Introduce FieldParameterElement.

frog/leg/elements/elements.dart

 // Copyright (c) 2012, 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.
 
 #library('elements');
 
 #import('../tree/tree.dart');
 #import('../scanner/scannerlib.dart');
 #import('../leg.dart');  // TODO(karlklose): we only need type.
 #import('../util/util.dart');
@@ skipping 28 matching lines @@
 class ElementKind {
   final String id;
   final int category;
 
   const ElementKind(String this.id, this.category);
 
   static final ElementKind VARIABLE =
     const ElementKind('variable', ElementCategory.VARIABLE);
   static final ElementKind PARAMETER =
     const ElementKind('parameter', ElementCategory.VARIABLE);
+  // Parameters in constructors that directly initialize fields. For example:
+  // [:A(this.field):].
+  static final ElementKind FIELD_PARAMETER =
+    const ElementKind('field_parameter', ElementCategory.VARIABLE);
   static final ElementKind FUNCTION =
     const ElementKind('function', ElementCategory.FUNCTION);
   static final ElementKind CLASS =
     const ElementKind('class', ElementCategory.CLASS);
   static final ElementKind FOREIGN =
     const ElementKind('foreign', ElementCategory.FUNCTION);
   static final ElementKind GENERATIVE_CONSTRUCTOR =
       const ElementKind('generative_constructor', ElementCategory.FACTORY);
   static final ElementKind FIELD =
     const ElementKind('field', ElementCategory.VARIABLE);
@@ skipping 285 matching lines @@
 
   bool isInstanceMember() {
     return isMember() && !modifiers.isStatic();
   }
 
   // Note: cachedNode.getBeginToken() will not be correct in all
   // cases, for example, for function typed parameters.
   Token position() => findMyName(variables.position());
 }
 
+/**
+ * Parameters in constructors that directly initialize fields. For example:
+ * [:A(this.field):].
+ */
+class FieldParameterElement extends VariableElement {
+  VariableElement fieldElement;
+
+  FieldParameterElement(SourceString name,
+                        this.fieldElement,
+                        VariableListElement variables,
+                        Element enclosing,
+                        Node node)
+      : super(name, variables, ElementKind.FIELD_PARAMETER, enclosing, node);
+}
+
 // This element represents a list of variable or field declaration.
 // It contains the node, and the type. A [VariableElement] always
 // references its [VariableListElement]. It forwards its
 // [computeType] and [parseNode] methods to this element.
 class VariableListElement extends Element {
   VariableDefinitions cachedNode;
   Type type;
   final Modifiers modifiers;
 
   VariableListElement(ElementKind kind,
@@ skipping 510 matching lines @@
     return result;
   }
 
   Node parseNode(DiagnosticListener l) => statement;
 
   bool get isSwitch() => statement is SwitchStatement;
 
   Token position() => statement.getBeginToken();
   String toString() => statement.toString();
 }