Fix generic function types in variable declarations (issue 29237)

pkg/analyzer/lib/src/dart/element/element.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.element;
 
 import 'dart:collection';
 import 'dart:math' show min;
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 3129 matching lines @@
     }
   }
 
   /**
    * If the element associated with the given [type] is a generic function type
    * element, then make it a child of this element. Return the [type] as a
    * convenience.
    */
   DartType _checkElementOfType(DartType type) {
     Element element = type?.element;
-    if (element is GenericFunctionTypeElementImpl) {
+    if (element is GenericFunctionTypeElementImpl &&
+        element.enclosingElement == null) {
       element.enclosingElement = this;
     }
     return type;
   }
 
   /**
    * If the given [type] is a generic function type, then the element associated
    * with the type is implicitly a child of this element and should be visted by
    * the given [visitor].
    */
@@ skipping 4024 matching lines @@
   void set hasImplicitType(bool hasImplicitType) {
     _assertNotResynthesized(_unlinkedVariable);
     super.hasImplicitType = hasImplicitType;
   }
 
   @override
   FunctionElement get initializer {
     if (_unlinkedVariable != null && _initializer == null) {
       UnlinkedExecutable unlinkedInitializer = _unlinkedVariable.initializer;
       if (unlinkedInitializer != null) {
-        _initializer = new FunctionElementImpl.forSerialized(
-            unlinkedInitializer, this)..isSynthetic = true;
+        _initializer =
+            new FunctionElementImpl.forSerialized(unlinkedInitializer, this)
+              ..isSynthetic = true;
       } else {
         return null;
       }
     }
     return super.initializer;
   }
 
   /**
    * Set the function representing this variable's initializer to the given
    * [function].
@@ skipping 270 matching lines @@
   void set inheritsCovariant(bool value) {
     _assertNotResynthesized(_unlinkedParam);
     _inheritsCovariant = value;
   }
 
   @override
   FunctionElement get initializer {
     if (_unlinkedParam != null && _initializer == null) {
       UnlinkedExecutable unlinkedInitializer = _unlinkedParam.initializer;
       if (unlinkedInitializer != null) {
-        _initializer = new FunctionElementImpl.forSerialized(
-            unlinkedInitializer, this)..isSynthetic = true;
+        _initializer =
+            new FunctionElementImpl.forSerialized(unlinkedInitializer, this)
+              ..isSynthetic = true;
       } else {
         return null;
       }
     }
     return super.initializer;
   }
 
   /**
    * Set the function representing this variable's initializer to the given
    * [function].
@@ skipping 1592 matching lines @@
 
   @override
   void visitElement(Element element) {
     int offset = element.nameOffset;
     if (offset != -1) {
       map[offset] = element;
     }
     super.visitElement(element);
   }
 }