Improve printing of generic function types and add tests

pkg/analyzer/lib/src/dart/ast/utilities.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.ast.utilities;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/standard_ast_factory.dart';
@@ skipping 7519 matching lines @@
     _visitNode(node.parameters);
     if (node.question != null) {
       _writer.print('?');
     }
     return null;
   }
 
   @override
   Object visitGenericFunctionType(GenericFunctionType node) {
     _visitNode(node.returnType);
-    _writer.print(' Function ');
+    _writer.print(' Function');
     _visitNode(node.typeParameters);
     _visitNode(node.parameters);
     return null;
   }
 
   @override
   Object visitGenericTypeAlias(GenericTypeAlias node) {
     _visitNodeListWithSeparatorAndSuffix(node.metadata, " ", " ");
     _writer.print("typedef ");
     _visitNode(node.name);
@@ skipping 322 matching lines @@
     _writer.print("show ");
     _visitNodeListWithSeparator(node.shownNames, ", ");
     return null;
   }
 
   @override
   Object visitSimpleFormalParameter(SimpleFormalParameter node) {
     _visitNodeListWithSeparatorAndSuffix(node.metadata, ' ', ' ');
     _visitTokenWithSuffix(node.covariantKeyword, ' ');
     _visitTokenWithSuffix(node.keyword, " ");
-    _visitNodeWithSuffix(node.type, " ");
+    _visitNode(node.type);
+    if (node.type != null && node.identifier != null) {
+      _writer.print(' ');
+    }
     _visitNode(node.identifier);
     return null;
   }
 
   @override
   Object visitSimpleIdentifier(SimpleIdentifier node) {
     _writer.print(node.token.lexeme);
     return null;
   }
 
@@ skipping 946 matching lines @@
     safelyVisitNode(node.parameters);
     if (node.question != null) {
       sink.write('?');
     }
     return null;
   }
 
   @override
   Object visitGenericFunctionType(GenericFunctionType node) {
     safelyVisitNode(node.returnType);
-    sink.write(' Function ');
+    sink.write(' Function');
     safelyVisitNode(node.typeParameters);
     safelyVisitNode(node.parameters);
     return null;
   }
 
   @override
   Object visitGenericTypeAlias(GenericTypeAlias node) {
     safelyVisitNodeListWithSeparatorAndSuffix(node.metadata, " ", " ");
     sink.write("typedef ");
     safelyVisitNode(node.name);
@@ skipping 322 matching lines @@
     sink.write("show ");
     safelyVisitNodeListWithSeparator(node.shownNames, ", ");
     return null;
   }
 
   @override
   Object visitSimpleFormalParameter(SimpleFormalParameter node) {
     safelyVisitNodeListWithSeparatorAndSuffix(node.metadata, ' ', ' ');
     safelyVisitTokenWithSuffix(node.covariantKeyword, ' ');
     safelyVisitTokenWithSuffix(node.keyword, " ");
-    safelyVisitNodeWithSuffix(node.type, " ");
+    safelyVisitNode(node.type);
+    if (node.type != null && node.identifier != null) {
+      sink.write(' ');
+    }
     safelyVisitNode(node.identifier);
     return null;
   }
 
   @override
   Object visitSimpleIdentifier(SimpleIdentifier node) {
     sink.write(node.token.lexeme);
     return null;
   }
 
@@ skipping 171 matching lines @@
     if (node.star != null) {
       sink.write("yield* ");
     } else {
       sink.write("yield ");
     }
     safelyVisitNode(node.expression);
     sink.write(";");
     return null;
   }
 }