable get setter {
+    if (!isConst && !isFinal) {
+      return _setter ??=
+          new PropertyAccessorElementForLink_Variable(this, true);
+    } else {
+      return null;
+    }
+  }
+
+  @override
   void set type(DartType inferredType) {
     assert(!isStatic);
     assert(_inferredInstanceType == null);
     _inferredInstanceType = inferredType;
   }
 
   @override
   TypeParameterizedElementForLink get _typeParameterContext => enclosingElement;
 
   /**
@@ skipping 23 matching lines @@
    * is an enum's `values` field.
    */
   final UnlinkedEnumValue unlinkedEnumValue;
 
   @override
   final ClassElementForLink_Enum enclosingElement;
 
   FieldElementForLink_EnumField(this.unlinkedEnumValue, this.enclosingElement);
 
   @override
-  ConstructorElementForLink get asConstructor => null;
-
-  @override
-  ConstVariableNode get asConstVariable {
-    // Even though enum fields are constants, there is no need to include them
-    // in the const dependency graph because they can't participate in a
-    // circularity.
-    return null;
-  }
-
-  @override
-  DartType get asStaticType => enclosingElement.type;
-
-  @override
-  TypeInferenceNode get asTypeInferenceNode => null;
-
-  @override
   bool get isStatic => true;
 
   @override
   bool get isSynthetic => false;
 
   @override
   String get name =>
       unlinkedEnumValue == null ? 'values' : unlinkedEnumValue.name;
 
   @override
-  DartType buildType(DartType getTypeArgument(int i),
-          List<int> implicitFunctionTypeIndices) =>
-      DynamicTypeImpl.instance;
-
-  @override
-  ReferenceableElementForLink getContainedName(String name) =>
-      UndefinedElementForLink.instance;
-
-  @override
   noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
 
   @override
   String toString() => '$enclosingElement.$name';
 }
 
 /**
  * Element representing a function-typed parameter resynthesied from a summary
  * during linking.
  */
@@ skipping 1007 matching lines @@
   @override
   final bool isSetter;
 
   final VariableElementForLink variable;
   FunctionTypeImpl _type;
   List<ParameterElement> _parameters;
 
   PropertyAccessorElementForLink_Variable(this.variable, this.isSetter);
 
   @override
+  ConstructorElementForLink get asConstructor => null;
+
+  @override
+  ConstVariableNode get asConstVariable => variable._constNode;
+
+  @override
+  DartType get asStaticType => returnType;
+
+  @override
+  TypeInferenceNode get asTypeInferenceNode => variable._typeInferenceNode;
+
+  @override
   Element get enclosingElement => variable.enclosingElement;
 
   @override
   bool get isGetter => !isSetter;
 
   @override
   bool get isStatic => variable.isStatic;
 
   @override
   bool get isSynthetic => true;
@@ skipping 30 matching lines @@
 
   @override
   FunctionTypeImpl get type => _type ??= new FunctionTypeImpl(this);
 
   @override
   List<TypeParameterElement> get typeParameters {
     // TODO(paulberry): is this correct for fields in generic classes?
     return const [];
   }
 
+  @override
+  DartType buildType(DartType getTypeArgument(int i),
+          List<int> implicitFunctionTypeIndices) =>
+      DynamicTypeImpl.instance;
+
   /**
    * Compute the type of the corresponding variable, which may depend on the
    * progress of type inference.
    */
   DartType computeVariableType() {
     if (variable.hasImplicitType &&
         !isStatic &&
         !variable.compilationUnit.isTypeInferenceComplete) {
       // This is an instance field and we are currently inferring types in the
       // library cycle containing it.  So we shouldn't use the inferred type
       // (even if we have already computed it), since that would lead to
       // non-deterministic type inference results.
       return DynamicTypeImpl.instance;
     } else {
       return variable.type;
     }
   }
 
   @override
+  ReferenceableElementForLink getContainedName(String name) =>
+      UndefinedElementForLink.instance;
+
+  @override
   bool isAccessibleIn(LibraryElement library) =>
       !Identifier.isPrivateName(name) || identical(this.library, library);
 
   @override
   void link(CompilationUnitElementInBuildUnit compilationUnit) {}
 
   @override
   noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
 
   @override
@@ skipping 762 matching lines @@
       if (type is InterfaceType) {
         Element result = type.lookUpGetter(name, compilationUnit.library);
         result ??= type.lookUpMethod(name, compilationUnit.library);
         return result;
       }
     }
     // TODO(scheglov): implement for propagated types
     return null;
   }
 }