Extract modelType out of ModelElement (#2583)

* clean up element types and add display aliases test

* Everything except the actual change I want to make

* Fix tests and update templates

* dartfmt

* remove scaffolding

* begin extraction

* Exclude InterfaceType.  Hacky.

* refactor continuing

* dartfmt, finish modelType extraction

* todo:ignore and no dynamic

* fix it all

* cleanup

* dartfmt and review comments

Author: jcollins-g

lib/src/model/accessor.dart

@@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:analyzer/dart/element/element.dart';
-import 'package:analyzer/src/dart/element/member.dart' show Member;
+import 'package:analyzer/src/dart/element/member.dart' show ExecutableMember;
 import 'package:dartdoc/src/element_type.dart';
 import 'package:dartdoc/src/model/model.dart';
 import 'package:dartdoc/src/render/source_code_renderer.dart';
@@ -16,11 +16,18 @@ class Accessor extends ModelElement implements EnclosedElement {
 
   Accessor(PropertyAccessorElement element, Library library,
       PackageGraph packageGraph,
-      [Member /*?*/ originalMember])
+      [ExecutableMember /*?*/ originalMember])
       : super(element, library, packageGraph, originalMember);
 
   @override
-  CallableElementTypeMixin get modelType => super.modelType;
+  PropertyAccessorElement get element => super.element;
+
+  @override
+  ExecutableMember get originalMember => super.originalMember;
+
+  CallableElementTypeMixin _modelType;
+  CallableElementTypeMixin get modelType => _modelType ??=
+      ElementType.from((originalMember ?? element).type, library, packageGraph);
 
   bool get isSynthetic => element.isSynthetic;
 
@@ -31,7 +38,7 @@ class Accessor extends ModelElement implements EnclosedElement {
   // The [enclosingCombo] where this element was defined.
   GetterSetterCombo get definingCombo {
     if (_definingCombo == null) {
-      var variable = (element as PropertyAccessorElement).variable;
+      var variable = element.variable;
       _definingCombo = ModelElement.fromElement(variable, packageGraph);
       assert(_definingCombo != null, 'Unable to find defining combo');
     }
@@ -85,12 +92,12 @@ class Accessor extends ModelElement implements EnclosedElement {
 
   @override
   ModelElement get enclosingElement {
-    if (_accessor.enclosingElement is CompilationUnitElement) {
+    if (element.enclosingElement is CompilationUnitElement) {
       return packageGraph.findButDoNotCreateLibraryFor(
-          _accessor.enclosingElement.enclosingElement);
+          element.enclosingElement.enclosingElement);
     }
 
-    return ModelElement.from(_accessor.enclosingElement, library, packageGraph);
+    return ModelElement.from(element.enclosingElement, library, packageGraph);
   }
 
   @override
@@ -104,9 +111,9 @@ class Accessor extends ModelElement implements EnclosedElement {
     return enclosingCombo.href;
   }
 
-  bool get isGetter => _accessor.isGetter;
+  bool get isGetter => element.isGetter;
 
-  bool get isSetter => _accessor.isSetter;
+  bool get isSetter => element.isSetter;
 
   @override
   String get kind => 'accessor';
@@ -118,8 +125,6 @@ class Accessor extends ModelElement implements EnclosedElement {
     _namePart ??= super.namePart.split('=').first;
     return _namePart;
   }
-
-  PropertyAccessorElement get _accessor => (element as PropertyAccessorElement);
 }
 
 /// A getter or setter that is a member of a [Container].
@@ -153,7 +158,7 @@ class ContainerAccessor extends Accessor with ContainerMember, Inheritable {
 
   ContainerAccessor.inherited(PropertyAccessorElement element, Library library,
       PackageGraph packageGraph, this._enclosingElement,
-      {Member originalMember})
+      {ExecutableMember originalMember})
       : super(element, library, packageGraph, originalMember) {
     _isInherited = true;
   }

lib/src/model/class.dart

@@ -334,8 +334,11 @@ class Class extends Container
   Iterable<DefinedElementType> get publicMixedInTypes =>
       model_utils.filterNonPublic(mixedInTypes);
 
+  DefinedElementType _modelType;
+
   @override
-  DefinedElementType get modelType => super.modelType;
+  DefinedElementType get modelType =>
+      _modelType ??= ElementType.from(element.thisType, library, packageGraph);
 
   /// Not the same as superChain as it may include mixins.
   /// It's really not even the same as ordinary Dart inheritance, either,

lib/src/model/constructor.dart

@@ -25,14 +25,17 @@ class Constructor extends ModelElement
     return super.characterLocation;
   }
 
+  @override
+  ConstructorElement get element => super.element;
+
   @override
   // TODO(jcollins-g): Revisit this when dart-lang/sdk#31517 is implemented.
   List<TypeParameter> get typeParameters =>
       (enclosingElement as Class).typeParameters;
 
   @override
   ModelElement get enclosingElement =>
-      ModelElement.from(_constructor.enclosingElement, library, packageGraph);
+      ModelElement.from(element.enclosingElement, library, packageGraph);
 
   @override
   String get filePath =>
@@ -61,7 +64,7 @@ class Constructor extends ModelElement
   }
 
   @override
-  bool get isConst => _constructor.isConst;
+  bool get isConst => element.isConst;
 
   bool get isUnnamedConstructor => name == enclosingElement.name;
 
@@ -70,13 +73,14 @@ class Constructor extends ModelElement
       'be removed as early as Dartdoc 1.0.0')
   bool get isDefaultConstructor => isUnnamedConstructor;
 
-  bool get isFactory => _constructor.isFactory;
+  bool get isFactory => element.isFactory;
 
   @override
   String get kind => 'constructor';
 
-  @override
-  DefinedElementType get modelType => super.modelType;
+  DefinedElementType _modelType;
+  DefinedElementType get modelType =>
+      _modelType ??= ElementType.from(element.type, library, packageGraph);
 
   String _name;
 
@@ -111,11 +115,9 @@ class Constructor extends ModelElement
 
   String get shortName {
     if (name.contains('.')) {
-      return name.substring(_constructor.enclosingElement.name.length + 1);
+      return name.substring(element.enclosingElement.name.length + 1);
     } else {
       return name;
     }
   }
-
-  ConstructorElement get _constructor => (element as ConstructorElement);
 }

lib/src/model/dynamic.dart

@@ -3,12 +3,16 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:analyzer/dart/element/element.dart';
+import 'package:dartdoc/dartdoc.dart';
 import 'package:dartdoc/src/model/model.dart';
 
 class Dynamic extends ModelElement {
   Dynamic(Element element, PackageGraph packageGraph)
       : super(element, null, packageGraph);
 
+  UndefinedElementType get modelType =>
+      throw UnimplementedError('(${element.runtimeType}) $element');
+
   /// [dynamic] is not a real object, and so we can't document it, so there
   /// can be nothing canonical for it.
   @override

lib/src/model/extension.dart

@@ -93,9 +93,6 @@ class Extension extends Container
     return _typeParameters;
   }
 
-  @override
-  ParameterizedElementType get modelType => super.modelType;
-
   List<ModelElement> _allModelElements;
   @override
   List<ModelElement> get allModelElements {

lib/src/model/extension_target.dart

@@ -2,6 +2,7 @@
 // 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.
 
+import 'package:dartdoc/src/element_type.dart';
 import 'package:dartdoc/src/model/model.dart';
 
 // TODO(jcollins-g): Mix-in ExtensionTarget on Method, ModelFunction, Typedef,
@@ -27,6 +28,8 @@ mixin ExtensionTarget on ModelElement {
     return _potentiallyApplicableExtensions;
   }
 
+  ElementType get modelType;
+
   List<Extension> get potentiallyApplicableExtensionsSorted =>
       potentiallyApplicableExtensions.toList()..sort(byName);
 }

lib/src/model/field.dart

@@ -23,7 +23,6 @@ class Field extends ModelElement
     assert(getter != null || setter != null);
     if (getter != null) getter.enclosingCombo = this;
     if (setter != null) setter.enclosingCombo = this;
-    _setModelType();
   }
 
   factory Field.inherited(
@@ -192,12 +191,6 @@ class Field extends ModelElement
     return _sourceCode;
   }
 
-  void _setModelType() {
-    if (hasGetter) {
-      setModelType(getter.modelType);
-    }
-  }
-
   @override
   Inheritable get overriddenElement => null;
 }

lib/src/model/getter_setter_combo.dart

@@ -180,7 +180,6 @@ mixin GetterSetterCombo on ModelElement {
     return buffer.toString();
   }
 
-  @override
   ElementType get modelType {
     if (hasGetter) return getter.modelType.returnType;
     return setter.parameters.first.modelType;

lib/src/model/method.dart

@@ -4,7 +4,7 @@
 
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/source/line_info.dart';
-import 'package:analyzer/src/dart/element/member.dart' show Member;
+import 'package:analyzer/src/dart/element/member.dart' show ExecutableMember;
 import 'package:dartdoc/src/element_type.dart';
 import 'package:dartdoc/src/model/model.dart';
 
@@ -23,14 +23,14 @@ class Method extends ModelElement
 
   Method.inherited(MethodElement element, this._enclosingContainer,
       Library library, PackageGraph packageGraph,
-      {Member originalMember})
+      {ExecutableMember originalMember})
       : super(element, library, packageGraph, originalMember) {
     _isInherited = true;
     _calcTypeParameters();
   }
 
   void _calcTypeParameters() {
-    typeParameters = _method.typeParameters.map((f) {
+    typeParameters = element.typeParameters.map((f) {
       return ModelElement.from(f, library, packageGraph) as TypeParameter;
     }).toList();
   }
@@ -51,7 +51,7 @@ class Method extends ModelElement
   @override
   ModelElement get enclosingElement {
     _enclosingContainer ??=
-        ModelElement.from(_method.enclosingElement, library, packageGraph);
+        ModelElement.from(element.enclosingElement, library, packageGraph);
     return _enclosingContainer;
   }
 
@@ -60,7 +60,7 @@ class Method extends ModelElement
       '${enclosingElement.library.dirName}/${enclosingElement.name}/$fileName';
 
   String get fullkind {
-    if (_method.isAbstract) return 'abstract $kind';
+    if (element.isAbstract) return 'abstract $kind';
     return kind;
   }
 
@@ -88,13 +88,17 @@ class Method extends ModelElement
   }
 
   @override
-  bool get isStatic => _method.isStatic;
+  bool get isStatic => element.isStatic;
 
   @override
   String get kind => 'method';
 
   @override
-  CallableElementTypeMixin get modelType => super.modelType;
+  ExecutableMember get originalMember => super.originalMember;
+
+  CallableElementTypeMixin _modelType;
+  CallableElementTypeMixin get modelType => _modelType ??=
+      ElementType.from((originalMember ?? element).type, library, packageGraph);
 
   @override
   Method get overriddenElement {
@@ -112,7 +116,8 @@ class Method extends ModelElement
     return null;
   }
 
-  MethodElement get _method => (element as MethodElement);
+  @override
+  MethodElement get element => super.element;
 
   /// Methods can not be covariant; always returns false.
   @override

lib/src/model/model_element.dart

@@ -12,10 +12,9 @@ import 'package:analyzer/dart/element/type.dart' show FunctionType;
 import 'package:analyzer/source/line_info.dart';
 import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/dart/element/member.dart'
-    show ExecutableMember, Member, ParameterMember;
+    show ExecutableMember, Member;
 import 'package:collection/collection.dart';
 import 'package:dartdoc/src/dartdoc_options.dart';
-import 'package:dartdoc/src/element_type.dart';
 import 'package:dartdoc/src/model/documentation_comment.dart';
 import 'package:dartdoc/src/model/feature_set.dart';
 import 'package:dartdoc/src/model/model.dart';
@@ -143,7 +142,6 @@ abstract class ModelElement extends Canonicalization
   final Member /*?*/ _originalMember;
   final Library /*?*/ _library;
 
-  ElementType _modelType;
   String _rawDocs;
   Documentation __documentation;
   UnmodifiableListView<Parameter> _parameters;
@@ -984,45 +982,6 @@ abstract class ModelElement extends Canonicalization
   String get linkedParamsNoMetadataOrNames => _parameterRenderer
       .renderLinkedParams(parameters, showMetadata: false, showNames: false);
 
-  ElementType get modelType {
-    var element = this.element;
-    if (_modelType == null) {
-      // TODO(jcollins-g): Need an interface for a "member with a type" (or changed object model).
-      if (_originalMember != null &&
-          (_originalMember is ExecutableMember ||
-              _originalMember is ParameterMember)) {
-        if (_originalMember is ExecutableMember) {
-          _modelType = ElementType.from(
-              (_originalMember as ExecutableMember).type,
-              library,
-              packageGraph);
-        } else {
-          // ParameterMember
-          _modelType = ElementType.from(
-              (_originalMember as ParameterMember).type, library, packageGraph);
-        }
-      } else if (element is ClassElement) {
-        _modelType = ElementType.from(element.thisType, library, packageGraph);
-      } else if (element is TypeAliasElement) {
-        _modelType =
-            ElementType.from(element.aliasedType, library, packageGraph);
-      } else if (element is FunctionTypedElement) {
-        _modelType = ElementType.from(element.type, library, packageGraph);
-      } else if (element is ParameterElement) {
-        _modelType = ElementType.from(element.type, library, packageGraph);
-      } else if (element is PropertyInducingElement) {
-        _modelType = ElementType.from(element.type, library, packageGraph);
-      } else {
-        throw UnimplementedError('(${element.runtimeType}) $element');
-      }
-    }
-    return _modelType;
-  }
-
-  void setModelType(ElementType type) {
-    _modelType = type;
-  }
-
   String _name;
 
   @override