Override modelType to match return type in TypeParameters interface (#1755)

Author: askeksa

lib/src/model.dart

@@ -818,6 +818,9 @@ class Class extends ModelElement
 
   Iterable<DefinedElementType> get publicMixins => filterNonPublic(mixins);
 
+  @override
+  DefinedElementType get modelType => super.modelType;
+
   List<Operator> get operators {
     if (_operators != null) return _operators;
     _operators = _methods
@@ -1111,6 +1114,9 @@ class Constructor extends ModelElement
   @override
   String get kind => 'constructor';
 
+  @override
+  DefinedElementType get modelType => super.modelType;
+
   String _name;
   @override
   String get name {
@@ -2484,6 +2490,9 @@ class Method extends ModelElement
 
   String get linkedReturnType => modelType.createLinkedReturnTypeName();
 
+  @override
+  DefinedElementType get modelType => super.modelType;
+
   @override
   Method get overriddenElement {
     ClassElement parent = element.enclosingElement;
@@ -4038,6 +4047,9 @@ class ModelFunctionTyped extends ModelElement
   // Food for mustache. TODO(jcollins-g): what about enclosing elements?
   bool get isInherited => false;
 
+  @override
+  DefinedElementType get modelType => super.modelType;
+
   FunctionTypedElement get _func => (element as FunctionTypedElement);
 }
 
@@ -5806,6 +5818,9 @@ class Typedef extends ModelElement
 
   String get linkedReturnType => modelType.createLinkedReturnTypeName();
 
+  @override
+  DefinedElementType get modelType => super.modelType;
+
   FunctionTypeAliasElement get _typedef =>
       (element as FunctionTypeAliasElement);