Migrate UnlinkedParam.defaultValue to UnlinkedExecutable.bodyExpr.

pkg/analyzer/lib/src/summary/summarize_ast.dart

 // Copyright (c) 2016, 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 serialization.summarize_ast;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/type.dart' show DartType;
@@ skipping 1026 matching lines @@
               }))
           .toList();
     }
     executables.add(b);
   }
 
   @override
   UnlinkedParamBuilder visitDefaultFormalParameter(
       DefaultFormalParameter node) {
     UnlinkedParamBuilder b = node.parameter.accept(this);
+    b.initializer = serializeInitializerFunction(node.defaultValue);
     if (node.defaultValue != null) {
       // Closures can't appear inside default values, so we don't need a
       // localClosureIndexMap.
       Map<int, int> localClosureIndexMap = null;
-      b.defaultValue =
+      b.initializer?.bodyExpr =
           serializeConstExpr(localClosureIndexMap, node.defaultValue);
       b.defaultValueCode = node.defaultValue.toSource();
     }
-    b.initializer = serializeInitializerFunction(node.defaultValue);
     b.codeRange = serializeCodeRange(node);
     return b;
   }
 
   @override
   void visitEnumDeclaration(EnumDeclaration node) {
     UnlinkedEnumBuilder b = new UnlinkedEnumBuilder();
     b.name = node.name.name;
     b.nameOffset = node.name.offset;
     b.values = node.constants
@@ skipping 277 matching lines @@
 /**
  * A [_TypeParameterScope] is a [_Scope] which defines [_ScopedTypeParameter]s.
  */
 class _TypeParameterScope extends _Scope {
   /**
    * Get the number of [_ScopedTypeParameter]s defined in this
    * [_TypeParameterScope].
    */
   int get length => _definedNames.length;
 }