Expose function contained in GenericTypeAliasImpl.

pkg/analyzer/lib/src/dart/element/element.dart

Index: pkg/analyzer/lib/src/dart/element/element.dart
diff --git a/pkg/analyzer/lib/src/dart/element/element.dart b/pkg/analyzer/lib/src/dart/element/element.dart
index 7ce582696aedfd08f6f0d0745ca17ca620d856e7..ea9a4281206ee0afeb8b179dd1bd997a4385cb59 100644
--- a/pkg/analyzer/lib/src/dart/element/element.dart
+++ b/pkg/analyzer/lib/src/dart/element/element.dart
@@ -5029,7 +5029,7 @@ class GenericFunctionTypeElementImpl extends ElementImpl
  */
 class GenericTypeAliasElementImpl extends ElementImpl
     with TypeParameterizedElementMixin
-    implements FunctionTypeAliasElement {
+    implements GenericTypeAliasElement {
   /**
    * The unlinked representation of the type in the summary.
    */
@@ -5097,10 +5097,7 @@ class GenericTypeAliasElementImpl extends ElementImpl
   CompilationUnitElementImpl get enclosingUnit =>
       _enclosingElement as CompilationUnitElementImpl;
 
-  /**
-   * Return the generic function type element representing the generic function
-   * type on the right side of the equals.
-   */
+  @override
   GenericFunctionTypeElement get function {
     if (_function == null && _unlinkedTypedef != null) {
       DartType type = enclosingUnit.resynthesizerContext.resolveTypeRef(