Resynthesize FunctionType(s) from Kernel.

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 4053 matching lines @@
     return hasModifier(Modifier.GENERATOR);
   }
 
   @override
   bool get isOperator => false;
 
   @override
   bool get isSynchronous => !isAsynchronous;
 
   @override
-  List<kernel.TypeParameter> get kernelTypeParams => null;
+  List<kernel.TypeParameter> get kernelTypeParams {
+    return _kernel?.function?.typeParameters;
+  }
 
   @override
   List<ElementAnnotation> get metadata {
     if (serializedExecutable != null) {
       return _metadata ??=
           _buildAnnotations(enclosingUnit, serializedExecutable.annotations);
     }
     return super.metadata;
   }
 
@@ skipping 4075 matching lines @@
             .resolveTypeRef(this, _unlinkedParam.type, declaredType: true);
       }
     }
   }
 
   /**
    * Create and return [ParameterElement]s for the given [function].
    */
   static List<ParameterElement> forKernelFunction(
       ElementImpl enclosingElement, kernel.FunctionNode function) {
-    if (function.positionalParameters.isNotEmpty ||
-        function.namedParameters.isNotEmpty) {
+    return forKernelParameters(
+        enclosingElement,
+        function.requiredParameterCount,
+        function.positionalParameters,
+        function.namedParameters);
+  }
+
+  /**
+   * Create and return [ParameterElement]s for the given Kernel parameters.
+   */
+  static List<ParameterElement> forKernelParameters(
+      ElementImpl enclosingElement,
+      int requiredParameterCount,
+      List<kernel.VariableDeclaration> positionalParameters,
+      List<kernel.VariableDeclaration> namedParameters) {
+    if (positionalParameters.isNotEmpty || namedParameters.isNotEmpty) {
       var parameters = <ParameterElement>[];
 
       // Add positional required and optional parameters.
-      for (int i = 0; i < function.positionalParameters.length; i++) {
-        kernel.VariableDeclaration parameter = function.positionalParameters[i];
-        if (i < function.requiredParameterCount) {
+      for (int i = 0; i < positionalParameters.length; i++) {
+        kernel.VariableDeclaration parameter = positionalParameters[i];
+        if (i < requiredParameterCount) {
           if (parameter.isFieldFormal) {
             parameters.add(new FieldFormalParameterElementImpl.forKernel(
                 enclosingElement, parameter, ParameterKind.REQUIRED));
           } else {
             parameters.add(new ParameterElementImpl.forKernel(
                 enclosingElement, parameter, ParameterKind.REQUIRED));
           }
         } else {
           if (parameter.isFieldFormal) {
             parameters.add(new DefaultFieldFormalParameterElementImpl.forKernel(
                 enclosingElement, parameter, ParameterKind.POSITIONAL));
           } else {
             parameters.add(new DefaultParameterElementImpl.forKernel(
                 enclosingElement, parameter, ParameterKind.POSITIONAL));
           }
         }
       }
 
       // Add named parameters.
-      for (var k in function.namedParameters) {
+      for (var k in namedParameters) {
         if (k.isFieldFormal) {
           parameters.add(new DefaultFieldFormalParameterElementImpl.forKernel(
               enclosingElement, k, ParameterKind.NAMED));
         } else {
           parameters.add(new DefaultParameterElementImpl.forKernel(
               enclosingElement, k, ParameterKind.NAMED));
         }
       }
 
       return parameters;
@@ skipping 1378 matching lines @@
 
   @override
   DartObject computeConstantValue() => null;
 
   @override
   void visitChildren(ElementVisitor visitor) {
     super.visitChildren(visitor);
     _initializer?.accept(visitor);
   }
 }