Make modelType/ElementType usage more consistent (#2573)

* 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

* Exclude InterfaceType.  Hacky.

Author: jcollins-g

lib/src/element_type.dart

@@ -62,10 +62,6 @@ abstract class ElementType extends Privacy {
 
   bool get canHaveParameters => false;
 
-  // TODO(jcollins-g): change clients of ElementType to use subtypes more consistently
-  // and eliminate createLinkedReturnTypeName (instead, using returnType.linkedName);
-  String createLinkedReturnTypeName() => linkedName;
-
   bool get isTypedef => false;
 
   String get linkedName;
@@ -90,7 +86,7 @@ abstract class ElementType extends Privacy {
   }
 
   /// An unmodifiable list of this element type's parameters.
-  List<Parameter> get parameters => const <Parameter>[];
+  List<Parameter> get parameters;
 
   DartType get instantiatedType;
 
@@ -149,22 +145,25 @@ class UndefinedElementType extends ElementType {
 
   @override
   String get linkedName => name;
+
+  @override
+  // TODO(jcollins-g): remove the need for an empty list here.
+  List<Parameter> get parameters => [];
 }
 
 /// A FunctionType that does not have an underpinning Element.
-class FunctionTypeElementType extends UndefinedElementType {
+class FunctionTypeElementType extends UndefinedElementType
+    with CallableElementTypeMixin {
   FunctionTypeElementType(DartType f, Library library,
       PackageGraph packageGraph, ElementType returnedFrom)
       : super(f, library, packageGraph, returnedFrom);
 
-  @override
-  FunctionType get type => super.type;
-
   @override
   List<Parameter> get parameters => type.parameters
       .map((p) => ModelElement.from(p, library, packageGraph) as Parameter)
       .toList(growable: false);
 
+  @override
   ElementType get returnType =>
       ElementType.from(type.returnType, library, packageGraph, this);
 
@@ -174,11 +173,7 @@ class FunctionTypeElementType extends UndefinedElementType {
     return _linkedName;
   }
 
-  @override
-  String createLinkedReturnTypeName() => returnType.linkedName;
-
   String _nameWithGenerics;
-
   @override
   String get nameWithGenerics {
     _nameWithGenerics ??= _renderer.renderNameWithGenerics(this);
@@ -216,7 +211,7 @@ class ParameterizedElementType extends DefinedElementType {
     return _nameWithGenerics;
   }
 
-  ElementTypeRenderer<ParameterizedElementType> get _renderer =>
+  ElementTypeRenderer<ElementType> get _renderer =>
       packageGraph.rendererFactory.parameterizedElementTypeRenderer;
 }
 
@@ -281,9 +276,6 @@ abstract class DefinedElementType extends ElementType {
     return _returnType;
   }
 
-  @override
-  String createLinkedReturnTypeName() => returnType.linkedName;
-
   Iterable<ElementType> _typeArguments;
 
   /// An unmodifiable list of this element type's parameters.
@@ -341,13 +333,14 @@ abstract class DefinedElementType extends ElementType {
 }
 
 /// Any callable ElementType will mix-in this class, whether anonymous or not.
-abstract class CallableElementTypeMixin implements ParameterizedElementType {
-  @override
+abstract class CallableElementTypeMixin implements ElementType {
+  Iterable<ElementType> _typeArguments;
+
   ModelElement get returnElement => returnType is DefinedElementType
       ? (returnType as DefinedElementType).element
       : null;
 
-  @override
+  ElementType _returnType;
   ElementType get returnType {
     _returnType ??=
         ElementType.from(type.returnType, library, packageGraph, this);
@@ -357,7 +350,6 @@ abstract class CallableElementTypeMixin implements ParameterizedElementType {
   @override
   FunctionType get type => _type;
 
-  @override
   // TODO(jcollins-g): Rewrite this and improve object model so this doesn't
   // require type checking everywhere.
   Iterable<ElementType> get typeArguments {
@@ -414,12 +406,16 @@ class CallableElementType extends ParameterizedElementType
 
   @override
   String get linkedName {
-    _linkedName ??= _renderer.renderLinkedName(this);
+    if (_linkedName == null) {
+      if (name != null && name.isNotEmpty) {
+        _linkedName = super.linkedName;
+      } else {
+        _linkedName = _renderer.renderLinkedName(this);
+      }
+    }
     return _linkedName;
   }
 
-  String get superLinkedName => super.linkedName;
-
   @override
   ElementTypeRenderer<CallableElementType> get _renderer =>
       packageGraph.rendererFactory.callableElementTypeRenderer;

lib/src/model/accessor.dart

@@ -4,6 +4,7 @@
 
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/dart/element/member.dart' show Member;
+import 'package:dartdoc/src/element_type.dart';
 import 'package:dartdoc/src/model/model.dart';
 import 'package:dartdoc/src/render/source_code_renderer.dart';
 import 'package:dartdoc/src/utils.dart';
@@ -18,10 +19,8 @@ class Accessor extends ModelElement implements EnclosedElement {
       [Member /*?*/ originalMember])
       : super(element, library, packageGraph, originalMember);
 
-  String get linkedReturnType {
-    assert(isGetter);
-    return modelType.createLinkedReturnTypeName();
-  }
+  @override
+  CallableElementTypeMixin get modelType => super.modelType;
 
   bool get isSynthetic => element.isSynthetic;
 

lib/src/model/field.dart

@@ -4,7 +4,6 @@
 
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/dart/element/element.dart';
-import 'package:dartdoc/src/element_type.dart';
 import 'package:dartdoc/src/model/model.dart';
 import 'package:dartdoc/src/render/source_code_renderer.dart';
 
@@ -199,9 +198,6 @@ class Field extends ModelElement
     }
   }
 
-  @override
-  CallableElementType get modelType => super.modelType;
-
   @override
   Inheritable get overriddenElement => null;
 }

lib/src/model/getter_setter_combo.dart

@@ -8,6 +8,7 @@ import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/source/line_info.dart';
 import 'package:analyzer/src/dart/element/element.dart';
+import 'package:dartdoc/src/element_type.dart';
 import 'package:dartdoc/src/model/model.dart';
 import 'package:dartdoc/src/utils.dart';
 import 'package:dartdoc/src/warnings.dart';
@@ -179,14 +180,10 @@ mixin GetterSetterCombo on ModelElement {
     return buffer.toString();
   }
 
-  String get linkedReturnType {
-    if (hasGetter) {
-      return getter.linkedReturnType;
-    } else {
-      // TODO(jcollins-g): this results in the wrong span class for the return
-      // type.
-      return setter.linkedParamsNoMetadataOrNames;
-    }
+  @override
+  ElementType get modelType {
+    if (hasGetter) return getter.modelType.returnType;
+    return setter.parameters.first.modelType;
   }
 
   @override

lib/src/model/method.dart

@@ -5,6 +5,7 @@
 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:dartdoc/src/element_type.dart';
 import 'package:dartdoc/src/model/model.dart';
 
 class Method extends ModelElement
@@ -92,7 +93,8 @@ class Method extends ModelElement
   @override
   String get kind => 'method';
 
-  String get linkedReturnType => modelType.createLinkedReturnTypeName();
+  @override
+  CallableElementTypeMixin get modelType => super.modelType;
 
   @override
   Method get overriddenElement {

lib/src/model/model_function.dart

@@ -66,8 +66,6 @@ class ModelFunctionTyped extends ModelElement
   @override
   String get kind => 'function';
 
-  String get linkedReturnType => modelType.createLinkedReturnTypeName();
-
   // Food for mustache. TODO(jcollins-g): what about enclosing elements?
   bool get isInherited => false;
 

lib/src/model/top_level_variable.dart

@@ -3,7 +3,6 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:analyzer/dart/element/element.dart';
-import 'package:dartdoc/src/element_type.dart';
 import 'package:dartdoc/src/model/model.dart';
 
 /// Top-level variables. But also picks up getters and setters?
@@ -86,8 +85,5 @@ class TopLevelVariable extends ModelElement
   @override
   String get fileName => '${isConst ? '$name-constant' : name}.$fileType';
 
-  @override
-  DefinedElementType get modelType => super.modelType;
-
   TopLevelVariableElement get _variable => (element as TopLevelVariableElement);
 }

lib/src/model/typedef.dart

@@ -4,6 +4,7 @@
 
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
+import 'package:dartdoc/src/element_type.dart';
 import 'package:dartdoc/src/model/model.dart';
 import 'package:dartdoc/src/render/typedef_renderer.dart';
 
@@ -49,8 +50,6 @@ class Typedef extends ModelElement
   @override
   String get kind => 'typedef';
 
-  String get linkedReturnType => modelType.createLinkedReturnTypeName();
-
   @override
   List<TypeParameter> get typeParameters => element.typeParameters.map((f) {
         return ModelElement.from(f, library, packageGraph) as TypeParameter;
@@ -79,4 +78,7 @@ class FunctionTypedef extends Typedef {
     }
     return super.genericTypeParameters;
   }
+
+  @override
+  CallableElementTypeMixin get modelType => super.modelType;
 }

lib/src/render/element_type_renderer.dart

@@ -87,10 +87,6 @@ class CallableElementTypeRendererHtml
     extends ElementTypeRenderer<CallableElementType> {
   @override
   String renderLinkedName(CallableElementType elementType) {
-    if (elementType.name != null && elementType.name.isNotEmpty) {
-      return elementType.superLinkedName;
-    }
-
     var buf = StringBuffer();
     buf.write(elementType.nameWithGenerics);
     buf.write('(');
@@ -168,15 +164,11 @@ class CallableElementTypeRendererMd
     extends ElementTypeRenderer<CallableElementType> {
   @override
   String renderLinkedName(CallableElementType elementType) {
-    if (elementType.name != null && elementType.name.isNotEmpty) {
-      return elementType.superLinkedName;
-    }
-
     var buf = StringBuffer();
     buf.write(elementType.nameWithGenerics);
     buf.write('(');
     buf.write(ParameterRendererMd()
-        .renderLinkedParams(elementType.element.parameters, showNames: false)
+        .renderLinkedParams(elementType.parameters, showNames: false)
         .trim());
     buf.write(') → ');
     buf.write(elementType.returnType.linkedName);

lib/src/render/parameter_renderer.dart

@@ -165,13 +165,12 @@ abstract class ParameterRenderer {
     if (param.isCovariant) {
       buf.write(covariant('covariant') + ' ');
     }
-    if (paramModelType is CallableElementTypeMixin ||
-        paramModelType.type is FunctionType) {
+    if (paramModelType is CallableElementTypeMixin) {
       String returnTypeName;
       if (paramModelType.isTypedef) {
         returnTypeName = paramModelType.linkedName;
       } else {
-        returnTypeName = paramModelType.createLinkedReturnTypeName();
+        returnTypeName = paramModelType.returnType.linkedName;
       }
       buf.write(typeName(returnTypeName));
       if (showNames) {
@@ -182,8 +181,10 @@ abstract class ParameterRenderer {
       }
       if (!paramModelType.isTypedef && paramModelType is DefinedElementType) {
         buf.write('(');
-        buf.write(renderLinkedParams(paramModelType.element.parameters,
-            showMetadata: showMetadata, showNames: showNames));
+        buf.write(renderLinkedParams(
+            (paramModelType as DefinedElementType).element.parameters,
+            showMetadata: showMetadata,
+            showNames: showNames));
         buf.write(')');
         buf.write(paramModelType.nullabilitySuffix);
       }