Use FunctionTypeAliasElement instead of GenericTypeAliasElement. (#2392)

Author: scheglov

lib/src/element_type.dart

@@ -40,8 +40,8 @@ abstract class ElementType extends Privacy {
       // TODO(jcollins-g): Remove reference to f.element.enclosingElement after
       // analyzer 0.41.
       var isGenericTypeAlias =
-          f.element.enclosingElement is GenericTypeAliasElement ||
-              f.element is GenericTypeAliasElement;
+          f.element.enclosingElement is FunctionTypeAliasElement ||
+              f.element is FunctionTypeAliasElement;
       if (f is FunctionType) {
         assert(f is ParameterizedType);
         if (isGenericTypeAlias) {

lib/src/model/model_element.dart

@@ -331,7 +331,7 @@ abstract class ModelElement extends Canonicalization
     if (e is FunctionElement) {
       return ModelFunction(e, library, packageGraph);
     } else if (e is GenericFunctionTypeElement) {
-      assert(e.enclosingElement is GenericTypeAliasElement);
+      assert(e.enclosingElement is FunctionTypeAliasElement);
       assert(e.enclosingElement.name != '');
       return ModelFunctionTypedef(e, library, packageGraph);
     }

lib/src/model/typedef.dart

@@ -24,8 +24,8 @@ class Typedef extends ModelElement
   String get genericParameters => _renderer.renderGenericParameters(this);
 
   List<TypeParameterElement> get genericTypeParameters {
-    if (element is GenericTypeAliasElement) {
-      return (element as GenericTypeAliasElement).function.typeParameters;
+    if (element is FunctionTypeAliasElement) {
+      return (element as FunctionTypeAliasElement).function.typeParameters;
     }
     return Iterable<TypeParameterElement>.empty();
   }