Fix stack overflow printing recursive function types (issue 28835)

pkg/analyzer/lib/src/dart/element/member.dart

 // Copyright (c) 2014, 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 analyzer.src.dart.element.member;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/constant/value.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
@@ skipping 213 matching lines @@
    * Initialize a newly created element to represent a field formal parameter,
    * based on the [baseElement], defined by the [definingType]. If [type]
    * is passed it will be used as the substituted type for this member.
    */
   FieldFormalParameterMember(
       FieldFormalParameterElement baseElement, ParameterizedType definingType,
       [DartType type])
       : super(baseElement, definingType, type);
 
   @override
-  bool get isCovariant => baseElement.isCovariant;
-
-  @override
   FieldElement get field {
     FieldElement field = (baseElement as FieldFormalParameterElement).field;
     if (field is FieldElement) {
       return FieldMember.from(
           field, substituteFor(field.enclosingElement.type));
     }
     return field;
   }
 
   @override
+  bool get isCovariant => baseElement.isCovariant;
+
+  @override
   /*=T*/ accept/*<T>*/(ElementVisitor<dynamic/*=T*/ > visitor) =>
       visitor.visitFieldFormalParameterElement(this);
 }
 
 /**
  * A field element defined in a parameterized type where the values of the type
  * parameters are known.
  */
 class FieldMember extends VariableMember implements FieldElement {
   /**
@@ skipping 122 matching lines @@
   /*=T*/ accept/*<T>*/(ElementVisitor<dynamic/*=T*/ > visitor) =>
       visitor.visitFunctionElement(this);
 
   @override
   FunctionDeclaration computeNode() => baseElement.computeNode();
 
   @override
   String toString() {
     StringBuffer buffer = new StringBuffer();
     buffer.write(baseElement.displayName);
-    (type as FunctionTypeImpl).appendTo(buffer);
+    (type as FunctionTypeImpl).appendTo(buffer, new Set.identity());
     return buffer.toString();
   }
 
   /**
    * If the given [method]'s type is different when any type parameters from the
    * defining type's declaration are replaced with the actual type arguments
    * from the [definingType], create a method member representing the given
    * method. Return the member that was created, or the base method if no member
    * was created.
    */
@@ skipping 649 matching lines @@
   DartObject computeConstantValue() => baseElement.computeConstantValue();
 
   @override
   void visitChildren(ElementVisitor visitor) {
     // TODO(brianwilkerson) We need to finish implementing the accessors used
     // below so that we can safely invoke them.
     super.visitChildren(visitor);
     baseElement.initializer?.accept(visitor);
   }
 }