Fix for issue 14497

editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/resolver/TypeResolverVisitor.java

 /*
  * Copyright (c) 2013, the Dart project authors.
  * 
  * Licensed under the Eclipse Public License v1.0 (the "License"); you may not use this file except
  * in compliance with the License. You may obtain a copy of the License at
  * 
  * http://www.eclipse.org/legal/epl-v10.html
  * 
  * Unless required by applicable law or agreed to in writing, software distributed under the License
  * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
@@ skipping 428 matching lines @@
     ClassElement definingClass = element.getAncestor(ClassElement.class);
     if (definingClass != null) {
       type.setTypeArguments(definingClass.getType().getTypeArguments());
     }
     element.setType(type);
     return null;
   }
 
   @Override
   public Void visitFunctionTypeAlias(FunctionTypeAlias node) {
-    super.visitFunctionTypeAlias(node);
     FunctionTypeAliasElementImpl element = (FunctionTypeAliasElementImpl) node.getElement();
-    element.setReturnType(computeReturnType(node.getReturnType()));
+    if (element.getReturnType() == null) {
+      // Only visit function type aliases once.
+      super.visitFunctionTypeAlias(node);
+      element.setReturnType(computeReturnType(node.getReturnType()));
+    }
     return null;
   }
 
   @Override
   public Void visitFunctionTypedFormalParameter(FunctionTypedFormalParameter node) {
     super.visitFunctionTypedFormalParameter(node);
     Element element = node.getIdentifier().getStaticElement();
     if (element instanceof ParameterElementImpl) {
       setFunctionTypedParameterType(
           (ParameterElementImpl) element,
@@ skipping 917 matching lines @@
       if (alias != null) {
         aliasElement.setTypeParameters(alias.getTypeParameters());
         type.setTypeArguments(alias.getType().getTypeArguments());
       } else {
         type.setTypeArguments(TypeImpl.EMPTY_ARRAY);
       }
     }
     element.setType(type);
   }
 }