Remove support for NewType typedef annotation

Summary:
I have no idea why I even implemented this in the first place.
I can't think of any applications where this might be useful.

The feature is completely unused.
The feature was not supported in the legacy generator (type aliases were used always):
https://www.internalfb.com/code/fbsource/[bbea5a1ec838]/fbcode/thrift/compiler/generate/t_go_generator.cc?lines=971

So I think we can safely kill it.

Reviewed By: leoleovich

Differential Revision: D52568785

fbshipit-source-id: 929d6f36f70e1f9608484ce9983a6f03cb44aef6

Author: echistyakov

third-party/thrift/src/thrift/annotation/go.thrift

@@ -38,10 +38,3 @@ struct Name {
 struct Tag {
   1: string tag;
 }
-
-// Annotation for declaring a typedef as a new type (rather than an alias).
-//
-//  type T1 = T2  // alias declaration
-//  type T1 T2    // type definition
-@scope.Typedef
-struct NewType {}

third-party/thrift/src/thrift/compiler/generate/t_mstch_go_generator.cc

@@ -684,7 +684,6 @@ class mstch_go_typedef : public mstch_typedef {
         this,
         {
             {"typedef:go_name", &mstch_go_typedef::go_name},
-            {"typedef:go_newtype?", &mstch_go_typedef::go_newtype},
             {"typedef:go_qualified_name", &mstch_go_typedef::go_qualified_name},
             {"typedef:go_qualified_new_func",
              &mstch_go_typedef::go_qualified_new_func},
@@ -697,10 +696,6 @@ class mstch_go_typedef : public mstch_typedef {
         });
   }
   mstch::node go_name() { return go_name_(); }
-  mstch::node go_newtype() {
-    return typedef_->find_structured_annotation_or_null(kGoNewTypeUri) !=
-        nullptr;
-  }
   mstch::node go_qualified_name() {
     auto prefix = data_.go_package_alias_prefix(typedef_->program());
     auto name = go_name_();

third-party/thrift/src/thrift/compiler/generate/templates/go/types/typedef.mustache

@@ -19,9 +19,7 @@
   This template generates a thrift typedef
 
 }}
-type {{typedef:go_name}} {{!
-}}{{^typedef:go_newtype?}}= {{/typedef:go_newtype?}}{{!
-}}{{#typedef:type}}{{> common/type}}{{/typedef:type}}
+type {{typedef:go_name}} = {{#typedef:type}}{{> common/type}}{{/typedef:type}}
 
 {{! new function }}
 {{> types/typedef_method_new}}

third-party/thrift/src/thrift/compiler/lib/uri.h

@@ -159,8 +159,6 @@ inline constexpr auto kHackModuleInternalUri =
 // go
 inline constexpr auto kGoNameUri = "facebook.com/thrift/annotation/go/Name";
 inline constexpr auto kGoTagUri = "facebook.com/thrift/annotation/go/Tag";
-inline constexpr auto kGoNewTypeUri =
-    "facebook.com/thrift/annotation/go/NewType";
 
 inline constexpr auto kGeneratePatchUri =
     "facebook.com/thrift/op/GeneratePatch";