Move a few shared selectors back to ast_selector

Author: wravery

src/GraphQLTree.cpp

@@ -253,13 +253,23 @@ struct ast_selector<enum_value> : std::true_type
 {
 };
 
+template <>
+struct ast_selector<field_name> : std::true_type
+{
+};
+
 template <>
 struct ast_selector<argument_name> : std::true_type
 {
 };
 
 template <>
-struct ast_selector<named_type> : std::true_type
+struct ast_selector<argument> : std::true_type
+{
+};
+
+template <>
+struct ast_selector<arguments> : std::true_type
 {
 };
 
@@ -268,6 +278,16 @@ struct ast_selector<directive_name> : std::true_type
 {
 };
 
+template <>
+struct ast_selector<directive> : std::true_type
+{
+};
+
+template <>
+struct ast_selector<directives> : std::true_type
+{
+};
+
 template <>
 struct ast_selector<variable> : std::true_type
 {
@@ -278,6 +298,11 @@ struct ast_selector<scalar_name> : std::true_type
 {
 };
 
+template <>
+struct ast_selector<named_type> : std::true_type
+{
+};
+
 template <>
 struct ast_selector<list_type> : std::true_type
 {
@@ -473,11 +498,6 @@ struct executable_selector<alias> : parse_tree::fold_one
 {
 };
 
-template <>
-struct executable_selector<field_name> : std::true_type
-{
-};
-
 template <>
 struct executable_selector<operation_name> : std::true_type
 {
@@ -488,26 +508,6 @@ struct executable_selector<fragment_name> : std::true_type
 {
 };
 
-template <>
-struct executable_selector<argument> : std::true_type
-{
-};
-
-template <>
-struct executable_selector<arguments> : std::true_type
-{
-};
-
-template <>
-struct executable_selector<directive> : std::true_type
-{
-};
-
-template <>
-struct executable_selector<directives> : std::true_type
-{
-};
-
 template <>
 struct executable_selector<field> : std::true_type
 {